Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
07-07-2022, 07:16 AM - 1 Like   #1
Veteran Member
Julie's Avatar

Join Date: Aug 2010
Location: Illinois
Photos: Gallery | Albums
Posts: 1,069
Lens Compatibility K-1/K-1 MKii

Hi all,

I haven't been active here in years, but I'm still a Pentax shooter (KS-2 and K-01 currently).

Looking to possibly add a K-1 MKii, I just wanted some clarification on the existing lenses I own and comparability.

I have a Sigma 18-35mm 1.8 DC Art and Sigma 17-50mm 2.8 DC EX HSM. From my understanding, both lenses should PHYSICALLY work on the K-1 because they're K-mount AF lenses, I will probably just get vignette, especially on the wider end? (if they won't work, what are some other comparable lenses? I'm fine with manual focus legacy glass, if that means saving a good chunk of $$$).

Also, if I do add another lens, I'm thinking Sigma 35mm 1.4 DG HSM Art - this will work fine both on Full Frame and my existing APS-C DSLRs, or no?

07-07-2022, 07:37 AM   #2
Unregistered User
Guest




QuoteOriginally posted by Julie Quote
Hi all,

I haven't been active here in years, but I'm still a Pentax shooter (KS-2 and K-01 currently).

Looking to possibly add a K-1 MKii, I just wanted some clarification on the existing lenses I own and comparability.

I have a Sigma 18-35mm 1.8 DC Art and Sigma 17-50mm 2.8 DC EX HSM. From my understanding, both lenses should PHYSICALLY work on the K-1 because they're K-mount AF lenses, I will probably just get vignette, especially on the wider end? (if they won't work, what are some other comparable lenses? I'm fine with manual focus legacy glass, if that means saving a good chunk of $$$).

Also, if I do add another lens, I'm thinking Sigma 35mm 1.4 DG HSM Art - this will work fine both on Full Frame and my existing APS-C DSLRs, or no?
All about your Sigma lenses.
Sigma Lenses - Pentax Lens Review Database
07-07-2022, 07:53 AM - 1 Like   #3
amateur dirt farmer
Loyal Site Supporter
pepperberry farm's Avatar

Join Date: Dec 2014
Location: probably out in a field somewhere...
Photos: Gallery | Albums
Posts: 41,283
QuoteOriginally posted by Julie Quote
Hi all,

I haven't been active here in years, but I'm still a Pentax shooter (KS-2 and K-01 currently).

Looking to possibly add a K-1 MKii, I just wanted some clarification on the existing lenses I own and comparability.

I have a Sigma 18-35mm 1.8 DC Art and Sigma 17-50mm 2.8 DC EX HSM. From my understanding, both lenses should PHYSICALLY work on the K-1 because they're K-mount AF lenses, I will probably just get vignette, especially on the wider end? (if they won't work, what are some other comparable lenses? I'm fine with manual focus legacy glass, if that means saving a good chunk of $$$).

Also, if I do add another lens, I'm thinking Sigma 35mm 1.4 DG HSM Art - this will work fine both on Full Frame and my existing APS-C DSLRs, or no?

welcome back

you are correct - with Sigma lenses, anything with 'DC' in the title of the lens is an APS-C lens and will physically work on a K-1, as you stated, you should expect some vignetting...

the FF lenses from Sigma will have the 'DG' designation, such as the 35/1.4 you mentioned...
07-07-2022, 08:16 AM   #4
Veteran Member
Julie's Avatar

Join Date: Aug 2010
Location: Illinois
Photos: Gallery | Albums
Posts: 1,069
Original Poster
QuoteOriginally posted by pepperberry farm Quote
welcome back

you are correct - with Sigma lenses, anything with 'DC' in the title of the lens is an APS-C lens and will physically work on a K-1, as you stated, you should expect some vignetting...

the FF lenses from Sigma will have the 'DG' designation, such as the 35/1.4 you mentioned...
Thanks, good to know! Didn't know that was what the "DC/DG" referred to.

So what would happen if I used the DG/full frame lens on my APS-C DSLR? It would work, but not behave as a 35mm, it would effectively be like a ~53mm because of the 1.5 crop factor?

07-07-2022, 08:21 AM - 1 Like   #5
amateur dirt farmer
Loyal Site Supporter
pepperberry farm's Avatar

Join Date: Dec 2014
Location: probably out in a field somewhere...
Photos: Gallery | Albums
Posts: 41,283
QuoteOriginally posted by Julie Quote
Thanks, good to know! Didn't know that was what the "DC/DG" referred to.

So what would happen if I used the DG/full frame lens on my APS-C DSLR? It would work, but not behave as a 35mm, it would effectively be like a ~53mm because of the 1.5 crop factor?

yes - it would change the field of view, but that's all....
07-07-2022, 08:46 AM   #6
Seeker of Knowledge
Loyal Site Supporter
aslyfox's Avatar

Join Date: Aug 2016
Location: Topeka, Kansas
Photos: Gallery | Albums
Posts: 24,563
this article might be worth the time to read:

QuoteQuote:
The Crop Factor Unmasked
Field of View vs Focal Length on various formats
By PF Staff in Articles and Tips on Jul 23, 2014
Read more at: The Crop Factor Unmasked - Articles and Tips | PentaxForums.com
07-07-2022, 09:40 AM   #7
Forum Member
geko5766's Avatar

Join Date: Mar 2009
Location: Trier
Photos: Gallery | Albums
Posts: 80
Hi there,

greetings from Germany.

These Abbreviations mean , if I do remember well: DC --> Digital compatible (APS-C) and DG --> Digital Grade (FF)
Please find a short list for Sigma lens explanantions here: https://www.pixolum.com/blog/fotografie/sigma-objektiv-abkuerzungen
It is in German though, but I think SIgma offers something similar on theri international website too.

I do have the 35mm/f 1.4 DG Art, unfortunately the last one made for Pentax mount. I would not miss it, although it is not WR, the only point not so positive.
I always used to have some Sigma lenses esp. the old 24-70 2,8 DG, The old 70-200mm F 2,8 DG , the 15mm DG.

i ADORE THE 15MM f 2,8 fish-eye , a really great thing (diagonal 180°) and the 8mm f 3,5 circular fish-eye. Both great for Panos.

So all is fine. The 18-35 is an Art and as such, it has an outstanding image quality. There are many pics of our Luxembourg based member fs999 - btw. only a few km away from Trier - that show its great performance. However, the vignetting is more than visible and cannot be completely removed.

Hope this may help.

Best from Trier
Georg

07-07-2022, 10:04 AM - 1 Like   #8
Moderator
Loyal Site Supporter
Wheatfield's Avatar

Join Date: Apr 2008
Location: The wheatfields of Canada
Posts: 15,903
QuoteOriginally posted by Julie Quote
Thanks, good to know! Didn't know that was what the "DC/DG" referred to.

So what would happen if I used the DG/full frame lens on my APS-C DSLR? It would work, but not behave as a 35mm, it would effectively be like a ~53mm because of the 1.5 crop factor?
This old chestnut might help:
It's an approximation of what various sensor sizes do to the same image.
As an aside, that's the house my father grew up in.

07-07-2022, 11:57 AM - 1 Like   #9
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 28,186
This only gives info on Pentax lenses but it will give you clarity on the breadth of possible outcomes for a crop lens:

Full Frame Coverage of DA Lenses: Comprehensive Test - Gear Guides | PentaxForums.com
07-07-2022, 12:18 PM - 1 Like   #10
Moderator
Not a Number's Avatar

Join Date: Mar 2012
Location: Venice, CA
Posts: 10,510
Checking with the Pentax Forums Lens Compatibility Tool:
Pentax K-1 and Sigma 18-35mm F1.8 DC HSM (Art) - Compatibility | PentaxForums.com
Pentax K-1 and Sigma 17-50mm F2.8 EX DC HSM - Compatibility | PentaxForums.com
Shows Compatible w/ Limitations Crop lens may not cover FF image circle for both lenses.

You could always shoot in crop mode on the K-1/ii at a much lower megapixel count vs full-frame mode.
07-07-2022, 12:23 PM   #11
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 28,186
QuoteOriginally posted by Julie Quote
Hi all,

I haven't been active here in years, but I'm still a Pentax shooter (KS-2 and K-01 currently).

Looking to possibly add a K-1 MKii, I just wanted some clarification on the existing lenses I own and comparability.
Sigma DC lenses are “crop lenses” and DG are “full frame” as was posted earlier. Additionally I posted a link that shows the exact nature of using a crop lens on ff has different levels of coverage often, which is something only learned by testing. Using the crop mode on the k-1 (any version) gives almost the same number of pixels as using a k-5 (any version) or similar body (k-30, k-50, k-5ii etc.) This is quite a respectable crop mode. I don’t think the lenses will disappoint you on the k-1 but in order to leverage the full 36mp you’ll need ff lenses.
07-07-2022, 03:41 PM   #12
Des
Loyal Site Supporter
Loyal Site Supporter
Des's Avatar

Join Date: Jan 2014
Location: Victoria Australia
Photos: Albums
Posts: 6,410
QuoteOriginally posted by Julie Quote
Looking to possibly add a K-1 MKii, I just wanted some clarification on the existing lenses I own and comparability.
Welcome back Julie. Since you are familiar with APS-C and have some good APS-C lenses, have you considered a K-3 mark iii instead?
07-07-2022, 04:15 PM - 1 Like   #13
Loyal Site Supporter
Loyal Site Supporter




Join Date: Jun 2009
Location: Tumbleweed, Arizona
Photos: Gallery | Albums
Posts: 5,700
For the Sigma 18-35/f1.8 on the K1/K1mkII here is a link with some examples across the various focal lengths of the lens on a full-frame body. The example images are down at the bottom of the thread and continues on to the second page.It works well but is heavily vignetted even at 35mm.

07-08-2022, 06:05 AM - 1 Like   #14
Pentaxian
Oldbayrunner's Avatar

Join Date: Mar 2013
Posts: 1,661
Here's my outlook.....I find the beauty the K1's is the fact that you can use some Apsc lens in full frame mode with little vignetting yet have the ability to use any of them in it's crop mode if it is really heavy. Yes pixels are lost in crop mode, to be honest unless your planning on ginormouse prints it wouldn't be that noticeable as your still getting that lovely capture & light gathering ability lets say of a K5lls, which was one of my favorite cameras. Even then with today's software ability one can easily compensate for that for larger prints. I only sold my K5lls because of the K1 mkll being very close to it in crop mode. As I've used my K1 mkll more and more I've paired down my Apsc equipment to only only having one Apsc lens left which is a 35mm macro lens and gathered more towards Full frame. It's easy to start off with some of the older F lens that aren't expensive and perform well on the K1 and progress from there.

For me it's like having the best of both worlds of full frame and apsc and I use it accordingly.

Maybe the downside is that as one acquires more lower Fstop full frame gear the weight difference can be a consideration but at my age I don't do long treks and I've invested in lighter tripod gear with it's ability to handle lens like the Dfa 70-200mm f2.8, Dfa 15-30mm f2.8 & Sigma Dg 150-500mm and one learns to take less gear.

Last edited by Oldbayrunner; 07-08-2022 at 06:12 AM.
07-08-2022, 05:24 PM   #15
Loyal Site Supporter
Loyal Site Supporter




Join Date: May 2007
Location: Flagstaff, Arizona
Posts: 1,626
QuoteOriginally posted by Not a Number Quote
You could always shoot in crop mode on the K-1/ii at a much lower megapixel count vs full-frame mode.
I would suggest the opposite: shoot in normal mode, and crop later - if you have to! Some lenses will do better than others as to vignetting. As a scientist, my mode is always save ALL the date you have, and throw anything away later!! If data are gone, you can't get them back (n.b "data" is/are a plural number - a fact widely ignored) but you can choose to throw away at any time, after the fact.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
art, dslr, full frame, full-frame, hsm, k-1, k-1 ii, k1, lens, lenses, mkii, pentax k-1, sigma
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
K-1 MKII - How to set focal length of manual lens? kwtodd1255 Pentax K-1 & K-1 II 18 12-21-2021 02:33 PM
For Sale - Sold: NEW PRICE: Pentax K-1 MkII w/FREE Shipping Michaelina2 Sold Items 7 10-26-2021 12:53 PM
Two Lens Kit for a K1 MkII dhodgeh Pentax SLR Lens Discussion 22 07-26-2021 10:36 AM
Sensor in K1 MkII successor? biz-engineer Pentax Full Frame 119 04-22-2021 06:45 AM
K1 mkII + D FA 24-70mm F2.8 €1181,23 Franc Pentax Price Watch 4 08-31-2020 02:42 AM



All times are GMT -7. The time now is 07:30 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top