Page 1 of 1

One shot at f32 or 4 shots at f8:?

Posted: 21.02.2005 01:51
by Borberg
It is tempting to shoot a macro picture in a single shot if the depth of field at f32 is large enough. But what will the result be?
After much experimenting with my Canon 1Ds and 100mm macro and 65 mm mpelenses I found that I achieve far superior results shooting 4 slices at f8 than 2 at f16 or 1 at f32 (the Canon lens does not go beyond f16, for good reasons!).

There is something which the Germans call "Brauchbare" or usable apertures which are calculated as follows:
Divide 50 by the magnification factor M + 1.
For 5x magnification the number is 50:6 = 8

For 1:1 magnification the result is f22, but my own tests with the Canon 100 Macro lens indicate that while the picture is "brauchbar" this term in German is not very complementary and means basically on the border of the usable. If you want a superior picture stick with f8 to avoid diffraction and shoot multiple slices.
Helicon Focus will takes less than 1 minute to combine 4 of them into a composite. Its well worth the time!

Posted: 08.03.2008 00:07
by Adrian
I would say that in most cases - it is not worth shooting at minimal apertures where diffraction is apparent.

Espeically with shooting in macro - you may save time making a photograph at f/32 but you are actually removing the whole potential of using the macro lens, the details are rendered much less aparent and if not visable.

oh and then again, all the defects such at sensor dust etc becomes apparent at these apertures where diffraction sets in.

focus stacking allows you to preserve the details by using apertures away from diffraction, perserving the actual potential of the macro lens while maximising depth of feild.

priceless.

F8 to F10 max for me - plus good link

Posted: 08.09.2008 08:09
by BrianS
Hi, Agree with both posts.

After much testing, (and the availability of tools like Helicon) I've found f8-f10 the sweet spot for my Canon 100-2.8 macro.

By f16 any gains in DOF are offset by diffraction.

This link has an excellent tutorial, and an interactive caclulator
http://www.cambridgeincolour.com/tutor ... graphy.htm

Brian