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Bluemilk82
12-03-2006, 06:49 AM
Hi there,

Am currently an owner of the Cannon SD800 IS. Have been trying to play around with the ISO settings. From what I read from the Internet, a higher ISO setting is needed when you are shooting in low-light conditions. What is a low light condition? Does a room that is lighted by fluorescent / light blubs/ halogen ( you get the picture, no pun intended). warrant a high ISO setting? Secondly, what is a high ISO setting?

Sintares
12-03-2006, 11:42 AM
You never need to use high ISO. Whether it would be usefull though depends on the situtation.

As you increase ISO the shutter speeds increase, but so does the noise introduced into the picture.

One reason to use it is if the shutter speed you are getting at low ISO is so slow that either moving subjects would be blurrred or the shutter speed is so low that camera shake would ruin the shot.

As an example, take trying to shoot pics at a party.

You could stick with low iso (which gives the least noisy pictures) and use flash.

That sort of ruins the moment so you try without flash.

In a dim party your shutter speed might be 1/30s or slower, people dancing are a total blurr, and if you are in a larger room, using a bit of zoom to reach to the other side might mean shake ruining the pic.

So, say you where on ISO 100 at 1/30s , going to ISO 200 would double the shutter speed to 1/60s, a little bit better, ISO 400 to 1/120s and ISO 800 to 1/240s
I am assuming of course the aperture is opened to the fullest (lowest f number)

In each case you would need to test whether the ability to speed the shutter to freeze a little bit more of the action is outweighed by the increasing noise the higher ISOs add to the picture.

If you are only printing 6x4 or smaller then you can probably get away with more noise, since it would be less visable.

In some cases of course, say taking pics of the city at night, you can use a tripod, so shutter speed is less a factor and you can use the lower ISOs with little problem.

Montross
12-07-2006, 05:05 AM
when you say noise, does that mean grainy pics? cause i believe sometimes grainy pics are a cool effect.

David Metsky
12-07-2006, 05:13 AM
Yes, noise can be equated to grain. It can be a nice effect, but most folks want to start with a clean shot. In general, it's not a good thing. Look at some of the reviews on this site to see how noise can make pics unusable.

-dave-

FLiPMaRC
12-07-2006, 08:59 AM
If you're not going to be using your shots to print anything over 5x7", I think you can get away with using ISO800. You can always PP the noise. But any prints 8x10 or larger, I think it's unusable.

orionthunter
12-31-2006, 11:19 AM
I have the SD 700 IS. For night shots I turn on the IS, turn off the flash and then set the camera to the lowest ISO that doesn't give me the camera shake warning.

ChL
01-19-2007, 06:58 PM
What do you think is more efficient on low light?

- a camera with IS and low ISO (max 400), then you can have a higher exposure handheld

or

- no IS and higher ISO like 800, 1600 (and no noise), with shorter exposure?

I wish a camera with some nice ISO 800 noise-free, and also IS, but seems like only the dSLR can do it, I need something smaller...

I'm trying to decide between noisier Canons IS... or Fuji high ISO, no noise, no IS:
http://www.dcresource.com/forums/showthread.php?t=28057

Pave
01-20-2007, 01:32 AM
What do you think is more efficient on low light?
- a camera with IS and low ISO (max 400), then you can have a higher exposure handheld
or
- no IS and higher ISO like 800, 1600 (and no noise), with shorter exposure?

It depends on what you intend to shoot. If you want to take a pic of something stationary (ex. some house, tree, etc.) the IS is a good option but when taking pictures of something moving (see above the post by Sintares) the IS is absolutely useless and you have to increase the ISO speed. The IS is useless in this situation because it only reduces blur created by the shake of your hands, it definitely can't reduce the blur caused by the movement of the subject.


I wish a camera with some nice ISO 800 noise-free, and also IS, but seems like only the dSLR can do it, I need something smaller...

I'm afraid that if you really need ISO 800 noise-free pics, so the DSLR is really the only option for you.


I'm trying to decide between noisier Canons IS... or Fuji high ISO, no noise, no IS:
http://www.dcresource.com/forums/showthread.php?t=28057

The Fuji probably has less noise but don't forget that even with that camera you'd probably never get absolutely noise-free pics when using high ISO. I'd recommend you to browse this site, write some questions to Fuji (resp. Canon) specific forums and read some reviews. It should be helpful...