Is anyone using a Pentax 300mm f4 Star lens with the Pentax k to micro four thirds?

Just wondering if anyone has tried this particular set up? I already use a Concept adapter to use my Pentax glass on my Fujifilm  cameras and it works great.  So I thought why not use why not take  advantage of thr crop factor with my GX8  & GX7 to get some great long distance shots.  I would appreciate any info if others have tried this out.  Cheers in advance 👍

John Cal wrote:

Just wondering if anyone has tried this particular set up? I already use a Concept adapter to use my Pentax glass on my Fujifilm cameras and it works great. So I thought why not use why not take advantage of thr crop factor with my GX8 & GX7 to get some great long distance shots. I would appreciate any info if others have tried this out. Cheers in advance 👍

Not sure which Pentax 300mm f4 lens you are referring to. I have the Asahi Pentax Takumar 300mm f4, and I have used it with m4/3 and it worked well. I can get some CA if shooting wide open. I also have the Olympus 75-300mm f4.8-6.7. Not yet sure if it is sharper than the older Takumar 300mm f4, but it sure is smaller and lighter.

Also have the Asahi Pentax Takumar 400mm f5.6 used here with an Olympus EM1. Example of a Scrub Jay at a farther than optimum distance, but it shows what the results can be.  I used a tripod and found focus to be easy to accomplish.

400mm Asahi Pentax Takumar - Original with Topaz AI Clear

The next image is from the same image, but I used Gigapixel AI at 4x to zoom in on the Scrub Jay. Considering the 800mm with crop factor, the resizing by 4x, the reach is in the ballpark with the Nikon P1000 super bridge camera, but with a somewhat larger sensor.

4x crop with Topaz Gigapixel AI

John Cal wrote:

Just wondering if anyone has tried this particular set up? I already use a Concept adapter to use my Pentax glass on my Fujifilm cameras and it works great. So I thought why not use why not take advantage of thr crop factor with my GX8 & GX7 to get some great long distance shots. I would appreciate any info if others have tried this out. Cheers in advance 👍

I used one on an IR converted PL-8. Not ideal; no aperture ring and of course manual focus, which is tricky on a 600mm equivalent prime lens except for a static subjects. But otherwise it's a great lens, worth a try.

If you are talking about the DA*, then you'll need an adaptor with aperture control otherwise the lens aperture will remain shut at f22 (whatever the min is).

RSTP14 wrote:

If you are talking about the DA*, then you'll need an adaptor with aperture control otherwise the lens aperture will remain shut at f22 (whatever the min is).

Hi Roger, I'm aware of that and ordered the adapter with the aperture contol, the same as my Pk to Fujifilm adapter which works well on my Fujifilm bodies.

Cheers

John

Wow that looks great. I have DA star f4 300mm so it looks like it may be a winner 🏆 thanks for sharing your photos much appreciated.

Kind regards

John

John Cal wrote:

Wow that looks great. I have DA star f4 300mm so it looks like it may be a winner 🏆 thanks for sharing your photos much appreciated.

Kind regards

John

You will need to develop a feel for how much to stop down that lens to get good results. Wide open on these older lenses is usually not nearly as good. The adapter you will be using is not likely calibrated in true f-stops. In that case, just make note of how far you have to go to get the best results. The lens will likely have a sweet spot were it is the best.

And use Aperture Priority Mode so that shutter speed can vary, and it is best to choose Auto ISO.

And I turn off shake reduction when on a tripod and I use a remote shutter release.

Good luck using this lens.

Thanks mate I post some pics when I get the adapter.

Yes I guess it will take a while to fine tune the best settings I post some images when I get the adapter. Thanks for the advice 🙏

Mike Micro 43 wrote:

John Cal wrote:

Just wondering if anyone has tried this particular set up? I already use a Concept adapter to use my Pentax glass on my Fujifilm cameras and it works great. So I thought why not use why not take advantage of thr crop factor with my GX8 & GX7 to get some great long distance shots. I would appreciate any info if others have tried this out. Cheers in advance 👍

Hi,

Yes I use the Pentax-A 645 300mm Green Star with 2x teleconvertor for moon shots. It works really well with my Olympus EM-1 mkII, although focussing is a bit tricky!

I've recently tried it with both the 2x teleconvertor and the 1.4x teleconvertor (2nd shot) and this seems to work pretty well too. I think it's great the way you can stack teleconvertors...

Actually the Pentax 645 2 x teleconvertor is really good - super sharp. It works well with my Pentax 645 120mm F/4 Macro well too.

Mike.

Oly EM-1 mkII + Pentax-A 645 Green Star 300mm F/4 at F/5.6 + 2 x Teleconvertor

Oly EM-1 mkII + Pentax-A 645 Green Star 300mm F/4 at F/5.6 + 2 * Teleconvertor + 1.4 x Teleconvertor

Awesome shots Mike 👏.  I'm looking forward to getting my adapter, moon shots are one of the reasons for buying it. I hope I can do it justice your shots are excellent 👌