This is how you replace the light seals of your analog camera

The following video (in English, with German subtitles) shows the process in detail:

 

If you own one or more analog cameras, then the chances are high that the light seals need to be replaced on one or all of them.

These small foam strips decompose over time and can cause light leaks that can completely ruin your photos in the worst case. In any case, image quality suffers, and unfortunately, over 90% of all cameras available on the market (even from retailers!) are sold with defective light seals.

 
Unless the seller explicitly states otherwise, you can assume that a camera is being sold with defective light seals.

Photo: So-called Lichtlecks or "light leaks" due to defective light seals

The exchange requires some time, patience, and nerves, but it can also be done by amateurs on a quiet afternoon. In this guide, I will show you step by step how to replace the light seals – just like we used to do in our small camera workshop. We have sealed hundreds, if not thousands, of cameras this way, and it has always worked reliably.

What you need

• Prefabricated light sealing set or foam mats in various thicknesses for cutting
  • Most of the time, you need a 1 mm thick mat for the seals on the back wall.
  • and a 2 mm thick mat for the mirror stop damper
• Rug knife, ruler, and cutting mat (for self-cutters)
• Cotton swabs
• Isopropyl alcohol (for removing old seals)
• Small slotted screwdriver for scraping off old seals
• Tweezers for the precise positioning of the new seals
• Painter's tape (to protect the closure during cleaning)
• Microfiber cloth and toothbrush (for final cleaning)

In our finished light sealing set you get everything you need for the replacement except for the solvent (isopropanol), including a special tweezers with an integrated scraper for stubborn sealant residues.

Photo: Contents of our light sealing set from Ausgeknipst with pre-cut light seals in various thicknesses and widths, cotton swabs, cold shoe cover (available as a bonus in Feb 2025) & special tweezers.

Which cameras are suitable for this guide?

The process is almost identical for most 35mm SLRs, e.g. Canon AE-1, Olympus OM-1, Pentax ME or Minolta SRT series.

Step 1: Remove the old light seals

You can usually find the old seals:

• At the top and bottom edge of the back door

• Around the hinge of the rear door

• On the mirror stop damper (not a real sealing material, but should be replaced often)

Here's how to remove the old seals:

1. Apply isopropyl alcohol to the old seals with a cotton swab.

Photo: Old seals can be dissolved with some isopropanol and can then be removed more easily.

2. Wait a moment until the material softens, and carefully scrape it out with tweezers or a small screwdriver.

Photo: With the back part of our tweezers, you can carefully scrape off the old seals. Be careful not to apply too much pressure, or you might damage the paint of your camera.

3. Make sure that no residues fall into the camera interior.

Photo: If old sealing material falls into the inside of the camera, you can hold the camera with the opening facing down and gently blow air into it with a blower. Sometimes it also helps to tap the camera gently from behind. Be careful: like with a baby that has choked ;)

4. Finally, remove the last particles with a cotton swab soaked in isopropanol. 

Photo: To remove the last remnants of the old seals, you can tear off a piece of cotton from a cotton swab with your fingers, clamp it in a pair of tweezers, and dip it in isopropanol. Then, you run the soaked cotton ball along the sealing groove until the cotton remains completely white. The more thoroughly you proceed here, the better the new seals will adhere later.

 

Photo: Removing the brittle mirror bumper on a Pentax ME Super

Tipp: Be especially careful when removing the upper and lower door seals. No alcohol should enter the locking mechanism of the rear door (usually at the top right), as it could damage the mechanism.

Photo: At this point, most cameras have a small opening for the automatic reset of the film counter. No old sealing material should enter here, as it can otherwise block the mechanism. 

Step 2: Insert the new light seals

After cleaning, you can insert the new seals:

1. If you are using foam boards, cut the strips to the exact size needed.
2. For pre-made adhesive seals, remove the protective film and carefully fit the strips into the grooves.
3. Press the strips into the correct position with tweezers.
4. Pay attention to the hinge to ensure that the seal fits well and the door continues to close easily.

Photo: New light seals are best positioned accurately with tweezers.

The most difficult part is the thin seals along the rear door grooves. If they twist, just stay calm and press them into the groove with the tweezers. These self-adhesive strips are a bit trickier to position, but you don't need to buy any special glue for that.

Step 3: Replace the mirror stop damper

1. Find the old mirror stop buffer (usually a foam strip above the mirror).
2. Carefully remove it so that no particles fall into the mirror box.
3. Cut the new damper to the appropriate size.
4. Place it exactly in the right spot with the tweezers.
   
   

Photo: Installation of the new mirror stop damper

Important: No alcohol on the screen! It can be permanently damaged.

Step 4: Final cleaning and inspection

• Remove any remaining dust with a toothbrush and a microfiber cloth.
• Remove the painter's tape from the closure.
• Close the rear door and check if all seals are properly seated.
  
  

Photo: Finally, clean your camera with some soapy water, a toothbrush, and a microfiber cloth.

 

Conclusion

Done! Your camera now has new light seals and should work perfectly again – no more light leaks!

This guide is designed for 35mm SLRs but can also be applied to medium format cameras or film cartridges with minor adjustments.

If you have any questions, feel free to leave me a comment or send us a message through the contact form in our online store :) I look forward to photos of freshly serviced cameras!

 

Have fun photographing and best regards, your Vladi! 🎞📸