Originally posted by sterretje This makes me confused about what stop down metering exactly is. The bold text can be read in two ways
1)
you can't do stop down metering with M42 lenses
2)
you can use stop down metering but it works different from K mount lenses
Without wanting to hijack the thread, can you explain or give a definition.
For me, it is
"closing the aperture to the intended 'value' and letting the camera determine the other variables for correct exposure."
It's what I do with M42 lenses in either Av mode or M mode with the green button.
PS
I only have M42 lenses, no manual K-mount lenses.
#2.
Perhaps we define it a little differently. To me, and this may just be MY definition, Stop down metering is setting the camera to exactly how you intend to shoot by setting the exposure manually with the meter. With M42 lenses, as you know, the dSLR camera cannot control the aperture so we need to use lenses that have the A/M switch so we can control the aperture (preset lenses aside). With the caveat that I've never used a camera that does not have 2 e-dials, this is how I go about it with K mounts (K/M).
1. M mode (rear e-dial set for shutter speed, Preview set for Optical)
2. Focus
3. Adjust aperture as desired
4. Pull Preview lever (this both shows DOF preview and activates the meter)
5. Adjust shutter speed as needed to center the meter.
6. Shoot.
With this method, the K/M lenses stay wide open until step 4. With M42 lenses (set to M) it works the same way except the camera is not stopping the aperture down, you are. While the meter is active in either case you can both turn the aperture ring and/or dial the shutter speed to get your desired meter reading. Steps 4 and 5 do this automatically (on the K10/20/7/5) by pressing the green button but it Centers the meter and that's not always where I want it.
With an A type (k mount) lens set on A in M mode, the preview lever will Not activate but a half shutter button press will. At that point set your shutter speed and aperture. Once set, if you half press the shutter release while changing either the aperture or shutter speed, the other will adjust to keep the same exposure. It works this way with A/F/FA lenses. I see no reason why it wouldn't be the same with DA/DA* lenses as well.
Hope that explains it..