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Mod your P6 Sonnar 180/2.8 for Pentax 67
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PostPosted: Wed May 02, 2012 11:49 pm    Post subject: Mod your P6 Sonnar 180/2.8 for Pentax 67 Reply with quote

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! Smile Here's a test shot:



Shoot the Shoot. by Dr. RawheaD, on Flickr


PostPosted: Thu May 07, 2015 2:58 am    Post subject: Reply with quote

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?


PostPosted: Thu May 07, 2015 3:01 am    Post subject: Reply with quote

billdababilonia wrote:
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?


They may have had several versions but aren't the physical dimensions of them pretty much the same? I can't give you a model number or anything, but in a given extension tube set, you want the shortest one (a Number 1 tube).


PostPosted: Thu May 07, 2015 4:21 am    Post subject: Reply with quote

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.


PostPosted: Thu May 07, 2015 4:30 am    Post subject: Reply with quote

billdababilonia wrote:
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.


Actually you're right, you just need the bayonet part, so it can be from any of the tubes, as long as this part can be easily screwed off:

https://www.flickr.com/photos/68874194@N06/6980690882/in/set-72157629565222860

There's minimal altering that needs to be done with the lathe of this. More on the lens side, but the whole process took less than an hour.


PostPosted: Fri May 08, 2015 1:08 am    Post subject: Reply with quote

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?


PostPosted: Fri May 08, 2015 1:10 am    Post subject: Reply with quote



PostPosted: Fri May 08, 2015 11:06 am    Post subject: Reply with quote

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


PostPosted: Sun May 10, 2015 12:47 am    Post subject: Reply with quote

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

if all goes well I hope to compare the 6x7


PostPosted: Sun May 10, 2015 5:19 pm    Post subject: Reply with quote

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


PostPosted: Sat Aug 01, 2015 8:20 pm    Post subject: Reply with quote

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