diffraction effects on a full frame sensor
I am used to avoiding exposures beyond f11 if i want maximum sharpness on DX format because of diffraction, it seems to me that the d700 is slightly better in this respect. I can shoot at f16 without problems...can you guys confirm this and explain why?
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#1. "RE: diffraction effects on a full frame sensor" | In response to Reply # 0hades Registered since 14th Oct 2007Wed 20-Aug-08 08:10 PM
Yes, you are right about that. The photo site is larger, that's why. If you want a perfect explanation, please check this article:
#3. "RE: diffraction effects on a full frame sensor" | In response to Reply # 1bclaff Registered since 25th Oct 2004Fri 22-Aug-08 10:42 AM
The Luminous Landscape article is quite thorough.
It rationalizes why testing should be performed with a Circle Of Confusion (COC) equal to the photosite size.
But they also "admit" that for practical purposes the COC required by the end result is the more important factor.
In My Opinion (IMO) we make too much of the theoretical limitations of diffraction. Unless you are cropping heavily or making very large prints to be viewed closely, diffraction is rarely a practical problem.
Photosites are effectively "pixel binned" by the visual acuity of the human eye.
Whether the underlying photosite is large or small the acuity of the eye covers the same area, so long as the COC is comfortably larger than the photosite size, photosite size doesn't really matter.
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#2. "RE: diffraction effects on a full frame sensor" | In response to Reply # 0
>... it seems to me
>that the d700 is slightly better in this respect.
It is not a fact that FX is "better" than "DX" in this respect. "Better" is a value judgement that doesn't have a simple answer. Its true that with FX diffraction doesn't begin to become evident until you stop down an additional stop, compared to DX, it is not true that that is always an advantage since you need to stop down that extra stop to recover the same depth of field that a lens with a comparable field of view would have on DX. As a result, if you ignor the number of the f/stop and compare apertures yielding matching DOF, you will find that diffraction begins to becomes significant at essentially the same DOF setting.
>I can shoot
>at f16 without problems...can you guys confirm this and
Diffraction is not a factor of the f/stop. It is a factor of the physical size and shape of the aperature opening. What f/stop is associated with a particular aperture size is a factor of the focal length of the lens. Shorter FL lenses show diffraction effects at wider apertures than longer lenses. For any one FOV, an FX body uses a longer focal length lens so for that FOV diffraction begins to show only at smaller f/stops.
Additionally, the fact that for any fixed megapixel size, an FX sensor has larger photosites than a DX sensor. This can lead to the FX sensor not recording some of the more subtle diffraction effects that the higher resolution (measured in photosites per mm) DX sensor can see.
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#5. "RE: I have to disagree" | In response to Reply # 4Len Shepherd Nikonian since 09th Mar 2003Fri 22-Aug-08 06:16 PM | edited Fri 22-Aug-08 06:18 PM by Len Shepherd
>From tests of my lenses you start to see diffraction at f/11 and by f/16 it has a noticeable effect.
For normal reproduction (as say in full page pictures of butterfly detail) there are few images sold using wider than f22 - including the odd one I have sold
Assuming theoretical (i.e. only detectable on an optical test bench using a low power microscope) optimum sharpness at f11 the difference between f8/11 and f11/16 is usually undetectable, and if it is an f5.6 lens the difference between f5.6/11 is usually greater than between f11/22.
Digressing the actual physical size of an aperture is not always the same physical size of the mathematical formula if a lenses is strongly retro focus or strongly telephoto. This means the sharpness aperture can vary by about 1 stop between lenses of different focal lengths.
To add to the complications in general wide angles reduce effusive aperture and telephotos increase effective aperture in close up photography. The sharpest aperture(in the sense of resolution)) also varies in this respect.
Assuming f11 or f16 is optimum aperture for a range of lenses or focus magnification is often unwise.
Photography is a bit like archery. A technically better camera, lens or arrow may not hit the target as often as it could if the photographer or archer does not practice enough.