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Photography QnA: Camera Lenses

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Category: Best Photographic Equipment to Buy : Camera Lenses

Have questions regarding how to use camera lenses? Check out this Q&A which covers everything you need to know about camera lenses. If you have questions regarding which one to buy check out this helpful article: Choosing Lenses.

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Photography Question 
Linda Buchanan
lindabuchananphotography.com

member since: 4/26/2005
  1 .  Sweet Spot of a Lens?
Does anyone know how to find out what the "sweet spot" is on different lenses I own? I have tried searching but I am not really finding the information. Thanks so much.

4/11/2008 10:27:03 AM

Mark Feldstein
BetterPhoto Member

member since: 3/17/2005
  Hey!
Actually, every individual lens may be just slightly different than other lenses of the same focal length and manufacturer. This is something you can easily determine by individual trial and error.
The ideal way is to set up a focusing target at a predetermined distance like 8-10 feet. Put the camera on a tripod, preferably with some kind of leveling device to ensure it's square and plumb to the focus target.
Then focus on the target and use the depth of field preview to stop the lens down to f8.0. You'll probably find the sharpest focus somewhere in the range of about f8.0 f11.5. Check the target and snap exposures starting at those stops. As you climb towards f16 through f22, again check the depth of field, and don't be surprised if the target seems soft or less sharp than it was at, say, 11.5. If it's sharper there or even down to f8 or 8.5, that would be the sweet spot for that particular lens.
Okie dokie? ;>)
Mark

4/11/2008 11:19:35 AM

Linda Buchanan
lindabuchananphotography.com

member since: 4/26/2005
  Thanks Mark, you are always so good to help me, I will try that this weekend. Another dumb question - I have dof preview on my camera, but it is a little difficult for my old eyes to see. I should also get the correct answer viewing these on the computer, right?

4/11/2008 1:08:10 PM

Alan N. Marcus

member since: 3/4/2006
 
Hi Linda,

Mark is on target as always --
Just to confuse you a little:

Camera lenses are converging lenses. Stated a different way, camera lens redirect light and cause light rays from the subject to be bend (change direction) inward. If we trace the path of rays as they transverse a lens and continue till they intersect the digital imaging chip’s surface, such a diagram resembles an ice cream cone. The apex or tip of the cone just kisses off on the surface of the light sensing chip.

Now consider that rays that pass exactly through the center are not redirected. They travel in a straight line until they n strike the digital chip. On the other hand, light rays coming from the periphery (edge) of the lens must be bent (redirected) significantly inward. It is these peripheral rays that are the most likely to miss their intended target. Like a line of shooters at the 50 yard line all firing a volley at a single target in the end zone, the likely result will not be one perfect circular bullet size hole but a larger hole with scalloped edges and a few stray misses. The shooters near the sideline are disadvantaged, they are further from target and thus more likely miss.

As you stop down the camera lens aperture this act blocks peripheral rays. Thus sharpness improves because the percentage of bull’s eye’s versus misses’ increase.

As you continue to stop down sharpness continues to improve. However, soon a higher percentage of rays than before will be just brushing by the edges of the blades of the Iris diaphragm aperture. These glancing blow with an obstacle also cause light rays to go astray. Thus, after a point, of stopping down, sharpness deteriorates. This action is known diffraction. While stopping down does increase depth-of-field, nevertheless sharpness deteriorates at the smaller apertures.

Each lens is different as to it’s sweet spot. As a rule of thumb it is likely to happen when the lens is about two to two or maybe two and a half f/stops down from maximum.

Alan Marcus (marginal technical gobbledygook)
Ammarcus@earthlink.net

4/11/2008 3:19:47 PM

Mark Feldstein
BetterPhoto Member

member since: 3/17/2005
  As thorough as always Alan. Thanks !

One thing I might add, Linda, is that your focusing target should be well lit with continuous lighting, say a photo flood or two set at 45 degree angles to the thing and not close enough to set it on fire. That extra gazoft in your lighting will make it easier to see edge to edge top to bottom of the entire frame inside the camera. Get the picture? ;>)

A pleasure as always Linda.
Mark
==========================
Go CUBS !!!!

4/11/2008 4:47:16 PM

Anonymous 

member since: 2/10/2008
  The sweet spot is between the focus point and the other surrounding focus points. So if you are off your mark a little your focus will still be good. This only works with higher end cameras where you have 45 focus point close to together. If you pick a focus point on your outside line forget it or on a model where they are to far from each other.

Sarah

4/13/2008 8:47:27 PM

Alan N. Marcus

member since: 3/4/2006
  Every lens has a so-called “sweet spot”. This is an aperture setting that yields maximum sharpness – resolution – contrast. The “sweet spot” is an optical phenomenon that is unrelated to the camera’s focusing mechanism. All lenses have a “sweet spot” this is true for applications apart from cameras.

Not to say that focus points are anything other than marvelous. In the distant past we focused under a black cloth hood with magnifier. Our cameras featured focus scales that forced us to guess at subject distance and then we set the focus dial. Our cameras evolved to include and optical rangefinder and we carried an handheld model to help us with the guess. When the twin lens reflex camera was introduces, the upper lens served exclusively for composing and focusing, it was a twin brother to the taking lens, we loved them. When the SLR’s came out we tossed away our rangefinders and we fell more deeply in love.

Now days, cameras with 47 point of focus are magnificent. Next likely cameras will be mentally coupled to your brain. All you will need to do is look out at the vista, think about a well composed well exposed ---- throw the camera up to your eye and presto --- a prize winner.

Alan Marcus (truly marginal technical gobbledygook)
ammarcus@earthlink.net

4/14/2008 9:15:08 AM

Rich Collins
BetterPhoto Member

member since: 6/24/2005
  Lots of great answers. I just thought I'd add a site which perhaps helps to answer your question from a technical perspective as well. This review of lenses will enable you to see the actual results of this reviewers tests. I know this may not be exactly what you asked but it does include elements of your inquiry & I think you'll find it quite enlightening from a practical sense.Here is the review:
http://www.wlcastleman.com/equip/reviews/17-40/index.htm

And here is the main site:
http://www.wlcastleman.com/

4/15/2008 12:44:57 PM

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Photography Question 
Karen l. Monte
BetterPhoto Member

member since: 11/10/2002
  2 .  The Lens Hood: What Is It?
I would like to get more information about the lens hood. I have one and I see them used, but I'm not sure what they do exactly. I would like any info on how to use it and what it is for?

8/12/2007 3:11:35 PM

Michael A. Bielat
BetterPhoto Member

member since: 2/23/2007
  Aside from looking cool and making your equipment look more expensive, the lens hood actually does some cool stuff for you.
It is mostly for use outside in the sun because lens hoods prevent the light from hitting the lens at extreme angles and causing the light to bounce around inside creating images that look like they have no contrast in them whatsoever. It also does stuff to remove lens flare, which is usually not something people want in their photos.
Having one on your camera also protects the lens and makes it tougher for the glass to get scratched and makes it tough to get finger prints on it and so forth. A lens hood "should" come with every lens but that isnt always the case.

8/12/2007 8:10:19 PM

Karen l. Monte
BetterPhoto Member

member since: 11/10/2002
  Thank You so much! Greatly appreciate your response.

8/13/2007 5:52:39 AM

Simon  A. Stone

member since: 9/21/2005
  i sell cameras all day, and I always tell people that it protects the lens. and shades the lens from glare, then without fail they ask when they should use one, and I say anytime you would wear a hat, it's like a hat for your camera. it keeps the sun out of its eyes.

8/14/2007 6:25:37 AM

Jerry & Karen Bengtson

member since: 3/16/2005
  You should always use your lens hood. Even indoors. You can still get light reflecting off your lens from indoor lights. So you want to use your lens hood anytime you use your camera.

8/14/2007 6:55:09 AM

Paul S. Fleming

member since: 4/27/2008
  Hi Karen, With the petal or rubber lens hood be aware if you use an on camera flash (I avoid using this as much as I avoid my wife when she is in a bad mood)if the hood is causing a shadow usually on the bottom of your image. The simple solution of course is if it does, just take off the hood. Please remember to put the hood back on as it is great protection for the lens. I know from personal experience. BTW the hood will not help if you shoot directly into the sun. You will have a lot of flair and washout in your pictures. Happy shooting, "ps" Fleming

8/14/2007 4:02:02 PM

Oliver Anderson
BetterPhoto Member

member since: 11/16/2004
  I put COOL stickers on mine...LOL Thats what I thought it was for.

8/14/2007 10:40:01 PM

Karen l. Monte
BetterPhoto Member

member since: 11/10/2002
  I just want to thank you all for answering this,very informative!
Karen

8/15/2007 12:55:57 PM

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Photography Question 
Bobbi  S. Tomes
BetterPhoto Member

member since: 2/27/2005
  3 .  Lensbaby for an Olympus?
I love the effects of the Lensbaby and want one. Is there one available for the Olympus e500? Most of the ones I have seen for sale have been for a Nikon or Canon mount. I saw some for an Olympus e1 or something like that, but I'm not sure if that's what I need or not.

7/8/2007 8:47:24 PM

  Bobbi, try checking the Lensbaby Web site, or contact them via e-mail and ask them. Or call them. They were very friendly and helpful when I ordered mine.

7/8/2007 11:47:44 PM

Marjorie C. Armstrong
BetterPhoto Member

member since: 12/4/2005
  yes there is a lens baby for the olympus e500. You will have three choices. Just go to the lensbaby website and put your camera info in and you are. It took a long time to grt my lensbaby from them, instead I oredered my from bandhphoto.com and was able to get it much sooner.

7/10/2007 4:56:25 AM

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Photography Question 
Mary C. Casey
BetterPhoto Member

member since: 5/24/2007
  4 .  Hoods and UV Filters
For my new wide-angle lens, do any of you use UV filters and or hoods? Do you feel either degrades the photo quality? Do you see a need for either, or both? Thanks!

7/5/2007 4:47:50 AM

Pete H
BetterPhoto Member

member since: 8/9/2005
  Hello Mary,
Lens hoods are a benefit for a couple reasons: 1) They (may) protect the lens if you drop your camera. 2) A well-designed hood will keep stray light out in some shooting situations. This will improve color and contrast. But be careful when selecting a lens hood. If it is too large, you will get (vignetting) at the wide angle.
Concerning UV filters, you will no doubt get a few opinions here, and there are trade-offs. Personally, I do not use UV filters. Some will say there is some protection when one is employed, and I suppose there is an element of truth there. I'm careful with my camera and lenses, so that argument holds no water for me.
The reason I do NOT use UV filters is this: I cannot see the logic in placing a piece of glass in front of a high-quality lens. Unless the UV filter is optically pure, you will have some degradation in image quality. Optical physics proves this well. If you care to explore this principle, it is known as the "Refractive index" (i.e) air-glass-air-glass. In other words, the light has to pass from the air to the UV glass, then through the air again to the lens glass.
Also, I do not see any real "filtering" using a UV filter anyway. Theoretically, it does indeed filter; in practice, the effect is not well seen. If you don't believe that, shoot a landscape with and without and compare ... besides, I more often than not am using a polarizer when outside anyway; so why have two filters in front of a great lens?
All the best,
Pete

7/5/2007 7:08:39 AM

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Photography Question 
Leisa Allen
BetterPhoto Member

member since: 2/7/2007
  5 .  Can I Use a Film Lens on Digital Camera?
I have the Canon XTi. Can I use a film lens on my digital camera? Any help would be appreciated!

6/18/2007 11:40:37 AM

Bob Fately

member since: 4/11/2001
  Leisa, the real question is if the particular lens you have will fit that Canon digital SLR. You need to give us more details as to what lens it is, exactly.
As long as the lens will fit on the camera (and communicate with it electronically), then optically, however, the lens should work. There is the so-called "crop factor" that comes into play due to the chip size being smaller than the 24x36MM frame size of film, so to give you an idea of how that lens will behave you should multiply its focal length by the crop factor. That is, if the crop factor for your camera is 1.6 (which I think it is), then if you put a 100MM lens on the XTi, it would appear to look like a 160MM lens would look on a film camera. It's like getting extra telephoto length for free, sort of. And it also means your wide-angle lenses lose their width - a 24MM lens, which is a nice W/A on film, effectively behaves like a 38MM lens, which isn't so wide.

6/18/2007 11:59:12 AM

Stephanie M. Stevens

member since: 4/20/2005
  Yes, you can use film lenses on your camera. You just wouldn't be able to use a digital lens on a film camera (or full-frame digital); this combination would cause vignetting. I buy film lenses for my Rebel XT so that if I move up to a full-frame later, I can use all of the lenses I already have.

6/18/2007 12:05:02 PM

Christopher A. Vedros
BetterPhoto Member

member since: 3/14/2005
  Leisa,
The real question that needs to be answered is what film camera did you use this lens on? If it is an autofocus lens from a Canon EOS film camera, then yes, it will work on your Rebel XTi. If it is a manual focus lens from an older Canon film camera, like an AE-1, then no, it won't really work on your Rebel XTi. You could make it fit with an adapter, but it would only partially work and wouldn't really be worth the trouble.
Chris A. Vedros
www.cavphotos.com

6/18/2007 12:21:31 PM

  There are two factors to consider here: Is the lens is a Canon lens, and is it EF mount? Most EF mount lenses made by Canon will work on a Canon Digital SLR. I have seen a few of the older EF lenses give what is called an "Error 99" message on the 10D and 20D. This literally locks up the camera and the battery has to be removed to reset it. Usually for a nominal fee or sometimes free, Canon will update the chip on the lens to make it compatible. The Error 99 problem occurs more often with EF lenses from aftermarket manufacturers such as Sigma. It indicates an electronic incompatibility with the lens.
Bottom line: try the lens with your camera before you buy.

6/20/2007 7:20:06 AM

Ronna D. Conseen
BetterPhoto Member

member since: 10/16/2007
  I am looking at an XTI, but should I get a good "wedding" lense before I buy a camera and then get a camera to fit the lense or can I find a good "wedding" lens to fit the XTI afterward?

2/18/2008 10:10:21 AM

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Photography Question 
May Thao

member since: 4/7/2007
  6 .  Lenses for Indoor and Outdoor Photography
What types of lenses would I need for indoor/outdoor photography besides the one that comes with the camera? I'm looking at doing more portrait photography but would like to have the ability to also do outdoor.

4/14/2007 10:07:04 PM

Michael A. Bielat
BetterPhoto Member

member since: 2/23/2007
  Tip: Don't skimp out on a decent lens. They are well worth it actually and have a high $$$ in re-sale value.

Now for the answers:
1.) Indoor portraits: You would have to be prepared for low light conditions. A fast lens (by fast lens, I mean one with a wide aperture) like f/2.8 would be what the doctor ordered. You can use a low f-stop (f/2.8), and it would allow you to get a higher shutter speed without subject blur. (Well worth it, if for the all the headaches you will save when looking at them afterwards). That is natural light. If you have an external speedlight/flash, then use that as well but BOUNCE the light, no direct flash please! Look into and read up on "flash fill." Anything around 70mm would be good for portraits. You don't want a wide-angle or fish-eye obviously, because they have a tendency to widen the subject and that is not good for portraits!
2.) Outdoor portraits: Same as the above but most likely with more available light on average.
3.) If by outdoor you mean landscape photography, then those usually require you to have a nice wide-angle lens. Something around 15-20mm gets you a good wide-angle. If you're shooting digital on a camera without a full-frame sensor, then there is a 1.5 or 1.3x factor, so your 15mm would actually end up looking like about a 22mm lens if on a film camera, so keep that in mind...
With all that being said, look into a fast lens - i.e., f/2.8 aperture if you have the funds.
Then look into a zoom (more versatile) in the region of 17-70mm or 17-200mm to get the most out of it.
I have to warn you, don't be suprised at the fast lens's price. It will be around $900 if you are lucky.

4/14/2007 10:30:41 PM

Contessa D. Wolverton

member since: 11/29/2005
  I recommend the Canon 50mm 1.4 for indoor portraits. But this would depend on what camera your using. The prime lenses are great for indoor and outdoor portraits. HTH

4/17/2007 12:41:24 PM

Mike Rubin
BetterPhoto Member

member since: 10/15/2004
  Along with what Contessa said "As I recommend the Canon 50mm 1.4 for indoor portraits. But this would depend on what camera your using. The prime lenses are great for indoor and outdoor portraits."

If you are on a budget, you can get the 50mm f/1.8 for less than $70 It's another great lens.

4/17/2007 1:44:11 PM

May Thao

member since: 4/7/2007
  I have a Nikon D80.....so I guess I could look for lenses for it with that specification. I do appreciate the response:)

4/17/2007 7:29:28 PM

Mike Rubin
BetterPhoto Member

member since: 10/15/2004
  You can get a Tamron 17-50 f/2.8 for under $450. The image quality is equal to that form the camera brand lens. It is available in a Nikon mount. In the case of Canon I gave up having IS (didn't need it) and saved over $500.
If I was using it more indoors in very low light, the IS may have been worth having.

4/17/2007 8:02:25 PM

Simon  A. Stone

member since: 9/21/2005
  sigma makes an amazing 105mm 2.8 macro lens with true macro. it was fast enough to do a macro shot hand held indoors, at iso 400 perfect for portraits and excellent macro. it sells for $400.00

4/19/2007 6:45:26 AM

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Photography Question 
Eric  Schneider
BetterPhoto Member

member since: 3/21/2003
  7 .  Image Stabilization
I'm looking into getting a new digital camera. I want it to be able to capture action shots such as baseball, motocross, etc. I imagine that it should shoot a couple of frames a second. I'd like it to have picture stabilization capability within the body or the lens, but I'm not sure where the stabilization is best suited. Can you educate me a little on this? So far I think I like the Canon EOS Digital Rebel XTi, which retails around $899. the lens option they offer with stabilization is another 800 bucks. Should I look at something else?

4/13/2007 11:00:30 PM

Bob Fately

member since: 4/11/2001
  Eric,
Image stabilization really pertains to the mechanical system used to keep a picture sharp if the shutter speed is too slow for handheld use. That is, if you hold the camera without using a support like a tripod and the shutter speed is slow enough (exactly how slow depends on the lens's focal length)m then your own body movement will cause some blur - IS is designed to counter that effect.
But if the subject is moving, IS does nothing to help - if the shutter is not fast enough, then the subject will blur, even if the camera is on a tripod. This means that for sports shots you want to use a faster lens - that is, one that will allow in more light to enable you to use a faster shutter speed. This is why you see the pros at those sporting events using those enormous lenses - they are long focal lengths with large apertures - so-called "fast glass".
So, perhaps you should look into getting a prime lens rather than a zoom. One that is faster than a zoom would be to allow you to get the fastest possible shutter speeds in a given lighting situation. Make sense?

4/14/2007 9:54:05 AM

  Pentax and Sony has Image Stabilization built into the camera, whereas Nikon and Canon, you have to purchase the VR or IS lens. If money is your issue, the first two cameras' Image Stablization works with all lens attached to the camera.

4/14/2007 10:19:55 AM

Pete H
BetterPhoto Member

member since: 8/9/2005
  Eric,

Bob's advice is sound.
"IS" is great for hand holding in low light (static) image capture. It can be a make or break for that shot you want in these situations. For moving subjects it won't help you much.

"IS" you should know are NOT all created equal.
In camera "IS" is pretty much a joke as this is nothing more than old technology known at one time as "BSS (Best Shot Selector.)

A true "IS" system is Gyro stabilized against inertial guidance references in the lens itself.

Yep..it is more expensive, and well worth the extra money.

All the best,

Pete

4/14/2007 8:17:40 PM

Greg McCroskery
BetterPhoto Member
imagismphotos.com

member since: 2/27/2003
  Eric,
Image stabilization is not limited to 'in lens' technology. Several makers other than Canon and Nikon offer true 'in body' stabilization that is very effective. Olympus has a new model, the E-510, that offers true in body 'IS'. The obvious advantage to in body image stabilization is the ability to use standard lenses.
God Bless,
Greg

4/17/2007 4:51:54 AM

Pete H
BetterPhoto Member

member since: 8/9/2005
  Greg,

Angle speed sensors to "shift" the CCD is not the best way to accomplish IS or VR, whichever you prefer.
Tey work, but not as well as gyro compensated systems.


All the best,

Pete

4/17/2007 6:12:18 AM

Irene Troy
BetterPhoto Member

member since: 5/27/2004
  Returning to the initial question concerning IS and its use for taking fast pictures: I owned the Konica/Minolta 7D which did have IS built into the camera. I found it terrific for capturing subjects in low light or trying to use a long lens when a tripod was not possible. I now use a Canon 5D and have two IS lenses. No matter what system you ultimately select, I’ve found IS to be pretty useless when you are attempting to capture action. According to what I have read, IS was designed more to help photographers capture images in low light situations when a tripod was not practical. It is not designed to help capture action. I do a lot of wildlife photography and have found that capturing moving wildlife effectively means using a long lens and shooting at a higher shutter speed. In low light situations I use a higher ISO and play around with both shutter speed and aperture in an attempt to get as sharp an image as possible. Bottom line: if capturing action is your goal, get a fast lens.

Irene

4/17/2007 6:21:40 AM

Charles E. Wright

member since: 9/15/2006
  As for IS, I use the Pentax K100d. Its IS has saved me quit a few times. I mainly use my camera for nature photography (mainly macro). As for action shots, I havent used it alot for that and when I have, ive never shot with out IS to see if there was a major difference.

Its built into the camera, as Dennis stated. The Pentax was a very cost effective way for me to go, since I didnt have to worry about the extra cost associated with lenses that have it built in. And the picture quality is right up there with Cannon and Nikon as far as im concerned (which im sure others would doubt. lol) I would take alook at the Pentax+lens kits if price is a deciding factor.

4/17/2007 8:26:17 AM

Simon  A. Stone

member since: 9/21/2005
  i work at ritz camera, I tried both the pentax and the sony both have pretty good results. but the sony has terrible lens problems, I have seen 4 or five come back with jammed or broken lenses, because the mount is wacky. I know that at ritz we have the nikon 55-200 vr macro with 2-3 stop vibration reduction for $250 you can hand hold down to 1/6 sec. whereas with sony I could only get it to 1/20 or 1/10 if I was lucky. I hope that helps

4/19/2007 6:49:25 AM

Eric  Schneider
BetterPhoto Member

member since: 3/21/2003
  Thanks everyone for the information. It has been very helpful with my decision. Your time and consideration are much appreciated!!! Thanks!
Eric

4/21/2007 5:48:20 PM

Leisa Allen
BetterPhoto Member

member since: 2/7/2007
  Eric,

I just bought the XTi and love it! If you get it through BHPhoto it is $769. Also, they have some pretty good deals on IS lenses right now. Just to let you know, an IS lens is a must have with this camera as it is lighter than the 30D or 5D.

4/22/2007 7:07:09 PM

Mary Ann Roesler

member since: 1/1/2007
  Another twist on the IS lens...not all photographers are created equal...I have rhematoid arthritis and as much as I loved my light Canon G3 I found only 1 out of 10 photos were sharp enough to satisfy me. I purchased a Canon EOS 20D the new model is the 30D and 2 IS lens. Not only is it easier to hold but every photo is coming out sharp. I admit I haven't tried fast motion with it yet and assume the above comments to be true. I know there must be others with disabilities or just those "golden years" that love photography and find they can't hand hold or carry the heavy tripod. Good luck with your Canon XTi...That was my second choice. Mary Ann

4/27/2007 10:58:29 PM

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Photography Question 
Michael 
BetterPhoto Member

member since: 2/27/2007
  8 .  What Is APO
Hi! Can anyone explain what APO is in relation to lenses? Thanks!

4/4/2007 8:18:00 AM

Pete H
BetterPhoto Member

member since: 8/9/2005
  Michael,
APO is simply shorthand for "Apochromatic." Uncorrected lenses exhibit Chromatic and Spherical abberations - which is the inability to focus ALL colors to a specified distance behind the objective lens. APO is not the only way to correct for this, though it is certainly the preferred and generally more expensive design. Hope that helps!

4/4/2007 9:27:47 AM

Jon Close
BetterPhoto Member

member since: 5/18/2000
  APO is a term also commonly applied to telescopes. While the same types of corrections are made to camera lenses, not all makers use the term. Leica, Zeiss, Sigma and Minolta use the term "APO" in naming their lenses. Canon, Nikon, Tamron, and others also make lenses well-corrected for chromatic aberrations and technically apochromatic, but do not use the term "APO". Instead, they tout the special lens elements used to achieve this, especially fluorite crystal and low-dispersion glass. Even there the different companies use different terms for essentially the same thing. UD (ultralow dispersion) and SUD (super low dispersion) in Canon, ED (extra low dispersion) in Nikon, LD (low dispersion) and AD (anomalous dispersion) in Tamron, SD (super low dispersion) and HLD (high refractive low dispersion) in Tokina, SLD (special low dispersion) and ELD (extraordinary low dispersion) in Sigma, etc.

4/4/2007 11:18:18 AM

Michael 
BetterPhoto Member

member since: 2/27/2007
  yeah thanx that helps. I was wondering because there are so many diferent abbr. out there and since I am kinda new to this, I wasn't sure what they all meant. :D
BTW, I hadn't thought to look online. thanx Pete.
PS thanx for all that info Jon. it certainly helps. :D

Michael

Editor's Note: Here's more from Jon Close:

See http://www.sigma-photo.com/lenses/lenses.asp
http://www.thkphoto.com/products/tokina/tokina-02.html
http://www.usa.canon.com/html/eflenses/lens101/glossary/index_a.html#apochromat

4/5/2007 5:07:54 AM

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Photography Question 
Shobin George
BetterPhoto Member

member since: 10/27/2005
  9 .  Lens Choice: Zoom or Fixed?
I am a bit confused. I have two options to buy - 28mm fixed lens with 2.8 aperture and 28-80mm D zoom lens with 3.5 aperture. Which one should I buy? I am getting both at the same price. Which would be better option, regarding clarity etc.? Looking for a helpful advice...

3/4/2007 9:14:06 PM

Jon Close
BetterPhoto Member

member since: 5/18/2000
  It depends on the specific make/model lenses. Not always the case, but generally the fixed or prime lens will be marginally sharper with less barrel/pincushion distortion at the borders, and have faster maximum aperture (f/2.8 two-thirds of a stop faster than f/3.5). Its design will be optimized for its specific focal length, while a zoom lens involves compromises necessary to give a range of focal lengths. And because a good prime lens can be constructed with far fewer lens elements, they have better resistence to flare/ghosting effects.
That said, zoom lenses can be quite good. Depending on the specific lens, conditions and technique, images captured with a zoom lens may be indistinguishable from those taken with a prime unless one is "pixel peeping" at extremely high magnification or enlargement.

3/5/2007 5:36:24 AM

Shobin George
BetterPhoto Member

member since: 10/27/2005
  Thank you for your response...

3/5/2007 9:03:04 PM

  I could not add a single thing, and certainly not as well as Jon already has, but my thoughts are of his answer completely....stick with the prime lens.
- Russ Amidon

3/6/2007 6:41:30 AM

Christopher A. Walrath
BetterPhoto Member

member since: 4/25/2006
  I agree. I have a Minolta XG-M and an srT101 and I have about seven lenses. All are prime. No zooms. It makes it tricky guessing which lenses you might need when you have to pack light, but I have always liked pushing myself to make the composition fit into the image area mandated by a fixed focal length lens. Of course this is my personal preference. You could have two lenses cover the whole gambit. i. e. a 28-135mm zoom and a 100-400mm zoom would give you everything you needed in just a couple of pieces. As for image quality, zooms were lesser in image clarity and sometimes would not focus well to infinity, about 25 years ago. These are not issues with newer lenses. But bear this in mind the older the lens is which you decide to use.

3/17/2007 3:18:46 PM

Kevin Ekstrom
BetterPhoto Member

member since: 5/20/2005
  There are many exceptions to the so-called "PRIME RULE".

My Nikon FE2 has a 35-70mm f/3.3-4.5 it's a shorter version of the earlier 35-70's.

This lens is TACK SHARP! Even in the macro mode at 70mm setting with 1:4.4 magnification. This lens retains it sharp image quality at all its focal lenghts.

6/28/2007 12:37:57 AM

Pete H
BetterPhoto Member

member since: 8/9/2005
  Shobin,

The advice given so far is good.
Primes are indeed sharper than multi-element designs.

It appears you are shooting digital.
Something we often forget about is that little problem known as sensor dust. Yeesh!
Changing leneses often will almost always lead to dust on the sensor; what follows is that fun job of cleaning the sensor. LOL

I personally grew so tired of cleaning my sensor, that I finally purchased a 18-200mm VR lens.

I am not all that concerned about the slow speed of this lens (3.5) since bumping up the ISO is easy with a digital...besides, 2.8 to 3.5 is really NOT that much.

With that said, I also have a 50mm prime @ 1.8. I absolutely find this lens amazing in color, contrast, sharpness and speed, and WILL use it when the situation calls for it.

It is a trade off of convenience Vs marginal quality.

Now; for the pro sports shooter, the situation is of course quite different, where 600mm primes are common, though few amateurs have the bank account to own these. (LOL) Watch any pro NFL game and you'll see these people on the sidelines, rarely with multiple lenses, but with multiple cameras!; nearly all fitted with primes.

AS for distortion in any large excursion zoom, don't sweat it; you can usually eliminate it with some savvy photoshop work.

Take it easy Shobin, you are suffering from what many do..It's called "lens envy"..There is no cure other than a fat bank account.


Pete

6/28/2007 3:02:32 AM

Shobin George
BetterPhoto Member

member since: 10/27/2005
  Thank you Pete, I have purchased 28-2.8 It is very sharp. I also have 28-200. So I went for 28-2.8. Thank you

6/28/2007 5:07:13 AM

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Photography Question 
Giordano Carlini
BetterPhoto Member

member since: 9/13/2006
  10 .  Lenses for Digital and Film Cameras
Hi,
I just entered the world of digital photography and I'd like to buy a 28mm lens (compared to film cameras) for my Nikon D70s. I know that if I want to buy a lens "for film cameras", I have to look for a 19mm lens (19*1.5=28.5), but what about lenses "for digital cameras"? Do I have to look for a 19mm even if it's "for digital cameras"? Or is a 28mm lens for a digital camera the same as a 28mm for a film camera? Thanks!

2/13/2007 7:50:04 AM

Jon Close
BetterPhoto Member

member since: 5/18/2000
  Focal length is a property of the lens design and does not change if mounted to a 35mm film camera or a smaller-sensored digital. To get the same angle of view that 28mm gives on the 35mm film camera, you need 19mm on the D70s - whether it be a "film" lens like the 18-35 f/3.5-4.5D AF, or a "digital" lens like the 18-70 f/3.5-4.5G AF-S DX.

2/13/2007 8:24:54 AM

Giordano Carlini
BetterPhoto Member

member since: 9/13/2006
  Thanks a lot Jon!

Giordano

2/13/2007 9:01:30 AM

Alan N. Marcus

member since: 3/4/2006
  Hi Giordano,

Welcome to the world of digital photography.

Most photographers gained their knowledge from books, teaches and self learning based on the 35mm camera. This is true because over the years the 35mm format become the defacto standard.

Most digitals will have an image sensor chip that is about 66% smaller. The size difference makes it a little difficult to make comparisons. Say we admire the performance of a 28mm wide angle as used on our 35mm. Now to duplicate this performance on our smaller digital, we must mount a lens that is about 66% shorter. So 28 x .66 = 18.4. Round this value up or down as you like, either 18mm or 19mm will about duplicate the performance of the 28mm on a 35mm camera.

We can do this backwards: We like the 19mm on our digital. What focal length to mount on our 35mm to duplicate this performance?

19 x 1.5 = 28.5mm

hint: multiplying by 1.5 is about the same as dividing by 66% (more popular because multiplication is easier than division).


Alan Marcus
ammarcus@earthlink.net

2/13/2007 9:19:59 AM

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