Mod your P6 Sonnar 180/2.8 for Pentax 67

[rawhead]

So after having read this post on Pentaxforums:

http://www.pentaxforums.com/forums/pentax-medium-format-645-6x7-645d/104940-180-300-czj-lenses-mounted-pentax-67-a.html

I've been wanting to convert a Pentacon 6 / CZJ Sonnar 180mm f2.8 to use on my Pentax 67II. With the help of Bob Crowley from the New55 project, the dream came true:




fr_35_size880 by rawhead_tech, on Flickr


The mod is relatively easy IF you have access to a metal lathe. It only involved removing some parts from the rear of the Sonnar (won't be used again), using the male end of a P67 extension tube, and removing some metal from the extension tube mount, and a couple places on the lens.

http://www.flickr.com/photos/68874194@N06/sets/72157629565222860/with/6980685754/

This set should explain the basic concept of the modification.


YES, it will give you infinity focus. YES, the image circle is more than enough! Here's a test shot:



Shoot the Shoot. by Dr. RawheaD, on Flickr

[billdababilonia]

hi
saw its adaptation, would make a too, my doubt is which of the extension tubes is correct, Pentax has several of these tubes.

can you help me?

[rawhead]

[billdababilonia]

thanks for the reply, the tubes in the length, are distinct from each other, I was afraid to buy a wrong and not working.

from what I have researched disassemble the tube, only the part of the bayonet will use to adapt?

http://www.getdpi.com/forum/attachments/gear-fs-or-wtb/73167d1369505119-fs-pentax-67-3-piece-extension-tubes-$80-_1020608-jpg

My doubt is how many mm I need to remove the back, telling how the size of the extension tube of the bayonet.

[rawhead]

[billdababilonia]

I think I'll be able to do the adaptation, understanding the process
Thank you.

In this photo made two arrows my doubts, the tube inside the lens red arrow
the distance there is 10.4 after sawed?

Another thing I was in doubt the base of the lens yellow arrow was also sawed?

[billdababilonia]

[araucaria]

I've always wondered how it compares to the pentax 165 2.8.

[billdababilonia]

I made a brief comparison in 35mm
the zeiss does better open.

if all goes well I hope to compare the 6x7

[littleearth]

I had both and they are good performers.
The Zeiss (MC) performed better in all aspects, and it has that amazing pop and microcontrast the Sonnar is known for. Unlike the 105mm, the 165mm never really impressed me.

The only issue with the CZJ is the build quality and the fact that it's a huge chunk of glass. On the other hand, after handling the Aero Ektar 175mm the Sonnar doesn't feel that heavy anymore.

165mm wide open and a little soft due to 1/60 handheld

[billdababilonia]

Hi littleearth

I saw that you mentioned EKTAR 178mm 2.5, think worth the inverstimento? I found a person who adapts to bodies 6x7.

thanks