Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
12-28-2007, 08:22 AM   #1
New Member




Join Date: Dec 2007
Location: Winston-Salem, NC - USA
Posts: 10
Pressure Plate dimples on IR film

Okay, I use Kodak HIE-135 infrared film, and plan to keep using it. No other film does what it does.

I use a KX. Started with a K-1000. Love em!!!

The down side to my film/camera is that since HIE has no anti-halation backing, I occasionally get the dimple pattern from the pressure plate reflected onto the negative. I need a pressure plate that is perfectly flat and no dimples.

The pressure plate from the KX is same as on K-1000. I tried a couple of modifications with bad results: I painted one pressure plate with body primer and sanded smooth, but not smooth enough - now have swirly pattern! I also tried taping black mylar to the plate, but the tape did not hold.

1) Is there any way to get a replacement pressure plate that has a completely smooth surface - no dimples?

2) If not, does anyone have any suggestions to make my previous efforts for modifying my plate work?

3) Should I use a different camera with a smooth pressure plate?

4) Don't EVEN tell me to use digital IR!!!


Thanks!
James C. Williams

12-29-2007, 09:49 AM   #2
Veteran Member




Join Date: May 2007
Location: York Region Canada
Posts: 642
QuoteOriginally posted by nighthawkjw Quote
Okay, I use Kodak HIE-135 infrared film, and plan to keep using it. No other film does what it does.

I use a KX. Started with a K-1000. Love em!!!

The down side to my film/camera is that since HIE has no anti-halation backing, I occasionally get the dimple pattern from the pressure plate reflected onto the negative. I need a pressure plate that is perfectly flat and no dimples.

The pressure plate from the KX is same as on K-1000. I tried a couple of modifications with bad results: I painted one pressure plate with body primer and sanded smooth, but not smooth enough - now have swirly pattern! I also tried taping black mylar to the plate, but the tape did not hold.

1) Is there any way to get a replacement pressure plate that has a completely smooth surface - no dimples?

2) If not, does anyone have any suggestions to make my previous efforts for modifying my plate work?

3) Should I use a different camera with a smooth pressure plate?

4) Don't EVEN tell me to use digital IR!!!


Thanks!
James C. Williams
When i shot IR film i used two cameras. One ,my old SP500 and the other, my PZ-1.

Both worked very well, no marks etc on the film.

If you can pick up an old spotty, that might be your best bet.

Dave
12-30-2007, 06:53 AM   #3
New Member




Join Date: Dec 2007
Location: Winston-Salem, NC - USA
Posts: 10
Original Poster
Thanks, Dave. Were you shooting HIE? This only happens with HIE. Do you recall if either of those pressure plates were perfectly smooth?
12-30-2007, 09:19 AM   #4
Veteran Member




Join Date: May 2007
Location: York Region Canada
Posts: 642
QuoteOriginally posted by nighthawkjw Quote
Thanks, Dave. Were you shooting HIE? This only happens with HIE. Do you recall if either of those pressure plates were perfectly smooth?
Yes HIE.

I just looked at the SP500m and PZ-1 and they have the dimples as well, but smaller and more of them.

But, i have never had any problems with those two cameras.

Dave

12-30-2007, 11:54 AM   #5
Veteran Member
OniFactor's Avatar

Join Date: Nov 2007
Location: Binghamton, NY, USA
Posts: 646
could you put some foil tape on there, or would it be too reflective?
12-31-2007, 07:06 AM   #6
New Member




Join Date: Dec 2007
Location: Winston-Salem, NC - USA
Posts: 10
Original Poster
Foil Tape...

Thanks, OniFactor. Foil tape would be very similar to the mylar, and yes, it would be very reflective which is not a bad thing. The trick is finding foil tape that is the size of the pressure plate. If you could direct me to a source, that might be the fix I need.

Dave, I am wondering if Pentax has only ever made one pressure plate for all 35mm SLRs!

~JCW
01-01-2008, 01:22 AM   #7
Pentaxian
Moderator Emeritus




Join Date: May 2007
Location: Edmonton Alberta, Canada
Photos: Gallery | Albums
Posts: 10,648
This might be a little off the wall but your idea of filling and sanding the plate might work if done a little differently. If you used 600-1000 grit paper glued flat to a perfectly flat surface such as a thick piece of glass, you should be able to get the plate perfectly flat. I did this with an old British motorcycle head that leaked oil. 1000 grit paper will make a finish as smooth as polished stone.
01-01-2008, 01:02 PM   #8
Veteran Member
OniFactor's Avatar

Join Date: Nov 2007
Location: Binghamton, NY, USA
Posts: 646
Foil Tape - Aluminum Foil Tapes - Acrylic Adhesive

2 and 3 inch widths available..

01-01-2008, 01:58 PM   #9
Inactive Account




Join Date: Nov 2007
Location: Upton, Ma.
Photos: Gallery
Posts: 108
You could have the plate powder coated in black produces a very smooth finish, or the use of very fine sandpaper but finish with wet/dry using a light weight oil as a lubricant and figure eight motion on a flat surface glass, marble, granite. The only problem with the sanding option is the removal of material and thus the reduction of tension on the film (holding it tight against the shutter window). There are many grades finer than 1000 grit available from an automotive autobody supply store the finer the better.

Last edited by sluggo913; 01-01-2008 at 02:01 PM. Reason: addition
01-02-2008, 02:45 PM   #10
Veteran Member
titrisol's Avatar

Join Date: Dec 2007
Location: In the most populated state... state of denial
Photos: Gallery | Albums
Posts: 1,098
what about one of those screen protectors for palm pilot?
those are pretty smooth and will adhere to the plate

I haveshot HIE with the Spotamtic and no marks.
Also the old Zeiss-Ikon rangefinders have smooth backplates
12-11-2014, 09:29 AM - 1 Like   #11
New Member




Join Date: Dec 2007
Location: Winston-Salem, NC - USA
Posts: 10
Original Poster
Solved

SOLVED - A much belated post to help others who may encounter this odd problem. I removed the pressure plate and sprayed a coating of black primer paint. After it dried, I wet sanded until it was smooth, put it in the camera and have had fabulous success.
12-11-2014, 03:58 PM   #12
Site Supporter




Join Date: Jul 2009
Location: Los Angeles, CA USA
Photos: Gallery | Albums
Posts: 647
Good solution!

I only use RF cameras for IR film. It is too much of a pain to keep attaching and removing the filter.

Which lens do you use?
12-12-2014, 06:29 AM   #13
New Member




Join Date: Dec 2007
Location: Winston-Salem, NC - USA
Posts: 10
Original Poster
I use a variety of lenses, usually either a 50mm f/1.2 Pentax (screw mount adapted) or a Tamron 24mm f/2.4. Occasionally I may use a longer lens, but only for details such as gargoyles. I have filters that fit the different lenses so don't need to change them so much. What kind of film are you shooting?
12-12-2014, 10:00 AM   #14
Site Supporter




Join Date: Jul 2009
Location: Los Angeles, CA USA
Photos: Gallery | Albums
Posts: 647
I used to use Kodak HIE BW with my Canon 7s/7s/7 cameras with a 50mm f0.9 lens. With the small DOF and the lack of anti-halation backing, I got isolated subjects with a "ethereal glow". Also I got to use faster shutter speeds(always a good thing for me. Framing and focusing was easy. Just line up the images in the VF then back off to the red mark. I never had to attach and remove the filter. I'd load up three bodies before I left the house, then change the lens in the field. The changing bag stayed at home!

I got about five or six properly exposed shots per roll. Focus was good on almost all frames.

I tried it with my film SLRs and it was difficult.

The last three or four years I've used my converted 720nm K10 exclusively with my 10-17 DA zoom, 15 DA, and 21 DA. I take a couple of test shots and dial in the exposure comp. I get a much higher keeper rate, only two or three badly exposed frames. I don't need to change rolls with a changing bag in the field. I carry ONE body, not three. I find it so much easier.

Where do you get the film? How much does it cost?

What advantage do you see with film IR over digital IR?
12-12-2014, 01:20 PM   #15
Pentaxian




Join Date: May 2011
Location: Santa Cruz, CA
Photos: Albums
Posts: 2,044
This thread got me curious as I have never heard of this issue so I looked at a few of my manual focus bodies to see what had dimpled pressure plates. All of my Pentax bodies have it starting with my original AP to my newest ME Super. There is a mix among all my other cameras of different brands. Given this distribution, I would have expected that this issue must have been more prevalent?
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!
dimples, film, k-1000, kx, pattern, plate, pressure
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
How do we put some pressure on Tokina? Peter Zack Pentax SLR Lens Discussion 13 02-14-2010 06:06 PM
Peer pressure for iPhone remote control app! Desi Digital Processing, Software, and Printing 6 06-29-2009 05:06 PM
No pressure MoiVous Post Your Photos! 2 06-24-2009 06:56 PM
Pressure Treated - a photo and frame experiment SouthShoreRob Post Your Photos! 7 12-31-2007 04:07 AM
Broken Pentax??!!?! Need a pressure plate... Bryce Pentax Film SLR Discussion 5 07-24-2007 02:02 AM



All times are GMT -7. The time now is 02:32 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