Grainy photos

AJ Jewell · May 30, 2006

I was just trying to get a feel for what the AUTO mode on my DSLR was doing in different lighting conditions and I noticed that when I take a shot in a poorly lit room (say just table lamps), the flash fires, but I get a pretty grainy image. My only guess would be that the ISO is too high, but would the auto mode do that rather than slow the shutter down?

darin3200 · May 30, 2006

Yeah, auto modes are for just pushing the button and getting a photo. Since most people using auto modes wouldn't understand camera shake or slow shutter speeds the camera is just going to boost the iso.

AJ Jewell · May 30, 2006

thought so, thanks.

So to take a photo like that well, I would just slow the shutter down, and use a low ISO? I find that when I do that I get tremendous camera shake, is this just un-trained hands, or do most people use a tripod?

darin3200 · May 30, 2006

First of all make sure the aperature on your lens if totally open to let in the most light. Shutter speeds resulting in camera shake vary from person to person, for some people its 1/30 and for other it can be 1/8. It just depends. Find the slowest shutter speed you can hold your camera at without getting shake and adjust the iso accordingly. Or you can also use a tripod and do a slow shutter/ low iso pic.

JamesD · May 30, 2006

Tripods are worth their weight in gold. Any tripod is better than no tripod, but the sturdier and more massive they are (up to a reasonable point, of course) the better.

Also, apparent camera shake is related to focal length as well as shutter speed. The general guideline is that if hand-holding the camera, you should use a shutter speed which is the inverse of the lens focal length.

So, if you're using a 50mm lens, use a shutter speed of 1/60 second for faster (1/60 is the closest you can get to 1/50 without going to 1/45, which would be too slow). If using 100mm lens, then 1/125 second. 300mm, 1/350 second. And so on and so forth.