Forgot Password
Pentax Camera Forums Home

Show Printable Version Search this Thread
04-22-2010, 10:29 PM   #1
Site Supporter
Ed n Georgia's Avatar

Join Date: Dec 2009
Location: Georgia
Posts: 925
FF/BF issue with one of my lens

I have a lens that may have a FF or BF issue. I have the K20D so I shoud be able to make the correction with the camera body.

However, can someone tell me just how to go about this task? Is there a chart I can pick up.

Any help will be appreciated.


04-23-2010, 02:27 AM   #2
Senior Member
iFoto's Avatar

Join Date: Feb 2008
Photos: Gallery | Albums
Posts: 177
sorry, the webside is in german - but googletranslater might help

Traumflieger-Report: mehr Bildschärfe mit dem Fokus-Detektor
04-23-2010, 03:18 AM   #3
Site Supporter

Join Date: Jan 2008
Location: Middle of Everywhere
Photos: Gallery
Posts: 1,169
Quick and dirty BF/FF test...

Eliminate the possibility that the camera is the culprit by doing some 'catch-in-focus' photos using a manual focus lens (M, K, or A mount). If you are getting fairly crisp images, move on to testing the lens:

1. Make a (say) 1/4 to 1/2 inch black dot by cutting a piece of black electrical tape, or paper then sticking the paper dot color side down to a piece of matte-texture clear scotch tape.

2. Stick the dot at eye-level on a sunlit (can be in the shade) textured wall that contrasts in color with the dot you just made (brick is perfect).

3. Stand at a distance of about six feet from the dot, but off-set by about 45 degrees.

4. Shooting along the flat plane of the wall, center the dot in your viewfinder and try to take a crisp photo of the dot (no tripod needed, hand held is OK). If you are testing a zoom lens, zoom in as close as possible (you may need to step back farther than six feet from the dot) then focus on the dot.

5. Review the resulting image at about 8 to 12x in your camera view finder. If the dot is in the middle of the most in-focus part of the image, you are good to go. If not, adjust the focus point using the simple in-body focus adjustment procedure described in the Manual. Might take several tries, but it works for me.


Last edited by Michaelina2; 04-23-2010 at 03:24 AM. Reason: typo

  • 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!
issue, k-mount, lens, pentax lens, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Similar Threads
Thread Thread Starter Forum Replies Last Post
Lens Hood Issue SA Photo Pentax SLR Lens Discussion 6 12-04-2009 11:51 PM
What to do lens issue foxycce Pentax SLR Lens Discussion 4 04-23-2009 04:46 PM
Help Identify Lens Issue jubei951 Pentax DSLR Discussion 2 03-24-2009 10:14 PM
Lens Review Issue FotoPete Site Suggestions and Help 2 10-28-2007 10:59 PM

All times are GMT -7. The time now is 11:51 AM. | See also:, 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?
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]