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Photography Question 
Ross Master
 

Depth of field in the studio


I'm taking my first steps into studio photography and I'm a little confused by how to achieve a good depth of field with studio flash.
I recently bought the Canon 10D which has a sync speed of 1/60 sec for studio flash use. I'm shooting a tall subject from close to it's base which is placed on a raised platform and I'm shooting along the surface to the top. I want it to be sharp at the base and as sharp as possible at the top. So I set the camera to 1/60 sec, take a meter reading at the top which might say f/5.6 for example but I loose depth of field before it gets to the top of the subject. Under continuous lighting I would simply change the shutter speed and change the aparture to f/16 for example or use AE mode. But with studio flash the shutter speed will have to stay at 1/60 sec right? When I change the aparture I'm changing the exposure and so underexposing or overexposing at certain areas. How do you maximise depth of field to ensure that as much of the subject is sharp as possible but maintaining correct exposure across the subject? I'd appreciate some advice.
Ross


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10/14/2003 3:09:15 AM

 
Jon Close
BetterPhoto Member Since: 5/18/2000
  The EOS 10D will sync at any shutter speed from B, 30 sec., down to 1/200 sec. You are not limited to 1/60.


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10/14/2003 8:17:03 AM

 
Piper Lehman
BetterPhoto Member Since: 7/20/2001
  The 10D only has a sync speed of 1/60s?!?!?! Oh my! I'm so glad I went with NIkon! LOL

Actually, I only get 1/180 with my D100, and I thought this was pretty sad.

I feel for you Canon guys...


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10/16/2003 6:26:22 AM

 
Ross Master   Hi Piper,

Don't get too cocky! The voltage limit of 6v is at the hotshoe and all digicams are about the same (though some Nikon coolpix I've read are 5v). What I'm trying to discover is what the sync voltage limit is on the PC terminal of the 10D. Nikon more readily disclose the tolerance of theirs but Canon are edgy and won't tell you. That's why I'm frustrated. Someone told me today that it can take 24v which is usually the highest output of modern flash units anway. I just want it officially confirmed. Have you confirmed your information? Please supply your evidence please. I'd check into that if I were you, damage is usually gradual not sudden if you're applying too high voltage to your terminal on a regular basis.

Ross


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10/16/2003 6:48:07 AM

 
Ross Master   Oh on synce speed - the sync speed is recommended at 1/200 sec (higher than the Nikon's 1/180) or less with non dedicated canon flashes but 1/60 sec with larger studio flash units (according to page 106 of the 10D's user manual).
I'm just going to buy a safe-sync regulator and then I can get on with my photography.

Ross


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10/16/2003 6:57:00 AM

 
Piper Lehman
BetterPhoto Member Since: 7/20/2001
  Here's what the D100 manual says about voltages and sync issues:

Negative voltages or voltages over 250V (!!) applied to the accessory shoe could not only prevent normal operation, but damage the sync circuitry of the camera or flash.

Rear-curtain sync cannot be used with studio flash systems, as the correct synchronization cannot be obtained.

Sync speed is 1/180s or slower* (slowest possible sync speed depends on exposure & flash modes chosen). I find nothing in the manual that implies that the sync speed increases or decreases with studio lights. 1/180s seems to be the max sync for any flash used.

I can't find anything else about hotshoe voltage limits in the manual. 250V sounds kind of high! Maybe I don't understand the info.

The D100 does not have a PC terminal. I had to buy the optional AS-15 hotshoe adapter in order to connect a sync cord to the camera. I also have an infrared flash tripper that is supposed to be safe to use on the camera's hotshoe, though it isn't a Nikon product, so I always worry when using it. The AS-15 HS Adapter only says to only use with Nikon speedlights -- doesn't say what the specific voltage limits are -- just that there ARE limits. Also does not even mention the connection of studio strobes via sync cord and adapter. This is strange when you think about it.

I have read about the Canon hotshoe voltage issues, but I've yet to see any warnings for the Nikon cameras. If you come upon anything, please post the info here!

p


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10/16/2003 8:11:03 AM

 
Piper Lehman
BetterPhoto Member Since: 7/20/2001
  Here's a question: If the max voltage for the D100 hotshoe is 250V, what is the watt/sec limit of a studio strobe connected via sync cord and AS-15 adapter/PC terminal? I'm so confuzzled!

I guess I need to study my strobe manuals! I'm using one 160 joule Alien Bees strobe and the rest of my lights are equal to or less than this in watt/sec power. Hmmmm. Does the watts/second designation directly correlate to the voltage of a particular strobe? Or are they all different? Hmmmm

I'm off to do some research....


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10/16/2003 8:18:19 AM

 
Piper Lehman
BetterPhoto Member Since: 7/20/2001
  http://alienbees.com/allspecs.htm

Here's the info on my strobe above. Looks like the sync voltage is 6V. I still don't understand the Nikon info -- 250Volts! What is that?


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10/16/2003 8:20:58 AM

 
Jon Close
BetterPhoto Member Since: 5/18/2000
  >>Oh on synce speed - the sync speed is recommended at 1/200 sec (higher than the Nikon's 1/180) or less with non dedicated canon flashes but 1/60 sec with larger studio flash units (according to page 106 of the 10D's user manual).
I'm just going to buy a safe-sync regulator and then I can get on with my photography.<<

Sorry, Ross. I didn't realize the 10D had that limitation on the PC sync. I wonder why that is?


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10/16/2003 11:05:13 AM

 
Ross Master   Yes it's all very frustrating isn't it? They tell you how to take care of the camera but they can't provide info about really important things like voltage limits - and using studio flash is something that photographers are very likely to do with this level of camera and the market it's aimed at. I'm sure thousands of people worldwide are just plugging them into strobes or powerpacks without any thought, confident "that's what the socket is made for" and unknowingly damaging their cameras. Perhaps this is a merketing ploy by Canon to increase trade at their service centres? Makes you wonder. I can't think why such informaton is made unavailable.

As I am unable to verify the sync voltage limit at the PC terminal, I'm going to have to assume it's 6v for the time being and therefore treat it like a compact camera and use a voltage protector and experiment in the studio to see what sync speed I can actually use. 1/60 sec is generally fine for portraits etc but I'm pretty sure from what I've read and some of the sample studio images taken with the 10D I've seen online which have given the EXIF data with it, that I can use a faster sync speeds. If anyone tries it before me then please post your findings. I'm in the studio on 26th October I think, so I'll keep you updated.

Ross


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10/16/2003 1:39:38 PM

 
Ross Master  
 
  Seeing Red
Seeing Red
Candid snapshot, handheld, Canon EOS 10D, Vivitar 100mm f/3.5 macro lens
© Ross Master
Canon EOS 10D Digi...
 
 
A bit off topic but what the hell, I don't usually take pics of flowers but since I was "seeing red" I thought I'd share! The roses are dying off now at the end of the season but that's life.

Ross


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10/16/2003 3:03:36 PM

 
Ross Master   Just a follow up to this topic. I bought a Safe sync for the Hotshoe and went to the studio for my shoot a few days ago. First problem I had was that the flashes wouldn't fire using the safe sync. The flashes were Bowens 400's and some really old flash (no idea what brand or power it was but it output somewhat so I'd have a guess about 600w/s). Anyway, with the studio booked, the model had driven an hour and half so I was in a bit of a fix. I threw caution to the wind and decided to use the PC sync socket. I used it without any apparent problems at all for the 4 hour shoot. Got me out of a sticky mess. I do feel like I've wasted my money on the safe sync though. I'd recommend that if you are going to get a safe sync then get the PC to PC version and not the Hotshoe to Hotshoe version. Perhaps the hotshoe version will work with other, newer strobes I don't know. Before anyone says about polarity, I changed the polarity of the stobes too but the safe sync still didn't work.

Anyway, as for sync speeds. Despite it saying the sync speed is 1/60 sec for the PC sync socket in the 10D manual, I did the entire shoot at 1/125 sec (more than adequate for portraits and fashion shoots) at apertures between f5.6 and f/16. I also tried it at 1/200 sec for a couple of shots with no problems at all.
I'm going to be using some Courtney flashes next Month and Elinchrom so I'll see how if it's the same with them and if I can get the safe sync to work with them. Keep you posted.

Ross


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11/13/2003 2:32:11 PM

 
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