How to repair an SLR camera lens aperature

Written by brandon getty
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How to repair an SLR camera lens aperature
The inner diaphragm of a lens can become sticky over time. (objectif image by David Antczak from

Many single-lens reflex (SLR) cameras manufactured in the 1960s and '70s were built to last--which is why so many functional ones can be found on the used and vintage market today. However, a common problem plagues many of the lenses on these cameras. The diaphragm, or the blades that close and retract to filter the light's passage through the lens (known as aperture), can become sticky, causing the blades to travel slowly. Sticky blades result in inaccurate aperture values and poorly exposed photos.

Skill level:

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Things you need

  • Micro screwdriver set
  • Tweezers (optional)
  • Plastic container
  • Microfiber cloths
  • Lens spanner
  • Cotton swabs
  • Lighter fluid
  • Lens cleaning solution
  • Lens tissue

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  1. 1

    Loosen and remove all of the screws that secure the metal mount ring at the rear of the lens and place them in a plastic container. You may find it helpful to use a set of tweezers to lift the screws out of the ring. Also lift off the mount ring and set it in the container.

  2. 2

    Remove any other securing screws around the rear of the lens barrel--depending on the type of lens you are working with, there may not be any additional screws.

  3. 3

    Grasp the edges of the rear lens element and twist it gently counterclockwise. Place it on a microfiber cloth. Depending on the make of your lens, there may an additional glass element beneath the rear. Remove this in the same fashion and set it next to the rear element on the microfiber cloth. Make sure you are able to differentiate between the two.

  4. 4

    Turn the lens over so the front element faces up. Grasp the edges of the lens nameplate (displays manufacturer name, lens focal length and other details) and twist it clockwise to remove it. Set it aside on a microfiber cloth. Some models require a lens spanner tool to remove the nameplate and the underlying rings. If this applies, fit the tool into the small notches on the inside of the nameplate and twist to remove it.

  5. 5

    Loosen and remove any screws that secure the front element. Set the screws in the plastic container.

  6. 6

    Grasp the edges of the front element and twist clockwise. If there are additional elements below the front element, also twist and remove these. Set them on a microfiber cloth in the order that you removed them.

  1. 1

    Turn the aperture selection ring so that the indicator mark aligns with "16." This will give you best access to the surface area of the blades.

  2. 2

    Moisten the tip of a cotton swab with lighter fluid. Wipe the surface of each blade individually with single, slow passes. Use a fresh tip and fluid for each blade. Flip the lens and repeat for the other side of the blades.

  3. 3

    Re-assemble the lens by performing Section 1 in reverse order. Ensure that you replace the optics in the order that you removed them.

  4. 4

    Clean the front and rear elements with a lens tissue dampened with lens cleaning solution. Wipe in a gentle circular motion, allowing excess solution to evaporate from the elements.

  5. 5

    Replace the lens and set the aperture to "16." Look into the lens and press the shutter button. If the blades close and retract without delay, your work is complete.

Tips and warnings

  • SLR lenses vary widely in their construction. Consult your owner's manual or research your model for specific information regarding disassembly (e.g., removing front and rear elements, thread direction).
  • Work in a clean, dust-free and well-lit area.
  • Do not attempt to disassemble your lens if you are inexperienced with camera or optics repair. Doing so may cause irreparable damage to the lens.
  • Avoid saturating the cotton swab with solution when cleaning the blades. Use only enough to wipe the blade surfaces clean of oil and dried lubricant.

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