Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
06-20-2013, 09:17 AM   #1
Pentaxian




Join Date: Apr 2010
Location: Wiltshire/Hampshire
Photos: Albums
Posts: 1,698
Pentax 67 focus problem

I have been missing (front focussing) the majority of my shots. On this roll I did a quick test - focussed where the screwdriver was pointing.

As you can see, it looks like my camera is off. I see there are small screws by the focussing screen - can anyone advise how best to adjust? I know I could send it off, but for the price I paid for it I'm wondering if there is a DIY solution (maybe using some ground glass and bulb)?

Thanks!




06-20-2013, 11:37 AM   #2
Site Supporter
tlong423's Avatar

Join Date: Aug 2011
Location: Kansas City
Photos: Gallery | Albums
Posts: 181
I had a similar problem (except it was short focusing in my case). I sent it to Eric Hendrickson for a CLA, and he determined that the previous owner has replaced the focus screen, but the screen had simply never been calibrated. Eric calibrated it as part of the CLA. It worked fine after that!

As near as I can remember, there are three screw adjustments for that calibration. If you really want to try doing it yourself, I know there is a service manual available online: https://docs.google.com/file/d/0B-EuLA51kH1SY2E0NjhiODctZmM0Zi00ZmVhLTgzMTQt...it?hl=en&pli=1
06-20-2013, 11:52 PM   #3
Veteran Member
Silent Street's Avatar

Join Date: Nov 2011
Location: Snobsville & Hipsterville, Vic AUS
Posts: 451
142 pages of very interesting reading, but I don't think it's a DIY thing.
06-21-2013, 03:37 AM   #4
Site Supporter
tlong423's Avatar

Join Date: Aug 2011
Location: Kansas City
Photos: Gallery | Albums
Posts: 181
QuoteOriginally posted by Silent Street Quote
142 pages of very interesting reading, but I don't think it's a DIY thing.
Oh, I would most definitely concur on that one.

06-28-2013, 08:24 AM   #5
Giveaway winner!
MysteryOnion's Avatar

Join Date: Dec 2007
Location: beantown
Photos: Albums
Posts: 889
Rob... if you are really looking to DIY it... These are the things you should know...

The upper trim/cover of the focus screen must come off via the screws and the alignment posts.
Underneath is the three adjustment screws to raise and lower the pressure plate to adjust the screen.
Do not poke or fiddle with chain or rollers.
You will need a lens that is known to be accurate at infinity.
You will need a tripod... heavy good tripod.
You will need a 15X or 30X loupe that can sit on top the surface of the screen and get close to the edge and corners, but not the frame.
You will need a subject to focus on that is at infinity and stationary.

The process is a simply one, it is to focus on the distant target and calibrate to the infinity at center and then equalize the adjustments of the three screws until the same target can be viewed in sharp focus from all corners and sides. If you have a window that faces a tall building and is mostly parallel plane to you. This is not a fast process, but it will work and I've had no issues with the four 6X7 bodies I had to correct for bad focus issues.

Then you can verify the closer distances to see if it is about even as well and then finally try a test roll.
06-28-2013, 09:30 AM   #6
Pentaxian




Join Date: Apr 2010
Location: Wiltshire/Hampshire
Photos: Albums
Posts: 1,698
Original Poster
Thanks - I whipped the top off to have a look, seems pretty straightforward.

I have noticed that if I put the lens up against the infinity stop, the horizon is out of focus and I have to back it off a bit. I am assuming my 105/2.4 infinity stop (my only 67 lens now) is accurate, so I'll try some adjustments next week and run a cheap roll of film through. Think I need to raise the screen?

If it's still off, nothing lost and I'll send it off to the pros. Thanks all!
06-28-2013, 11:52 AM   #7
Pentaxian




Join Date: Feb 2009
Location: Arizona
Posts: 868
Agree, I would say raise the screen.
07-01-2013, 07:23 AM   #8
Pentaxian




Join Date: Apr 2010
Location: Wiltshire/Hampshire
Photos: Albums
Posts: 1,698
Original Poster
Well, that was easy.

Wound the 3 screws holding the screen all the way down
Wound them up equally half a turn at a time
Checked each time against infinity using the viewfinder (remembering to take the lens off each time)
Fired a test roll

et voila!



P67
105/2.4
Superia X-tra 400 at ASA 200

07-03-2013, 11:32 PM   #9
Veteran Member
Silent Street's Avatar

Join Date: Nov 2011
Location: Snobsville & Hipsterville, Vic AUS
Posts: 451
That's a distinctively very odd-looking scene more reminiscent of the effect of tilt applied with a PC lens to create an off-centre focus 'peg'. There is a zone of sharp focus on the left which is not replicated on the right. Tweak more.
07-03-2013, 11:48 PM   #10
672
Site Supporter




Join Date: Dec 2010
Location: santa monica
Photos: Gallery
Posts: 412
Silent Street , there is nothing in the frame right midground to focus on, thats why its out of focus.
07-03-2013, 11:59 PM   #11
Pentaxian




Join Date: Apr 2010
Location: Wiltshire/Hampshire
Photos: Albums
Posts: 1,698
Original Poster
QuoteOriginally posted by 672 Quote
Silent Street , there is nothing in the frame right midground to focus on, thats why its out of focus.
+1.

A far from scientific shot!

Real results will be from my next few rolls. I am optimistic.
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!
camera, medium format
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Pentax 67 - 1:2,4 105mm - Aperture problem Josias Pentax Medium Format 26 08-07-2012 05:34 PM
Pentax 67 TTL pentaprism meter problem? bienemaya Pentax Medium Format 9 04-24-2012 06:06 AM
Pentax 67 120mm soft focus lens karlfoto Pentax Medium Format 13 12-29-2011 05:16 PM
Wanted - Acquired: Pentax 67 Folding Focus Hood (waist level finder) goddo31 Sold Items 2 08-16-2011 09:18 PM
Pentax 67 TTL Prism Problem dellos Pentax Medium Format 3 02-08-2011 05:02 AM



All times are GMT -7. The time now is 09:59 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