Question about ISO

[jdrtrainwatcher]

I need to know what ISO # for different situations. I usually try and use the lowest ISO possible for the amount of light available, I always thtough the the lower the ISO, the better quality the picture has. I would also like to know what ISO # I should use for nightime long exposure shots, I have been using 200, which is a slow as my camera will go.



Thanks in advance,
Jonathon

[JRMDC]

It depends on the camera. What do you use?

[jdrtrainwatcher]

I use a Nikon D70s.

[Joe the Photog]

Jonathon;

I still use the lowest ISO possible to get the shot. If I'm correct, the D70 is basically the Nikon version of the 300D, which is what I use. The 300D doesn't do well with high ISO. It gets very noisy and grainy. I think I've gotten decent results with an ISO of 400, but I try not to go above 200 and usually just stay at 100.

You can get software to get rid of noise out of pictures, but I'd always prefer to do most of the work with the camera in my hand and not at the keyboard in post.


Joe

[JRMDC]

In general for night shots, since you are using a tripod anyway and since you are not trying to stop action so you don't gain anything by using a faster shutter speed, you use the lowest ISO to get the best quality.

[Mgoldman]

Originally Posted by JRMDC

In general for night shots, since you are using a tripod anyway and since you are not trying to stop action so you don't gain anything by using a faster shutter speed, you use the lowest ISO to get the best quality.

If you have subjects in your picture that might move, actors or stars, for instance, you might want to set a higher ISO to lessen the amount of time the shutter is open to prevent capturing any unintentional movement.

/Mitch

[567C]

ISO with film is easier to comprehend than the digital images we see. Shooting film before "digital" required a knowledge of what you were doing. Film speed (ISO) f-stop, and shutter speed. We also needed a light meter, either built into the camera, or a hand held unit, to measure the light. Take a look at this page for an insight to "ISO" Regards, Robert.

http://en.wikipedia.org/wiki/ISO_5800:1987

Originally Posted by jdrtrainwatcher

I need to know what ISO # for different situations. I usually try and use the lowest ISO possible for the amount of light available, I always thtough the the lower the ISO, the better quality the picture has. I would also like to know what ISO # I should use for nightime long exposure shots, I have been using 200, which is a slow as my camera will go.



Thanks in advance,
Jonathon

[a231pacific]

Jonathon,

Basically you need to start with shutter speed and aperture and figure out what you need for the shot. If it's a moving train, then you need a speed around 1/500 second. Then you decide how much depth of field you want and select your aperture to do that. Let's say you want f/8. Then it's simply a matter of selecting the ISO that will give you that aperture and shutter speed. On a nice sunny day, ISO 100 would be fine.

The "Sunny 16" rule states that on a sunny day, the shutter speed is the reciprocal of the ISO at f/16. At a shutter speed of 1/500, the rule would indicate that you should use an ISO of 125 at f/8. In actuality, you would probably use ISO 100 and f/7.3. If I remember correctly, the D70 will only go down to ISO 200, so you could shoot at 1/800 at f/8. That should stop any motion just fine and give a good depth of field.

As has been said about night shots, you need to decided how long you can keep your shutter open without something moving. I used to use ISO 400 for night shots when I had a D70. Going up to ISO 800 added noticeable noise, but there are times when noise is better than motion in the picture. I would take hand held night shots at ISO 1600 if that's what it took for a steady photo.

I took the attached photo in Stettler, Alberta, after shooting the grain elevators at sunset. I was walking though town and found this great sign on the local jewelry store. I shot it at f/5, 1/80 second and ISO 800.

Michael Allen