I also have a K-70. I tested it on my pc, Ubuntu, updated kStars and the Indi drivers. Pentax DSLR Native driver, camera in MSC mode, bulb - what I have dreamt of since I started using Stellarmate/kStars a couple of years ago
I’ll update Stellarmate on my Pi4 and see if that also works (why wouldn’t it?)

Then please check in KStars running on the pi in the Indi Panel which pixel size is reported (it's get updated while taking the first photo). The k70 got 3.88, but it is stated 3 in my case. This leads to errors while platesolving because the fits header isn't correct.

If you get also 3, there is an error sonewhere, otherwise something is wrong with my Setup/Hardware.

I'm running Stellarmate 1.5.4

Pixelsize is also 3 here, I haven’t tried to change it.

Changing ISO works now as you described it @DrawsACircle

I usually stuck around at ISO800 when i do my 300 seconds exposures, but nice to know. Double checked it. Camera settings in INDI are updated and after the exposure camera is also set to the desired ISO (when disconnecting it). Great!

I think except the wrong pixel size and bit depth (now 8 bit, should be 16 i think) everything is working fine now as long as you stuck to MFT mode. PTP mode isn't working on 64bit sadly. Maybe Pentax updates their SDK when they release their new APSC camera this year (who knows).

Maybe it would be a good idea to remove the PTP mode. Don't know how many people still use a RPi 3 which only runs 32bit. LiveView would be nice... but i used to do focusing using a bahtinov mask on the camera display and then power everything else up. And maybe my carplug problem is then also gone. On the other hand, if someone uses an autofocuser i think liveview is needed, am i right?

But that belongs to Karl's decision.

I also usually stick to ISO800, but in case you want to change it, being able to do so remotely via kStars is a lot easier.
You don’t need liveview if you use an autofocuser, it shoots and calculate FWHM (the lower the better), adjust focus, repeats until the lowest value has been reached.
That’s also why being able to adjust both ISO and shutterspeed remotely is a must (I have an ASI EAF).

Ahhh... good to know. Never used an autofocuser, thought it will use for calculation a video stream.

But i switched from a refractor to a newtonian telescope a week ago. I read a lot about focus instability related to newtonian telescopes and that an autofocuser will save a lot of lightframes.

So LiveView is only usefull for planetary imaging (btw, tried this two days ago the first time using my ZWO 120mm Mini Guider attached to my 750/150, it worked, but i didn't know what i was doing. I got Jupiter and 3 of his moons, but way too bright. But sum stacking the ser file in siril worked... next time )

I have the autofocuser attached to my refractor and use a Bahtinov mask on my SW 200PDS Newt.
I’ll use liveview when adjusting focus on my newt.
I have only tried planetary imaging once, that was also with my K-70, video mode. I have considered trying to use my 120mini, still on my to-do list

I hadn't thought of sum stacking the live view video for planets--just assumed it wouldn't work because it was too bright. That'd be an interesting use case.

I am surprised ISO is working in MSC mode for you guys. For me, it says it changes, but when I go to the images, they're reporting the original ISO. The camera will change to the ISO if I unplug it and plug it back in, but that's kind of pointless. There's an old ISO issue in pktriggercord that they could never resolve, and I just assumed it was manifesting itself here.

The Ekos autofocuser routine relies on getting FITs images from the driver. Because the driver takes a long time to convert the image to FITs, the autofocuser routine is unbearably slow on anything less than a RPi4 (which makes it annoying slow instead of unbearably slow). So live view is nice for at least getting close. As is the ability to take a lower resolution picture in PTP mode, since that speeds up the FITs conversion.

(Hmmm, I did just have an idea though--I wonder if I can could add an option for the driver to downsample or clip the original image before FITs conversion, to speed things up. I'll add that to my list of things to look into).

@Noideaforanae - As far as the 64 bit question, is StellarMate actually running on a 64 bit OS? I'm using a 32 bit OS (Raspberry Pi OS / Raspbian) since I didn't see an improvement when I tried 64 bit Ubuntu Mate. Long story short, PTP mode should work on the Rpi4, if you're using a 32 bit OS.

However, if you are in fact using a 64bit OS, that would rule out PTP mode removal as being a possible solution to your car charger problem, since the 64bit version of the driver already builds without it.

(I have debated removing PTP mode support to make things less confusing. I decided against that path originally because I wanted to provide the maximum possible support. But as more people provide feedback, if the possible scenarios in which PTP mode could be useful keeps dwindling, perhaps that is a decision to revisit. I could, after all, make a separate driver that supported PTP mode available to those who wanted to compile it themselves).

@karlrees

Sorry... checked again... 32bit OS i think i messed something up. Since i am using a 32bit OS... PTP mode is still not working for me @drawsacircle Did you tried PTP mode and are you using a RPi4 too?

And you are right Karl. ISO settings in Ekos don't work. The ISO you set is written in the file header, but the cam is using heir ISO. Did some tests and checked the images. Look the same. One at ISO 100 and one at 102400. The second one should be only white and totally overexposed... but looks the same as the one shot at ISO 100

Cheered too soon

Last I remember, StellarMate was using Ubuntu Mate. Is that still the case? Also, did you install from the package, or compile it yourself? This may be the issue where the toolchain on Ubuntu Mate doesn't compile libricohcamerasdk correctly. (One of the many frustrations that could be solved if Ricoh would just open up the SDK, or even just recompile it).

Just before the camera takes a picture, the screen blinks a couple of times, shows the ISO set on the camera. But when you check the FITS file afterwards it shows the ISO chosen in EKOS. I can also see the stretch values in the FITS viewer changes.
I just checked ISO800, not ISO102400, so you're right Noideaforaname, we did celebrate too early.
I'm pretty sure though, that I've been able to change ISO using PkTrigger, but I might be wrong.
Anyway, setting exposure time for me is a huge step