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06/15/2005 07:34:33 AM · #1 |
how? turn the focus ring to infinity? tried it today, don't think it works.
Focus will be out if i turn the zoom ring (17-40) even tho the focus is at infinity.
Any tips from the IR gurus here? other than taking the IR filter on and off to focus.
8sec, f5.6, iso 400
pic done with 300D, 300mm f4
edit: me and my poor grammar
Message edited by author 2005-06-15 07:51:20.
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06/15/2005 07:44:34 AM · #2 |
| Didn't I read somewhere that you need to focus differently for IR? If memory serves me correctly, lenses used to focus past infinity with an IR marking, so you would know where to focus for IR. |
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06/15/2005 07:56:01 AM · #3 |
when i shoot IR i try for f16-f22 to get max DOF and shift focus a bit
short within the DOF range on the lens
some lenses have a red/white dot infinity. side of the standard focus which denotes IR focus point - but these are rarely found on zooms
oh & have never been able to get a good IR image off my 300mm f4
DOF is just tooooo short even at f32
Message edited by author 2005-06-15 08:03:03. |
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06/15/2005 09:05:46 AM · #4 |
Another way is to focus w/out the IR filter, switch to manual focus so it won't change, then attache the IR filter and take the photo.
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06/15/2005 10:50:34 AM · #5 |
Originally posted by FranziskaLang:
Another way is to focus w/out the IR filter, switch to manual focus so it won't change, then attache the IR filter and take the photo. |
Yes but focus changes when shooting IR. What's in focus in visual is not necessarily in IR, depending on the lens. Many lenses have a special IR marking on the focus scale - easiest thing to do with those is simply pre-focus, then adjust so the number you were focused at corresponds to the IR marking, then put your filter on.
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