The first thing to understand is that Pentax Q cameras have very small sensors: 1/2.3" (5.6x crop factor, 12MP) for the first Q and Q10 models and 1/1.7" (4.6x crop factor, 12MP) for the last Q7 and Q-S1 models. It is possible to mount non-electronic (manual focus) lenses, but such large crop factors make them rather useless except in a few specific cases.
The only original adapter for MF lenses is
the "Pentax Adapter Q for K-mount Lenses". It has the advantage of a built-in [mechanical] leaf shutter, but it is quite rare and expensive. Other [non-original] adapters are non-electronic, I have two such non-electronic adapters. And I have tested them with
my Pentax Q (with the latest 1.14 firmware).
As you would expect from Pentax, the Pentax Q offers Av and M modes for non-electronic lenses. In Av mode, the light meter (Center-weighted and Spot) works, so the camera sets the shutter speed according to the conditions. Auto ISO can be used in Av mode. Note that Auto ISO cannot be used in M mode, all camera parameters (shutter speed and ISO) are set by the user.
The sensor-shift image stabilization (SR) works with non-electronic lenses, the camera asks for the focal length when switching on (also available in the menu).
The SR can be activated in Live View to stabilize the image during manual focus.
MF Assist magnifies the image to make manual focusing easier.
Press the OK button to activate the magnifier. Turn the e-dial to change the magnification factor (x2-x4), the magnification area can be moved with the cursor buttons (press OK to return to the center). Press the shutter-release button halfway to turn the magnifier off.
Focus Peaking is supported.
It looks like a coarse sharpening with a white border around the focused objects.
Full image (without Focus Peaking):
Full image (with Focus Peaking):
MF Assist (without Focus Peaking):
MF Assist (with Focus Peaking):
Looks unusual to me, but it helps.
The Pentax Q doesn't have a built-in mechanical shutter, but some Pentax Q lenses have a leaf shutter. With other lenses the camera's electronic shutter is used.
As I wrote before, the original Pentax K adapter has a leaf shutter, that can be used with Pentax K lenses. But non-original adapters have no shutter, so the electronic shutter of the camer is used.
Apart from the rolling shutter problem, the electronic shutter has a slow shutter speed limit: 2"-1/8000 (1/13-1/8000 with a flash). Bulb mode is also not available with the electronic shutter.
Also note that a built-in ND filter is not available with non-electronic lenses, as an ND filter is part of some (4 of 8) Pentax Q lenses and not part of the camera.
Overall, the Pentax Q's support for non-electronic lenses is good, but the large crop factor ruins it.
