Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
04-08-2011, 04:49 PM - 1 Like   #1
Forum Member
leping's Avatar

Join Date: Sep 2010
Location: Chicago, IL, USA
Posts: 82
Pentax 67 55mm/f4 late lens fixed tilt modication

There have been recently quite a few messages asking how did I do the tilt modification on the Pentax 67 55mm/f4 late model lens, after I had it mentioned in at least one of my posts, so I am here to share my successful and unsuccessful stories.

The following URL describes one way to do it, not exactly my originally way (the author did not thoroughly understand me), and by this along it is hard to get the down tilt up to the desired ~1 degree range:

Effeunoequattro - Il Portale Della Fotografia analogica e digitale

However, after seeing his method, I recently re-worked my sample to include his mod, in additional to my original one, which went much deeper into the lens, with much more risks. It is really hard to describe, but maybe one day I should shoot a series of instruction pictures if there are enough interests, taking the risk that I can be unable to put things back one more time or break something. With now two spacers in stead of one inserted into 2 gaps, I am getting about 1.2 degrees overall, which fits my need pretty well.

Nevertheless, I volunteered to mod another copy of the same lens for a forum member, but could not loose the three inner screws no matter how hard I tried, so that I could only complete the easier "outer" mod, as documented in the web link.

Also, remember that, after the mod(s), the lens become a fixed tilt lens for only the vertical shots (unless you need a horizontal swing, and it happens to be along the right direction, i.e., the close subject is on the left side of the frame). It is fine with me, because the purpose is to help the near-far kind of composition and the down tilt is mostly needed shooting vertical. Another problem is, the original lens structure of course was not designed with such gap(s) created in mind, so the aperture ring will become very stiff, and can be adjusted only with little force.

I examined the structure of almost all the other P67 fixed focusing lenses, but found only the 55mm/f4 late has the room for mods like this, looking at the components from the rear.

Need not to say it is not a easy, a readily practical, or a perfect mod of any kind, and anyone trying this takes his/her big risks, even I managed to get one copy working great, selfishly for myself.

Unfortunately, 55mm is no longer a true wide angle on the much smaller 645D sensor (becoming 40mm in 35mm term, using the short side equivalency which makes sense to me as I print 4:5), so that the value of such tilt mod becomes much less significant in the digital age. Needless to say, a shift/tilt P67 to P45 lens adapter is what we are all really waiting for.


Last edited by leping; 04-08-2011 at 10:09 PM.
04-10-2011, 05:54 PM   #2
New Member




Join Date: Mar 2011
Location: Gilbert, Arizona
Posts: 9
I'd love to see some examples from this lens mod. I have played around tilting my 45mm lens just inserted into the body but not rotated and locked. What is the near distance you can focus at and still keep infinity reasonably sharp?
05-13-2011, 10:15 AM   #3
New Member
desertglow's Avatar

Join Date: Jan 2010
Posts: 19
Hello, I am the author of the "light" version of the mod.

If I remember well I could reach more or less from 1 meter to infinity.

It would be really nice to modify the 45mm, I will try and do that one day or another.
The 45 has a nicer "superwide" look and I would rarely miss the need of shooting horizontally, more rarely than the 55.

.... and to be honest I haven't used very much the modified 55....
06-12-2011, 07:05 AM   #4
rlj
Junior Member




Join Date: Nov 2009
Posts: 29
I recently modified a late P67 45mm lens (not 55). It was actually very easy. I followed Leping's suggested method for the 55mm lens (see above links). I removed the center black plastic cover and then unscrewed the mounting plate. It does not have to be completely removed, simply lifted off about 20 degrees over the 2 mounting screws where you wish to place the shim. The shim can then be slipped in, between the chosen 2 screws, and the mounting ring re-positioned, followed by replacement of the black plastic shield with it's 3 screws.

I chose to shim opposite from the vertical tripod mount position (so tilts are vertical---portrait style). I placed a 1.65 mm thick plastic fragment (about 3 x 4 x 1.7mm) between the pair of mounting ring screw holes. Care must be taken to not over-tighten these screws, esp the ones away from the shim position. If you over-tighten, the mounting ring distorts and you cannot mount the P67/P645 adapter.

The 1.65mm shim gives about 1.2 degrees of tilt when using the 45mm lens on the P645D (an effective focal length of about 35mm). This is exactly what is needed for Scheimpflug tilts when the camera/lens is 6 feet off the ground and the subject is the ground receding to infinity.

If the subject is 1.5 feet off the ground (say a field of flowering plants) and the camera is still at 6 feet, the subject plane difference is now 4.5 feet, and the required tilt is 1.6 degrees, not so far off (and besides, you want to use at least f11, which will overcome slight tilt errors, and to focus about ~2/3 into subject matter to maximize the correction).

Thus, this fixed 1.2 deg tilt is very practical for landscape work (however, it is not useful for table top photography, which requires much greater tilts).

Attached Images
 

Last edited by rlj; 06-14-2011 at 06:33 AM.
06-13-2011, 03:51 PM   #5
Pentaxian




Join Date: Feb 2009
Location: Arizona
Posts: 912
......or instead of modifying the 55mm, one can use the 55-100 zoom at 55mm at f/32 and get a DOF of 42 inches to infinity.
06-25-2011, 02:54 PM   #6
New Member
desertglow's Avatar

Join Date: Jan 2010
Posts: 19
QuoteOriginally posted by rlj Quote
I recently modified a late P67 45mm lens (not 55). It was actually very easy. I followed Leping's suggested method for the 55mm lens (see above links). I removed the center black plastic cover and then unscrewed the mounting plate. It does not have to be completely removed, simply lifted off about 20 degrees over the 2 mounting screws where you wish to place the shim. The shim can then be slipped in, between the chosen 2 screws, and the mounting ring re-positioned, followed by replacement of the black plastic shield with it's 3 screws.

I chose to shim opposite from the vertical tripod mount position (so tilts are vertical---portrait style). I placed a 1.65 mm thick plastic fragment (about 3 x 4 x 1.7mm) between the pair of mounting ring screw holes. Care must be taken to not over-tighten these screws, esp the ones away from the shim position. If you over-tighten, the mounting ring distorts and you cannot mount the P67/P645 adapter.

The 1.65mm shim gives about 1.2 degrees of tilt when using the 45mm lens on the P645D (an effective focal length of about 35mm). This is exactly what is needed for Scheimpflug tilts when the camera/lens is 6 feet off the ground and the subject is the ground receding to infinity.

If the subject is 1.5 feet off the ground (say a field of flowering plants) and the camera is still at 6 feet, the subject plane difference is now 4.5 feet, and the required tilt is 1.6 degrees, not so far off (and besides, you want to use at least f11, which will overcome slight tilt errors, and to focus about ~2/3 into subject matter to maximize the correction).

Thus, this fixed 1.2 deg tilt is very practical for landscape work (however, it is not useful for table top photography, which requires much greater tilts).

NICE work, very interesting!
07-12-2011, 03:08 PM   #7
Pentaxian




Join Date: Feb 2008
Photos: Gallery | Albums
Posts: 420
For use on the 645D, I wonder if it would be possible to modify the 67/645 adapter for tilt? No risk to the lens and the adapter could be used to supply tilt to any lens. The mounting flange of the adapter is held to the adapter body by six screws; it might be possible to insert a shim between the mounting flange and the adapter body. I might try it when I have some time.
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, gaps, lens, medium format, mod, p67, risks, tilt
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Tilt lens options for Pentax? d.bradley Pentax SLR Lens Discussion 24 11-10-2012 03:03 PM
Wanted - Acquired: HARTBLEI 65mm Super-Rotator Tilt Shift Lens for Pentax K Ishpuini Sold Items 2 07-15-2010 04:43 AM
35mm and 80mm tilt shift lens for Pentax High Roads Photo Photographic Technique 6 09-07-2008 03:41 AM
Where is pentax 135 mm fixed lens? ogl Pentax SLR Lens Discussion 54 05-24-2008 10:26 PM



All times are GMT -7. The time now is 03:26 AM. | 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