iso question

hi guys been playing about with camera and different settings etc. i had set my iso to 100 on a setting and i've noticed on pics i expected to be dark the iso setting has changed? does the d3100 change automatically on certain settings? the iso is showing up in red in the info

In the camera menu, you have "auto-iso" set to on. If you want to have it not automatic, set it to off.

What Marcel said.

where is the auto iso setting?

Menus. Check your manual.

glesgaboy said:

where is the auto iso setting?

Click to expand...

Look in your Custom Settings Menu. It's all in your owners manual.

cheers guys, was sure i changed it in there. obviously not. dumbass

Remember to confirm any changes in settings, otherwise it will just change back to what it was previously .... I've made that mistake a couple of times when I was sure I confirmed it

I had the same problem and then found this thread!

I wonder when set to auto, why camera often selects high ISO like 5000+ to Hi1 even when there is sufficient light like indoor shots inside home during daytime?

On auto ISO, you should be able to set the maximum the camera can select. Again, this will be in your manual which should be your best friend when setting up/learning your camera.

Can you give example settings Mobi.

With a 35mm f1.8 on my D5100, in Aperture priority it will only raise the ISO to stop the shutter dropping below 1/100.
In Shutter priority it only raises the ISO if the aperture reaches maximum opening.

That seems like excellent auto ISO choices.
The minimum recommended shutter for a 35mm lens is 1/35 so the auto ISO is keeping around 3 times above the minimum on Aperture priority. Remember though, that's the minimum, not a recommended speed. It's generally better to be well above the minimum speed.

Other lenses will vary but I guess it will have a similar formula to keep the ISO as low as possible until the recommended slowest shutter or widest aperture is reached.

I love the auto ISO feature with it's maximum cap, it's a fantastic feature.

Examples

35 mm, f/5.6, 1/60, ISO 6400
34 mm, f/5.0, 1/15, ISO 3200
30 mm, f/5.0, 1/25, ISO 6400

My earlier post mentioned the minimum shutter stopping at 1/100, I thought it was because of Nikon knowing the focal length the lens was (or set to), but I had the 70-300 mm on today and I had to go into settings to increase it to the minimum I wanted with that lens.

Are you in P mode, I hate that mode but know others love it.

Can't remember. Either P or A mode.

Try it in A, S or M, auto ISO works exactly as expected.
In P mode the camera doesn't work how I want it to so it never goes there.