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10-08-2017, 02:39 PM   #1
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Focus on 645Z with 80-160 zoom

I have an 80 to 160 zoom for my 645Z, and I thought I'd use it for a couple of moon shots. Not the ideal length, I know, but when I tried it at infinity, I found that it was just that last bit out of focus. Not super close to in focus, but close enough to see that it wasn't really spot on. This lens seems to perform properly for everything else, and I'm a bit puzzled as to why it failed here. The moon was low in the sky, so more atmosphere to look through, but it just seemed more off than I had expected.

I haven't yet had a chance to try it with the moon at a higher point in the sky, so there's still that to try.

Thanks for any help or suggestions.


10-08-2017, 04:15 PM   #2
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Infinity on the lens doesn't correspond with true infinity. You'll have to do a bit of trial and error; focusing with the help of live view magnification can come in really handy for that.

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10-08-2017, 11:59 PM   #3
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many of us, myself included, don't really trust our copies between 130 and 160 mm for much of anything stellar. just sort of mushy. great at 80 to 120 mm !

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