FF mirrorless mount -- go thin or go with EF?

[MayaTlab]

The issue with short flange distances is that it becomes more difficult to build wide angle lenses that will cover full frame. The sharper angle of the light rays striking the sensor causes more light fall off which must be compensated for by boosting the ISO of the outer photosites.

I think its a bad solution, its workable, but a compromise in quality.

A shorter flange distance doesn't cause any compromise on lens design relative to a longer flange. It only has potential benefits.

It's just that, given current sensors' dislike for acute ray angles, it's harder then it used to be with film to exploit this potential. But not impossible as some of Sony's FE lenses show (some FE lenses are dramatically smaller than their DSLR counterparts, taking into account the shorter flange, like the 28mm f2 - yes, I know, it's got software correction, and no IS, but it's one stop faster than the equivalent Canon - and nearly all of them use the extra space for elements), and maybe won't be a problem long term.

 

[MayaTlab]

Canon will use the EF mount. However, they will modify it slightly to accept a new lens type - EF-T. The new EF-T lenses will only mount on full frame mirrorless cameras. (In the same way as EF-S lenses only mount on APS-C bodies).

The EF-T lenses will extend further into the camera body. This gives designers the option to reduce the size of the protruding, exterior part of the lens. It will also allow Canon to claim full compatibility with existing EF lenses and also display size reduction benefits with the new EF-T lenses.

I think this is a very bad idea. First, it's not just about shoving lens elements inside a lens mount, but also motors, cams, and other bits. The EF mount is large, but is it large enough ? My guess is that some designs that would have been possible with a shorter flange won't be possible with this solution. Second, it's going to be a lens cap and accessories nightmare (you'll have to produce, sell, maintain, use, two lines of lens caps, and the lens caps will be bigger). Third, it's only going to make changing lenses more annoying than it needs to.

 

[MayaTlab]

Not sure why people tend to be against adapters to increase the flange distance. They are simple - no glass, no optics, no nothing. I used one with my Olympus OM-D. You put it on. You leave it on. You forget you even have it on fairly quickly. What could be easier? You get the advantage of a slightly smaller, lighter camera and you can use all your EF lenses. Works for me.

This. The adapter should be reasonably small and unobtrusive (ideally, it will be identical to the current M adapter). While you're accumulating your new mirrorless lenses, you use the adapter as needed. It should be a smooth transition.

Unless Canon insists you use the adaptor by limiting native the mirrorless FF mount lens offerings.

There's a strong argument to be had that since FF mirrorless and FF SLR glass are basically the same size/specs, Canon's not going to be a in a hurry to migrate the EF glass over -- it won't save mirrorless owners any size and Canon would have to spin up a new mfg line for those lenses. If they go skinny with the FF mirrorless mount, what's to stop them from only offering a smattering of smaller primes in the new mount and forcing us to use EF through an adaptor?

My guess is that, in fact, Canon will most likely be in a hurry to replace all of their EF lenses, regardless of specifications, and just because of one thing : USM.
Nearly all lenses with fast AF and made for mirrorless don't use ring-type USM motors and most of them seem to use linear motors (like the Sony 35mm f1.4 FE). I suppose there is a very good reason for that.
It's one the reasons I think it's wishful thinking to believe that any current EF lens will work particularly well on a mirrorless, regardless of whether it's got an EF mount of is adapted to a shorter flange mount, and has on sensor PDAF sensors or not.
I've used 43 lenses on an EM1. It's not bad, and totally serviceable for some applications, but compared to dedicated m43 lenses, or a reflex PDAF system, it's much slower and somewhat more unreliable.
Perhaps I'm wrong though and Canon will find a way to make those USM lenses perform as well as dedicated lenses. The Nikon 32mm for the 1 system is SWM, for example - but maybe Nikon's using the SWM label for a technology that isn't ring-type USM/SWM, just like Canon's USM or STM designations can correspond to quite different AF technologies.

 

[Bernard]

Canon will use the EF mount. However, they will modify it slightly to accept a new lens type - EF-T. The new EF-T lenses will only mount on full frame mirrorless cameras. (In the same way as EF-S lenses only mount on APS-C bodies).

That solution is the worse of both worlds. You are creating another incompatible lens mount that looks just like an EF mount, which leads to confusion and frustration. Things are bad enough already with EF-S lenses that don't work on a FF body, even though they almost fit. On top of that' you get none of the advantages of mirrorless because you've lost all the flexibility.

I hope that Canon will do the rational thing and use the existing EF-M mount. It's big enough, and it will allow them to take advantage of a shorter flange distance. Sure, you need an adapter for EF lenses, but that adapter already exists and it's really good. The only issue with it is price, they can work on that.

I think people get confused with the flange focal distance and the size of the grip. There's no real link, only the fact that you can make a smaller camera with a shorter mount. It doesn't mean that all mirrorless cameras will be tiny!

 

[Bob Howland]

The issue with short flange distances is that it becomes more difficult to build wide angle lenses that will cover full frame. The sharper angle of the light rays striking the sensor causes more light fall off which must be compensated for by boosting the ISO of the outer photosites.

I think its a bad solution, its workable, but a compromise in quality.

Wouldn't the same issue of angle sharpness be worse with smaller lens mounts, such as the M-mount compared with the EF mount, necessitating smaller lens rear elements?

 

[Don Haines]

Is a Full-frame lens to EOS-M speed booster possible?

Don't know, but one would think that if Metabones could, they would. They currently don't sell one for the EOS-M mount.

So, it's either:

1) Not possible due to there not being enough room (i.e. the flange distance of EOS-M is too close to that of EF to pull it off), or

2) EOS-M is too small a market for Metabones to make this for.

Gotta believe it's the former and not the latter, but I'm just speculating.

- A

I would think that if it's possible, there would already be an EF to EF-S speed booster........

 

[Sportsgal501]

SL2 should be mirror-less. ...if they decide to make it.

 

[ahsanford]

I think people get confused with the flange focal distance and the size of the grip. There's no real link, only the fact that you can make a smaller camera with a shorter mount. It doesn't mean that all mirrorless cameras will be tiny!

+1. This poll is about the mount. In a clean slate world, any combination of large/small mount and large/small grip could conceivably coexist.

But keep in mind that a 400 prime, an 85 f/1.2, a 70-200 f/2.8 is going to get bolted on this rig on day one -- EF or adapted EF. Done deal. Take it to the bank.

So in my mind, though the mount and grip are independent variables, that 'heavy lens reality' has a grip conversation starting at Rebels and undoubtedly going bigger. I personally see a 70D sized grip at a minimum.

- A

 

[Loswr]

Is a Full-frame lens to EOS-M speed booster possible?

Don't know, but one would think that if Metabones could, they would. They currently don't sell one for the EOS-M mount.

So, it's either:

1) Not possible due to there not being enough room (i.e. the flange distance of EOS-M is too close to that of EF to pull it off), or

2) EOS-M is too small a market for Metabones to make this for.

Gotta believe it's the former and not the latter, but I'm just speculating.

- A

I would think that if it's possible, there would already be an EF to EF-S speed booster........

EF to EF-S isn't possible, same flange distance means no room for the optics. There was a suggestion some time back they were working on EF to EF-M:

http://www.canonwatch.com/is-metabones-working-on-a-speedbooster-for-eos-m/

 

[ahsanford]

COMPANION POLL HERE:
http://www.canonrumors.com/forum/index.php?topic=28231.0

- A

 

[yakman]

Is a Full-frame lens to EOS-M speed booster possible?

There is/was one from a Korean company.

There is no much reason to buy one such for EOS M.
For the same price or lower you can get a used Canon 5D.
You get the speed boost and a camera at the same time.

 

[yakman]

The issue with short flange distances is that it becomes more difficult to build wide angle lenses that will cover full frame. The sharper angle of the light rays striking the sensor causes more light fall off which must be compensated for by boosting the ISO of the outer photosites.

I think its a bad solution, its workable, but a compromise in quality.

I thought shorter flange distance is easier for short focal length lenses? Or simpler design to achieve same results

 

[PhotographyFirst]

The issue with short flange distances is that it becomes more difficult to build wide angle lenses that will cover full frame. The sharper angle of the light rays striking the sensor causes more light fall off which must be compensated for by boosting the ISO of the outer photosites.

I think its a bad solution, its workable, but a compromise in quality.

I thought shorter flange distance is easier for short focal length lenses? Or simpler design to achieve same results

That was only true with film. Unless some different type of sensor tech appears, it does not work well with digital yet.

 

[FTb-n]

I voted for the EF mount. If I was interested in a FF mirrorless, it would be for the small body that can leverage my existing EF lenses. In this case, I wouldn't want to mess with adapters.

If I need a more compact system, then the APS-C based M system would suffice.

 

[StudentOfLight]

Is a Full-frame lens to EOS-M speed booster possible?

There is/was one from a Korean company.

There is no much reason to buy one such for EOS M.
For the same price or lower you can get a used Canon 5D.
You get the speed boost and a camera at the same time.

The 5D is 13MP so wouldn't a EOS M3 with it's 24MP and newer sensor technology deliver better IQ given full-image-circle light?

 

[AvTvM]

Of course a Canon FF mirrorless should come with a new, native short flange-distance mount [unless EF-M really is large enough to create FF image circle lenses without major issues - I seriously doubt that].

That's the only way to get small(ish) camera bodies and some small(ish) prime lenses for the most frequently used focal lengths [between 24mm and 100mm] for those who want the option of a small kit - all the time or for some tasks/situations. Plus the option to adapt all sorts of lenses with longer flange distance.

For other users who prefer a large body with many physical control points and chunky grip and/or use large EF lenses [fast primes, heavy zooms, long tele lenses] all the time or most of the time, a small, Canon will certainly also make somewhat larger mirrorless cameras with larger grip. Adaptor is no problem in real life - just leave it on the camera - think of it as an extension of the camera body.

There is no rational reason for all the "adaptor angst" ... I use EF and EF-S glass on my EOS M (1) quite frequently. No problem. It is mechanically stable enough. Weight of larger lenses (eg 70-20 / 2.8 II) has to be supported by left hand anyways - on any camera. EF-M adapor is mechanically stable and precise. Have no issues whatsoever. Also love the adapter since it also serves as removable tripod foot for any EF lens. 8)

 

[ahsanford]

There is no rational reason for all the "adaptor angst" ... I use EF and EF-S glass on my EOS M (1) quite frequently. No problem. It is mechanically stable enough. Weight of larger lenses (eg 70-20 / 2.8 II) has to be supported by left hand anyways - on any camera. EF-M adapor is mechanically stable and precise. Have no issues whatsoever. Also love the adapter since it also serves as removable tripod foot for any EF lens. 8)

I have no mechanical adaptor angst -- Canon won't put something out that will not support the load. But do we know that adaptors will not affect the responsiveness of the lens's AF? That'd be a killer.

- A

 

[Mt Spokane Photography]

The issue with short flange distances is that it becomes more difficult to build wide angle lenses that will cover full frame. The sharper angle of the light rays striking the sensor causes more light fall off which must be compensated for by boosting the ISO of the outer photosites.

I think its a bad solution, its workable, but a compromise in quality.

Couldn't DO be used to mitigate that problem? It's my understanding that enhanced bending of light is what they do.

I've yet to see any wide angle DO lenses, they seem most useful for telephoto. Perhaps there is not much market for $7,000 16mm lenses?

 

[9VIII]

The issue with short flange distances is that it becomes more difficult to build wide angle lenses that will cover full frame. The sharper angle of the light rays striking the sensor causes more light fall off which must be compensated for by boosting the ISO of the outer photosites.

I think its a bad solution, its workable, but a compromise in quality.

I thought shorter flange distance is easier for short focal length lenses? Or simpler design to achieve same results

That was only true with film. Unless some different type of sensor tech appears, it does not work well with digital yet.

Sensor performance doesn't negate lens design. 24mm lenses would be much simpler if we had a 24mm flange dinstance. Sensor tech is constantly changing and should basically be ignored.
Theoretically BSI should solve most of the digital vignetting issue.

 

[9VIII]

My opinion is that they should stick to the EF mount at first, and if they release a new mount it should be larger and able to accommodate 50mm sensors in the future.