[nighthawkjw]

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

[pentkon52]

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

[nighthawkjw]

Thanks, Dave. Were you shooting HIE? This only happens with HIE. Do you recall if either of those pressure plates were perfectly smooth?

[pentkon52]

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

[OniFactor]

could you put some foil tape on there, or would it be too reflective?

[nighthawkjw]

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

[Peter Zack]

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.

[OniFactor]

Foil Tape - Aluminum Foil Tapes - Acrylic Adhesive

2 and 3 inch widths available..

[sluggo913]

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.

[titrisol]

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

[nighthawkjw]

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.

[lmd91343]

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?

[nighthawkjw]

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?

[lmd91343]

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?

[LesDMess]

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?