Pentax K-1 or Sony a7c for Pentax K/M lenses?

Since I have mostly Pentax K/M lenses, it makes sense to use a native Pentax K-1 [Mark II] full-frame camera instead of the Sony a7c I chose. 

But there are reasons against it.

1. Pentax K-1 is very large and twice as heavy as the Sony a7c.

(source)

I already had a negative experience with Pentax K10D. It was bigger than my previous Pentax *ist Ds, so I used it much less. And the K-1 is even bigger and heavier than K10D.

2. In practice, you can mount only Pentax K and M42x1 lenses on the K-1. And the adapter for M42x1 is awkward. While I also want to use M39x1 rangefinder lenses (too short flange focal distance for Pentax K) and Nikon F (no glassless adapter for Pentax K) lenses.

3. The Live View mode on the rear LCD screen solves manual focusing problems, but the optical viewfinder doesn't provide as much accuracy as an electronic viewfinder (with magnification of a selected focus area, and in-body image stabilization).

4. Pentax K/M series lenses (i.e. without the "A" position of the aperture ring) work only with the fully open aperture in Av mode of K-1. To close the aperture (via the lens diaphragm actuator) while shooting you need M mode, where you have to do manual metering by pressing the "green" button (without AutoISO, while TAv mode is not available as far as I know). Whereas a Pentax K pre-set like adapter (with aperture control ring) in Av mode of Sony a7c (with AutoISO if desired) is more convenient for me.

5. Pentax K-1 [Mark II] is more expensive than Sony a7c. It's reasonable, but it doesn't satisfy me.

I like the K-1's sensor movement capabilities: Pixel Shift, Composition Adjustment, ASTROTRACER.

Still, I chose the Sony a7c as a compact and, importantly for me, mirrorless (short flange focal distance, EVF) camera.

See also related notes:

• Pentax K-m: Manual focus lenses (2024-01-23)

Image albums:

• Pentax
• Photo