K1 in crop mode. How is it for you?

I am heavily invested in DA lenses, with no immediate intention to change any, but am attracted to the possibility of the K1 as an upgrade to the K3II, so for those of you with the K1, how does the crop photo quality compare to your APS-C bodies please?

Thanks Smudge.

Don't forget that some DA lenses aren't far off full-frame (DA*55 and DA70 for example)

Thanks LennyBloke. That would be an added bonus.

I'm loath to start changing out perfectly good DA glass though, (a) because I like the added 'range' offered especially on the longer lenses, (b) the additional weight of D-FA glass vs. DA equivalents, (c) I can use my DA lenses with any of my five APS-C bodies, and (d) the cost.

I slightly regret selling the DA 50-135mm as it was excellent for what it does and i think I would have been happier keeping it and using it in crop than using a tamron 70-200mm in ff.

But back to your question: it really depends on your lenses. And if you shoot crop you will still have an improved af, good live view, the tilting screen, etc. Lots to look forward to!

I have used a few DA's, because I'm not keen on buying a 15-30 that doesn't take filters (without scaffolding).. The 10-17 is fine from 15mm. The 12-24 is fine from about 18mm. Also the 35mm f2.4, 50mm f1.8, and 70mm f2.4 all seem fine. The Sigma 18-35 f1.8 is supposed to be ok from 24mm. My 300mm and 560mm are also fine

Thanks Alan. Do your comments relate to DA lenses in crop or FF mode please? My thinking is to use the K1 in crop mode only in order to get full sensor coverage from my DA lenses.

I'm referring to the FF mode John. In crop mode it is very similar to a K5iis with better AF

Any DA lens will work on the K-1 the same as on a K5iis at the same resolution and will, by default, use them as APS-C lenses. However many DA lenses cover a larger area than an APS-C sensor and the K-1 can be made to over-ride the default APS-C setting and use them at either full frame or 1:1. Some DAs are completely acceptable at full frame, and some with only marginal loss of definition and/or vignetting, Two of Pentax's cheapest lenses, the DA35mm f2.4 AL and DA50mm f1.8 perform particularly well in full frame mode being based on earlier 35mm film lens designs.
If you indicate which lenses you are concerned about I'm sure someone will have tried them by now and report about their level of compatibility if that might be of interest.

Thanks JAK, but my concern is simply will photographs made using my DA lenses on a K1 in crop mode result in the same or better IQ when compared with the output from my K3II, all other factors being identical.

Well there's no AA filter, so not quite the same as a K5ii and the dynamic range is slightly higher on a K-1, but only marginally so there are differences. Why not compare the images at http://www.imaging-resource.com/PRODS/pentax-k1/pentax-k1-image-quality.htm and http://www.imaging-resource.com/PRODS/pentax-k5-ii/pentax-k5-iiA7.HTM because you know what you're looking for?
Often the ultimate IQ depends on the processing of the image and your work flow to achieve that. Given the same lens on either body I would say the final images should be close but with slightly better definition from the K-1 due to lack of the AA filter. They won't be the same because they use different sensors, but certainly similar as both come from the same stable.

Thanks JAK, but although I have a K5II, it's the K3II (which I also have) that I want to compare the K1 against. Could be then that the K1 with DA lenses would not be a significant upgrade over the K3II with the same DA glass, but clearly would be if I bought FF lenses to go with it.

It depends on the DA lenses you have (we've been here before!) Some DAs are compatible in varying degrees (but some aren't.) You may well be able to use your DAs in FF mode but I've said that without knowing which you have so can only say that in general terms.
The K-1 has nowhere near the image noise of the K3 variants and as regards APS-C mode will be closest to the K5iis. Some regard the IQ of the K-3 variants as being inferior to the K-5iis (but I'm not in that camp myself and still use my K-3 on occasion.)
Getting FF lenses would make sense in the longer term if you get a K-1, but you may not need or even want to ditch your DAs. Some DAs are FF in disguise!