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Old Oct 3, 2007, 7:55 AM   #1
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I'm considering the purchase of a ultra zoom (10x-12x) digital camera something comparable to the Canon S5IS. I'm wondering about the image clarity/stability at the longer lens shots especially in lower light when the shutter speeds are slower. How do these cameras do under these conditions at the higher magnificatoions? I will be using this mostly in situations that prohibit the use of a tripod.
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Old Oct 3, 2007, 9:31 AM   #2
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The usual rule of thumb is that good IS is "worth" about one to one and a half full f-stops. Remember that IS does nothing about subject motion. But, assuming that the only motion that is relevant in a shot is your shaky hands,if you have to shoot at 1/60 sec with IS, it would be as steady -- and the resulting image as crisp --as if you were shooting at somewhere between 1/120 and 1/150 sec without IS.

To understand how desireable that is, remember that the usual rule of thumb for how fast a typical experienced photographer needs to shoot in order to avoid camera shake is the reciprocal of the 35-mm equivalent focal length. For example, if you zoom to 400mm equivalent, you should shoot at 1/400s to not worry about camera shake (but still use as good technique as you can muster, or all bets are off.) So IS would lower that to 1/200 or possibly 1/150s.

So, the real answer to your question (to my opinionated mind) is you need a tripod or other supporting surface if you are shooting at long focal lengths in dim light, IS or no IS.

[edited for clarity]
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Old Oct 5, 2007, 5:19 PM   #3
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How does the ISO setting figure into the discussion of these cameras with longer tele? Would there be an advantageto having a camera with an upper limit to the ISO of 6400 compared to anotherwith a ISO of 1600? everything else being equal?
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Old Oct 5, 2007, 5:49 PM   #4
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There are three settings that affect the exposure: Aperture (the relative diameter of the light path), Shutter Speed (the duration of the exposure), and ISO Speed (the sensitiivity of the image sensor.)

You can adjust any one of these for a desired result (to stop action, or to alter the depth of field), and the others can compensate for your choice to obtain a proper exposure.

Image Stabilization helps to prevent motion blur from camera shake, which means that you can use a longer shutter speed if you want to, without suffering the consequences of not holding the camera steady enough. You can use that longer shutter speed to reduce the aperture, the ISO Speed, or both.

If the camera also had a very high ISO Speed setting available, you could take photos in lower light than you might otherwise. Together, higher ISO Speed settings, larger aperture lenses,and longer shutter speeds with the help of IS would allow you to take good quality photos in less light.
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Old Oct 5, 2007, 9:30 PM   #5
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Good answer, thank you. Now lets vary the resolution. Given a long lens in low light with image stabilization and a high ISO it seems to me 12 mpxl would produce a better image than equipment with 8 or even 10 mpxl, is that correct?
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Old Oct 5, 2007, 9:52 PM   #6
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coloradoice wrote:
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Given a long lens in low light with image stabilization and a high ISO it seems to me 12 mpxl would produce a better image than equipment with 8 or even 10 mpxl, is that correct?
12MP in a box camera will produce a better image than 8MP or 10MP.

There is, however,another consideration: Pixel Density.

The more pixels a manufacturer squeezes onto the same size image sensor, the more likely a single pixel will be unduly influenced by a neighboring pixel, resulting in noise. This is a known problem, and mostly only occurs at higher ISO settings. So, all things being equal, a 12MP 1/1.7" image sensor at ISO 3200 is more likely to produce noise than a 10MP or 8MP sensor of the same size at the same ISO. Newer image sensors implement methods to reduce or disguise noise, but the jury is still out on how successful they are.

So there is the potential that a 12MP image sensor may actually produce a worse image at high ISO than a 10MP or 8MP image sensor. (You didn't expect this to be simple, did you? [suB]:-)[/suB] )

Another solution is to use a physically larger image sensor, but now we're talking about dSLRs.
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Old Oct 6, 2007, 9:32 AM   #7
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No, I did not expect this to be simple, your responses have been succinct and helpful.

Now back to zoom/magnification. What do you think the maximum zoom would be (for one of the compacts) and still be able to get good/sharp images with had-held shots? In less tha ideal light? Less than ideal light might be: cloudy day in a narrow canyon but not trying to shoot pix with a great deal of movemet. Wouldn't it be nice if we could take our potential selections out into the field for a trial test before purchase!
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Old Oct 6, 2007, 11:18 AM   #8
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I don't think it would as fun or useful as actually taking a picture with a camera and seeing what happens. That's because:

1. different cameras have varied sensors. Some do much better in low light than others. I think the Fuji S6000fd is generally acknowledged as the low light champion among superzooms. But it doesn't have IS. It is just a 6 megapixel camera(plenty for me) and its full zoom is just 300 mm.

2. different cameras have different maximum apertures at full zoom. Some top out at f3.2. Others top out at f4.8. All other things being equal, the bigger the maximum aperture, the more light the camera can take in and the brighter the image will be.

3. some people are really good at holding the camera relatively still. while others aren't. This is important whether or not your camera has IS.

and, most importantly, I think,

4. different people have different opinions on what constitutes a good picture. How much noise is acceptable? How big an image do you want to print? Can you use noise reducing software?

I had the Fuji S5200 and S9100. Now I have the Olympus SP-550. The latter has an 18X optical zoom. It also has a maximum ISO setting of 5000. I have used it to take pictures of night games in professional baseball. I used the ISO of 3200. They weren't great. A lot of detail was lost. But it did freeze the action when lower settings produced blurry images. Maybe I could print 4" X 6" pictures from them.

Some stores let you use a camera for several weeks before returning them for a refund or exchange. I think it would be more useful for you to take advantage of such policies and use the camera in various settings and see what it can do in various settings. How good is good enough for you? Nobody can say but you.
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Old Oct 6, 2007, 11:39 AM   #9
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First, the word 'Zoom' all by itself doesn't mean anything. The lenses used in P&S and Ultrazoom digicams have an adjustable focal length, and the focal length determines the angle of view. At a short focallength, a lens has a wide angle of view, while at a long focal length, an lens has a narrow angle of view and high magnification. The 'Zoom' refers to the ratio of the shortest focal length to the longest. So a lens that has a focal length adjustable from 6mm to 72mm has a 12x (read '12 power') zoom.

Typically, the lenses in P&S digicams don't go very wide, and Ultrazooms just go longer than P&Sdigicams, not wider. So your choice of lens depends not on its 'zoom' but on whether its focal length will cover what you want to shoot.

Another aspect of selecting a lens isits range of apertures. Aperture is the size of the hole light passes through, is expressed in f-stops which are the ratio of the diameter of the aperture to the focal length. Typical lenses on P&S and Ultrazooms have a maximum aperture of about f/2.8, but only at the wide angle. Since themaximum diameter of the aperture stays the same while the focal length changes, the maximum f-stop of a lens drops off (gets larger numerically)as the focal length gets longer.

You have repeatedly raised lighting as an issue, so I mention all this because P&S and Ultrazooms do not perform well in low light without help, and a pop-up flash is only a little help.

The only photographic situation you've mentioned so faris "cloudy day in a narrow canyon". I suspect that you probably don't live at the bottom of a narrow canyon, but are just looking for a camera that will work well on the occasion that you find yourself in one. You might be able to get something out of a P&S or Ultrazoom in that situation, but they are not generally well suited for it.

So perhaps you could be more specific about the types of photography you want to do.

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Old Oct 6, 2007, 3:59 PM   #10
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i'm a big fan of the S5-IS and consider it and it's predecessor the S3, to be some of the best digicams out there.

that being said, if you want to work out in low light using lower ISO settings, imo a dSLR is your best bet, but there you run into some tradeoffs if budget is a factor. the pentax K100d with built in IS costs about the same as an S5, and you can get a Sigma 28-200mm f/3.5-5.6 for it for $150. true, it's a slow lens for shooting in low light so that's the tradeoff here.

on the other hand, a cloudy day is not really low light - if you work with your shutter speed, you could get away without IS in that sort of lighting.

in that case, you could get a canon rebel XT off amazon and get a consumer zoom lens from sigma. a big advantage there is that the higher ISOs on canon dSLRs show much less noise than any digicam. also i have gotten good results with my 30D and a $150 sigma 55-200 lens, and even though the lowest f stop is 3.5, it still give me more light than my fuji S9100. i have used that lens on cloudy days handheld and gotten great results. since the rebel takes the same lenses, and basically has the same settings, it should get very similar results.
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