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Old Jun 23, 2005, 9:07 AM   #11
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There is an old 'rule of thumb' from the 35mm film world that says: "You can handhold a shot if your shutter speed is at least the reciprocal of your focal length".That would mean that you can (probably) handhold a 135mm lens if your shutter speed is 1/135th or faster. As your focal length increases then the need for faster and faster shutter speeds increases too. I have a 1000mm mirror lens and, if I wanted to handhold that lens, I would have to make sure I had a shutter speed of 1/1000th or faster...which is a problem considering that it is fixed at f16.

If you can't get that shutter speed then you need some form of stabilization. For many years this was a tripod (or some other stabilizing platform).IS lenses (and cameras) provide another option to increase stabilization.

For the most part, IS lenses are of most use in hand-held telephoto situationswhere camera shake can ruin the picture since a tiny tremor of the hands is magnified by the lens.

However, IS lenses are of less value in low-light, slow shutter speed situations. People think that they are going to get better pictures of their active children if they get an IS equipped camera but, while the IS willhelp the problem of shaky hands at slow shutter speeds...the shutter speeds are still SLOW and the subject you are photographing is still moving...and will be blurred. Also, most indoor shots are not taken at extreme telephoto so being able to handhold a shot at a shorter focal length is easier in any case.

Imagine placing a regular camera on a tripod (where it is completely stable) and taking a picture of a moving subject. The subject movement (which is beyondthe tripod's stabilizing influence) will be the deciding factor in whether the image is blurred. In those situations, photographers have used another method for stopping action in a moving subject...flash!

The bright, momentary flash effectively freezes motion independently of the tripod OR the shutter speed..in fact, many cameras automatically set themselves to a predetermined 'sync speed' and simply let the flash stop the motion. That works for hand tremor as well.

For indoor shots, a good flash beats IS any day but for outdoor telephoto shots...unless you want to carry a tripod (and many of us do!) IS is the answer.
Meryl Arbing is offline   Reply With Quote
Old Jun 28, 2005, 2:24 PM   #12
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Join Date: Mar 2005
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Dear PvB, Slipe, Geeek204, Davexx1, Meryl and everybody else,

Just a brief word of thanks to you all for taking the time and trouble to help me out with my image stabilization problem. One of these days I'll take the plunge, and I have a strange feeling that when I do I'll discover afterwards that I made the wrong choice!

It's like buying a computer: there's always the worry that something better and cheaper will come along the day after you part with your cash.

So my best wishes to all of you. I've enjoyed reading your comments. May your photographs all be prizewinners!

FrankkM is offline   Reply With Quote

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