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01/12/2005 09:42:10 AM · #1 |
Hi
On EOS lenses with focus scale you can focus past infinity. In the manuals is say something like "allows you to focus past infinity for better focus in some climate" and really not helpful.
So, my Q is: [bWhen and why do you use this[/b]. Hot & Humid or Cold & Dry or whatever.
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01/12/2005 09:45:23 AM · #2 |
With extremes of temperatures the lens barrel expands or contracts, the air inside expands or contracts, introducing small variations as to what infinity is. So that little leeway helps overcome that.
Message edited by author 2005-01-12 09:45:45.
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01/12/2005 09:46:09 AM · #3 |
I believe in high temps it expands making it not past infinity but correct focus.
Tim |
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01/12/2005 10:14:16 AM · #4 |
| Doesn't IR photography require you to focus beyond infinity? |
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01/12/2005 11:42:20 AM · #5 |
my manual focus and zoom lenses from the A-1 had a separate line for IR images if I am not mistaken....
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