Discussion in 'Open Discussion' started by Dave in Wales, Mar 5, 2013.
Features - Is your camera diffraction limited? If so, why? - Digital Photography Now
I thought when diffraction starts kicking in is also dependant on lens itself, as well. For example some zoom lens models are sharpest at certain focal lengths, when wide open and start losing resolution as soon as you start stopping down.
e.g. my former sigma 18-200 II @18mm was sharpest when wide open (3.5)
Source; Sigma 18-200mm f/3.5-6.3 II DC OS HSM Review
canon 15-85mm @15mm is sharpest when wide open
source; DxOMark - Canon EF-S 15-85mm f/3.5-5.6 IS USM
For those here, who would like to investigate this topic a little further :
Diffraction-limited system - Wikipedia, the free encyclopedia
Don't worry about it too much!
LensRentals.com - Overcoming My f / Entekaphobia
LINK WAR! lol
I have no problem using small apertures, I use f/16-f/22 all the time, and I've had prints made up to 20x24 and its fine, is it a bit less sharp, yup is it so unsharp that its useless no. I would rather trade a bit of sharpness for getting the shot I want.
Oh no. not this again. Diffraction rarely matters imo. in real world experience the shutter will lose more sharpness than the diffraction. I'm not talking about taking pictures of graphs or brick walls which I bet are linked... Shoot f22 or f256 if you need it.
I also think diffraction isn't such a big issue.
With m4/3 an aperture of f6.8 usually gives as much dof as is required for most shots, it's very rare for me anyway to use an aperture greater then that. If you are shooting full frame then yes you may need to use f11 - 16 to get the dof required but not with m4/3.
I think that Roger from LensRentals gives some food for thought. Basically what he writes is that while diffraction hits at some point, carefull post processing can overcome most losses.
At some point in the near future, I think I am going to try a few things for myself. Observing diffraction at 100% on screen view of unprocessed images might indeed differ from well sharpened large prints...
I've always wondered how this affects Macro shots ?
To get full detail across the frame people tend to favour smaller apertures.
As has been many times decried by the nay sayers about micro four thirds: the "equivalent" depth of field for any aperture is 4 times deeper than that aperture at the "equivalent" full frame focal length. It is 2 times deeper than the DOF for the same aperture at the "equivalent" APS-C focal length.
I've shot full frame (film) and APS-C and for the most part I find I don't need to stop down as much on mft when I need more DOF in a shot.
So, that might constitute and advantage at times for mft. If you shot APS-C and normally stopped down to f/16 for a shot, you only need f/11 for mft cameras. If you shot full frame and needed f/16, you should only need f/8 in mft cameras.
Some good talk from Pekka Potka on diffraction limiting: pekkapotka - Journal - Being Diffraction Limited
Not sure what you mean by 4 times or two times, but I like to keep it in my head as full stops. So, shooting f/2 on my 17mm on m43 would be similar in DOF to 26mm 2.8 on APS-C and 35mm 4.0 on FF.
1 stop = doubling DOF
2 stops = quadrupling DOF
I figured it was something like that, but I have a much better feel for stops than for the actual measurements. Some others might too, so I thought I'd just introduce the language -- just in case.
lol! I think in terms of distance so I guess that's why I expressed it that way. Whatever works to give one "rules of thumb" to operate by is good!
How about the venerable old pinhole lens? Around F/64 to F/128 or so depending on some of the estimates I've seen and when you use one of them diffraction is your best friend. If there were no diffraction there would simply be no image.
Seriously, the lens/camera is not the problem. The problem is photographers who stop the lens down further than necessary to get the result they want. Note that I said "further than necessary to get the result they want" because sometimes you're happy to trade sharpness for a bit more depth of field. All choices are compromises, including choice of aperture. It's only the wrong choice if it works against what you're trying to achieve, and it is most definitely the right choice if it works towards what you're trying to achieve. People make choices, not the equipment. It's a user problem, not a gear problem.
This sums it up perfectly.
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