Originally posted by MichaelErlewine Is there any way to have LiveView look at am image and if you want to change the shutter, as you do, it will increase or decrease the light on the subject in LiveView?
Anyway to disable forcing the aperture all the way open?
There is a work-around...
If you switch the camera to movie mode (small switch under the function dial) then you can have exposure preview in live view with a K-mount manual-aperture lens.
Since the lens does not have an "A"uto-aperture setting the camera software cannot accurately control it, so you must still stop down the lens by holding the depth-of-field preview switch that D1N0/jatrax described to preview exposure and depth-of-field at an aperture other than wide open.
You can use the movie mode to visually take your exposure reading the way you like, then switch back to stills mode if you're taking a photo. The ISO might change when you switch between still and movie mode, so make sure to set the ISO in stills mode the same as the exposure reading you took in movie mode. It is also not possible to set a shutter speed slower than 1/30 in movie mode, so it may not be useful to you.
If your lens has an "A" setting, then you do not need to go to movie mode at all.
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I don't know why changing ISO and shutter speed in stills mode with a manual-aperture lens doesn't generate an exposure preview, seems like something that could be patched in firmware since the function exists in movie mode.