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10-21-2008, 07:09 PM   #16
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Why would you ever want to focus past infinity?



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Neil

10-22-2008, 06:44 AM   #17
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QuoteOriginally posted by nulla Quote
Why would you ever want to focus past infinity?



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Neil
You're right, probably for focussing on beings from an alternate dimension. Silly me.

But seriously, yeah, sounds like this is just part of the manufacturing process and a way to make the lenses cheaper to make...
so, does the 16-50 go past infinity?
10-22-2008, 08:52 AM   #18
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Pentax added focus range limiters to large supertelephotos too--to minimize "searching" due to the long "throw" of the focus system.

Regarding focusing past the infinity mark--according to the Pentax Operating Manuals for several FA* telephoto lenses (80-200, 300/2.8, 600/4, 250-600/5.6)
"The distance scale on the lens stops slightly past the infinity mark. This allows the lens to focus on a point past the infinity scale in the case where a temperature change causes the focusing point to shift."
10-22-2008, 02:02 PM   #19
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QuoteOriginally posted by Miserere Quote
My question would be...why focus at infinity at all? You're throwing away half of your DoF by doing so. Hyperfocal is the way forward.
I think focusing at infinity can be very useful to obtain the maximal sharpness of objects located at infinity... like stars and the moon. When I take this type of pictures, a very precise focus is needed and I feel the hyperfocal rule would not give optimal results.

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