How about diffraction on full frame? Is it any better than on DX? Would f22 or even f32 give good results?
#1. "RE: diffraction and full frame" | In response to Reply # 0PaulBennett Registered since 09th May 2008Fri 03-Oct-08 08:34 AM
DX vs FX is relevant on border or off-center issues but diffraction (distortion due to light bending around a sharp edge-the iris) will be the same, center image, regardless of format.
Diffraction is always present on any lens with an iris, but the distortion is extremely small, getting masked by the much greater amount of light present at f16 or larger stops.
If your conjecture is focused at off center diffraction distortion, that a larger exit angle might affect distortion due to diffraction, there would be a marked difference between tele and wide angle lenses which have several orders of magnitude difference in exit angle than the slight difference between DX and FX formats.
Or am I not understanding your premise?
#2. "RE: diffraction and full frame" | In response to Reply # 0briantilley Nikonian since 26th Jan 2003Fri 03-Oct-08 08:57 AM
This topic was discussed (including some good references) in this thread from 6 weeks ago.
I don't pretend to understand all the technical and optical minutiae of the Airy Disk and so forth, but if I interpret things correctly, the D700 has about 1 stop more "headroom" in terms of diffraction effects than the D300; if you could use f/11 on a D300, f/16 would be usable on a D700.
HOWEVER, this is not really because the sensor is physically larger, it is because the pixel diameter is greater. A 28 MP FX sensor and a 12 MP DX sensor would have similar diffraction effects.
Waiting to be corrected by the experts...
#4. "RE: diffraction and full frame" | In response to Reply # 2st_m Registered since 11th Oct 2006Fri 03-Oct-08 11:15 AM | edited Fri 03-Oct-08 11:15 AM by st_m
"HOWEVER, this is not really because the sensor is physically larger, it is because the pixel diameter is greater."
Yes, exactly. The effect of diffraction is the same on any camera, because it does take place in the lans, not on the sensor.
But a sensor with larger pixels won't record its blurring as precise as a sensor with smaller pixels.
Now when you compare two sensors with same pixel number but different sensor size (D700 and D300), the D700 is "better" in that regard, because it uses more of the information (full frame) the lens produces, but only gets the same effect of diffraction.
"optical minutiae of the Airy Disk"
If you image a light point, e.g. a suitable laser, with a lens, the image of that point cannot be a point, but is spread out into a tiny area. That is the effect of diffraction and unavoidable.
If one plots a curve of the light intensity as a function of the distance from the center of this image, this is almost a Gaussian curve, and may be described as such for most apllications. But a thorough evaluation shows, that it actually is an Airy function, with many maxima and minima further away from its bright centre.
#8. "RE: diffraction and full frame" | In response to Reply # 0
There is a lot of garbage repeated about diffraction.
As a rule of thumb the optimum optical aperture is one stop smaller on FX than on DX, but as regards depth of field for the same viewfinder crop DX has one stop more dof than FX.
Whilst it is true diffraction influences optical quality smaller than the optimum aperture other lens aberrations influence optical quality wider than optimum aperture.
What gets ignored in most debates is if f11 is the ideal aperture for a lens/body/focus distance combination then either f8 or f16 similar quality (just about indistinguishable off any optical test bench) give , as does f5.6 or f22.
f5.6 and f22 generally need enlarging to A3 or greater to start to see minor differences - and often dof is a far more important consideration.
If you are happy to shoot at f5.6 or f8 there is absolutely no scientific reason not to shoot at f16 or f22 - other than dof and shutter speed considerations.
Sorry to "sink a myth" but my F100 and D3 at f22 do not show the "diffraction horrors" that are suggested in pixel size/diffraction discussions.
If I need f22 I use it - if I need f2 I use it - and get sharp results with either
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.
#9. "RE: diffraction and full frame" | In response to Reply # 8IntegrityPhotos Registered since 26th Apr 2006Sat 04-Oct-08 10:59 PM
"If I need f22 I use it - if I need f2 I use it - and get sharp results with either".
In essence, I agree with Len on this. Although it's beneficial to keep in mind the theoretical diffraction limits of your DSLR's sensor, from a practical standpoint, it's often both necessary and desirable to exceed these limits. An example is in macro photography, where it's often necessary to use f22 or smaller to obtain the desired DOF of the image. Even though there may be some minimal effect of diffraction, the desired result would not be available without using the much smaller apertures.
"If everyone possesses some measure of this intangible quality called creativity, photography is unprecedented as an outlet for its expression." - Ansel Adams