Canon's FF Mirrorless Camera Will Have Same Internals as EOS 6D Mark II

[Don Haines]

People go FF for image quality.

Shorter flange distances means the light hits the sensor at a greater angle, causing vigneting, and the associated drop in image quality.

Going FF with a newer and shorter mount/flange distance puts these two factors into conflict.

How do you resolve this?

 

[slclick]

People go FF for image quality.

Shorter flange distances means the light hits the sensor at a greater angle, causing vigneting, and the associated drop in image quality.

Going FF with a newer and shorter mount/flange distance puts these two factors into conflict.

How do you resolve this?

Curved sensor?

 

[Don Haines]

People go FF for image quality.

Shorter flange distances means the light hits the sensor at a greater angle, causing vigneting, and the associated drop in image quality.

Going FF with a newer and shorter mount/flange distance puts these two factors into conflict.

How do you resolve this?

Curved sensor?

A curved sensor makes it better for light coming through a point, but as the rear element gets larger (fast lenses) a curved sensor becomes less effective, and eventually worse than a flat lens.....

 

[Orangutan]

People go FF for image quality.

Shorter flange distances means the light hits the sensor at a greater angle, causing vigneting, and the associated drop in image quality.

Going FF with a newer and shorter mount/flange distance puts these two factors into conflict.

How do you resolve this?

Curved sensor?

A curved sensor makes it better for light coming through a point, but as the rear element gets larger (fast lenses) a curved sensor becomes less effective, and eventually worse than a flat lens.....

I believe there have been patents for better microlenses, which could accommodate this at some point. Remember that this is conservative Canon we're talking about: they won't dump all this tech into one product until they've extensively tested the both the performance and the market.

 

[AvTvM]

You claim Sony going too thin with the mount makes their lenses enormous, but I have yet to see the dissertation on why a 5mm more flange distance would magically make FF lenses 25mm shorter.

read my posts. it is not ehat i wrote.

mistake with Sony E-mount is the *combination* of 1) too narrow throat width (46.1mn) and 2) too short FDD (18mm) *for FF image circle*.

if you cant see the corners of the sensor looking through mount hole, it is a problem already. incoming light needs to be "bent around corner" even at "normal FOV/focal length". i contend that narrow throat width is the bigger problem with Sony E-mount for FF sensor. the problem is then further exacerbated by very short FDD.

and yes, just a few mm more throat width *and* a bit longer FDD would have shaved off the 25mm spacer/built in adapter in Sony FE lenses. no, i am not an optics expert. nut i habe closely looked at the relation beteeen lens mount parameters (width AND flangd focal distance) and associated lens sizes. evidence is pretty clear.

 

[Antono Refa]

You claim Sony going too thin with the mount makes their lenses enormous, but I have yet to see the dissertation on why a 5mm more flange distance would magically make FF lenses 25mm shorter.

read my posts. it is not ehat i wrote.

mistake with Sony E-mount is the *combination* of 1) too narrow throat width (46.1mn) and 2) too short FDD (18mm) *for FF image circle*.

if you cant see the corners of the sensor looking through mount hole, it is a problem already.

The diagonal of an FF sensor is 43.3mm, why wouldn't the corners be seen when looking through a hole 46.1mm wide?

 

[Loswr]

if you cant see the corners of the sensor looking through mount hole, it is a problem already.

The diagonal of an FF sensor is 43.3mm, why wouldn't the corners be seen when looking through a hole 46.1mm wide?

Because he has eyes, he can look at pictures of the a7R II and he can't see the corners of the 'sensor' through the mount hole.

Here's the thing...in the AvTvM Universe, the 'sensor' goes right to the very edges of the piece of silicon. Out here in the real world, there's a non-light sensitive border around the edge. In fact, the difference can be seen on those pics of the a7R II, if you look closely. But looking closely is apparently among the many things which AvTvM does poorly.

 

[ahsanford]

People go FF for image quality.

Shorter flange distances means the light hits the sensor at a greater angle, causing vigneting, and the associated drop in image quality.

Going FF with a newer and shorter mount/flange distance puts these two factors into conflict.

How do you resolve this?

You could also push the rear element of the lens further away from the sensor, effectively building some of that regular FF SLR mount back into the lens -- the 'lens tube' effect AvTvM keeps referring to.

But I'm only seeing this with f/1.4 primes and f/2.8 zooms and UWA lenses with the Sony mount. A number of other lenses (f/2 primes, non-UWA f/4 zooms, etc.) seem to not need this. Just curious, why is this so? Does the diameter of the rear element have something to do with this?

- A

 

[dak723]

People go FF for image quality.

Shorter flange distances means the light hits the sensor at a greater angle, causing vigneting, and the associated drop in image quality.

Going FF with a newer and shorter mount/flange distance puts these two factors into conflict.

How do you resolve this?

You could also push the rear element of the lens further away from the sensor, effectively building some of that regular FF SLR mount back into the lens -- the 'lens tube' effect AvTvM keeps referring to.

But I'm only seeing this with f/1.4 primes and f/2.8 zooms and UWA lenses with the Sony mount. A number of other lenses (f/2 primes, non-UWA f/4 zooms, etc.) seem to not need this. Just curious, why is this so? Does the diameter of the rear element have something to do with this?

- A

It might be debatable whether other lenses don't need the "lens tube" or should have it, too. I only have experience with the the Sony FE 28-70 kit lens - and when I bought it with the Sony A7 II, I thought the lens was defective it was so lacking sharpness away from the center. I traded it in for another kit (this time with the original A7) and the results were the same. At the time, I knew nothing about flange distance - I just thought Sony made crappy lenses. The other kit lens, the more expensive Sony FE 24-70, has similar reveiws - at least according to the review on Imaging Resource. They write:

Despite carrying the Zeiss branding, which is typically indicative of high-end results, we felt that the Sony FE 24-70 Zeiss lens fell a little short of our expectations. At 24mm, the lens displays good sharpness right in the center of the frame, even wide open, but outwards and especially in the deep corners it's noticeably soft. Surprisingly, even stopping down doesn't improve the corner softness at 24mm, and by ƒ/16-ƒ/22, diffraction comes into play and reduces sharpness all around even more.

Zooming out to 35mm and 50mm improves sharpness significantly, especially in the corners, and throughout the aperture range (until diffraction hits at ƒ/22). However, as we saw at 24mm, 70mm on the Sony FE 24-70 displays a decently sharp center, but with considerably softer corners that aren't much improved by stopping down. Surprisingly, corners at 70mm appear even softer than they do at 24mm.

 

[Bob Howland]

I can't believe you folks are still arguing about this. So here are my trivial comments:

1. I want a FF camera, perhaps MILC, that is lighter than my 5D3 but not necessarily smaller. Likewise, I'd like lighter lenses. If that means using a 24-70 f/4 instead of a 24-70 f/2.8, then so be it.

2. I don't see how converting the M-mount to FF buys Canon anything, since current M-mount lenses are for APS-C sensors and couldn't be used on a FF M-mount camera. Furthermore, the EF-mount isn't that much larger than the M-mount, 54mm vs 47mm, as I recall.

3. At one time, I thought creating a new FF mount by simply reducing the EF mount flange distance, might be a good idea. I've changed my mind, since it forces Canon to introduce a fourth lens line to support it. If only current EF lenses (plus an adapter) would be used with the new lens mount, then why not effectively make the adapter part of the camera?

4. A Canon FF MILC in a rangefinder configuration might be interesting, although I'm not sure I would buy one.

 

[Loswr]

2. I don't see how converting the M-mount to FF buys Canon anything, since current M-mount lenses are for APS-C sensors and couldn't be used on a FF M-mount camera.

By that logic, the EF-S mount doesn't buy them anything, because those lenses are for APS-C sensors and can't be used on FF mount dSLRs.

Think of it from the opposite direction...full-frame EF lenses can mount natively on APS-C dSLRs. Canon sells lots more crop than FF bodies, but already owning some FF glass makes the upgrade more palatable. The same driver would eventually apply to MILCs.

 

[pokerz]

I can't believe you folks are still arguing about this. So here are my trivial comments:

1. I want a FF camera, perhaps MILC, that is lighter than my 5D3 but not necessarily smaller. Likewise, I'd like lighter lenses. If that means using a 24-70 f/4 instead of a 24-70 f/2.8, then so be it.

2. I don't see how converting the M-mount to FF buys Canon anything, since current M-mount lenses are for APS-C sensors and couldn't be used on a FF M-mount camera. Furthermore, the EF-mount isn't that much larger than the M-mount, 54mm vs 47mm, as I recall.

3. At one time, I thought creating a new FF mount by simply reducing the EF mount flange distance, might be a good idea. I've changed my mind, since it forces Canon to introduce a fourth lens line to support it. If only current EF lenses (plus an adapter) would be used with the new lens mount, then why not effectively make the adapter part of the camera?

4. A Canon FF MILC in a rangefinder configuration might be interesting, although I'm not sure I would buy one.

More mounts mean more new modern lens for us, Canon is trying hard to fade out old USM lens.

 

[Antono Refa]

if you cant see the corners of the sensor looking through mount hole, it is a problem already.

The diagonal of an FF sensor is 43.3mm, why wouldn't the corners be seen when looking through a hole 46.1mm wide?

Because he has eyes, he can look at pictures of the a7R II and he can't see the corners of the 'sensor' through the mount hole.

This photo demonstrates the problem isn't with the 46.1mm diameter, but rather with other stuff inside it obstructing the view to the sensor.

 

[Loswr]

if you cant see the corners of the sensor looking through mount hole, it is a problem already.

The diagonal of an FF sensor is 43.3mm, why wouldn't the corners be seen when looking through a hole 46.1mm wide?

Because he has eyes, he can look at pictures of the a7R II and he can't see the corners of the 'sensor' through the mount hole.

Here's the thing...in the AvTvM Universe, the 'sensor' goes right to the very edges of the piece of silicon. Out here in the real world, there's a non-light sensitive border around the edge. In fact, the difference can be seen on those pics of the a7R II, if you look closely. But looking closely is apparently among the many things which AvTvM does poorly.

This photo demonstrates the problem isn't with the 46.1mm diameter, but rather with other stuff inside it obstructing the view to the sensor.

Not sure if you kept reading my post beyond the part you quoted, so I put the rest of my post back in italics for context. My point was that there's nothing 'obstructing the view to the sensor' and thus there's no problem at all, since the entire light-capturing area of the sensor can be seen.

The only problem is in AvTvM's imagination.

 

[takesome1]

Think of it from the opposite direction...full-frame EF lenses can mount natively on APS-C dSLRs. Canon sells lots more crop than FF bodies, but already owning some FF glass makes the upgrade more palatable. The same driver would eventually apply to MILCs.

Let me run this by you and see if your universe lines up with the real.

The EF lens existed before EF-S. The EF-S of course gave an upgrade path but it also gave entry level customers an affordable compact option.

You think that Canon has done this in reverse now. The APS-C M mount will be used on both it and the full frame M.

For this senario to play out we have to assume that Canon applied their wisdom and research in such matters and it is designed that way. The M mount can be used on a FF. You have looked at the math and formulas yourself and it can?

You are not suggesting that the current set of M lenses can be used on a FF, rather that a lens dedicated to a FF will be released and it will work on both cameras?

In this senario it would explain why Canon has been slow releasing a FF. It is not just the camera but the lens that must be released. This plan was implemented before the release of the M1.

 

[Loswr]

Think of it from the opposite direction...full-frame EF lenses can mount natively on APS-C dSLRs. Canon sells lots more crop than FF bodies, but already owning some FF glass makes the upgrade more palatable. The same driver would eventually apply to MILCs.

Let me run this by you and see if your universe lines up with the real.

The EF lens existed before EF-S. The EF-S of course gave an upgrade path but it also gave entry level customers an affordable compact option.

You think that Canon has done this in reverse now. The APS-C M mount will be used on both it and the full frame M.

For this senario to play out we have to assume that Canon applied their wisdom and research in such matters and it is designed that way. The M mount can be used on a FF. You have looked at the math and formulas yourself and it can?

You are not suggesting that the current set of M lenses can be used on a FF, rather that a lens dedicated to a FF will be released and it will work on both cameras?

In this senario it would explain why Canon has been slow releasing a FF. It is not just the camera but the lens that must be released. This plan was implemented before the release of the M1.

Exactly. I have no doubt Canon was planning for both APS-C and FF mirrorless well before the EOS M launch. I don't know for sure that the EF-M mount can support FF, but the EF-M mount specs are a match to Sony's E-mount used on their FF MILCs, so that's likely the smallest possible mount that would work.

In spite of AvTvM's viewpoint that such a mount is 'a mistake', I'd argue that, since for many people a major advantage to mirrorless is the smaller size, using the smallest mount possible is a very reasonable choice.

I don't think those factors have much to do with why there's not yet a Canon FF MILC...that's more to do with the overall market (still 3:1 favoring dSLRs), and the fact that competitors MILCs aren't taking market share away from Canon.

 

[AvTvM]

it does not make a difference to MIl body size, whteher the hole is 46mm or 50mm in net diameter. It dioes not make much difference to MILC body size , whether FDD is 18mm or 24mm. It makes a HELL OF A LOT OF A DIFFERENCE however to combination of *size, image quality and cost* of lenses.

 

[Loswr]

it does not make a difference to MIl body size, whteher the hole is 46mm or 50mm in net diameter. It dioes not make much difference to MILC body size , whether FDD is 18mm or 24mm. It makes a HELL OF A LOT OF A DIFFERENCE however to combination of *size, image quality and cost* of lenses.

The most appropriate response to that is your own words (note that I use the term 'words' loosely):

no, i am not an optics expert. nut i habe closely looked at the relation beteeen lens mount parameters

 

[AvTvM]

i find iphone typing a bit difficult. I'd prefer a keyboard with real keys too. So please bear with me and don't draw premature conclusions. Even if this is a lot to ask of the Neuros of this virtual world.

 

[Rocky]

The short lens distance (18mm) of both Sony and EOS-M is forcing the lenses to have some very "interesting design" in order to minimizing the light fall off at the corners. I do not own Sony camera, therefore I can not talk about it. I do own EOS-M camera. The EF=M 22/2 have an unusually LARGE rear element. The 11-22 mm is a retractable lens. We have to move the the lens out 15mm for the 11mm focal length. Effectively make the flange distance to be 33mm( for a 11mm lens). All of these is to increase the light ray angle to be closer to be 90 degree. On top of that the EOS-M has built in correction for light fall off.
Leica M (digital) is with flange distance of 27.8mm. It also has light fall off problem (not as severe as the EOS-M or Sony). in order to be able to use the regular film lens. It combat the problem in two ways. 1. Micro lenses are off-set at the corners ( they may have the pattern right for that). 2. Software correction in the camera.
The minimum opening for the Leica flange is 40mm. The EOS-M is 42mm.