Was having a trawl through photomacrography articles on the web and found this:-
http://www.modernmicroscopy.com/main.as ... =65&page=1
DaveW
Applying an Abbe Criterion to Photomacrography
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DaveW,
That article by Ted Clarke is an excellent reference.
I found it very helpful in an extended discussion in the old forum last December, regarding the effect of sensor size on DOF and achievable resolution in a single exposure (no stacking).
That's an interesting topic that we've not revisited in detail for a while, although I allude to it from time to time.
The bottom line is that smaller sensors require smaller f-number settings (wider aperture relative to the focal length -- the absolute diameter of the aperture turns out to be constant).
A useful summary (from this posting fairly late in the thread) is that
That article by Ted Clarke is an excellent reference.
I found it very helpful in an extended discussion in the old forum last December, regarding the effect of sensor size on DOF and achievable resolution in a single exposure (no stacking).
That's an interesting topic that we've not revisited in detail for a while, although I allude to it from time to time.
The bottom line is that smaller sensors require smaller f-number settings (wider aperture relative to the focal length -- the absolute diameter of the aperture turns out to be constant).
A useful summary (from this posting fairly late in the thread) is that
The key point with respect to Clarke's article was that...small and large sensors have no differences in DOF at the same resolution, if and only if you can set corresponding f-numbers. (Noise differences are still important; see earlier posts.)
Sensor size becomes an issue for DOF when conditions require f-numbers that are achievable for the larger sensor but not for the smaller sensor. This is primarily an issue when attempting to get narrow DOF for artistic purposes. For example, it is feasible to shoot at f/2 on a 22.2mm sensor, but it is not feasible to shoot at the corresponding f/0.5 on a 5.55mm sensor because no such lens would be available. In macro work, a similar although less extreme problem may occur at moderately high magnifications.
--Rik4. Because of diffraction, there is a maximum overall DOF that depends only on M_tot (total magnification) and your tolerance for fuzziness. That maximum DOF does not depend on sensor size, but the f-number needed to achieve it does, following the scaling rules listed above.
5. One recommended value for nominal f-number at maximum DOF in a sharp print is 220/(M_tot+M_enl). (See http://www.modernmicroscopy.com/main.asp?article=65 )