[Sam Dennis]

Has anyone tried this lens on the K1 in terms of full frame coverage? My sister just ordered a K1 and kit lens, but wants to get a prime lens like the Sigma Art 35 when her bank account gets back off life support from buying the K1. I thought maybe the plastic fantastic 50 would be good in the meantime since it is inexpensive, relatively and she also has the K3 and K10 crop sensor. Thoughts? Experiences?

[edmundrt]

I have used the DA50 to shoot plenty of 35mm film, mostly on the Z-1p. I find the full-frame performance satisfying - there is some vignetting wide open (but this is not uncommon for any fast 50) and there is a little corner deterioration at wider apertures, but as you can hopefully see from the attached pictures it does a good job.

[stevebrot]

There are a number of threads where the DA 50/1.8 on FF is discussed. Conventional wisdom is that the image circle is inadequate for consistent coverage without vignette when used with the 24x36 format. Corner and edge performance sharpness is also sub-par. Those observations confirm the official Ricoh position regarding the lens. That being said, there is are a number of forum members who enthusiastically use that lens on the K-1 over the FA 50/1.4 and other available fast 50s. I don't own a K-1, but have shot the DA 50/1.8 on 35mm film and was not impressed (visible vignette on visual inspection of negatives and quite soft in the corners).


Steve

[pres589]

The DA50, DA40XS, and DA35 f2.4 (not the Macro) are all inexpensive lenses that appear to cover the full K-1 image circle with little to no vignetting. Lots of threads about this already. Out of the three I believe the DA50 is the least able to cover the K-1's sensor properly.

[Sam Dennis]

Thanks, she just let me know she could not resist ordering the Sigma Art - so this is a problem solved. Love this forum. Love Pentax. Love my old K10.

[Na Horuk]

Hope she doesn't have trouble with the Sigma Art AF! The DA 50mm f1.8, or better yet the DA* 55mm f1.4 can still be used alongside a 35mm lens The DA* 55mm is famous for nice bokeh and amazing portraits, and it has silent AF and WR. Premium lens!

[pres589]

I didn't think that the Sigma 35 Art had AF issues...

There's so many awesome pictures taken and shared here on PF.com with the DA*55 and the K-1 that it would be hard to ignore that lens.

[Na Horuk]

I didn't think that the Sigma 35 Art had AF issues...

I may be wrong? I seem to remember its not as bad as the 18-35mm, but its not quite 100%, either. But feel free to check more threads on this lens - I don't own the Sigma lens! Didn't mean to derail the thread
https://www.pentaxforums.com/userreviews/sigma-35mm-f1-4-dg-hsm-a1.html
Some reviews about the AF are a bit mixed. Its still a pretty stunning lens, though. And you can still use MF :P with a bit of practice, I got quite fast with MF on my older manual lenses

[Paul the Sunman]

The Sigma 35mm Art is just fine on my K1, though it consistently over-exposes on the K3. However, your sister should make sure the lens she bought has the new bevelled mount so that it doesn't scratch the K1 body. If it's old stock, it may still be the original mount. If so, Sigma swap the mount free of charge.

[timautin]

I find the DA50 (and the 35) excellent (given the price, size and weight) with the K1, for landscapes at f8-11. I didn't really try shooting something else. She can still order the 50 and sell it if she doesn't like it, it's so cheap!

[clackers]

These were all shot with the DA50 and the DA35 'plastic fantastics' one afternoon on the K-1.

[pres589]

These were all shot with the DA50 and the DA35 'plastic fantastics' one afternoon on the K-1.

clackers, what are your two cents regarding the DA50 and the K-1, especially considering vignetting and IQ in corners?

[clackers]

clackers, what are your two cents regarding the DA50 and the K-1, especially considering vignetting and IQ in corners?

It's fine. May even vignette less than the FA31 wide open at infinity.

People who've only shot APS-C don't realise how spoilt they are.

Plenty of legacy and modern FF lenses vignette wide open.

In an age of post-processing, they're not a problem.

[Na Horuk]

In an age of post-processing, they're not a problem.

Yea. And it can be used for artistic effect - a lot of people add vignetting digitally to emphasize the subject.

The DA 50mm f1.8 comes from the optical lineage of M 50mm f1.7, A 50mm f1.7, F and FA 50mm f1.7. Its a long line of FF lenses, with minor tweaks throughout the decades. The DA mostly has rounded aperture blade and better lens coatings than the old ones.
You can use the sample photo archive to look for photos taken with DA 50mm on K-1:
Pentax Camera & Lens Sample Photo Search Engine - PentaxForums.com
SMC Pentax-DA 50mm F1.8 Reviews - DA Prime Lenses - Pentax Lens Reviews & Lens Database
There is also a thread "DA lenses on Full frame" with user tests done to see which DA lenses are good, and just how good, on FF.

Think OP already made their decision, but posting in case anyone searches for this info sometime later

[timautin]

A few pictures with the DA plastic wonders on the K1 in FF mode:

DA35:













DA50:







EDIT: I attached 100% crops of the last image (taken with pixel shift).