Pentax 645 lens advice needed.

Feral Donkey · Apr 3, 2006

Hi. I'm upgrading from my 35mm rig to Pentax 645 right now and I'm wondering has anybody used the Pentax 67 lenses on the 645 body with the adapter ring? If a person is to do that would it work out OK or would the adapter ring act like a short extension tube and mess with getting the focus to infinity?

Thanks.

ThomThomsk · Apr 4, 2006

I think that you will get a lot more response if you ask this question on APUG, in the medium format forum:

http://www.apug.org/forums/forumdisplay.php?f=51

Thomsk

Alpha · Apr 4, 2006

I'm just curious...why do you want the 67 lenses on the 645?

Feral Donkey · Apr 4, 2006

Because there's some pretty nice lenses that I'd like to use. There's a 150 F2.8 and a 165F2.8. I'm thinking about owning a lens in that length. So far I have a 75F2.8, 55F2.8, and a 200F4. The 200 F4 is a pig. Also those 67 lenses are made to make a sharp image circle bigger than 6X7 so when covering 6X4.5 it'll be using the center of the image circle so you know it'll be razor sharp.

usayit · Apr 4, 2006

OMG... thought I was the only one who likes to shoot with those Pentax MF cameras... I don't think I've ever met another person with a Pentax MF camera. Never-the-less, I enjoy both of mine quite a bit; 645 ( 3 primes with 1 zoom ) and 67 ( 2 primes ). Both are great field cameras and the 645 is a joy to shoot handheld. I've been considering getting a 645n to add to my collection.. prices have really dropped recently.

You can get the pentax adapter from BHphoto ( use the link below ). It will allow you to mount 67 lenses on a 645 body. As far as I know, it will maintain infinity focus and metering. The increased lens to focal plane distance on a 67 supposedly allows for the adapter to still maintain infinity focus on a 645 body. I don't have any experience with it but it was my understanding that you won't see any better performance between equivalent 67 and 645 lenses on a 645 body. Anything gained by the "larger image circle" is lost as a result of the use of an adapter. On top of that, 67 lenses tend to be quite a bit heavier and bulkier than the 645 lens. It seems that the original intent was to allow the use of a 645 body as a somewhat more compact backup camera to a photographer with a 67 system.

Good luck and let me know how it works out. If you get good results, I might just pull the trigger and get that adapter. I've been toying with the idea for a while.