iso speed

What ISO speed to you use most? 100 or 200. What do you usually have it set for landscapes .Thanks

There are a lot of variables, ISO is only one. For landscapes: available light, depth of field, and a tripod present all play into effect. If I have a tripod and I am looking to attain a wide depth of field, I will stop down to f/22 or something and to get the least amount of noise possible, use ISO 100. Now, this is on my 30D. If you are shooting with an older model, specifically one that had high long exposure noise issues, you will have to balance long exposure noise and ISO noise. A higher ISO will produce noise, but so will long expusures. It may be necessary to sacrifice some depth of field and open up the apature a little to allow for a shorter exposure. If I have no tripod (on a hike or something) I may have to sacrifice noise or depth of field (or both if it is a dusk) to achieve a sharp image.

These are just examples. I don't have a "usual" setting for my ISO. As a general rule, you put it as low as possible, but it is a setting just like aperature and shutter speed that should be taken into consideration in each scenerio.

My rule of thumb... I use the smallest ISO with which I can still get a sharp photo when hand holding the camera. It depends on available light and shutter speed, of course.

I use iso 100 unless the available light will not let me use either the aperature setting or shutter speed setting I prefer. I then start increasing the iso from 100 to 800 to give correct exposure of the picture. If I have to go beyond iso 800 for correct exposure, I stop there and start making compromises on the aperature and shutter speed settings.
But there are a lot of qualifiers - I'm not shooting sporting events or weddings, I'm not trying to be creative and produce a special effect, I'm not using a tripod, etc, etc - just walking around taking pictures of friends, parties, parades, buildings, landscapes and everyday things.

I change ISO all the time depending on lighting conditions.

I always select the ISO after first determining what type of exposure is required to achieve the result I'm looking for. Generally I pick the aperture first (unless there is motion involved and then the shutter speed is first), followed by the ISO setting to achieve the shutter speed desired. If the ISO required is higher than 800, I usually rethink the aperture or shutter speed to keep the ISO below 800.

I tend to leave mine on 200 for most 'general' shooting, however, as everyone else has said, if the light falls and you need that small apperture or high shutter speed I change it.
For any landscape shots (particularly if on a tripod or using my IS lens) I like to change to 100 (If I remember!)
If i'm shooting horses eventing (which I do regularly) I always use 400 or sometimes higher depending upon the light. Having faster lenses helps as well, and as people here have said, it is really just another part of the exposure equation.

If I'm shooting a concert, I'm normally at 800 or 1600.

I'm in Nova Scotia right now, shooting a lot of landscape stuff, and have been using an ISO of 100...

Does anyone here ever use ISO 3200?
If so - for what circumstances?
On the 20D this is a custom function setting - which needs to be turned on first, then dialed in. Is there a reason why it's a custom function setting, instead of just a dial in setting?

I use ISO 3200 frequently for night racing action. I'm actually pretty impressed with the shots. Sure there is some noise but not enough that the shot is total garbage.

Thanks for all replies .I use my Feisol tripod a lot shooting waterfalls so I always use 100
for that. 200 for general but with 17-85is I can stay at 100.I am trying to use tripod a lot more.

See my answers below

HPZ wrote:
Does anyone here ever use ISO 3200? YES
If so - for what circumstances? When needed (too little light)
On the 20D this is a custom function setting - which needs to be turned on first, then dialed in. Is there a reason why it's a custom function setting, instead of just a dial in setting? So that only people who know what they are doing use it...

You can always correct noise in the image up to a point ... try that with motion blur.

Best regards,
Andy

I generally use ISO 200, and will switch sometimes at night to bring my shutter speed up. But all in all it's usually set to 200.

I have used ISO 3200 but only whilst 'playing' - If you expose properly then it's not too bad really, you can always remove noise with various filters or plugins in PS or Neat Image etc. to help.

I think it's a custom function because it is not an actual ISO setting as such, but simply a doubling of 1600 electronically, a bit like a digital zoom on a p&s camera - I'm sure I read that somewhere, but can't recall where. Canon obviously don't think it's that good but if you really want it you can turn the option to use it on.
Of course I stand to be corrected on this last comment...

I have used ISO 3200 many times when in a pinch. Very usable with Neat Image or Noise Ninja afterwards. Its better to get a good grainy image than a blurry clean image.