[f22]

I currently have the DA 18-135mm f/3.5-5.6, the DA 50mm f/1.8 and the DA 55-300mm f/4-5.8, all APC-S Crop Pentax lenses. Has anyone been able to use these lenses in FF mode on the K-1 body without vignetting or other issues?

I'm interested in repurposing these lenses from my K-50 until I can eventually get some FA lenses for the K1. ANd I'd like not to have to put the K1 in Crop Mode unless these lenses flat out won't cover the K1 sensor in Full Frame mode.

Has anyone tried these lenses on the K1 in FF mode, and what was the outcome?
Thanks in advance.

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Last edited by f22; 11-23-2016 at 11:24 AM.

[BigDave]

I have not tried these specific lenses but my advise is give them a try. Manually put the K-1 into FF mode and see where the vignetting starts. I have a 10-20mm sigma and it is fine from 20mm down to about 14mm. Below that vignetting increases as I zoom down to the 10mm setting. You may find that the lenses have more coverage than just the APS-C format, so you may get something between APS-C and FF.

I'm with you on this. You bought the glass, now get some use out of it!

Regards,

[f22]

Thank BigDave. Yes, I am trying to extend the use of these from the Crop world I live in now. I am not yet in possession of the K1, which is why I posed the question to those specific lenses that have tried already. I figure if I can immediately starting using what I've already got successfully, I'm going to just buy the K1 body only, instead of a bundled lens purchase.

[Adam]

I've tested all DA lenses on the K-1 and am working to summarize the results.

Most lenses have either dark corners or blurry corners at one or more focal lengths. The 18-135mm is particularly bad, but the 55-300mm is usable at the tele setting with only minimal cropping.

The only lenses that work perfectly are the 200, 300, and 560mm. The DA* 55 and DA 35mm F2.4 come very close, too.

Adam
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[pathdoc]

I have not noticed significant vignetting from the DA50/1.8 in the limited use I have put it to on later Pentax film bodies; however, the pictures I took had relatively dark backgrounds which would tend to mask it, and were informal candid shots on which small imperfections would not be of much significance. They were also taken in P mode with flash, which means stop-down to between f/4 and f/8 AFAIK, and that might again affect the lack of problems I noticed.

[lytrytyr]

I currently have the DA 18-135mm f/3.5-5.6, the DA 50mm f/1.8 and the DA 55-300mm f/4-5.8, all APC-S Crop Pentax lenses. Has anyone tried these lenses on the K1 in FF mode, and what was the outcome?

Check out the DA lenses on

PENTAX K-1 Laboratory | PENTAX K-1 Special site | RICOH IMAGING


Here's another tip:

If you correct (or even overcorrect) for barrel distortion in PP,
that changes the rectangular image to a pin-cushion,
stretching out the corners.

Often, that's good enough to eliminate vignetted or otherwise poor corners.

[Kevin B123]

There is also the square crop mode, the DA lenses should work fine in that if can live that. I don't have one to test that out sadly

[VoiceOfReason]

The 18-135 slightly vignettes on APSC cameras. No way will it work well on the K1. I haven't even attempted it due to that.

[surfar]

The !8-135 is crop mode only,....some people report that the 50f1.8 vignettes, well I find it usable(will test it again soon)


!8/55 usable from 24mm....55-300 useable...16/45 usable from 20/22ish....50-200mm usable from around 60mm


DA 40ltd useable..






And it can depend on the background too....if its blue sky vignetting will definitely be noticeable, other darker backgrounds and some slight vignetting is disguised






So,OP 2 out of 3 are ok.....the 55/300 is my most used lens on my K1




the" square crop mode, the DA lenses should work fine in that if can live that. I don't have one to test that out sadly "


Very SAD!....But I tested all my Das that vignetted in FF mode and square mode eliminates some....and the square mode suits some photos(thanks Ricoh!)

---------- Post added 11-24-16 at 06:56 AM ----------

https://www.pentaxforums.com/forums/attachments/16-pentax-news-rumors/324333d...e-imgp1979.jpg


This is from K1, just a jpg resized...no PP....its from the 55-300 DA, and I may have had a 1.4x TC on too(cant recall)

[Na Horuk]

This thread might be of assistance: https://www.pentaxforums.com/forums/54-pentax-lens-articles/31629-da-lenses-f...ts-thread.html

Also, this tool for quick searches (The Image Format option): Pentax Lens Search | PentaxForums.com

[f22]

Thanks to all for the great feedback, suggestions, and for the links to other useful sites on this topic! Thank you all.

It seems it's worth the plunge to get the K1 body,and experiment with each of my lenses to see which may work with minimal vignetting. I'd rather crop a bit off the margins in PP than reduce to 15 MP Crop Mode. The K-1, even in APC-S mode, would offer better DR, higher ISO range, and Pixel Shift technology, than the K-50 has. I really am very happy with my K-50 results with these lenses. I guess the real issue is not just the image circle, but chromatic aberrations or geometric distortion using DA lenses in FF mode with these too? Or is that a non-issue?

[RobA_Oz]

I'd rather crop a bit off the margins in PP than reduce to 15 MP Crop Mode.

As mentioned above, don't ignore the optional square crop mode in the K-1, which provides a different way of seeing your subject, or a harking back to the past for those who used film of various sizes with 1:1 aspect ratios. Your photos in square crop will reduce from 36 to 24MP, as a result, as well as avoiding those embarrassing vignette corners.

[f22]

As mentioned above, don't ignore the optional square crop mode in the K-1, which provides a different way of seeing your subject, or a harking back to the past for those who used film of various sizes with 1:1 aspect ratios. Your photos in square crop will reduce from 36 to 24MP, as a result, as well as avoiding those embarrassing vignette corners.

I'll definitely try that once I get the camera and see how that works. Thank you and KevinB123 for first posting the idea. That is definitely a good tip!

---------- Post added 11-23-16 at 06:38 PM ----------

The !8-135 is crop mode only,....some people report that the 50f1.8 vignettes, well I find it usable(will test it again soon)

That's surprising. When I first saw the K-1 made available, it was shipping with the 18-135 lens as a kit. And more surprising is that it was listed as Discontinued by Pentax at that time.

[surfar]

The 18-135 is still in production and ships as a kit lens with the K70,I've never seen any K1s as a kit...always body only.Perhaps the 28-105 could be considered the "kit"lens for the K1?

[MikePlunkett]

I've used the DA 50mm f1.8 in FF on the K-1 and have been very happy with the results. I've seen evidence that it vignettes a bit wide open, but at f8 for example it works beautifully.