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The questions above are good and through magic, I can answer at least one of them...I believe you are using an A-series or newer lens with electrical contacts on the mount face. As noted above, it is normal for your lens to be wide open when using the viewfinder. It is also not unusual for the lens to be stopped down when using live view, though how much it stops down depends on the scene brightness. The lens will stay open except for bright conditions where it will stop down to reduce the light striking the sensor. The only other time when it should stop down is when doing DOF preview or when actually doing an exposure. The aperture will stop down to the appropriate setting at exposure time regardless of where it is when viewing.
So, why the dark frames when using other than live view? The two views use different meter systems, but they usually have fairly close agreement. To figure it out, the first step is usually to determine if the issue is metering or exposure control...
- Camera on tripod or counter top and pointed at a well-lit subject
- Turn OFF auto-ISO and use fixed ISO
- Use multi-segment (matrix) or center-weighted average metering
- Switch to M mode
- Visually confirm that the aperture is wide open. If it is not, there is an issue with either the lens or the camera aperture control.
- Set your exposure using the optical viewfinder metering and an aperture of f/8
- Do the exposure
- Switch to live view
- Without changing any settings or subject framing position, do a second exposure
- Review both images. The exposure should be identical.
- Check that live view metering indicates a setting close to that of the optical viewfinder
If either of the last two points fail, there may a issue with exposure control (aperture, shutter, or ISO) that is likely independent of the which view is used. (These things tend to be intermittent.) If exposures are the same, switch back to optical viewfinder and do 20 exposures using the same settings. All 20 images should have identical exposure. If not, there is an exposure control issue.
Steve
Last edited by stevebrot; 03-10-2017 at 10:17 AM.