Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
11-26-2011, 03:06 AM - 1 Like   #1
Site Supporter




Join Date: Apr 2009
Location: Hilo, HI
Posts: 70
Nikon 135mm f/2 AI adapted to PK

During the Thanksgiving downtime, I did some surgery on my newly acquired Nikon 135mm f/2. I knew from previous threads that it was possible to directly mount old F-mount lenses to Pentax cameras, but I wanted something that locked at the 12 o'clock position and had a usable focusing scale. The conversion was quite simple and is mostly reversible. The mount was removed with a JIS cross-point screwdriver (important, since the heads are NOT Phillips, and the threads are locked in place) and replaced with an aluminum spacer and PK-M42 adapter. The spacer and mount flanges combined were about 0.95mm thick, so the lens focuses a tiny bit past infinity. Here's a comparison with a C/Y Planar 85/1.4 and a Nokton 58/1.4. In the last picture, you can just make out the aluminum spacer and brass flange. These were simply glued together with metal cyanoacrylate. All of the "machining" was done with a jeweler's saw and a Dremel tool. The AI-indexing ridges were filed down just a hair (less than a millimeter) to get the lens to sit flush with the camera-side mount.









Here are a couple of images from the lens, both at f/2. I haven't had much time to shoot with it due to the typically rainy Portland weather.





It is quite sharp wide open, but suffers from purple fringing and a "glow" under high-contrast situations (kind of what you expect with long, large aperture lenses, though). Sharpness doesn't improve much upon stopping down, but contrast and PF issues improve by f/2.8 or f/4. The defocusing characteristics are generally very creamy, except for bright point highlights. For the record, my girlfriend thinks that it's the ugliest lens she's ever seen

I'd like to convert more Nikon lenses by replacing the lens mounts with a spacer and a Pentax bayonet. This method is more labor intensive, but is cleaner and more secure. Maybe a 35/1.4 or a 28/3.5 shift would be next

11-26-2011, 04:10 AM   #2
Pentaxian




Join Date: Nov 2008
Location: Bangalore
Photos: Gallery
Posts: 2,450
Great job!!! nice pics.
11-26-2011, 04:44 AM   #3
Pentaxian
RonHendriks1966's Avatar

Join Date: Jan 2009
Photos: Gallery
Posts: 8,714
Good job done!
11-28-2011, 11:10 AM   #4
Site Supporter




Join Date: Apr 2010
Location: SF, CA
Photos: Gallery | Albums
Posts: 78
yes!

11-29-2011, 02:20 AM   #5
Site Supporter




Join Date: Apr 2009
Location: Hilo, HI
Posts: 70
Original Poster
Thanks for the kind words everyone! I hope to have more photos with the lens once my K5 comes in the mail
11-30-2011, 11:02 AM   #6
Pentaxian
dcshooter's Avatar

Join Date: Jan 2011
Location: Washington DC
Photos: Gallery | Albums
Posts: 4,605
The lens might be ugly, but your girlfriend is cute!
11-30-2011, 11:33 AM   #7
Pentaxian
ducdao's Avatar

Join Date: Dec 2009
Location: Montreal/Vermont
Posts: 2,160
QuoteOriginally posted by dcshooter Quote
The lens might be ugly, but your girlfriend is cute!
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
135mm, f/2, k-mount, lens, lenses, mount, nikon, pentax lens, slr lens, threads
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
For Sale - Sold: Nikkor 24mm f/2.8 Ai-s **ADAPTED TO PENTAX** deadwolfbones Sold Items 26 08-04-2011 09:21 AM
Pentax 67 Lenses Adapted to... Dougg Pentax Medium Format 5 03-26-2011 04:07 PM
For Sale - Sold: Nikon 135mm f/2 Ai'd (US/CAN) deadwolfbones Sold Items 4 08-02-2010 06:43 AM
For Sale - Sold: Nikkor Ai 105mm f/2.5, adapted to Pentax K-mount (US/CAN) farfisa Sold Items 3 05-06-2010 01:45 PM



All times are GMT -7. The time now is 08:59 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top