DA Limited lenses on the K-1


garywil

Link Posted 11/12/2017 - 22:18
Hello,
Do the DA Limited lenses (15MM, 21MM, 40MM, and70MM) have a sufficient image circle to permit use on the K-1 camera in 1:1 crop without imposed top/bottom crop?
Thanks

smudge

Link Posted 11/12/2017 - 22:44
The 15mm and 21mm are only suitable for use in crop mode. I have the XS version of the 40mm, which works well in F/F with only a small amount on vignetting at f2.8 which improves when stopped down. I imagine the 40 ltd would perform in the same way. The 70mm performs very well in F/F with less vignetting than some designated F/F lenses.
Regards, Philip

smudge

Link Posted 11/12/2017 - 23:09
Just to add to my previous comment, I just tried the 40mm on the K1 in 1:1 crop mode and the coverage is good even at f2.8. The 21mm has to be stopped down to f8 to get good 1:1 coverage. The 15mm cuts the corners even at f11.
Regards, Philip

ronniemac

Link Posted 11/12/2017 - 23:10
I've just run a quick test on the 5 DA Limiteds wide open and then stopped down to F8 and F22 with the K-1 set at 1:1 crop.

The 15mm has vignetting issues at all F stops, but the others are fine. There is some slight vignetting with the 21 wide open, but I was able to correct this easily in post processing, it's okay at smaller apertures.

If you want, I can upload to Fickr and share.

It's nice that four of these lenses are good on K-1 at 1:1 crop

Never have I photographed a magnolia wall with such intensity!

PS Smudge, I was still writing when you posted. Looks like we have reached the same conclusions.
Last Edited by ronniemac on 11/12/2017 - 23:14

smudge

Link Posted 11/12/2017 - 23:22
Yes, it's been an interesting exercise. I have never used the 1:1 crop before but I may well do in the future - it widens the range of suitable lenses considerably.
Regards, Philip

garywil

Link Posted 11/12/2017 - 23:38
Thanks so much for your investigations Smudge and Ronniemac. I don't yet have the K-1 but have had this question in mind for quite some time. I have thought that these small lenses might open some real possibilities in FF at 1:1. Many years ago, the Hasselblad SWC with its 38MM Biogon rendered what would be the equivalent of a 16MM on the K-1 if used with a 1:1 crop. Thanks again to both of you for your thorough answers.

ronniemac

Link Posted 12/12/2017 - 00:31
It's worth noting that quite a few Pentax primes work in FF on the K-1 - approximately 15 current lenses last time I counted, plus one zoom. Some of these are based on earlier lenses designed for film. It's also good to know that every DA lens will work in APS-C crop mode anyway.

Although the best results are from new lenses specifically designed for FF digital, I am having a lot of fun a whole raft of inexpensive A and FA legacy lenses.

This link will let you see my magnificent magnolia wall through all 5 Limited primes at f/22, f/8, and wide open apertures.
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