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Old Oct 26, 2010, 5:10 AM   #11
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Originally Posted by algold View Post
Track, you can always use dof calculator to check how much dof you get with your particular settings: focal length, aperture and distance to your subject. Then just take a few test shots and decide for yourself when the loss of sharpness due to diffraction is more than the gain of more dof with smaller apertures. If you don't have enough dof, use focus stacking or artistic selective focus - whatever works better for you.
Here is the link to the dof calculator:
http://www.dofmaster.com/dofjs.html

On a side note, Canon's kit zoom is a nice and compact lens, but it's nowhere near a true macro lens. It's great for close-up photography, but 28cm minimum focus distance is just not enough to fill the frame with your subject. It is possible to use it with extension tubes or a close-up lens, or you can reverse it, but that's another story.
regards,
Alex
Well, I have not heard of the diffraction before, so I will test it out.

I tried using the calculator, but at anything below two inches, it displays a negative depth of field (-0.01).

And yes, I'm shooting at under an inch away at 55mm because of close-up lenses (a set of three, as I wrote before). They work wonderfully.
I dare say I have no reason to get a true macro lens for casual work.
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Old Oct 26, 2010, 3:28 PM   #12
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Originally Posted by Track View Post
... and there were defects with the stacked result.
...
You didn't say what the defects were.

One possible problem with focus stacking is that the magnification can change with the focus: it will change if you are using bellows and might change with other methods of close focus.
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Old Oct 26, 2010, 4:00 PM   #13
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Originally Posted by Track View Post
Where as, at f/32, it was truly amazing to be able to zoom in to every part of it and see it in focus.

That's what I gather so far.
Actually they were equally fuzy. I'll caveat that a bit, it is possible that with 3 close-up lenses on a zoom lens there may have been enough uncorrected aberrations that were masked by f/32 to make diffraction moot.

A. C.
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Old Oct 26, 2010, 4:07 PM   #14
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You didn't say what the defects were.

One possible problem with focus stacking is that the magnification can change with the focus: it will change if you are using bellows and might change with other methods of close focus.
The folks that are really into focus stacking are typically using a moving stage for either the camera or the subject or both.

A. C.
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