Specs:

Lens:
250mm

Aperture:
f/5.5 to f/22
15 bladed aperure

Closest Focus:
3.3m (11ft)

Weight:
580g

Mount:
M42

Covers:
Standard 35mm film size (24×36 mm negative)

Image quality

Wide open:
Not crazy sharp
Fairly mild soft corners
Little vignetting

Renders very good at all apertures.

Build quality

Very good and built like a tank.


Conclusion

Did expect a bit better image quality wide open but it renders nicely.
This is a quite old lens and I would guess somthing like the 50s with the exakta mount.
Build quality is as a rock like most camera gear from this time.
Quite lightweight and a tripod mount is always a nice plus.

Can be a bit tricky to focus a f/5.5 lens on a SLR intended for manual focus.
The focus aid doesn't work at that aperture.
Not a problem you find on a Digital SLR especially if you use liveview.

Thumbs up:
Built like a tank
15 bladed aperture
Fairly lightweight


Thumbs down:
Sharpness wide open




Technical Info
Scanner: Plustek OpticFilm 7600i
Film: Rollei RPX 100
Developer: Kodak D76