How to prevent flare in a METABONES Canon EF adapter (mark 111)

Sony’s new A7r is a remarkable camera but the Metabones EF lens adapter supplied with it has serious flare. Sony seems uninterested in the problem, even though it provides the adapter under a rebate arrangement when you buy an A7 & A7r.

In my opinion the flare is caused by light reflecting off the angled ridged plastic interior of the adapter and onto the sensor. A simple way to prove this is to mount a lens on the adapter and shine a small LED torch vertically from above the back of the lens mount. Do this at night or in a very dark room. Before I added the black flocking material I could see a reflection of the adapter’s interior in the rear element of a Canon 17-40mm lens. No reflections where visible after the material was added. (Note: Canon mount this black material to the rear of all L series lenses and to lens hoods).

The flare is more evident when you’re shooting under certain lighting conditions. For example, long exposures with overcast skies, and around rainforests, waterfalls, with night shots and architectural interiors. I made tests with the Metabones EF adapter and a $15 Chinese unit with black flocking. Both pictures were taken on a tripod using an exposure of 20 sec at f19, the only aperture I could use with an EF lens on a manual adaptor. The Metabones flared, but the Chinese cheapy didn’t,  see comparison photo.

HOW TO KILL THE FLARE

I wrote to Sony about the flare and got this reply:

"Thank you kindly for your email and raising your concerns about the recent issues you have experienced with your Metabones adapter you recently received via redemption with your ILCE7.

While this product was provided via a SONY promotion with the ILCE7, this adapter is not a SONY product or design and you will need to address these concerns about adapter and its possible design flaws with Metabones directly, so the correct specialist support is provided to you and hopefully a resolve in this issue.

Due to the adapter being a third party unit, we cannot provide technical assistance nor guarantee full compatibility or functionality with this product.

While there are certainly many fixes that have been posted and made available online, I would strongly suggest contacting Metabones for assistance, as any altering of the adapter would null any warranty that is applicable with this unit. "

After reading a pathetic reply from Metabones on the net about this problem I decided to fix the adapter myself. That you actually have to do this with an adapter made by Metabones is ridiculous, but here's the instructions of what I did.

  • Cut out paper templates to match the interior of the adapter (photo 1).
  • Mask the electronic contacts in the front of the adapter then carefully file away the black plastic ridges with a small flat-ended file to make extra room for the flocking material. This step might not be necessary if you use a material with a lower 'pile' than the material I had on hand (photo 2).
  • Apply thin double-sided tape to the paper templates.
  • Peeled away the tape backing and stick the templates to the black flocking material.
  • Cut around the edge of the black flocking and peeled away the templates. This also cleans away any loose fibres from the material (photo 3).
  • Mount the black flocking to the sides first, then the top, then the bottom and also the two small pieces in the sides, just inside the lens mount.
  • Finished (photos 4 & 5).

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