F55: The search for the perfect Canon EF mount adapter for FS7 (shimmable adapter?)

J

jackcklam

Active member
Hi all,

As we are readying for the arrival of the Sony FS7, I have been looking for the perfect adapter from the E-mount of FS7 into a Canon EF mount. I know there are quite a few options in the market right now. Namely Metabones makes one that has electronic control of the iris of Canon EF lenses.

However, I'm mostly concerned by the accuracy of the adapter's flange depth. I have a cinevised zoom lens by GL Optics with EF mount (the Sigma 18-35mm/1.8 rehoused). I also plan to buy a set of Schneider FF lenses, which is EF and PL switchable. I know a camera's flange depth is such a critical thing, it requires very high level of precision engineering. I would expect the flange depth of each FS7 is subjected to sample variations.

So I am looking for a E-mount to Canon EF adapter that is shimmable. It is also important to have 1/4" thread on the bottom to help support the adapter. Electronic iris control is not my first priority. The perfect design should have a locking mechanism similar to Optitek's Prolock.

Do you have any suggestion?
 
I feel your pain about these issues. I went Nikon for the f3 and got a good solid adapter with the Prolock but even that was not adjustable back focus. Fortunately you could adjust back focus on the F3, and I was able to get my back focus perfect for nikon and all my zooms were par focal. I'm going to lose that security though because I want to go EF on the FS7 to get image stabilization.

. I don't think you can adjust back focus with the FS7 which is a drag. The only bright spot here might be the speed booster adapter because that does have a back focus adjustment. I'm a little unclear as to whether that will function the same as an adjustment would on a an adapter that didn't have an additional magnifying glass on the back . i hope so.
My experience with Nikon was that no matter what a manufacturer said about the flange focal depth of the adapters- they all varied.

i doubt you will be able to shim but its an interesting idea. Let us know if it works.
 
While the Metabones adapters are not designed to be shimmable, they are designed with a very fine pitch thread inside the mounting flange. The intended purpose is to be able to adjust the flange distance. While not as perfect, nor as stable as shims, they serve the intention. There is, because of the tolerances needed in a screw thread, a very small amount of runout. While this might affect centering and tilt, the errors are quite small and the thread is lockable after it is set.
 
What I don't understand is why you do fear that the FS7 would have such a poor tolerance of fabrication in the first place ?

Even if this camera is not "hand built" like a RED or an Alexa, I do believe Sony has enough, dare I say "experience" in the the camera domain, to built theirs with the tolerances one has to expect.

I believe the Metabones are the best EF to E mount "smart" adapters on the market. You could also go with the smart adapter from MTF Services which, IMHO, is not that "smart" because the aperture control is via an (expensive) external box.

Schneider FF lenses are very good for the price (though I find them to have quite some chromatic aberrations wide open) so you should get a Speedbooster (ULTRA if you can) to mate with them. You have a screw for the micro-adjustment of the optical group on it, so you can achieve what you want with it.

Metabones adapters have a (removable) threaded mount for lens support system too.

Cheers.
 
Anyone have experience throwing a Nikon > Ef adapter piggy backed onto a an EF> E mount adapter . I have all Nikon lenses for F3 and hope to switch to EF for the FS7 but during the transition am hoping that will work.
 
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