I have a few problems with exposition with my Canon 70D: with same camera settings I get random EXIF data for focal lenght and aperture.
This is the setup
- Table with white paper as white background.
- Two strobe flash lights with umbrellas at the each side about 45° angle (triggered by hot shoe trigger on camera) manually set power, no TTL.
- Canon 70D camera on tripod.
- Camera settings in "M": ISO 100, 1/160, f9.0, Metering Mode: Evaluative metering.
- I use a 18% grey card to get proper white balance, set the WB to "custom" and get the WB data from the picture of the grey card.
- I also use an exposimeter to check that I have the best metering and it is all fine.
- Subjects are bags or similar leather products.
After I take pictures, that should all be the same exposition, I notice that there are a few difference between the photos. In fact I took two consecutive photos, not touching the camera or anything, of the same subject on the table, and one looks darker than the other (actually I can't show the products because they are trademarks).
Surprisingly, when I went to check the EXIF data, I found that they are quite different than the camera setup, and that seems explaining why some photos are darker/brighter than others.
Why that happens? Is my camera malfunctioning?
Please check the two screenshots (sorry the software is not in english but you can guess...=.