Monthly Archives: March 2013

Olympus XA light-trap repair

Before going digital around 2002 I used Olympus cameras (OM1, OM1n and XA) the SLR’s were sold but I decided to keep the XA, unfortunately when I tried to use the camera a few years later it was clear when opening the camera that the light-traps were in bad condition, after a film was exposed and printed it was clear that the problem was not only cosmetic, there were visible streaks and fogging on the film, at the time I thought that this could be remedied, but I put the camera away and more or less forgot about it. Early this year while browsing through Flickr I found that there was quite a following for this old classic camera, I therefore decided to make a repair to the seals and breathe life into the camera again, but first of all I had to check that it was in working order, fortunately I had removed the batteries before putting the camera away, after buying and installing two new LR44 batteries I could see that the electronic shutter and exposure meter were in working order so I decided to go ahead.

The biggest problem was sourcing a suitable material for the seals, the old ones had been made of some very thin self-adhesive foam that had perished , so all that was left was a powdery or sticky residue, I could find nothing thin enough for this project, then I stumbled upon a suitable material at home! This was a sheet of a matt black foam material that had been used as part of the packaging of a mini electric screwdriver, it was about 1mm thick, slightly too thick, but I found that if I cut a strip and used a rolling pin from the kitchen it was compressed to a stable thickness of about 0.5mm which looked suitable. OK now we have the material, but the most time consuming part was removing the old light traps and residue, before starting work on this I put a piece of tissue over the rear lens to protect it from the the material that was to be removed, I also removed the film pressure plate from the backplate to aid the material removal/installation. I tried several different tools but in the end I found that the most suitable tool was a toothpick that was cut off with a sharp knife to form a chisel, with this it was very easy to get under the sticky surface and lift it from the back-plate of the camera without damaging the internal painted surface, do not use metallic tools for this, it is extremely easy to scratch the paint! The only part were I could not use this tool was the latch section of the backplate, here I had to use the pointed end of the toothpick due to lack of room for the whole width (quite fiddly).

Once the actual physical material was removed it was necessary to clean the surfaces with a solvent, or in my case two, I found that the wife’s acetone free nail polish remover worked but seemed to spread out the sticky residue, I therefore used denatured ethanol for the final cleaning, all cleaning was done by applying the solvent to the head of a cotton bud, these were the solvents I had available, I have not tried it but I would guess that Isopropyl alcohol would be suitable as well, do not use pure acetone, I am almost certain it will remove the paint from the backplate!

The next job was to cut strips of the foam material, top and bottom strips are approximately 2.5 to 3mm wide, the large piece closet to the hinge is 11mm wide and a very thin strip for the groove in the latching section is about 1.5mm wide, I tried using scissors but the result was not good so I used a modelling knife instead, cut using a ruler or similar straight-edge to get a clean straight cut against a good underlay. All that was now left was to cut the strips to suitable lengths and glue them into place, for this I used a small tube of contact adhesive, applying first a layer to the camera back and then to the strips of foam material, apply a very thin film of adhesive, I found that the easiest method for doing this was to squeeze out a blob of the adhesive onto a piece of paper and then use a small piece of card (cut to the right width) as an applicator, normally one would wait a few minutes before positioning the material but the film of adhesive is so thin that it dries almost immediately, do not rush this stage, glue only one section at a time , start applying the material from one end and lay down carefully, contact adhesive adheres directly so you will have no second chance and no possibility of adjustment, once in place you can trim any excess material if the strip was too long, any adhesive that is visible beside the strip can be removed by very carefully rubbing with the top of an index finger, be extremely careful not to damage the foam strip when doing this, it is easily damaged!

Final job, make sure the camera is free from rest products from the removal and glueing process, then replace film pressure plate, if all is correct the back should snap closed on its latch without using pressure and if you check very carefully when closing there should be no deformation of the back, open and close several times and you should see marks left in the material from the opposing edge in the camera. If all is well remove the tissue protecting the rear lens and load a film, good shooting!

Note: Test image below is taken direct from a negative scan using my Minolta Dimage Scan Dual III film scanner, image has not been modified.

Foam before rolling to half the thickness

Foam before rolling to half the thickness

Perished light-traps

Perished light-traps

New light-traps, note marking from opposing edge

New light-traps, note marking from opposing edge

 

First test image from camera after light-trap repair

First test image from camera after light-trap repair

 

 

 

A DIY focus rail

I have recently become interested in focus stacking and although my first attempts were not too bad I have come to the conclusion that a focus rail is necessary if I want to get better results, a perfect DIY project! The project is now under-way and should be ready for testing in early April 2013, the idea is to produce a unit that can be made from cheap components and require the minimum amount of machining, although I have turned a couple of of parts for the unit I am building they could have been produced with hand-tools, not so pretty perhaps but it could be done, once the project is finished and tested I will post a description on this blog, I am trying to keep the total price to around £20 (approx. €20).

Update: 29/03. I should be able to show a preview of the finished unit within the next two weeks.

Update: 28/04. Unit finished, write up can be found here.