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Old Feb 19, 2007, 10:57 PM   #1
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Okay, I'm really tired of reading reviews on Canon A640 and A710IS models... I think my hesitation is somewhat common.

My question is, does "every" camera need Image Stabilization? Is there any criteria? I can totally understand the need of IS in 12x zoom cameras, but what aboutthe other ones? Then, come to think of it, I realized somehow all "new" models would benefit from having IS, but since CanonSD900 doesn't, I'm very confused.

As far as I'm concerned (and please correct me if I'm mistaken, I'm definitely not a professional photographer), Image Stabilization is only effective (well, that's sort of debatable...) when ZOOMING in low light/marginal conditions, allowing you to shoot without having to use a higher ISO (which generally means more noise) or actually allowing you to use a higher ISO in those situations without decreasing the quality of the picture.

My questions is, would A640 benefit from having IS, since it has a 4x optical zoom?Wouldn't a tripod (and a nice slave flash) be a lot more effective for indoor shots? What about outdoor shots on sunny days, why would IS be important? Would it stop pictures from being blurred due to camera shake in that condition?? Is there an ISlens I could purchase later on and adapt to A640 (if I ever buy that camera), since I hear its image quality is better than A710's?

(Personal opinion... I notice IS doesn't remove the blur, but simply "masks" it most of the time.)

I'll be very glad to hear from you. This forum has alwaysbeen incredibly helpful.
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Old Feb 19, 2007, 11:16 PM   #2
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The rule of thumb is that shutter speed should be 1/focal length or faster.

So, if you're zoomed into 50mm, you'd want 1/50 second or faster. If you're shooting at 100mm, you'd want 1/100 second or faster, etc.

That's just to prevent blur from camera shake, not subject movement. So, it depends a lot on what you'd be shooting.

That's also a "rule of thumb", not an absolute. Some people can hold a camera much steadier than others.

The shutter speed needed to reduce blur from subject movement is a bit more complicated. That depends on your focal length, subject distance, direction of movement, speed of movement, and desired print size.

That's because the human eye needs a certain amount of movement before it senses blur, which will depend on the percentage of the frame the subject occupies, print size and more.

Most stabilization systems give you 2 stops or more benefit for blur caused by camera shake (which means that you'd need shutter speeds 4 times as fast to prevent blur from camera shake without stabilization).

A true lens or CCD shift based stabilization system doesn't mask the blur -- it moves either lens elements or the camera's image sensor so that the camera doesn't see any shake, based on gyro sensors that detect camera movement and tell the lens element or CCD where to move in response to it. That way, the sensor sees a stabilized image. Now, there are some digital type stabilization systems that don't work that way. But, the A700IS uses a mechanical stabilization system (moves lens elements in response to camera shake).

The shutter speeds you are able to achieve in a given lighting condition will depend on the lighting level (usually referred to as EV for Exposure Value), the aperture you're shooting at (and the largest available aperture will be dependent on the lens you're using and may vary by the focal length you're shooting at), and the ISO Speed.

See this handy exposure calculator for more info on how these variables interact to allow the camera to properly expose an image. Note that film speed is the same thing as ISO speed.

http://www.robert-barrett.com/photo/...alculator.html

There are many times that I've appreciated having anti-shake in a camera. But, it depends on what you're shooting. If you're shooting with a bright enough lens and a high enough ISO speed to achieve the desired shutter speed, then it's of limited value.

Ditto for moving subjects at most focal lengths (since you'd usually want your shutter speeds to be fast anyway, and anti-shake won't help with blur from subject movement). For low light shots of moving subjects, a camera with a bright lens (larger available apertures, expressed by smaller available f/stop numbers) that can shoot at higher ISO speeds is a good idea to keep shutter speeds fast enough. But, in very low light, sometimes blur from camera shake can be worse than the blur from subject movement, depending on how still your subjects are, if your shutter speeds get real slow.

A tripod is always a good idea. But, if you don't want to use one (or can't use one), then stabilization systems can be very handy.

No -- you can't add a stablized lens to a camera like the A640.


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Old Feb 19, 2007, 11:38 PM   #3
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JimC wrote:
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Most stabilization systems give you 2 stops or more benefit for blur caused by camera shake (which means that you'd need shutter speeds 4 times as fast to prevent blur from camera shake without stabilization).
That's great then. Thank you
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Old Feb 19, 2007, 11:55 PM   #4
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One other comment...

If you can use a flash (and you're within the flash range), shutter speed and stabilization are not as important in darker environments (typical interiors)

That's because the flash itself has the effect of freezing the action, regardless of shutter speed, as long as it's providing most of the light. The flash burst is usually short (typically varying from around 1/1000 second to 1/20,000 second), and the subject is only properly exposed during the flash burst duration.

So, you can get good photos at very slow shutter speeds with flash, as long as ISO speed is low enough so that ambient light is not exposing your subject. In that case, stabilization wouldn't help a thing.

But, if you wanted to "drag the shutter" to let in more ambient light so that the flash is not providing as much of it, stabilization could come in handy indoors with a flash, too.

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Old Feb 20, 2007, 12:02 AM   #5
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I'm just trying to "get rid" of A710IS ... So any other ideas are welcome.

You think a better flash would help? A better flash and a tripod... *laughs*
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Old Feb 20, 2007, 12:49 AM   #6
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That depends on what and where you're shooting.

Sometimes, you can't use a flash (or don't want to use a flash). But, sometimes a tripod isn't going to help either. There are conditions where you need a fast (bright) lens and higher ISO speeds, and in some conditions you may not be able to take acceptable quality photos, no matter what camera you use. Any camera/lens/flash combination will have limitations.

In many low light scenarios, a DSLR can be a better tool, since you can get brighter lenses and have higher available ISO speeds. Or, sometimes, a combination of all of the above can be nice to have (stabilization, higher ISO speeds, and a bright lens).

If you can use a flash (and stay within the flash range), a flash can be a good tool.

It's not like it needs to be a one or the other type of decision either. I'm shooting mostly with a Konica Minolta Maxxum 5D now, and it has stabilization for every lens (including brighter priimes), as well higher ISO speeds (up to ISO 3200). Sometimes, all of the above is nice to have.

But, at other times, I'll use a flash (and I've got more than one external flash I can use with it) depending on what and where I'm shooting. I even "mix 'em up" in the same conditions, taking some photos with flash, and others without flash. It's always a good idea to have a decent flash as part of your arsenal if budget permits.

Your best bet to decide what you need would be to give members a better idea of the conditions you're shooting in and where you're running into limitations with your existing camera (I'm assumiing from your last post that it's probably the A700IS now, so correct me if I misundertood that part).


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Old Feb 20, 2007, 1:53 AM   #7
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I haven't bought my camera yet.

I don't really demand much. I'm planning to take random pictures, I don't think I'll be photographing landscapes, mainly people (indoors and outdoors) and objects. Manual mode is important.

DSRLs are usually big and too expensive. I don't really think I need one.

I've read lots of reviews, seen all kinds of pictures everywhere, from all kinds of people (amateur/experienced photographers), in all conditions... and I'm exhausted.

I like both cameras, I like A640's swivel LCD,pictures seem to beslightlymore realistic, aaaand... it's on Steve's Best Digicams list, that's quite a plus!!I'm sure he wouldn't recommend me something meia boca.

On the other hand, A710 has IS, although I hear it takes a long time for the camera to recycle flash and there's no swivel LCD. I like the pictures too, but they sometimes look a little too processed, maybe they are supposed to be anyway.

*sigh* Tough decision.
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Old Feb 20, 2007, 2:14 AM   #8
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Any choice is going to be a compromise. As a general rule of thumb, the camera with the weakest batteries is going to take longer to recharge the flash, all else being equal (and it rarely is).

Since the A700IS uses 2 AA batteries compared to the A640's 4 AA batteries, recycle time is going to be slower. Steve will comment on general timing in the Conclusion Section of each review here. But, your actual recharge time is going to vary by subject distance, ISO speed and more. That's because the flash burst can be shorter for a closer subject (allowing faster recharge times for the capacitor, since it won't be fully discharged).

Make sure to take flash range into consideration, too. It looks like Canon does offer a small external flash that can be used as a slave if range is an issue (and you'll find some third party "digital aware" slaves on the market, too).

I'd try them out in a store and see which model feels best to you. Sometimes, a lot of things are hard to judge from reviews (ergonomics, viewfinder usability, etc.).


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Old Feb 20, 2007, 2:23 AM   #9
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:ak47:<< This is so therapeutic.

Thanks for the tips.
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Old Feb 20, 2007, 8:26 AM   #10
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lemon_yellowsun-

JimC is great! He is very experienced and knowledgeable and is ever so willing to share his experience and knowledge in a very kind and caring way. As JimC mentioned, every camera choice represents so kind of compromise when the camera is paired with your own personal choices and shooting conditions.

With DSLR cameras now as small as the Nikon D-40, the Olympus E-400,and the Canon XT and XTi, the traditionalperception the DSLR cameras as beingbig clunky cameras, no longer holds true. Just be aware that the DSLR camera with its much larger imagers, fast lenses, up to F1.4 and F1.2, and high available ISO settingsrepresent a unique capabilty that most point and shoot cameras cannot offer. And yes, Canon and Nikon also have IS equipped lenses as well. Those IS equipped lenses really come in handy when the shutter speeds get very low.

Finally noise is far less a problem with DSLR cameras than point and shoot cameras, once again, due to their much larger imagers.

MT/Sarah
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