[Sigmoid]

I have their 645 to K adapter. It also mounts the lens slightly rotated. This has never bothered me, because I don't have any lenses with non-rotating feet.

What has bothered me with it was internal reflections. It really needed to be flocked. After doing that it was fine. (Originally I used a piece of black sock, later I bought flocking material on ebay. Performance was fine with the sock too.)

Thanks for the input.

[Sigmoid]

Hey, guys-

My search for a workable solution to the 400mm f4 6x7-to-K Mount setup continues.

I purchased a used-but-like-new genuine Pentax adapter from KEH. Does anyone know what the function of the little threaded knob on the side of the adapter? Looking inside, the knob location seems totally blank.

What could its function be?

Sig

[nightfly]

Hey, guys-

My search for a workable solution to the 400mm f4 6x7-to-K Mount setup continues.

I purchased a used-but-like-new genuine Pentax adapter from KEH. Does anyone know what the function of the little threaded knob on the side of the adapter? Looking inside, the knob location seems totally blank.

What could its function be?

Sig

When used with 67 lenses with a built-in tripod mount, this adapter allows the camera to change its position vertically or horizontally while the lens remains on the tripod.

[Sigmoid]

When used with 67 lenses with a built-in tripod mount, this adapter allows the camera to change its position vertically or horizontally while the lens remains on the tripod.

Thanks for the information!

Yes, I see! I finally got enough hardware pulled together to mount it on my HD Feisol tripod and discovered how it works.
Unfortunately, the large diameter of the focus ring makes it really challenging to make the lens fit on my new Wimberly-knockoff gimbal head so I'll have to address that issue next.

Sig

[sbjornda]

I recently acquired the 6x7 Bellows. It uses the external bayonet to attach to the camera. This is my first piece of equipment that uses the external bayonet.

I have a cheap 6x7->K adapter but it only uses the internal bayonet.

I bought a better quality 6x7->K adapter from KEH that has flanges for external bayonet but its locking mechanism doesn't work with the bellows, so my K-mount camera ends up rotating freely when mounted to the bellows. Not a good idea.

The bellows seem to need the locking mechanism where the locking pin protrudes through the mount, just like the camera body does. However, the second 6x7->K adapter I bought seems to release via a little button on the side of the barrel, like the auto extension tubes (for inner bayonet) do. Ironically, the first 6x7->K adapter I bought does have the locking pin, but lacks the external flanges.

Does anyone know of a 6x7->K adapter that has both the external flanges and the locking pin that works like the camera body does?

Thanks,
Sterling

[LisaXXDavidson]

The only reason I am thinking about doing it is to save weight. My lens is so heavy already, and an ME Super would not be much to add to it. An 67ii is certainly a lot heavier.

[gofour3]

I recently acquired the 6x7 Bellows. It uses the external bayonet to attach to the camera. This is my first piece of equipment that uses the external bayonet.

I have a cheap 6x7->K adapter but it only uses the internal bayonet.

I bought a better quality 6x7->K adapter from KEH that has flanges for external bayonet but its locking mechanism doesn't work with the bellows, so my K-mount camera ends up rotating freely when mounted to the bellows. Not a good idea.

The bellows seem to need the locking mechanism where the locking pin protrudes through the mount, just like the camera body does. However, the second 6x7->K adapter I bought seems to release via a little button on the side of the barrel, like the auto extension tubes (for inner bayonet) do. Ironically, the first 6x7->K adapter I bought does have the locking pin, but lacks the external flanges.

Does anyone know of a 6x7->K adapter that has both the external flanges and the locking pin that works like the camera body does?

Thanks,
Sterling

The original Pentax 6x7 to K-Mount adapter will have both the inner and outer bayonet mounts.

https://www.manualslib.com/manual/499030/Pentax-6x7-Lens-Adapter-K.html

Phil.

[RICHARD L.]

Here is a picture taken with a K5 mounted on a 645 FA 400 mm f/5.6. The sensor being APS-C with a magnification factor of 1.5X, the result is similar to using a 600 mm lens on Full-Frame.

[cobbu2]

One advantage of using MF lenses on DLSRs is that the 6x7 lenses can be shared when traveling with both types of bodies thus saving space, weight and redundancy. I have a forthcoming Yellowstone trip next summer and plan to bring both my P6x7 and one of my Pentax APS-C bodies (either the K-3ii or my newly-acquired KP).

Here's an example using the SMC Macro-Takumar 6x7 135/4 on my K-5: