How does i-Contrast work?

Started Aug 23, 2010 | Discussions thread
ForumParentFirstPrevious
Flat view
Corncob Forum Member • Posts: 87
How does i-Contrast work?

When I got my G11 a month ago I tried taking some test photos with and without i-Contrast switched on. I couldn't see any significant difference between the images when viewed on my PC screen so deleted them and left i-Contrast switched off. Now I have tried again and found very obvious differences, which puzzles me.

Both times I used P mode and took photos on a sunny day in my garden. The only differences in procedure seem to be that I now always use -1/3 exp compensation and have the Custom Colors set for High on Contrast, Saturation and Sharpness (High is one notch above default). I took pairs of photos with i-Contrast set first off then on, trying to match the frames. It's not perfect because I didn't have a tripod but the lighting should be the same. For pairs of photos the ISO, F-stop, and shutter speed were set the same.

In about 80% of pairs the ones with i-Contrast set on are obviously lighter than with it off. It seems to brighten the whole picture and it's difficult to tell whether or not it increases the difference between highlights and shadows.

All of the image data from the camera is the same for pairs except for three factors but I don't know the significance of these numbers. They are under Maker's Notes: the 'Measured EV', 'Focus Distance Upper', and 'Exposure Time'.

For example for one pair of photos:
Measured EV: 9.91 (without i-Contrast) and 10.03 (with)
Focus Distance Upper: 382 (without) 317 (with)
Exposure Time: 1/1141 1/1046

I'd be grateful if someone could explain how these EV values are different within a pair when ISO, F-stop and shutter speed are the same. I've no idea what Focus Distance Upper means.

Also, can anyone explain how i-Contrast works? I've searched for information but cannot find anything. I don't want Canon's secret software code but it would help to know the principle. Then I might be able to judge when it would be useful and when not.

ForumParentFirstPrevious
Flat view
ForumParentFirstPrevious
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow