Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
10-29-2009, 05:26 PM   #16
Forum Member




Join Date: May 2009
Location: Dallas, TX
Photos: Gallery
Posts: 76
Now we just need to figure out how to get SDM drive motors into our homemade lenses. I think my first project will be to convert an old Mamiya 50mm f2 into a soft focus left (remove all elements except the front). I'll let you know how that goes.

11-05-2009, 06:28 PM   #17
Site Supporter
k0og's Avatar

Join Date: Nov 2008
Location: Rolla, Missouri
Photos: Gallery | Albums
Posts: 622
Polaroid Copal Oscilloscope Lens on K100D Super

This is GREAT - it's LBA without the "B" - ha, ha!

Thanks to Nick C for the inspiration, I decided to pursue a free lens...

I found a very old Polaroid oscilloscope camera lens in my junk box,
and decided to see if I could mount it on my K100D Super
and use it to take pictures.

It is a Japanese Tominon in a Polaroid Copal shutter, 127mm f4.7,
5-inch focal length, shutter speeds ranging from 1/125 second to
T setting which keeps shutter open. The aperture and
shutter work perfectly, and the glass is in excellent condition.

I found that I could mount the lens on the K-mount base of
my macro extension tube set, then could mount the K-mount
base with lens on my macro extension bellows. The bellows
easily focus the lens at 5 inches for a good infinity focus, and
the bellows racks out several inches to achieve focus as close
as a few inches for extreme macro photography.

Here are a few sample pictures taken with the lens shutter
kept open with the "T" setting and focusing by adjusting
the bellows. Various f stops were used to test the sharpness
of the lens wide open as compared to stopped down a few
stops. The Pentax K100D Super body was used as normal
for manual lenses to meter in Av mode and take the exposure.





Lens wide open (f4.7)


Lens stopped down (f11)


An infinity-focus test with lens at f11


A macro with the lens racked out


Taking a picture into the light, I don't see much sign of flare. It seems surprisingly immune, and appears to have some coating on the lens.


This was fun - maybe not all that useful, but fun!

-Joe-
11-06-2009, 04:41 PM   #18
Veteran Member




Join Date: Nov 2008
Location: The Untied States
Photos: Albums
Posts: 1,882
I've always been interested in doing stuff like this, but I'm not very keen on how to go about it. I found what I believe is an englarging lens, 500mm f/5 with two parts to the lens, that I'd like to turn into something usable. Can anyone give any advice?
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!
apertures, diy, k-mount, lens, lenses, pentax lens, results, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
LBA on a (real cheap) budget LittleSkink Pentax SLR Lens Discussion 6 03-16-2010 11:17 AM
DIY (read: Cheap) Safe Sync SOldBear Pentax Camera and Field Accessories 12 05-15-2009 05:56 PM
LBA - CBA am I too cheap? Lowell Goudge Pentax SLR Lens Discussion 12 12-02-2008 01:02 PM
Cheap DIY macro lens! ftpaddict Pentax SLR Lens Discussion 9 11-25-2008 01:00 AM
LBA - cheap Vivitar axl Pentax SLR Lens Discussion 6 01-07-2008 03:00 PM



All times are GMT -7. The time now is 09:14 AM. | See also: NikonForums.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