[kindakaa]

The weekend tested Sony A7 + Pentax 31mm F1.8 Limited and Sony RX1 (Zeiss 35mm F2.0 lens)
This is not a full test and comparison of lenses, and simply amateur images.
Just did two shots: first RX1, then A7.
At the same ISO and aperture. All shots on ISO=100. Click image to view full size.

Summary:
Pentax is no worse than new Zeiss lens.

f=13


f=13


f=11


f=5.6


f=2.8


f=5.6


f=5.6


f=4


f=4


f=11


f=2


f=5.6


f=11


f=8


f=8


f=2.8


f=11


f=2.8


f=11


f=2


f=5.6


f=8

[normhead]

Interesting... thanks for posting. That would be an amazing PowWow grounds.

[Driline]

Did you make your daughter climb all those stairs? LOL

I like the A7 and FA 31 shots better. More contrasty and the highlights don't seem to be as blown out as the RX.

[RobA_Oz]

Very interesting, thanks. You'd be tempted to say that the FA31 has better micro-contrast, by looking at the clouds, but I'd be cautious about making a definite judgment about that, unless the same body was used for both. I'm assuming the two sensors in the A7 and RX1 were similar, if not identical, and the in-camera processing would be similar, but there's bound to be small differences there.

Thanks for taking the trouble to compare and post these.

[starjedi]

Thanks for this post. It seems that at F2 FA 31 is sharper and more contrasting a little bit..

[kindakaa]

Did you make your daughter climb all those stairs?

Certenly. She went very quickly. But I had to rest 10 times before you reach the end of the stairs :-)

Before compare, I thought that the results of the Sony RX1 with a new lens will much better than 31 lim. But in the end I was very surprised that the old lens has given very good results.
I think for future FF Pentax camera 31 lim would be an excellent choice.

[btnapa]

The weekend tested Sony A7 + Pentax 31mm F1.8 Limited and Sony RX1 (Zeiss 35mm F2.0 lens)
This is not a full test and comparison of lenses, and simply amateur images.
Just did two shots: first RX1, then A7.
At the same ISO and aperture. All shots on ISO=100. Click image to view full size.

Summary:
Pentax is no worse than new Zeiss lens.

f=13


f=13


f=11


f=5.6


f=2.8


f=5.6


f=5.6


f=4


f=4


f=11


f=2


f=5.6


f=11


f=8


f=8


f=2.8


f=11


f=2.8


f=11


f=2


f=5.6


f=8

Thanks for the post. Very interesting real life comparison. It seems to be a dead even match. To my eyes, the 31 has more contrast. The other obvious difference is the warmer colors of the 31. The greens have a more yellowish tint to them.

This comparison reminds me of a wedding I shot back in 2000. Those were the last of my film days. I shot with Nikons and my friend who was the second camera shot with Canons. When I got the proofs back, I noticed the same color difference in the the two systems. Nikon had the warmer colors and the Canon had the cooler colors. I never thought about color difference upto that point. With Photoshop and RAW processing, it is easier to match color theses days but with film it was a lot harder.

[redcat]

thanks for sharing, the difference is minor and on a Pentax, the FA31 is unbeatable

[Sandy Hancock]

I see no reason to regret my choices.

[pinholecam]

Interesting and thanks to the shootout.

I read a long discussion on FM forums where it came down to FA31ltd being one of the better choices as a 35mm replacement to the RX1 (on A7).
It was more focused on the technical aspects of the likely 35mm lenses though.

What you have done here is certainly interesting.
In real World use and pictures, the 31ltd seems better for those shallower DOF shots to me. (despite all that discussion on technical qualities)
But thats what Pentax said when they designed the Limiteds as well. (that they slightly disregard numerical values for a more 'descriptive' rendition of real world objects)

[RobA_Oz]

I see no reason to regret my choices.

"Je ne regrette rien" perhaps?

Neither do I, and what this comparison does show is that a 14 year-old Pentax interchangeable-mount film-era lens design can perfectly well hold its own against a modern fixed-mount digital Zeiss lens design.

[formercanuck]

The boken on the Zeiss at F2 looked a little more pleasing than the 31mm.
Other than that..

[richmondthefish]

Cool comparison. I'll have to revisit these images on my retina iMac at home but on this HP display at work I'm generally liking the output of the FA31 a little more but they are close. FA31 seems a little cleaner though not sure if I would actually favor that look on all the photos. I'd say the portrait might favor the RX1 but that also has a tiny bit advantage in focal length.

Sony A7 bodies are cheap now so maybe a consideration for me to find a full frame use for my FA77

[pathdoc]

Nice shots. The FA 31 is definitely in my future.

How do the Sony body and the Pentax lens interface? I assume, given the mirrorless nature, that some sort of glassless adapter could be used, but what about stop-down and data contacts? Or are we in the same sort of situation as with Takumars on Pentax DSLRs, with the lens being manually stopped down and metering in aperture priority mode?

[clackers]

Or are we in the same sort of situation as with Takumars on Pentax DSLRs, with the lens being manually stopped down and metering in aperture priority mode?

Correct.