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mattc
05-17-2007, 12:00 PM
hey evreyone im new here but i was just reading the noise thread and thats a big problem i have been having so how do you know what iso to use? i know 800+ for sports motion and things but why would a higher iso make still pictures not as good? im just shooting with a canon sd 630 and im planing on a dslr in a couple months id like to learn and know as much as i can

David Metsky
05-17-2007, 02:16 PM
The higher the ISO, the greater the sensor's sensitivity to light. That allows you take in enough light in a shorter amount of time, so you can use a faster shutter speed. But, the cost of that is that you get a lot of random noise because the sensor is being triggered at a much lower level.

The SD630 will have lots of bad noise when you go over ISO 400. The pictures may be useable for small online use or 3x5 prints, but if you try to go bigger you will see a degradation in the image. The SD630 doesn't give you any controls to speak of, just ISO and WB, so that's about all you can do. A dSLR will give you full control over aperture, shutter speed, and ISO, as well as handling high ISO much better because the sensor is a lot bigger.

For the SD630, try to use no greater then ISO 200. I occasionally use 400 if I'm desperate, but that is only as a last resort.

-dave-

ktixx
05-17-2007, 02:19 PM
hey evreyone im new here but i was just reading the noise thread and thats a big problem i have been having so how do you know what iso to use? i know 800+ for sports motion and things but why would a higher iso make still pictures not as good? im just shooting with a canon sd 630 and im planing on a dslr in a couple months id like to learn and know as much as i can

I think you are getting shutter speed and ISO confused. The faster the shutter speed the more stopped the motion that is why you want a faster shutter speed for sports. ISO is a factor in determining how fast the shutter speed will be. A higher ISO will allow light to be captured faster making the usable shutter speed faster but also increasing the noise. The lower the ISO the less the noise, but the slower the shutter speed. Basically shoot with the lowest ISO that you can to achieve the shutter speed you want.
Ken

nd66
05-21-2007, 08:30 PM
A good article HERE: (http://www.dpreview.com/articles/compactcamerahighiso/)

.

cgl88
05-25-2007, 06:14 AM
Photography needs the skill of tradeoff: higher ISO means you can capture action whilst letting less light in (faster shutter). It also means more noise. The best situation is sports pics outdoors, but if you are indoor, you have no choice but to take shots that are noisy at higher ISO. You can clean it up with software: neat image or noise ninja. Or keep your prints 4x6. Sometimes the noise won't be noticeable in the latter case.