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Photography Question 

Topcon lens mount adapter

Adapting a camera back to the lens or equipment of choice seems difficult sometimes. I wish to adapt a Fuji FinePix S2 Pro camera back to a Topcon TRC-50EX. This is a retinal fundus camera with internal lens systems and internal flash. Would a Topcon-to-T-mount adapter coupled with a T-mount-to-Nikon adapter allow the Fuji camera back to attach to the Topcon? The S2 Pro is advertized to be built off of the Nikon D-100 body allowing for use of Nikon lenses.

Any comments about using Nikon lenses on the Fuji FinePix S2 Pro camera back or on the Topcon adapter set-up described above would be most appreciated.


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2/27/2005 9:57:47 AM

Ed D. Talusan   I want to do the same, adapt a canon
EOS camera body to a Topcon TRC 50F
fundus camera.

Steve, pls email me when you find a solution. I have emailed,
2 weeks, no answer.

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12/9/2005 2:42:30 PM

Steve    Ed,

I am not sure about the Topcon TRC 50F, but the 50EX is a full feature digital-ready mydriatic fundus camera. The gentleman at did respond to my e-mail, but it took a few months. He should be able to build you the adapter you wish, but you still may have problems with exposure, adapter lenses and flash timing. You may benefit from using an intervelometer.

I decided the time needed to design and construct a complete adapter system of my own was not worth it, and so purchased a Topcon fundus camera adapter from the U.S. sales representative of For about $6000 I got a fully finished adapter that fits on to the top camera port of the Topcon TRC 50EX. I purchased a used Nikon D1H digital SLR camera on-line and a new desktop PC running at 3 GHz with plenty of memory and hard disk storage. I also use an external hard drive for back up storage.

The camera adapter comes with a cable to connect the Nikon flash ports to the Topcon trigger port. A firewire cable connects the Nikon D1H to the computer. Other than Windows XP, I use the readily available Nikon Capture software (purchased from Nikon on-line) and JASC Photoshop (mostly to flip and rotate photos), each of which costs about $100. The camera adapter uses neutral density filters to adjust the image exposure, which seems somewhat simplistic but does the job. I get very nice color fundus photos and angiogram photos using the Nikon JPEG color and black-and-white settings, but am still experimenting with the RAW setting.

The best part is that if any of the components fail, they can easily be replaced, and for less cost than the annual service contract Topcon or any of the other commercial firms charge.

Best of luck with your project.


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12/10/2005 5:49:32 AM

Eugene Foley   Steve,

I was very excited to find your solution on this forum. I am of the mind that high res digital slr is the more logical solution than digital video capture.

Could you please update me on your success with the digital slr conversion for you TRC-50EX fundus camera? I am in a similar position to yourself in that I have the same fundus camera and would like to use an SLR rather than a digital video.

Are you still happy with this setup or would you go a different route in light of your experience?



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4/10/2006 9:52:59 PM

Michael H. Cothran   Steve,
Just to clarify one point, the S2 is built on a Nikon N80 body, not a D-100. And one other issue about lenses/T-mounts - I am not sure whether or not you will be using any metering electronics in the S2, but only modern lenses with electrical contacts will activate any metering in the N80/S2. So while your T-mount system may accept the S2 (or vice versa), it will not activate the meter.
Michael H. Cothran

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4/11/2006 11:58:20 AM

Steve    Michael - Thanks for the info.

Eugene - I am very happy with my homemade setup. I have been using it daily since the summer of 2005 and have "mothballed" by digital video setup. I have experienced not one single problem since I started using my Topcon 50EX - Nikon D1H setup. I have used only JPEG images, as speed of processing is important for me. I have not yet gotten around to figuring out how to manipulate the RAW images to my liking. Again, all hardware is easily replaceable and all software is inexpensive (Photoshop, Nikon Capture, etc.) Storage is through the standard Windows XP package.

The downsides are the following: The adapter was slow to acquire and a little pricey. I wanted to build my own, but as stated above, found it better to use an established product. I chose the D1H to ensure rapid data transfer, but might consider a used D1x next time. The D1H images are perfectly good from which to treat, but I bet the D1x would produce higher resolution images. The images do not come onto the computer screen in large format, just a small thumbnail. This can be a little hard to see during angiography. I sometimes find that in a series of rapid photos, we only find out later that we were a little out of focus. This is, of course, photographer dependent. Also, this method does not allow for a timer image to be easily attached to each angiogram image, as with commercial packages. I rarely find this a problem and can determine slow filling, etc. just from the images. The data is embedded in each image, but I have not yet found an easy rapid way to display this information. Lastly, this setup does not allow for a customized way to store the images. I just create a Windows folder for each person, as well as subfolders for photos and angios and then further subfolders for dates. Windows has search functions if you need them. I back everything up with an inexpensive external hard drive.

Would I do it again? You bet. I am thinking of putting together another system. The two together would still cost less than the Topcon and Zeiss quotes for one complete system!



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4/12/2006 3:24:58 AM

George    Steve,

I am also interested in setting up a fundus camera setup with a digital solution. I have an even older system, a 50-VT, but I think I have successfully decoded the 15 pin output on the topcon camera. If you are interested, I'd be happy to share. I've decoded it from a polaroid setup. Is your setup via the top port of the camera or via the 35mm back port? Also does the cable you purchase connect directly to the hotshoe and the 15 pin connector? IS there any electronics in that cable (resistors, caps, etc)? Finally, how far were you able to get to find an adapter for the rear port to, say, a nikon, or canon?



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4/24/2006 3:26:49 PM

Steve    George,

The 50-VT is an older camera, and is not "digital ready" as I have read. I am not sure what that means. Knowing the 15 pin code would be a great help to setting up your custom system. The commercial adapter I use fits onto the top Polaroid port and not the rear port. This is no big problem - we just push the "top port" button on the 50-EX and keep the plastic factory cover over the back port. Using the rear port for an adapter and camera might get kind of bulky back there.

The cables that connect the Nikon, Topcon, and computer have no internal electronics of which I am aware. No cables connect directly to the adapter; they connect the Nikon D1H to the Topcon 50-EX and the Nikon camera to the computer via firewire. This means, the adapter is just "short-circuiting" the appropriate pins in the Polaroid connector to allow the Topcon to flash. Without this, one cannot get the Topcon 50-EX to flash. The flash apparently sends a trigger signal to the 15 pin adapter which the Nikon uses to trigger its shutter. The image is then transfered to the computer in the usual way via a firewire cable.

Hope this helps you in your set-up.


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4/25/2006 4:00:31 AM

George    Thanks for your response. I have yet another fundus camera, the 50-?ex or 50x, in my other office with the polaroid back that I am borrowing for the 50-VT. The polaroid camera is mechanically a little different in the location of the 15pin connector but electronically, the two 15-pins are identical (as far as I can tell). So your setup would also work for the 50-VT. I have been able to fire the strobe while shorting out pins (I believe) 14 and 15 together. The trigger on the joystick shorts out pins 2-3. The rest of the pins deals with multiple grounds, shutter open, shutter close, and a few others. I was told just the opposite that the 50-VT is similar to the 50-EX (or X) and could be adapted to digital photos. I would like to get the adapter setup if it weren't for the cost. I only paid 2k for my fundus camera setup and can't see to pay 6k for the wires?

If you have the camera sitting on the top port, how do you know if your in focus? I've read previously that you had some problems with that since the thumbnails are so small once transferred to the PC. Idealy, if the 35mm back would give you a larger optical viewfinder, you can have the camera sit in the usual back location and focus thru the eyepiece. I love how large the Topcon 35mm optical viewfinder is!

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4/25/2006 12:45:14 PM

Steve    George,

The issue of focus rests with the fundus camera and the photographer's skill. Whether you place your Polaroid back on the top mount or you put a 35 mm back with an appropriate adapter, the image will focus onto the camera back. I agree that the Topcon viewfinder is great and use that one rather than the 35 mm camera viewfinder. My comment about the out-of-focus issue was that if the photographer is having a little trouble, you might not as easily note that images are a little out of focus from viewing small thumbnails on a computer screen, but see it later when you view the larger images. Focusing is the same as with any setup- look through the Topcon viewfinder and focus as usual!

The issue of cost is a subjective one. While you may have only paid $2000 for your fundus camera, it will cost more than that to digitize it. I find it more appropriate to compare the cost of digitizing it yourself to the cost of a commercial setup. Those start around $20,000 for a decent full feature package. If you can digitize for about $10,000 you are doing great. Sorry about these numbers. As in most cases, you get what you pay for. A new computer with software will cost about $2000, a used Nikon D series camera back also runs around $2000. The adapter is about the only item that you can try to make yourself and save a few thousand. I eventually decided that it was not worth my time and effort to re-invent the wheel. Your custom adapter will need a Topcon to Nikon lens mount (probably custom made), a housing with lens to put the image in focus, and wiring to trigger the camera back with either neutral density filters in the housing or use of an intervelometer to adjust the intensity exposure. It can obviously be done, but it will cost you time, money, and effort to put this together.

Note that saving money by using an older computer is not advised. They just do not have the power, memory, and speed of the current ones. Also, you really need a professional camera back, such as the Nikon D series. Lower priced consumer or prosumer grade camera backs will not work well either.

These are just my humble thoughts. Good luck on your project.

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4/26/2006 3:22:15 AM

George    Steve,

I've finally got a working solution with a canon EOS rebel XT attached to the rear port of the camera. It turns out the mount on the fundus camera is a Canon FD mount! So one needs a EOS to FD mount (which are very easy to find) on ebay and other areas. One question I have for you is that in your solution with the Nikon, what speed do you have the camera set at? Mine seems to fall between 1/50 and 1/60. 1/50 seems to be overexposed and 1/60 seems to be underexposed. Is this where your neutral density filters comes in? It seems that the timing from the camera's hotshoe is triggering the flash a little too late. I don't know if you have a similar problem. Also the camera "hole" from the 35mm port is not exactly centered. So my adapter and the camera doesn't take a dead on centered shot. Again more advice is needed here.

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5/2/2006 2:20:07 PM

Steve    George,

Congratulations on your solution. It sounds like that should work pretty well. My Nikon D1H is set at 1/15 seconds and we use the various neutral density filters and Topcon TRC-50EX flash settings to optimize the images. We use a darker filter for the color photos and a lighter filter for the angio images. Maybe you can try to purchase some inexpensive neutral density filters to place on your mound between the Topcon and Canon to see if you can find an optimal combination or two. Another way that might work, is to purchase an intervelometer (a few hundred dollars - Google "Time Machine" to find one, but there are others) to have better control over the flash timing that you write about. I thought about doing that at one time, but never tried, so I cannot say for sure that it will help you.

Keep us all updated on your progress.

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5/5/2006 8:47:10 AM

George    Neutral density filters seems to the be the right answer for the overexposure problem. On the 50-VT, there are selections to place neutral density filters on the (for lack of better words) "light" portion of the illumination dial. This dial allows me to place a green color light or other filters in front of the strobe to decrease the intensity. I made a "neutral density filter" out of the static semi-translucent bag from those electronic parts bag and that seems to reduce the brightness of the strobe. Now I have to refine the adapter between the EOS and the camera so that the image is exactly centered and fills the entire camera. As it is right now, the camera only captures about 70% of the central image. Does your setup allows you to see the entire image at 50 degree field?

Thanks for your input.

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5/5/2006 10:14:17 AM

Steve    George,

My adapter is proprietary so I do not know how it is configured. It separates the Nikon camera back from the Topcon unit port by about 8 inches. This provides room for four different neutral density filters selectable with a rotating knob. It also provides room for a series of lenses, which is how I believe the image is made to be centered and full.

By the way, are you transferring images to your computer in real time with a firewire or USB2 setup? How is image transfer going?

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5/6/2006 4:29:23 AM

George    I'm still working on that portion of software. Canon, as well as Nikon, does provide a way to remotely capture the picture and tranfer it to USB. Luckily the Rebel XT that I'm borrowing has a fast USB 2.0 interface. For viewing the image, I have the video out port connected to a 6.0" LCD TV to get a bigger image after each shot to verify the focus. You might have a similar port on your camera. All of my images are on CF cards for now.


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5/6/2006 10:16:46 AM

Steve    George -

Is the converter you are using a Canon FD "LENS" - to - EOS body unit or a Canon FD "BODY" - to - EOS body unit?


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5/10/2006 3:32:54 AM

George    The topcon camera has the same connector as a canon FD camera. So it would be a EOS body to FD lens. This would be an example on ebay:

Although I did not quite use this same adapter, I am tempted to get it just to try. What I did was to take off the topcon camera connector (held by the four little screws) and attach it to a T2 to EOS adapter. The T2 to EOS adapter looks like this:

The reason I chose this adapter was because of the thickness and size of the ring. The ring has enough "meat" in it so that I can drill holes in it to fit the four little screws.

Hope that helps.


it withbuy a T2 to eos adapter and take the topcon connector off the camera.

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5/10/2006 1:34:39 PM

George    Forget the last line there. Can't seems to edit the post.

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5/10/2006 2:36:38 PM

Steve    George,

Thanks for the info on the adapters. I might give it a try. Using the rear port would give timing data that I cannot easily get from using the top port.

You mentioned earlier that you had decoded the 15 pin Topcon connector. I would like to learn what you have found. Can you please explain the pin details? (Are you referring to the computer pin connector found on the Topcon base or the flat metal pins positioned near the lens mount?) How do you "short out" the pins?



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5/11/2006 3:55:30 AM

Eugene Foley   Steve,

Steve thanks for your update on the 50EX adaptor. I have learnt so much from you and George and am deciding which way to go.

Regarding timing data I have been looking into programs that extract EXIF data. Perhaps you already know all of this stuff. The EXIF data is part of every JPEG file. EXIF data includes a lot of data but importantly the time stamp down to the second. Once this data is extracted the time of individual angiogram photos can be worked out to the second. I am looking at free or inexpensive programs that extract this data and either add the time data to the filename (add a patient name or ID to the detailed time stamp and we should be set) for easy filing or stamp the actual image. There are lots of these small programs out there. Once I settle on the most convenient system I will post my findings.



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5/11/2006 5:42:39 AM

George    Steve,

the pins that I'm referring to are the top 15 pin (what the electronics industry calls the "DB-15" connector). I have not played with the rear port pins yet but they are similar (Some are actually the same pins as the top ports). Unfortunately because of the decentration of the rear port, I'm not able to get the timing data to show up on the picture. The 50-VT has a small window to the left of the actual image that shows this information and because I'm only capturing about 70% of the actual image, part of that information is lost.

In regards to actually "shorting out the pins", the typical hotshoe on your camera does that for you. On the hotshoe itself, there is a metal bracket that is connected to ground and a large central contact. When a shot is fired, the central pin and the ground pins are connected together by the camera. What I did was to find the actual pins on the DB-15 connector, measure the voltage (15 volts) and polarity and connect it to the hotshoe. I then figured out where the actual central trigger button is connected to and wired that into the Canon EOS's remote trigger port (which is a simple stereo plug). So when you press the central trigger on the joystick, the Canon EOS takes a shot and fires the hotshoe (which fires the strobe).

Eugene, I am interested in your solution to the timing data. That may come in handy. Did you already setup your system as well? What sort of setup did you use.

I think ultimately I will move the camera to the polaroid top port. The viewfinder on the EOS and Nikons are just not big and clear enough compared with the LARGE topcon camera viewfinder. I do need some help with the optics on the top port. I can't seem to get a clear image with the EOS, with or without a lens. Steve do you mind sharing what sort of lenses are in your setup? The polaroid actually uses a 14D lens anteriorly. But I can't figure out the optics to get an image on the EOS.

BTW, my setup looks very similar to this image:


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5/11/2006 9:53:13 AM

George    Notice that in that setup, the camera is a EOS 5D with a full 35mm image sensor. Part of my problem is that the image sensor on a Canon Rebel is a smaller APS sensor with a cropping ratio. I'm thinking with the smaller ratio, the image is smaller as well. The fundus camera in the photo is a 50FT which is a simpler version of the 50VT that I have. The major difference is that the 50FT does not have a polaroid port and therefore no exposed DB-15 port (which is probably why there is a black box to trigger the whole setup). The white wire on the right of the black box probably connects to the joystick button.


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5/11/2006 11:41:15 PM

William B. Baer   I have a very old Topcon fundus camera which uses a bayonet-mount camera body which is, I believe, compatible with the Topcon RE and DM SLR cameras. The camera body is a limited version designated "AM" and has no shutter speed controls. I use it exclusively for color fundus photos in low volume. My question is: would the adaptor mentioned in the discussion above be likely to fit my fundus camera so that I could adapt a digital back? I have in mind to find a used full frame back from Canon or Nikon which could be found at a fairly reasonable price. The whole camera is at least 25 years old but still works for what I need it for. There are no electrical connections from camera back to camera in my setup other than flash which can be controlled through an adaptor.

Appreciate any and all advice.

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5/16/2006 12:21:52 PM

Eugene Foley   George and Steve,

I await a TRC50IX that will arrive any day. As soon as I verify it is ok I will buy the same adaptor that Steve uses and attach a D2H and possible wireless transmitter.

This is the second trip around and I cannot afford to lose more time.

I did use the setup in your weblink with TRC 50F and Nikon D70. The white wire you refer to syncs the xenon flash from the camera hotshoe and works well. The joy stick is not used to trigger the camera, the oposite in fact. The camera triggers the flash. A hand held infra red remote control can be used to trigger the digital camera but this is still not ideal. The APS sized Nikon D70 sensor made for difficult focussing. My TRC 50F had some serious centre lens blur issues which were considered irreparable so I decided not to proceed. With a full size sensor Canon DSLR it might have been a good setup. It did however confirm to me that an adaptor for a DSLR is a reasonable way forward.

I also considered a 50VT and had one nearly bought. I was however warned by a company that does digital video conversions that the 50VT mirror mechanism for the top polaroid port is too fragile for heavy use and that parts were not available for repair. I cannot verify this information but it made me seek a newer fundus camera. I did not need the hassle.

A colleague bought a digital video conversion that cost in excess of 21k for his 50X and is having lots of software issues. Several months later reasonable 1.3 megpixel photos but no angiograms to date.

I was ready to prefabricate an adaptor when I happened upon this excellent forum and Steve's posting.

All the best,


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5/16/2006 4:54:16 PM

Steve    Eugene,

Congratulations on your setup. The TRC50IX is the top-of-the-line model and should allow you to do anything you wish. As you note, the Nikon D70 does not seem to work well for this purpose. I am also not sure about the D2H. I have never used one, but when I was researching Nikon cameras, it seemed to me that the D2H might might have some issues using it in this way. If possible, you may wish to borrow one first just to see that everything works the way you want.

Note that with D1 series camera you do not need any remote trigger, wireless or not. With the appropriate connectors, the camera takes a picture whenever you fire the Topcon TRC 50 EX/IX joystick trigger. This is the "normal" way to take fundus photos and is most natural for the photographer.

As I mentioned previously, the only drawback to this setup is the lack of timing data on the picture images since you are using the top "Polaroid" port which was only intended for color images, not angio images. I have looked at some of the EXIF programs on the web to extract this info, but have found none worth getting yet.

Also note that when you receive your TRC-50IX it will not flash unless you have a camera back or a workable adapter set-up attached. My Topcon sat collecting dust for about 3 months until I had everything I needed to put it all together. To check yours, you will need a 35 mm camera back. I did not wish to get one since it would never be used. If you have an old one or can borrow one, you can check out your Topcon right away.

Also, I would suggest arranging for instant computer download with the inexpensive program available at Saving images to a camera card and transferring them later to a computer drags out the whole process and is not necessary. In a busy clinical set-up, anything that makes the process quicker and smoother is desired.

Best of luck.


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5/17/2006 3:42:34 AM

George    William, you might want to contact the person who owns that website to see if their adapter would work. Last time I check, they wanted around 2-3K for the setup (without the digital camera). If you can control the flash externally, then it would not be problem to mount it on the hotshoe and find an adapter to physically mount the camera (use my solution from above). Sounds like you don't need to have any fancy software or interface to capture the image.

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5/18/2006 9:59:19 AM

William B. Baer   Thank you for responding. I think the idea of using a T4 adaptor and adapting it to my Topcon fundus camera might work. I just need to find an appropriate T4 adaptor. The camera mounting boss for the camera is about 2.625 in diameter and the three screws which hold it in place are on a somewhat smaller circle. If the T4 adaptor is about 2.5" or larger, I could grind off the flange with the threads on the side away from the bayonet and drill matching holes in the flat part. I have learned that the Topcon bayonet is identical to that of the Exacta cameras, for what it is worth. All of these devices are obsolete to the point of antiquity. Thanks again.

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5/19/2006 12:35:01 PM

It's been almost 6 months. Have anyone done anything interesting with their digitial fundus camera yet? I've finally perfected the proper setup. Would like to hear and see what other's have been doing.

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9/27/2006 1:27:31 PM

It's been almost 6 months. Have anyone done anything interesting with their digitial fundus camera yet? I've finally perfected the proper setup. Would like to hear and see what other's have been doing.

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9/27/2006 1:51:06 PM

Lance Le   Hi all,

Searching through the web and found this site. Just want to put a little input in here. I had a gentleman in Dallas that helped me with the conversion of Topcon TRC-FET. It cost approimately 1500 for Assembled Low-Profile adapter ring (to the Pentax *ist D SLR digital camera), 3-way Trigger-box which allow u to use the joy stick trigger,and electrical
dampening hot-shoe connector/adapter, which help prevent your camera from burning.

He's currently help me build an adapter for the Topcon TRC-50FT model, which could take a while. I also called and they quoted me 12K for the complete set up, which is rediculous.

I will upload some pics if anyone interested.


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9/29/2006 12:01:17 PM

George    I would be interested in seeing some photos. Since the TRC-FET has only one port, how many degrees are you able to capture? I was able to mount the camera to the back of my TRC-50VT but found the viewfinder on my EOS Rebel to be too dim to be useful for focusing unless you crank the lighting way up. I wounded up putting the camera on the top port and via some lens work, I am able to capture the full 50 degrees.


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10/5/2006 6:55:28 PM

George    BTW, is this guy from Dallas a chinese ophthalmologist who does this on a part time bases? I might have spoken to him.

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10/5/2006 6:57:41 PM

Lance Le  
the FET is about a 30 degree field. However, I was able to get about 35 to 40 degree shot. I'm still new at photography so the fundus photo still a lil blurry on some shots.

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10/6/2006 9:01:36 AM

Lance Le   You can see some photos in my gallery. I talked to the OD who helped me convert this digital camera in Dallas (he's a caucasian optometrist), and he told me if anyone interested in have it done, you can email him at His name is Jeff Ray. According to him, he has successfully convert these camera to digital TRC-WT, the TRC-NW2, and the hand-held Kowa RC-2 to digital.

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10/6/2006 9:13:19 AM

George    Very nice! I like the scotch tape approach to things. Only kidding. Do you have any problem focusing thru the pentax viewfinder? I couldn't get an adequate focus via the EOS rebel viewfinder. How do you guys setup the gallery so I can upload some photos myself?

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10/10/2006 3:05:44 PM

Lance Le   The adapter that I have is able to rotate the camera 360 deggrees. The adapter is not very tight (hence the scotch tape). I flipped the Pentax upside down so I don't have to invert the pictures. Focusing through the pentax view finder is a little harder than the original 35mm camera back since the view finder of the Pentax is a smaller. The lighting is a little dim like you said, especially with dark fundus patients. The Pentax also have a 1 diopter accodomation lenses, so that would help out a bit.

The guy who helped me build this adapter is currently working on replacing the light with infared light which would convert the camera to non-myd. Can't wait.

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10/10/2006 3:29:17 PM

George    I figured out how to upload the photos now and have a few to show. Like you, I'm also starting out with fundus photos but have taken quite a few already. I would be curious as to how the infrared concept would work since you have to focus it somehow. I'll upload my setup as well with the 50VT fundus camera. I have yet to install that same flash "safe-sync" on my EOS since the Xenon trigger is about 15V and canon calls for only 6V max. I also have to enclose all the circuits and the wires into a DB-15 plug to make it look pretty.


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10/10/2006 10:06:34 PM

Lance Le   George,

As far as the infared concept, I haven't talk to the O.D. who helped me with this process. I will get back with you as soon as I hear anything, but from my understanding is that all non-myd camera is based on this infared technology.

I have a few question regarding the 50FT adapters. Is what I need look something like this? for the EOS camera body.

or this for the Pentax body.

Also, the 50FT does have the polaroid adapter port which locate on the right side of the camera.


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10/18/2006 2:10:19 PM

Jeff Ray   Hello - I've just encountered this thread tonight, and wanted to throw in my two Lincoln's worth.

I am the OD who is working with Lance; I very much appreciate his postings here. I am currently working on the IR system he mentioned, as well as additional conversion kits for some of the older Topcon fundus cameras; also a conversion kit for the Kowa RC-2 handheld fundus camera. (Making time for those pesky patients is a bit problematic!)

As I progress with these various projects, I'll be happy to post what I can here, if there is interest. I have recently invested in some additional lathing and milling equipment, in order to improve the ring adapters I use, and am working with Topcon to obtain some additional info on the electronics of the various incarnations of their product line. As I check some of these items off the list, I'll post here first (as this seems to be a more active forum on fundus cameras, with some very experienced individuals).

Congrats to all who have experimented with their various models - you've done some excellent work.

Regards, Jeff

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10/21/2006 10:58:59 PM

Sasha David Gant   George

I am working on the exetension tube to fit a Canon EOS 5D to the polaroid top opening, I think it is doable. I will put this to the forum if I get a decent image. Could you please give me the pin number for the 15 v differential leads and the leads for the target switch pin numbers.



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10/27/2006 2:52:43 PM

George    Hi all,

I have not check this site for a while (been playing with the new EOS XTi). In response to Lance's question, yes the adapter is the one pictured for both cameras. I don't know what the 50FT looks like but you may not be able to use those adapters. The 50VT that I have, the camera port is off centered and the pins for the topcon camera gets in the way if the use that adapter. Your best bet is to get an adapter without the center lens, like the pentax one. You also would not get the view that I get (see my gallery) since the smaller APS-C size sensor of the pentax or the EOS resizes the image. Again, I don't know the optics of the 50FT or the polaroid port for that matter.

In response to Sasha's question, the 15-pin port is rather complicated. There is no easy "target" switch pin connected directly to the joystick. The port is made for the polaroid back which gets a signal to open the shutter and then to advance the film. Timing the crucial as the mirror flip for a second and then the flash is triggered. I'm at home now and I'll have to get the exact number for the pins to short out to trigger the flash when I'm at work. There are also some optics involved in getting an image from the polaroid port, I hope you know. It's not simply hook up the camera with an adapter and shoot away.


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11/1/2006 10:00:54 PM

David Rosenblatt   Hello - I came across this discussion and its like a gift from heaven

We're planning a little experiment to take a used fundus camera and turn it into a digital fundus camera that can take pictures at different wavelengths (colors). We will be trying a couple of digital cameras and CCDs and also be changing out the light source. We're trying to decide between a Topcon TRC 50X and 50VT. If anyone has an opinion which would be easier to build adapters for and also get access to the Xenon and Halogen bulbs, We'd be grateful for the inputs Thanks, as we're a bunch of crazy physicists who are new to this game.

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11/8/2006 9:58:27 AM

George    The 50X and the 50VT uses similar setups. Whatever will work for the 50VT should also work for the 50X, but the timing is a little different between the two. The 50VT is a lot older camera and may have the common upper port solernoid problem, that you may have heard about. They both have the same adapter at the rear port and the top port connectors are probably the same. I have both cameras at the different facilities that I'm in. I have not tried my 50VT setup with the 50X. What is the purpose of taking pictures at different wavelengths? Is there some medical application to all of this?

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11/9/2006 11:26:21 PM

David Rosenblatt   Hi George,
Thanks for they reply. There are several medical applications involving combining the images taken at multiple wavelengths with digital image processing in order to improve early diagnosis capability:
1. Improving contrast for vessels and capillaries to enable automatic grading.
2. Extracting information about pigments and their distribution.
3. Mapping oxygen distribution.
You have to be able to take the series of pictures very quickly, which is why we are swapping out the light source. Do the 50VT and 50X have similar access to the bulbs? I'm less concerned about the solenoid issue since we will be spending alot of time inside the camera and will learn to fix this. We will be using one port for low resolution video and the second one for high speed high resolution CCD Camera.
Regards, David

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11/10/2006 1:50:53 AM

Sasha David Gant   Hi George
Thanks for the pin details of 15PD
in my 50 VT when I short pin 2 and 3 I get the xenon flash go off, I tried to short 14 and 15 pin no effect was recorded. Wondering if you have any other information regarding pins connected to the shutter and the joy stick trigger.

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12/3/2006 5:07:09 PM

Richard Hom   Anyone with experience or knowledge of converting a Kowa RC2 film to digital?

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12/6/2006 11:06:02 AM

Donald Zero   Hello,

New here and I'm looking at digital camera systems for fundus imaging as well. I'll throw out a hint and then ask my question..

I read on another thread of someone using a $4.29 radioshack xenon 300w strob bulb as a replacement for the $400 to $800 flash bulbs that the topcons use. His was the older TRC-FE model, so I'm not sure exactly what they all use, but might be worth experimenting with. I did a quick search on radioshack's website and there is only one xenon bulb, so it should be easy to find if needed.

Now to my question. I'm looking for information on older Kowa retinal cameras. From the pictures I've seen, it looks like they all have the same mount for polaroid and 35mm attachment, but I'm having trouble figuring out which it is. Does anyone have a good way to find out? There aren't any old manuals online that I can find that list this sort of thing.

Richard, and others:

try a search here:

There are some interesting retinal photo articles there, with pictures in the .pdf's..

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12/7/2006 3:34:02 PM

Donald Zero

This is an article that discusses the image size difference in non "full frame" digital cameras. It also talks about the pin layout which some of you were discussing above.

Talks about conversion of an older zeiss and also a topcon 50EX.

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12/7/2006 11:51:38 PM

George    Donald,

Try going to a photography store (one with a nice old man with plenty of time) and try all the adapters of the different cameras. That's how I spent the time to figure out that the Topcon mounts are actually old Canon mounts. Thanks for the article, BTW.


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12/8/2006 2:55:45 PM

Bulent Kose   George
I am very happy to find the group wondering same thing with me
I am triying to attach fujifilm s3 digital slr camera to topcon trc50IA
actually I attacthed s2 camera to zeiss fundus camera 3 years ago and it works perfectly
BUt with this topcon altough try many kind of lenses I have same problem with you I can get only %70 image becouse of the sensor size
you mention that solved that problem
how did you solve the problem can you get entire image?
Can you give some detailed info
best regards

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2/27/2007 10:59:06 PM

Gil Montano   geoge how did you perfect your system and how much did it end up costing you?


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3/20/2007 7:32:04 PM

Gil Montano   george, I have a topcon trc 50x,
can you send me the step by step instructions on how to convert it to digital.


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3/20/2007 7:34:31 PM

Donald Zero   Hello,

Been a while, thought I'd report in.

I ended up getting a really good deal on a KOWA FX-50C.

I made a homemade (proprietary kowa to nikon) mount. I bought a Nikon D40, mostly because I also have a photo slitlamp that uses the nikon mount as well. I'll hopefully eventually just buy a Canon 5D and not have to worry as much about the crop.

What I've done is this. I installed a webcam in the eyepiece of the kowa, and have a small monitor that uses the included webcam software. I've constructed a little circuit with a few IR LEDS and a 9V battery and been experimenting with placing it along the path of the light source, in place of the regular lamp. The webcam picks up the IR but the iris does not react to the IR (sort of a DIY nonmyd).

So far I've learned the webcam is really poor quality, which I could have guessed. I'm also not convinced LEDs are the best IR source, but think they may work with some type of modification.

After further tinkering, I've discovered the wires that need to be shorted to trick the solenoid and flash to fire without pressing the button. This was a big one, because I didn't blow anything!!. The plan is to add a button of my own somewhere next to a usb keypad (wireless maybe?). A button on the keypad would be configured to take a picture in NIKON CAMERA CONTROL, and would be synced up to the aforementioned button so it would all be at once.

I like the idea of a wireless keypad just to reduce the number of cords. No idea if all of this will work, and still think the best pictures are going to be with dilated pupils anyway, but its interesting to try.

I'm not too worried about IR causing health issues, because of the greatly reduced output once in the optical path of the flash, but does anyone have access to what type of IR LEDs are used in current autorefractors or nonmyd cameras? Power output, etc? I'd like to be doubly safe before using this on patients.

Anyway, I doubt too many people are using the older KOWA cameras, but thought someone might get ideas from my ramblings. In case anyone does read this for the FX-50C specifically:

the two wires to short to get the solenoid and flash to go are the top and the far left one (as you are looking in to the mount of the kowa). They are the blue and the black wires. Be careful...

good luck

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4/13/2007 11:50:41 PM

Donald Zero   forgot to ask, does anyone have a recommendation on a good type of camera to attach to the eyepiece? I keep seeing sony 1/3" superHAD CCD on a lot of the random IR nightcams, but am unsure if the quality is that much better than a webcam. I'm guessing it can't be any worse...

I've also looked at getting a camera, but the problem there is removing the IR filter as some of the newer models are coatings instead of a removable glass/plastic piece. Plus, all those screws are plentiful and easy to loose.


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4/13/2007 11:54:45 PM

George    The best camera for IR is the nikon 5400. It has a filter, there are many sites that tell you how to remove it, there is a threaded mount, and a flip-out LCD. Plus it's cheap...on ebay of course. Watch out for the sensor recall on that model.

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4/28/2007 3:13:34 AM

George    It really does not take a whole lot to convert the Topcon cameras. It costed me less than $50 to do the whole thing. Plus I used some common ophtho parts lying around. The hard part is figuring out the wiring, the optic pathways, and I'm still not 100% finished. About 99.9%. I still have to figure out why my images are inverted. But I've literally taken close to 1000 photos now. See my gallery for some.

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4/28/2007 3:19:31 AM

Jeff Ray   George - Perhaps I can be of some assistance. There are multiple revisions to the Topcon 50 series fundus units, and even within the same model there is a variation in timing and wiring. I have sent an email to you with some details. We may be able to put together a good summary if you'd like. Regards, Jeff

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4/28/2007 8:34:46 AM

Pablo Daniels  
para adaptar una camara digital al puerto polaroid de un topcon trc 50f a traves de un cable de sincro cuales son los contactos que producen el disparo?
hay 8 y solo son 2 los que lo producen.
adjunto fotos.
gracias por la ayuda.

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6/15/2007 3:36:27 PM

Bob    RE: Topcon 50 VT
I am new to this group, my apologies for asking questions you may have already answered.

I would like to get my 50 VT to accept a digital camera back. The video cam corder does not have enough resolution and small CCD area so I gave up on that.
Question 1: Is there a high resolution version of a cam corder that could work?

Question 2: The 35 mm camera mount on the 50 VT seems to be topcons T1 medical bayonet fitting. How did you get your camera to adapt to that ( or is the VT different from the 50 FT )?
Did I understand that George got the canon rebel xt to attach to the topcon 50 vt back camera port?

Question 3:Is there enough light from the illumination tube to take digital photos with out the flash ?


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8/9/2007 4:19:45 AM

David H. Gosiengfiao   Donald,
To fool the Kowa into firing without a camera body, short pins 1,3, and 4. Do not short pin 2 as it will blow a fuse - it feeds 24V!

BTW, how did your project go? I am thinking of upgrading my fx500 to digital too but am not sure about the adapters needed. I think the original camera back has a shallow flange to film distance. The EOS 5d has a flange to film distance of 44 mm. Would you have any idea?


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8/12/2007 7:19:41 AM

Donald Zero   For the FX-50C, I figured out a way to fire the flash without shorting any of the pins. The pins are essentially unreachable when the camera is mounted anyway, so I think it works better this way.

Are you saying the 5D EOS would be a good camera for this, or not?

I don't have the film camera back (only the polaroid), but think I've found a picture of one online. It looks like there is a circular piece of glass inside the camera, similar to a trial lens. I'm not sure if its more for protection, or allows for some type of focusing as well.

I'm really leaning towards the full frame sensor instead of screwing around with the cropping of the smaller sensors.

You bring up a good point, it may always be out of focus with the eyepiece if the flange to film distance is off.


Bob, I think it would be very difficult to get a picture through the illumination tube without a flash. Pretty much all camcorders will be inferior to any of the current digital SLR cameras.

I do think the fujifilm infrared camera is an interesting item. Its made for crime scene investigators, and is one of the first SLRs with a live preview. Somewhat pricey, though.

Looking at costs for new digital fundus cameras has got me interested in this again.

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8/12/2007 11:49:37 AM

George    Bob,

What you need is a EOS to canon FD adapter. It's basically the same adapter that you mount the old canon lenses (pre-digital) to the EOS rebel camera. There is an off-set to the tube, since the 50VT camera back is not centered. There's also a cropping factor, making the 50 degree more like 30 degree. And there's the problem with the small and dim eyepiece of the EOS (making the focus next to impossible without cranking up the light). So you really want to try to place the EOS on the top port. That's where I have mine mounted. Look at my gallery for photos.

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8/15/2007 7:38:16 PM

Donald Zero   I am taking my Kowa fx50c/Canon 5D combo to my office tomorrow, weather permitting.

I was curious to know what exactly is everyone's opinion on using a ND filter either before the flash, or before the slr. Is it more a matter of ease of use, or is there a specific reason? Trial and error?

I've put the idea of changing it to a nonmyd on the backburner for the time being.


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1/1/2008 10:00:07 PM

Gil Montano   does anyone know if the KOWA RC-XV2 can be converted to digital?


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1/2/2008 10:17:22 AM

Jeff Ray   Gil -

I have just recently acquired one for this express purpose.

I have already successfully converted a number of Topcon units, and am looking forward to doing the same with these Kowas. If you'd like, I'll be happy to email when I've got a working solution (from the specifications, I see no reason why it should not be "do-able").

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1/3/2008 10:01:49 PM

Brian Anding   Jeff Ray,
Please contact me. I've lost you email address.
Brian A

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1/30/2008 6:56:36 AM

Bob    A knowledgeable telescope designer suggested that I have the Topcon back modified. He says there are ways to put a full sized ccd at the film plane and the image capture software comes with the ccds. I do not have the name of the photographic machine shops that do this...if it can be done. Question : are there timing problems with the flash that different if using a ccd rather than film ? What other problems does the group expect (other than money ).

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1/30/2008 10:17:29 AM

George    I've visited that idea previously. The problem is that these CCD's are prohibitively expensive. They are essentially full frame CCDs. Think of the price of a EOS 5D. A while back, the idea was to make a digital back so that people can use their film SLR bodies. But I think cost and dirt factors are problems (among others).

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1/30/2008 2:42:52 PM

Richard Dolphijn   Question for George,

I want to upgrade my TRC-50VT to digital. My upper port relay lens is fitted with the Fd to Eos or Nikon adapter. In order to get the same view as the lower port viewer, I took a 10mm Fd extension tube. I ordered a 270 degree 5 pin male and female DIN connector for the joystick to separate the shutter connection. This connection will lead to a 2.5mm mono plug after which you can choose the universal remote cable needed. Your project is finished. Maybe you want to share some information. I need some information for "how to" the electrical connections.Any information is welcome Could you also upload the pictures, I couldn't find them.



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8/3/2013 4:42:26 PM

Richard Dolphijn   In my previous message I mentioned 270 degree DIN connector. This isn't correct and should be 240 degree.

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8/4/2013 2:31:27 PM

David M. Dickman   Anyone figure out the pins on the rear connector of the trc-50EX? Thanks. The info here in this thread is great.

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10/18/2013 8:43:23 AM

Steve    The 9 pin D connector at the base of the camera has this configuration: Pin #1 = Flash, Pin #2 = Flash Ground,
Pin #7 = Trigger, Pin #4 = Trigger Ground. I do not know about the rear connector.

Try: Scott, J. R. Journal of Ophthalmic Photography 2002;24(2):55

Also try:

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10/19/2013 8:08:36 AM

David M. Dickman   Thanks. Very helpful. I was able to get a copy of that article. Any idea if that db9 will work if the digital camera is on on the lower port? I had heard that image quality is better through the lower port than the upper. Thanks again.

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10/21/2013 7:27:00 AM

Carlos Hermosilla  

hello I m ophtalmologyst I have a retinal camera TRC 50x and I need conect eos canon 50 D I need trigger for conect it . I need to work digital form thank you where I can get it?

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5/19/2015 3:18:53 AM

Carlos Hermosilla   hello I need to know which are the 15 pines of conector of the trc 50x it is in the upper of retinal camera.
flash? ground flash?. trigger? ground trigger?
whit that information I will try to conect my digital 50d canon thank you

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8/17/2015 2:29:21 PM

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