iso question

[rzanology]

I have this dsc-t1 over here, im not too sure how to use the iso settings. It has 100, 200, 300, 400. My question is. Which is better for outdoors and indoors. Thanks guys.

[Suhit Gupta]

ISO (basically) means how sensitive you want you camera sensor to be to outside light. If you are in very bright sunlight, you want your camera to be at ISO 100 which would make it less sensitive while in dim settings, ISO 400 would be preferrable. Of course, some cameras have problems with graininess at really low or very high ISOs but I haven't heard of any such major problems with the T1.

Suhit

[rzanology]

Thank you very much. Now perhaps i can get some proper pics out of this thing.

[backpackerx]

Perhapse the best thing to do is use the auto setting for important shots until you master the ISO in less important/experimental shots. Usually Auto does a decent job at selecting the ISO but errs on the higher ISO setting side.

The camera shutter speed will adjust to whatever ISO you choose within limits. The lower setting is usually the best for less noise and grain but if it causes shutter speeds to be so slow that you get camera shake then you defeat the purpose.

[rzanology]

okay one more question (maybe not the last lol) Lets say im taking an indoor pic, iso to 100 and flash to...normal or high? Will that make a diffrence?

[backpackerx]

Here are the basics:
ISO is how "fast" the film or in your case, digital sensor reacts to light. In layman's terms, a low ISO means you need longer or brighter light exposure than you would for a higher ISO setting. It's just like film, ISO 100 film reacts slower to light but has less grain because the film grains are smaller. You need more light for low ISO. That is accomplished 3 different ways. A slower shutter speed to let light in for a longer period, a bigger aperature (opening) to let more light in, or more supplimental light like a flash.

Higher ISO film needs less light exposure to get results but creates more noise in the picture just like 800 ISO speed film is grainier than 100 speed.

The sweet spot is finding the best compromise between shutter and aperature and light conditions using the lowest practical ISO.
You could always shoot at 100 but you'd notice that indoors the camera would need the flash more than normal and without flash, the shutter speed would be too slow to get sharp, hand held shots in many cases.
So, general rule of thumb is 100 outdoors in bright conditions, 200 -400 in overcast conditions. Usually you need 400 or so indoors to have a good shutter speed.

Try this to see what I mean. Turn the flash completely off. Go inside at night and take a picture of something moving at 400 ISO. Then do the same at 100 ISO. If you could get a 1/125 sec shutter speed shot at ISO 400 you'll only get a 1/30 shot at ISO 100. (I think I did the math right) You'll see the difference in the blurring of the motion and probably the image noise in the 400.
Using a flash will sync the shutter at a certain speed (like 1/60 for most film cameras) so up close it won't be noticeable but at ISO 100 you'll get dramatically less flash range than at ISO 400 because of the slower "sensor" speed.

Ok, that was probably confusing and maybe I could restate it better so feel free to ask for clarification.