I agree with that, I'll try it again as I also have a rubber lens hood on it so maybe that is having a slight effect, albeit less than the obvious effect on the 28mm. It's easy to forget that the lenses are back to their normal 35mm status and that a wide angle isn't a standard lens any more!
Oddly, the cheap 35mm seems to be more useful than the 35mm limited on full frame.

I suspect the FAJ was downrated once the longer range 16-45 & 18-55's came on stream, but given one can pay £££ for full frame extreme wide angles (and I'd include anything from 20mm down in that), that FAJ is a little marvel. Glad I grabbed it as I can't think of any other similar lens for FF, it's hardly any larger than the 18-55.

+1 please!

Some real world images from the K-1 with DA lenses. All show the full frame out of camera jpeg downsized to 1000 pixels in Photoshop Elements for the forum.
I'll start with some truly budget lenses that many will already own.

DA 35mm f2.4 @ f7.1 (The plastic fantastic)


As far as I can see it is fully compatible with no obvious vignetting. I'm sure I read that its design is based on one of the older film 35mm lenses.

DA 50mm f1.8 @ f7.1 (The other plastic fantastic.)


Again absolutely fine. These report to the camera as crop lenses but the crop setting can be changed to FF instantly using the new mode dial (much better implemented than on other cameras requiring delving into menus.) Perhaps Ricoh/Pentax will rue the day they designated these as DA rather than DFA. By the way, that's a rook or crow in the sky in the centre, not a sensor issue with the camera (I hope!)

Now the limiteds.
DA 35mm f2.8 Ltd @ f7.1


Some vignetting here so not completely FF compatible, but extra width/height may well prove usable.

DA 21mm f3.2 Ltd @ f7.1


Vignetting more obvious here. Not to say it can't be used for FF in some instances though (eg a square image or letterbox panorama.)

DA 15mm f4 Ltd @ f8


Probably best kept to crop mode!

DA 70mm f2.4 @ f7.1


It might as well be a full frame lens. No issue whatsoever. In fact, that's good - here's another with it!
DA70mm f2.4 @ f6.3



DA 14 f2.8 @ f7.1


Not much use at all on full frame.

Should you have one of the original standard lenses supplied with the istD, Pentax's original digital offering, the FAJ 18-35mm, it is a full frame lens and covers practically the same field of view as the DA12-24 does on APS-C. So how does that perform?
FAJ 18-35mm @ 18mm f8



FAJ 18-35mm @ 22mm f8



FAJ 18-35mm @ 35mm f9


I guess it might find a place in many Pentaxians gadget bags again, 'cause it isn't bad at all. A decent 18mm lens for the price of that is nothing short of amazing. (I only acquired it within the last month!)

Another lens I tried today was a Pentax-A 28mm f2.8. You have to remember to focus it but it ought to be fine.
Pentax-A 28mm f2.8 @ f7.1


Well I got some vignetting on that which I hadn't noticed at the time. But I have had a rubber lens hood on it for APS-C so suspect it's caught the edge of that. With FF one has to remember these things!

And to finish today, a close up of a tulip with the Pentax-FA 50mm f2.8 Macro


This is the only image here I've cropped (a bit off the top !)

Hope all that helps.

I haven't got a DA40 Ltd to help (though have several M series pancakes as well as the XS.) To me it never really seemed a useful focal length for APS-C yet was my favourite on the ME. Many film compacts had 40mm lenses or thereabouts. So the DA40 might make a great standard lens on the K-1 if it proves to be compatible.

I've taken some more images today with the other DA limiteds I do have, this time outdoors so not of a blank wall! I'll post them here shortly. It should give a good idea of what is, and what isn't FF compatible. but even if they aren't compatible, they'll still work as intended in crop mode.

Competition is now up and running. Closing date midnight (BST) Sunday May 8th.

Sorry Alan, can't help you with that one. My nearest is a Sigma 150-500, which as it happens I also tried yesterday (500mm @ f6.3) :


That's the full frame image.

Out of interest, none of my lenses have failed to work as expected, albeit a Tamron Adaptall 2 105mm with an auto PK mount seems to over expose slightly.


Given it hasn't been used for yonks I might have taken it by surprise. The actual definition is excellent and the raw file can be corrected to give a good image.
The images are all out of camera jpegs reduced in Irfanview to 1000 pixel width for the forum.

Hope I've shown one doesn't have to spend a fortune on new lenses to supplement the camera purchase. The old non digital ones really are still good for it (as I was hoping.)

Yes you're right about the pixel density comparison. I very rarely do not need to crop an image so with the K-1 there will be a few more to spare.

This is an APS-C size image taken with a Pentax-F 28-80mm [email protected] in crop mode yesterday while I was trying things out (the lens came from a car boot sale a year ago.) It really wouldn't be significantly different if taken on an APS-C camera.



.... and much the same thing at full frame (same lens 80mm but @ f8 ) :

Thanks for your comments John. In K-1's crop mode they must surely be very similar to taking them on a K-5, K3 etc. All the full frame mode does on the K-1 is to force the camera to store the image from the whole sensor, saving the edges we haven't seen before. As I've discovered, some lenses work well for part of their focal range as well as a dedicated full frame lens, in the case of the extreme wide angles that was a bit of a surprise, and the fact that the 55-300 works OK as a full frame 300mm telephoto, albeit not quite as good as the DA*, but then it never did!
I bought a couple of newer FF zooms in preparation for getting the K-1 as all my existing ones are M or K series and I couldn't afford to get the latest FF Pentax offerings. While those old M & K's will work fine, it is a nuisance having to set the focal lengths continually for the shake reduction to work. A couple of older FF's came up here in the for sales section; one was a Sigma EX DG 24-60mm f2.8 and the other a SMC Pentax-FA J 18-35mm F4-5.6. Neither cost the earth and both are proving fine (thank you sellers.)
Some have said that to benefit from the new sensor, the latest glass is needed. Fine if one can afford them! But I'm of the opinion that any imperfections in older glass are less magnified when using them on a larger sensor (by a factor of 2/3rds) and the imperfections will only return to 'normal' when the image is cropped again (back to APS-C size!) This was the logic in the dim distant past so I doubt that has changed.
So at the end of gthe day, if one can squeeze a bit of extra width out of a lens in an area where definition isn't usually quite so critical, the DA's will often allow that. In the worst case scenarios you'll still get the field of view they were originally intended to have.
So if you're pondering a K-1 but think you'll need to spend a fortune on new glass, then you certainly won't. While dedicated new glass might be better, it certainly isn't essential.

SMC Pentax-DA 16-45mm ED-AL @19mm f6.3


19mm is the point the vignetting is almost eliminated. Vignetting significantly worse at wider focal lengths but from 20-45mm is unnoticeable and lens quite usable.

By comparison to an unshaved 10-17 this is the Sigma 8-16m HSM @14mm f7.1 (also unshaved!)
From 8 to 13mm the FOV is similar with edge blanked out like the Pentax/Samsung 10-17mm. I suppose shaving that might help too, or buy a Ricoh Theta.
Field of view achievable is slightly less than the 10-17 but is rectilinear.