[08amczb]

My silver KP arrived today. Here is my first impression after setting up lightroom defaults and playing a little with the camera. (I'am swithing from a K-30)

-The per pixel high ISO performance is approximetly 1.5 stops better, this with the resolution increase means my auto ISO limit increased from 1600 to 6400. "Emergyency" high ISO pushed to 25600 now.
-The new front dial firs looks uncomfortable, but it's very well placed, so it's comfortable.
-The grip is not as comfortable as the K-30. Ok, I have realy bg hands, but this is the most annoying thing now. I hope it gets better while Iam getting used to the KP. (I'am using the large grip and my favorite lens is the 50-135.)
-Pushing the ISO slows down the camera, it definitly cooks the RAW files, but I don't care, the results are realy good and the slow down doesen't seems a real problem.
-Costumizability is just great.

I'am going to an event today, I will try out the camera there.

[Imp]

Thanks! Keep us posted!

[rawr]

Pushing the ISO slows down the camera

Seems inevitable. With any camera, the images (RAW especially) get a lot bigger as ISO climbs higher, hence pushing the files around the system gets slower.

All of the specs used for camera fps, buffer performance etc in the industry, inc Pentax, are at ISO 100.

[08amczb]

For showing the image on the back screen the image processing algorithm needs all pixels, there is no compression, so file size is independent from ISO. Write out speed is influenced by the ISO of course, but the KP shows the image before it has finished writing out, so the slow down, wich kicks in at ISO16000 must be some software tweeking. After my first event I think the slow down isn't a problem at all.
I forget to write, the sutter is so much more silent than the K-30.
See my yesterday experience here:
KP first event shooting experience - PentaxForums.com

[anu l]

Seems inevitable. With any camera, the images (RAW especially) get a lot bigger as ISO climbs higher, hence pushing the files around the system gets slower.

All of the specs used for camera fps, buffer performance etc in the industry, inc Pentax, are at ISO 100.

This could also mean that Pentax is using a high quality noise algorithm with the KP to have better high ISO performance.

Other than ISO performance, the biggest curiosity is how well the KP performs in continuous tracking AF and how it compares with D7200 and 80D.

[08amczb]

Today I've done some testing on AF-C performance. A little later I will upload 100% crops from the frames.
Reviewing on the back of the camera I think we will continue complaining, but it's not completly unusable. (Definitly better than my K-30, but I've never used a K-3, so I can't compare.)

---------- Post added 03-04-17 at 05:03 PM ----------

And here are the test cases and images:
Pentax KP Continous focus test - PentaxForums.com

[rawr]

For showing the image on the back screen the image processing algorithm needs all pixels, there is no compression, so file size is independent from ISO.

It's an interesting topic. File size is certainly dependent on ISO for RAW's - normally with any camera, high ISO = more [hard to compress] noise = more data = bigger RAWs than low ISOs. A good related article:

Why Higher ISO Leads to Larger File Sizes

[08amczb]

Compression is the last step before writing to the card. Processing done on the non compressed "full" data. I know image processing, because I built a digital X-ray machine once. Only the write out speed influences the available RAM size, so the high ISO file size only affects indirectly the image processing. Altough they can use different algorithm for high ISOs so cooking the RAW. I think this is the case.

[08amczb]

The KP hardly has any hot pixels in long exposeur! I've shoot at 20 minute, F8, ISO 100, slow shutter speed noise reduction off, and it was hard to find hot pixels. Fnally I found some in darker areas, but I noticed them only in 400% zoom. (Approximetly 8C degree = 47F degree out there now.)