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Old Feb 4, 2005, 10:21 AM   #11
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So just to go back to the original question.

Richie answered this question. Yes, you should include the 'crop factor'. But this is just a guideline and will vary from person to person.

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Old Feb 4, 2005, 11:20 AM   #12
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That ROT (rule of thumb) is just a suggestion of a speed that might produce acceptable images if your handholding technique is very good.Under enlargementsyou will still be able to see the difference in sharpness between a tripod mounted shot and a handheld shot.

Some people are able to handhold longglass and get good shots with shutter speeds much slower than the suggested ROT. Just like some people are very good and steady with a rifle, and some can't hit a barn close up with a chain-gun. What you can manage has a lot to do with your technique, stance, breath control,and how much you practice it.

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Old Feb 4, 2005, 2:11 PM   #13
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Yes, that is exactly what I'm saying. The feather detail on a bird is usually very fine. Capturing that usually requires more shutter speed than you might think. Also, the brain fills in details in things is knows well, like the human face. Does it matter that every eyelash is tack sharp? No. There are several factors that contribue to sharpness. Quality lenses, proper fstop, and good camera.

We'll rule out a lower quality camera as there is little that can be done in that situation.

Lenses almost always work better when stopped down a bit. So if you have an f2.8 lens, the majority of f2.8 lenses work better at f4 or even f5.6. Usually (some where around or above f8 ) they start getting worse again. So for sharpness reasons if you can stop down a bit you should. Just don't go too far (and loss of shutter speed usually prevents stopping down too far any ways.)

But if you don't use a fast enough shutter speed it doesn't matter what fstop or how good a lens you use. You will get a blury picture (ok, unless you are on a tripod. I've gotten shocking good photos with proper technique at 1/8th of a second @ 600mm. But I had the time to do it right and I took many pictures.)

So you should try for a good shutter speed (1/1000 or even a bit higher for stationary birds) at a reasonable fstop. Don't forget that you get a larger depth of field the more fstop you use. So if I had the choice between 1/1000 f5.6 or 1/2000 f4. I would probably take 1/1000 (as I know I can get good shots at that shutter speed and having more DOF to get more of the bird in focus is desirable.) Now if I was at 100ISO, I might go to 200ISO and just increase the fstop. The shutter speed would stay the same.

I feel that after a certain point more shutter is wasted and you should consider using a lower ISO or larger aperture.

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Old Feb 6, 2005, 5:50 PM   #14
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Richie Hatch wrote:
Quick Answer..... Multiply by 1.6 so a 50mmm should be shot at 1/80th.

I understand that we are just talking about a general rule to help here, and that only the user will be able to determine what is right for them, however what is the rationale for multiplying the focul length by 1.6X on a reduced frame body to get your ROT?

Optically the lens performs the same on either the reduced frame body, or a 35mm. It is only that part of the image circle is cropped out on the reduced frame bodies. With a given telephoto lens, a small shake of say1 degree off the subject, will have the same effect in terms of movement on the subject regardless of which body you use.
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Old Feb 8, 2005, 10:08 PM   #15
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I think tim is correct here, and thanks for all the imput on pic:!:
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