Powershot G15 ISO in aperture mode

[aranpedro]

Hello to everyone,

there is a question that I cannot answer myself about the ISO in Powershot G15. When I work in Aperture mode I can set up the maximum ISO that the camera will use depending on the ambient light available.

The weird thing to me is that the camera selects a high iso when there is enough light available. For instance, information about one of my picture is: ISO 800, f. 2.0, 1/400. How is it possible that shooting to 1/400 the camera selects an ISO of 800??? It sounds stupid to me since you stilll can shoot up to 1/60 without having vibration problems and the camera should always select the lowest ISO to avoid noise.

Can anyone enlight me about this issue?

Thank you!

[cicopo]

You might think that way but it doesn't look like Canon's engineers do. I quit using Auto ISO after finding out my 1D mark 4 chose to use ISO 12800 EVEN though I had a 580 EX flash supposidly in control. Just take it out of Auto ISO & go from there. use

[aranpedro]

Thank you Cicopo for your comment. I can understand you very well...there must be something we miss from the way that the software it is configured because it doesnt look very intelligent to rise up the ISO when you can shoot at lower speed.

As you can select the maximum ISO speed to be used in aperture mode I will try to "force" the camera to choose a lower shutter speed. Its so anoying to me when you findout processing your pictures that the camera has rise up the ISO when there was more than enough light.

[smack53]

When the engineers designed the G15 camera parameters, I believe they strived to have the camera attain 14%-18% grey for the best white balance with the fastest shutter speed, and that bumps up the ISO to compensate. It really does not depend so much on the light metering, which would make more sense to me. I'm with Cicopo on this as I stopped using the Auto ISO and setting max ISO ranges for the very reasons that you have stumbled on to, and instead I have learned through trial and error what the best ISO settings would be.

Just curious if you shoot in RAW or JPEG. I had noticed that my G12 is better in the RAW mode about automatic settings, but still not perfect. If you are in JPEG, do you have the I-Contrast set on? If so, that can have an impact on the settings the camera wants to select. Try with the I-Contrast off to see if you get better results. The I-Contrast is not available in RAW, so that could be the difference here.

Steve M.