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Pentax Adapter K for 645 Lens (645 to K mount) Review RSS Feed

Pentax Adapter K for 645 Lens (645 to K mount)

Reviews Views Date of last review
4 32,855 Fri June 5, 2020
Recommended By Average Price Average User Rating
100% of reviewers $155.00 10.00
Pentax Adapter K for 645 Lens (645 to K mount)


This is an adapter allowing you to use Pentax 645 mount lenses on K-mount bodies, including DSLRs as well as film SLRs.

You will have to use stop down metering as the adapter neither has aperture contacts nor an aperture stop down lever.

Autofocus is not supported. AF lenses will have to be focused manually.

Pentax Adapter K for 645 Lens
©, sharable with attribution
Image Format
Full-frame / 35mm film
Lens Mount
Pentax K
Light Loss
0 stops
0 elements, 0 groups
Mount Variant (Rear)
Mount Variant (Front)
645 AF
Weather Sealing
Diam x Length
Production Years
(in production)
Engraved name: PENTAX ADAPTER K FOR 645 LENS
User reviews
This adapter allows for mounting Pentax 645 lenses on a K-mount camera.
The only exposure modes supported are M and Av with stop down metering, and Bulb. The adapter has no aperture stop down lever and no lens information contacts.
The adapter can be stacked with the 67 to 645 adapter thus allowing Pentax 6x7 lenses to be mounted on a K-mount camera.
Full-Frame Support
Price History:

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Sort Reviews by: Date | Author | Rating | Recommendation | Likes (Descending) Showing Reviews 1-4 of 4
Loyal Site Supporter

Registered: October, 2018
Location: Quebec City, Quebec
Posts: 2,659
Lens Review Date: June 5, 2020 I can recommend this lens: Yes | Price: $90.00 | Rating: 10 

Pros: Tight fit, excellent baffling, a must-have accessory.
Cons: None.

Pentax K1 mounted on a 645 FA 400 mm f/5.6, Av mode with stop-down metering. Picture taken from 1 kilometer away.
Loyal Site Supporter

Registered: September, 2017
Location: Medellín
Posts: 1,286
Lens Review Date: December 23, 2019 I can recommend this lens: Yes | Price: N/A | Rating: 10 

Pros: Build quality, compatibility.
Cons: Knob hits mirror box on some DSLR camera models.

If you happen to have both systems, this does the trick with the best absolute fit you can find. The only thing you have to keep in mind, is that the rotation lock knob can hit the mirror box while attaching it to some DSLRs. I learned that the hard way.
Site Supporter

Registered: February, 2010
Location: Salzburg
Posts: 1,259

1 user found this helpful
Lens Review Date: December 5, 2011 I can recommend this lens: Yes | Price: $125.00 | Rating: 10 

Pros: sturdy, useful

Excellent adapter, which I've used frequently. It is solid, and allows to use the excellent range of 645 lenses to be used on the digital cameras. No complaints.
I paid either 100 or 150$, I cannot remember to be honest, so I averaged it. It came from a forum member and was well looked after.
Site Supporter

Registered: February, 2009
Location: Wisconsin
Posts: 423

1 user found this helpful
Lens Review Date: September 6, 2010 I can recommend this lens: Yes | Price: $250.00 | Rating: 10 

Pros: build quality
Cons: none

I paid a ton for this directly from Pentax, but I wanted it fast. It was on backorder everywhere else. It is a solid piece of equipment that should last forever. I use it to mount my FA645 120mm macro and FA645 80-160mm on my K-7.
Add Review of Pentax Adapter K for 645 Lens (645 to K mount)

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