Doe's there exist any multilayer for M lenses?

R2D2 wrote:

Larry Rexley wrote:

R2D2 wrote:

YehudaKatz wrote:

R2D2 wrote:

Can you tell us what your definition of a "multilayer" is? Thx.

R2

Thanks. Basically a Tele-adapter for EF-M.

None that I’m aware of either. I suppose because there aren’t any dedicated EF-M telephotos to make use of it.

The “Rexley Special” would be the next best thing (375mm actual).

R2

This thread inspired me to make another attempt at the 'Rexlar' native EF-M teleconverter... I wanted to see if I could get it working with at least one EF-M lens. I've documented my attempts to make an EF-M native TC in 1 or 2 other threads, out of a 'cheap' vintage Vivitar 2x teleconverter. Its optical assembly is very short --- giving it the best chance of success in the very short EOS M optical path... but knowing that it would probably not have great image quality.

Here's my home-made TC, with the vintage Vivitar 2x optical assembly mounted into the 10mm MOVO EF-M native DG extension tube:

Another great project Larry! You should produce and market these "Rexlars!"

Thanks for sharing!

R2

As always, I appreciate your feedback.

In my profession (software engineering) what I did is called 'proof of concept.' I wanted to see if it was possible to use any teleconverter with a native EF-M lens. The question of an EOS M teleconverter comes up from time to time in this forum.

I had good luck with the Canon EF-mount Kenko 1.5x SHQ teleconverter with the EF-S 55-250 IS STM (a popular and inexpensive lens) after modifying the lens to EF mount, and to my surprise, it ended up being good enough become part of my kit. I'm glad that it appears to have helped and inspired others.

My inclination to push the boundaries probably comes from my training (physics), where avenues are often explored to learn something new, which ultimately may or may not prove to be of practical value.

Interestingly, I found that several sets of teleconverter optics I tried to make work with EOS M just didn't work at all, with any lens. Most EF-M lenses are designed to focus internally - with their rear elements at a fixed distance from the sensor, adjusting focus (and magnification for zooming) internally. EF-M Zooms essentially have a 'variable-teleconverter' built into their optical path - and this doesn't play well with a very short flange distance.

My takeaway is this: with such a short flange distance, an M teleconverter would only work if its optics were just a few millimeters thick. Good TC optics just aren't that short.... good ones require 5-7 elements which are far thicker than just a few mm. The only 'case' that I got to work (out of 12 native EF-M lenses I tried) required modifying the lens physically, pushing the TC topics forward into the barrel of the lens - which understandably most people don't want to do!

Canon may have designed the EOS M with the major objective to make the camera and lens as physically small as possible (again proof of concept) and took this to its endgame well - commendable for a major camera manufacturer. You and I and many in this forum have realized, and appreciate, that they achieved this objective. No other system from another manufacturer approaches the minimalist size and weight of the M system.

Another payoff of this is some exceptional lens designs available for the APS-C crowd at reasonable prices --- notably the EF-M 32mm f1.4, the Siggy 16 and 56mm f1.4's ---- such lenses may not be feasible with even slightly longer flange distances.

And while they were at it, Canon came up with the exceptional M6 Mark ii, with the 32 MP resolution sensor, and although it's not a pro-quality build, it's a great 'enthusiast' level camera at a very reasonable price point.  Canon has already 'corrected' this 'mistake' by discontinuing the M6ii and coming out with its 'replacement' at the 'proper' price point of $1500 for the R7 body.  I think folks will realize this and the M6ii used prices may not drop any time soon.

However, at some point their engineers and market analysts must have realized that the 'super-small' M system had physical limitations that would limit the system's capabilities and growth potential. It wasn't the ultimate 'system of the future.' Or perhaps the M system was always intended only as a consumer-level APS-C system.

Canon is known for taking the long view --- they were the first the make the painful and shocking (at the time) departure from their 'legacy' FD lens mount to the 'new' EF AF mount, leaving a massive set of users with a set of incompatible lenses. Time has proved them right, with a technically superior mount that didn't need 'expensive' backward compatibility that other camera manufacturers had to bear. So it isn't all that surprising that Canon would ultimately abandon the M mount if it isn't future-proof --- we have the precedent in the FD mount.

Notably the more future-proof RF system, with its slightly longer flange distance, does support teleconverters. Of course Canon has them available... for a price.