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10-31-2019, 09:23 AM   #1
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Focus issues with sigma lens

I have a sigma 70-200mm f2.8 EX APO and when I use the focus adjustment system I got lots of front focus. I adjusted it down as far as It will go on the fine adjustments but it seams to still front focus. I thought I was fallowing the instructions pretty well. I had the aperture set to 2.8 the zoom to 200. I'm pretty sure I was about 1.8m away from the card when focusing. Will the distance mater that much or is it common to have this problem? Thank you.
Stache

10-31-2019, 09:54 AM   #2
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QuoteOriginally posted by Stache Quote
I have a sigma 70-200mm f2.8 EX APO and when I use the focus adjustment system I got lots of front focus. I adjusted it down as far as It will go on the fine adjustments but it seams to still front focus. I thought I was fallowing the instructions pretty well. I had the aperture set to 2.8 the zoom to 200. I'm pretty sure I was about 1.8m away from the card when focusing. Will the distance mater that much or is it common to have this problem? Thank you.
Stache
Not sure if I understood your question. Yes, the distance matters. I tend to believe you are familiar with DOF as a term. This parameter is very narrow for large apertures (1.4, 2, 2.8), so if you missed with the distance, you are in trouble. You have to be exact and precise with the distance (that is what rulers are for).
10-31-2019, 09:58 AM   #3
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QuoteOriginally posted by Vasyl Quote
Not sure if I understood your question. Yes, the distance matters. I tend to believe you are familiar with DOF as a term. This parameter is very narrow for large apertures (1.4, 2, 2.8), so if you missed with the distance, you are in trouble. You have to be exact and precise with the distance (that is what rulers are for).
I'll have to double check my distance. Thought I was right on. I'll see what happens. Thanks
10-31-2019, 05:55 PM - 1 Like   #4
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