The DA/DA* series of lenses were designed specifically for the Pentax APS-C sized Digital Cameras. The Pentax APS-C sensor is 23.5mm x 15.7mm, and the DA/DA* lenses have an image circle big enough to cover the diagonal length of the sensor.
We don't actually know the image circle of every lens that Pentax designed for the DSLRs currently equipped with the APS-C sized sensors. What we know is that if the image circle is smaller than the diagonal of a FF sensor, vignetting will occur.Click on the picture to the above right to find out more about APS-C/FF
Although my lenses are comprized of more FA and C lenses, I have been building my DA/DA* lenses arsenal since my first Pentax DSLR, the *ist D. Currently I have the DA 10-17mm, the DA 18-55mm II, the DA 16-45mm, the DA 50-200mm, the DA 70mm Limited, the DA* 200mm and the DA* 300mm.
Last week, I decided to get a roll of 35mm film, have it developed in prints as well as on CD, and try all my DA/DA* lenses on an older 35mm SLR, the Pentax PZ-10. I chose the PZ-10 because it was the only old SLR in my very humble collection that had a working battery. Because the DA/DA* lenses have no aperture rings, I could only go by shutter priority. So my examples do not necessarilly compare the 35mm results with the K20D results, as I am not certain of what the aperture was on the PZ-10. However, it's a good reference to determine which lens will produce images acceptable on future FF DSLRs and which will produce too much vignetting. (Of course, you can always crop the vignetting portion) The film I used was Fujifilm Superia @ ISO 400. I took a picture with each lens attached to the PZ-10 and then did the same with my K20D set at ISO 400 in shutter priority (Sv). There was a few days between the shots with film and the shots with the K20D. So basically, I focused on a US flag we have in the parling lot at work, and stood approximately at the same place. The left photos were taken with the K20D and, of course, the right photos were taken with the PZ-10 .
So here are the results. I probably don't have to add many words, the pictures should speak for themselves. Here goes:
DA 10 - 17mm @ 10mm
DA 10 - 17mm @ 17mm
DA 18 - 55mm II @ 18mm
DA 18 - 55mm II @ 55mm
DA 16- 45mm @ 16mm
DA 16- 45mm @ 45mm
DA 50- 200mm @ 50mm
DA 50- 200mm @ 200mm (I guess the aperture must have been very small on the PZ-10 here.) There should be less vignetting at 200mm!
DA 70mm Limited @ 70mm
DA* 200mm @ 200mm
DA* 300mm @ 300mm
So...you can see that some of the lenses will be very compatible with FF DSLRs and some seem to have vignetting, specially in the wide angle portion.
Thank you for reading,
Yvon Bourque
UPDATE 10/18/2008 @ 7:10 P.M. Pacific Time.
I just realized that this topic is hitting home for many. If I get enough requests, I will go ahead and purchase a used Pentax AF 35mm SLR from EBay with the capability of selecting the aperture from the camera (I'm not sure which model does that). Following that, I will test every DA & DA* lenses in both formats, 35mm/FF and APS-C size. I will test each lens at all available aperture, using a tripod positioned exactly at the same place for all shots (35mm and K20D), and show the results here. Let me know your thoughts in the comments at the bottom of the post.
14 comments:
Very interesting test, none of the tested prime lenses showed vignetting.
It'd be good to know which aperture was used. I believe that lenses with no aperture ring used in old bodies will always work in the minimum aperture (F22-F32, depending on the lens), but I cannot assure it. If that's the case wider apertures may, perhaps, show some light falloff near the image corners.
Another possible issue is image quality near the borders. If the lens was designed for APS-C sensors, even if it covers full frame, the image quality in the borders of the FF sensor may not be good as in the APS-C area. Some aberrations such as field curvature, astigmatism, coma and image distortion are usually harder on the edges.
Yvon, it's a shame you don't have one of the film cameras that allows you to control the aperture from the body, then you could test vignetting at different apertures.
I'm not surprised by your results; the lenses that vignette are those zooms that were designed specifically to replicate the old 35mm FoV on APS-C. There is no point to using these lenses on a full-frame sensor anyway, so who cares if they vignette? :-)
Yvon,
Could you have a second look at the "DA 16- 45mm @ 16mm" shots? The AOV is smaller than for the 18-55mm shot...
Best,
Jostein
This test could really use a redo with apperture controlled.
I myself find the DA 70mm results most interesting. It seems as if there was some vignetting on the dslr. Were they shot with lense hood off/on?
Jostein,
I think that the 16-45mm K20D images are backward. The 16mm shot needs to be reversed with the 45mm sgot and vice versa. It was getting late and I was rushing to put the article on the blog. Thanks to pointing it out.
Miserere,
IFrom the "get-go", I knew this was not going to be a scientific test. It does show that the Primes do a heck of a lot better. My next step would be to get one of the latest Pentax 35mm SLD that the aperture can be selected from the camera. To be fully accurate, one would have to test one lens at a time and at every aperture, Maybe that could be a weekly topic with one lens a week. I'll see if I can find a used Pentax 35mm SLR on Ebay with that capacity.Other readers could also help with the lenses I don't have.
Cassio,
You are correct aboutsome problems at the edges. However, some could be fixed with some post processing. Remembering that only about 5% of the DSLRs are used by Professionals, it may not be as crucial to the average photographer as a hobby. My point is to show that if Pentax does produce a full frame sometimes in the future, you don't have to necessarilly change all of your lenses. Also, future FF DSLR will likely have more pixels to work with and cropping may still produce better pictures than the APS-c DSLR of today.
odyn, All shots were taken without the hoods.
Bonjour Yvon!
Tu ne cesses de nous épater par ton Blog!
Vraiment, tous ces articles (sur les produits) auxquels tu dois évidemment passer de longs moments à créer sont dignes de mention.
Nous devrions donc t'inscrire en nomination comme étant le "Pentaxian" le plus populaire.
J'invite donc tous ceux et celles qui ont contribué à ce site par leurs commentaires, de faire parvenir un courriel à Pentax et leur faire part de leur enthousiasme envers Yvon et son site Web!(Blog).
Sur une note différente: je remarque que dans ton dernier article sur la compatibilité des objectifs DA*/DA au format pleine grandeur (24 x 36 FF), on peut donc utiliser ces objectifs sur un appareil "normal", non-DSLR.
Cela prouvera encore une fois que les produits Pentax demeurent encore LE choix pour des années à venir.
Merci pour tous ces articles .... nous en sommes très appréciatifs!
JP
Hello Yvon!
You never cease to impress us with your Blog! Really, all those articles (about the products) to which you must obviously spend a long time to create, are worthy of mention. We should nominate you as being the most popular “Pentaxian".
Therefore, I invite all who contributed to this site with their comments, to email Pentax and to inform them of their enthusiasm towards Yvon and his Web site! (Blog).
On a different note: I notice that in your last article on the compatibility of the DA*/DA lenses to the full size format (24 X 36 FF), one can use these lenses on a 35mm SLR. That will prove once again that the Pentax products will still remain the choice for years to come. Thank you for all these articles…. we are very appreciative!
JP
Good work, Yvon.
My own limited "testing" has produced similar results. The 40mm and 70mm DA primes seem to work just fine for full frame but the 21mm vignettes very heavily. From looking through the viewfinder, my 16-45 seems to be OK from about 21mm onwards but that's just through the finder. It's a pity that Pentax don't appear to have any plans to introduce a full frame
DSLR because they could steal a march on the competition when it comes to size and weight.
It would be nice to know what the aperature was on the 35mm camera. Is there a way to find out?
Yvon, you truly are a master Pentaxian, that's for sure. I just have one question to ask about DA and full frame. Is it true that some DA lenses are at risk of damage in a 35mm SLR? I seem to remember there was some indication that they protrude farther into the camera body than 35mm lenses.
Michael,
I don't believe that would be an issue. There is plenty of room between the mirror and the lens flange. Measuring my 35mm camera, there is 19.78mm from the edge of the mirror to the face of the lens mount flange. On the K20D, the dimension is 18.31mm. That is 1.5mm shorter so the DA lenses have approximately 1.5mm more room when used on a 35mm camera.
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