# x100 What am I doing wrong?

Started Feb 10, 2013 | Discussions thread
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 Re: x100 What am I doing wrong? In reply to zenpmd, Feb 11, 2013

No stupid questions, zen, only stupid answers ( . . . . I HOPE this isn't one of 'em!).

'Infinity' focus (and hopefully, those of you who are far more astute technically will chime in) is, for example, what the camera would focus the lens at (or you on a manual focus rig) to shoot landscapes, the sky, in other words where the lens is mechanically at its furthest focus.  What I was speaking of above is as you (or the camera IQ) stops down the lens (f2, 2.8, 4, 5.6, etc.) the range of things distance-wise approaching you from that infinity setting increases.

Consulting one of my old books, that calculator says (35mm equivlalent lens like the X100) that a f11, everything from 8-9 feet out to infinity is in focus.  In other words, everything from 8 or 9 feet out to the horizon (outdoors) is in focus.   As we said,  this decreases as we open the lens up:  At f2, everything from about 50 feet out is in focus.  We needed these tables much more in the film days:  No we can check focus via the LCD to see if everything needed is 'in'.  And of course, how much depth of field varies by the situatiion, the type of photo, what impression you're trying to make.  Focus (or the lack of it) is one more tool in the toolbox.

You can consult the depth of field calculator apps quoted above, or the next time you're around a manual focus lens, look down at the focus ring:  You'll see a indicator mark showing what you've selected and on lots of them you'll see that mark straddled on either side by f-stop numbers.  Those will line up with the distance numbers on the focus ring.  You read it as everything between, say, the f11 pair is in focus.  Or you could line up the infinity mark (looks like an '8' laying on its side) on one of them, and this means everything from the other f11 mark to infinity is in focus.  Some autofocus interchangeable lenses are marked this way (in either case, usually primes, not zooms), but not all.

All the Best,
JW

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