[pendennis]

I own a Vivitar 200 f3.5 TX with the M42 TX adapter. I've been looking for a TX K Mount adapter, but with no luck, so far.

I don't want to "Rube Goldberg" this, but would there be any disadvantage to mounting a M42-to-K on the M42 TX?

PS - I have a "Wanted" post looking for a TX K Mount, but no replies yet.

[Just1MoreDave]

The lens should mount fine with no trouble. I can't remember if you'll have trouble with the aperture. If the M42 to TX adapter has an Auto/Manual switch, you can use it. But if it doesn't, it's like the T4 adapter - the only way to close the aperture blades to the aperture ring setting is to push in the M42 pin. Then you have to modify the adapter to get manual aperture control, using the ring.

[marcusBMG]

There are posts discussing this - links can be found if you browse relevant lens reviews (search soligor and vivitar). the T4/TX M42 mount has a momentary switch, that is you have to hold it to keep the aperture closed, so either use an adapter to PK with a lip that depresses the auto pin (like this one), or, it's not difficult to "mod" the mount so that the pin is always "in" and rotating the aperture ring will close the iris.

[TwoUptons]

A Vivitar TX in K mount was one of my rare happy scores on Goodwill... and that took a while, so I feel your pain.

I haven't been particularly excited about the TX lenses I've tried, but I did get a 24mm recently that seems to really like my H1a. I have a roll in now I'm looking forward to...

-Eric

[Andy123]

I have both a 300mm and 24mm tx and t4 which I really liked when shooting film with a Fujica st901. Both were good. the 300 out performed most of my 300 mm zooms. I did modify the m43 t4 to hold the apeture even with the Pentax m42 kmount adapter but then it reduced the use ability for the screw mount film cameras. So while it is relatively easy to mod the t4 or tx to a manual apeture I agree the k mount adapter with the plate to activate the m43 pin is a better option.
Andy

[PDL]

I bought my Pentax TX adapter from KEH almost eleven years ago. I use it on my 300mm (originally for Fujica too, ST-801, ST901 and AZ-1) at least once a year shooting for The Seattle Piano Institute. I have also used it when shooting on vacation (New Zealand) and during a workshop shooting birds in the Skagit river delta. I still have the Fujica's and the Fujica mount. The lens is pretty good, rather low contrast, but the reach is what I need.

Keep looking, the adapters are out there. You might have to buy an additional lens to get the lens.