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09-12-2007, 11:25 AM   #1
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MF zoon lenses and IS

So when you use a manual focus lens you have to input the focal length into the camera by hand for the IS system to function correctly. What value should you use for a zoom lens......for really critical shots i guess you could change it after you know about what FL you'll be using, but other wise.....middle of the zoom range I'm guessing, or maybe the low end so that you have correcting and undercorecting but no over correcting?

09-12-2007, 12:21 PM   #2
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There's been a bit of discussion on this one. I could be wrong but I think the consensus is to input the widest FL, as being the safest course.
09-12-2007, 08:18 PM   #3
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Any chance you remember some keywords I can use to find those old threads?
09-12-2007, 08:46 PM   #4
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Hi rdc,

If you zoom frequetly with a manual focus lens, the best thing to do would be to input the low end of the focal length into the camera, since setting an overliy high value may make the SR oversensitive, thus actually blurring your photo instead of improving it!

I ran a quick search and found a thread that you might be interested in:

For more threads, search for "Shake reduction manual lenses". The forum search engine disregards common conjunctions such as "and," so you don't need to include those.

I hope this helps!

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09-12-2007, 09:38 PM   #5
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Yeah I found that thread too, but coulden't find any others.

The lowest setting does make some sense to me, but I was hoping for a more conclusive answer.....perhaps I'll have to do some testing, although getting a consistant amount of shake might be tricky.

I wonder what the frequency of camera shake is......pretty low.

A vibrator held against a tripod might work, but I don't have one handy.
09-13-2007, 05:25 AM   #6
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Not to disagree with everyone who has suggested using the lowest focal length setting, BUT, I believe the general recommendation is to do the following.

If you are just walking around taking random snaps, at all focal lengths, the camera should be set to the middle of the range, such that on average, the error in the setting is minimized. If you know what focal length you are shooting, and usually on zooms this is one of the two extremes, (min or max focal length) set it accordingly.

Setting for the minimum focal length does not necessairly give you the best images, and note that the old rule of thumb, shutter speed = 1/focal length, means that shortest focal lengths will generally need less stabalization than longer ones, You are using IS generally because you have a long lens and not enough light, but are photographing a stationary object.

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