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Author Topic: Canon EF 40mm f/2.8 Pancake Coming [CR3]  (Read 18876 times)

elflord

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Re: Canon EF 40mm f/2.8 Pancake Coming [CR3]
« Reply #75 on: May 23, 2012, 05:54:41 PM »
I don't see Canon's mirrorless system using the EF mount -- there's not much point removing the mirror, but keeping the space for it. This is designed to be paired with an APS-C DSLR.  The point of it is to serve as a budget compact walkaround prime. It's not fast compared to a high grade zoom, but it is fast compared to the kit zoom.
Why not? Think of the Pentax K-01: it's an APS-C mirrorless system using the Pentax K mount. And Pentax also offers a 40mm f:2.8 pancake for the K-01. Why shouldn't Canon introduce a similar - hopefully less ugly - system?

Why not ? Because if you use an SLR mount with a longer flange distance, you eliminate the size savings that you would otherwise derive from removing a mirror box. The K-01 is about the same size as the Canon Rebel XS (not quite as high because the viewfinder is removed but width and depth are similar).

Canon already have the capability to build an SLR that is close to the size of the Pentax K-01, the only thing missing are small APS-C lenses (Pentax have several).

They're much better off building a mount with a shorter flange distance which would still allow them to adapt EF mount lenses, then also ship an EF-mount adapter with full electronic coupling (so that it works with EF mount lenses).

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Re: Canon EF 40mm f/2.8 Pancake Coming [CR3]
« Reply #75 on: May 23, 2012, 05:54:41 PM »

maxxevv

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Re: Canon EF 40mm f/2.8 Pancake Coming [CR3]
« Reply #76 on: May 23, 2012, 10:41:55 PM »
Speaking hypothetically, if a smaller sensor was used with a EF mount, couldn't the distance between the lens mount and sensor be reduced ?

No you can't.  The flange to sensor distance is fixed as that is the 'projection plane' of the image for a given lens design. The specific design distance which an image is to be projected , relative to its flange mount plane.


Rocky

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Re: Canon EF 40mm f/2.8 Pancake Coming [CR3]
« Reply #77 on: May 24, 2012, 03:38:28 AM »
Pantax K-01 has the right idea. It let customer use their existing k mount lens WITHOUT adapter. At the same time, Pentax also supplies smaller lens for customers that  want to keep the system small. People may agrue that keeping the mirror box will make the camera bigger. The reality is that with the 'pancake lens" the size should be the same as other mirrorless with the lens mounted.
I thinks Canon should use K-01 as a model and improve on it. The EF mount is large enough to let the lens "sinks" within the mount. That can make the system very small.
Also canon needs to give us fast AF. Even the S100 and the G12 are too slow.
« Last Edit: May 24, 2012, 03:50:00 AM by Rocky »

elflord

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Re: Canon EF 40mm f/2.8 Pancake Coming [CR3]
« Reply #78 on: May 24, 2012, 08:09:53 AM »
The reality is that with the 'pancake lens" the size should be the same as other mirrorless with the lens mounted.
Not true, because other mirrorless cameras also have pancake lenses.

There are two key distances -- the distance from front to rear element and the distance from the rear element to the sensor (the flange distance).

On a micro 4/3 camera, the flange distance is 20mm, so with a pancake lens you have 20mm + the depth of the pancake lens (20mm for the Panasonic 14mm pancake).  Flange distance for most SLRs is over 40mm, so regardless of how thin the pancake is, you get a larger package.

The two reasons that mirrorless cameras are smaller are (1) they use a shorter flange distance which reduces the distance between front element and sensor by about an inch (so they are about 1 inch thinner for similar optic) and (2) they remove the viewfinder. Mirrorless systems do tend to include more pancake lenses but it is also possible to make pancakes for SLRs (e.g. Pentax make several, Voigtlander also have some). In other words, if you use an SLR mount, you gain little or no size advantage by going mirrorless (again, you lose some height if you throw away the viewfinder)

paul13walnut5

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Re: Canon EF 40mm f/2.8 Pancake Coming [CR3]
« Reply #79 on: May 24, 2012, 11:07:26 AM »
Quote
Quote from: Haydn1971 on May 23, 2012, 03:52:42 PM

    Speaking hypothetically, if a smaller sensor was used with a EF mount, couldn't the distance between the lens mount and sensor be reduced ?


No you can't.  The flange to sensor distance is fixed as that is the 'projection plane' of the image for a given lens design. The specific design distance which an image is to be projected , relative to its flange mount plane.

Changing the distance between the mount and the sensor would render exsisting EF & EF-s lenses redundant, or at least unable to focus at infinity.

However, there may actually be more in this...

Canon have already adapted the EF mount so that EF-s lenses can be used, EF-s being lenses with shorter back focus, where the rear element protrudes deeper into the camera throat (thus the need to prevent EF-s lenses mounting on cameras with full frame mirrors)

So if the EF-s idea can work, then could an extension of this idea work?  Retaining the EF / EF-s mount and flange distance, but with shorter back focus again lenses, ("EF-x?") so reducing the extension of the lens in front of the camera?

Obviously this would probably mean a mirrorless body but crucially retain an APS-C sensor.  Remove the pop up flash, or move it off centre, and you now have a smaller body.

This would make the overall package of camera + lens smaller.  Which is a more desirable objective.  I mean, how daft do m43 cameras look with anything other than a pancake on them?

Such a solution would mean that although EOS-X users could use their EF and EF-s mount lenses, regular EOS FF and EOS APS-C users could not use the "EF-x" lenses....

UNLESS.. The EF-x lenses could initiate MLU when mounted, say a collapsable design where the rear element stays well forward until the lens is mounted and MLU engaged.  So long as your EOS has live view then your EF-x lens would be fine.

I think I've cracked it.

Rocky

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Re: Canon EF 40mm f/2.8 Pancake Coming [CR3]
« Reply #80 on: May 24, 2012, 12:16:30 PM »
The reality is that with the 'pancake lens" the size should be the same as other mirrorless with the lens mounted.

On a micro 4/3 camera, the flange distance is 20mm, so with a pancake lens you have 20mm + the depth of the pancake lens (20mm for the Panasonic 14mm pancake).  Flange distance for most SLRs is over 40mm, so regardless of how thin the pancake is, you get a larger package.

It is not fair to use MICRO 4/3 as the size comparision.  I am talking about APS-C or even FF in my suggestion

funkboy

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Re: Canon EF 40mm f/2.8 Pancake Coming [CR3]
« Reply #81 on: May 24, 2012, 01:26:06 PM »

So if the EF-s idea can work, then could an extension of this idea work?  Retaining the EF / EF-s mount and flange distance, but with shorter back focus again lenses, ("EF-x?") so reducing the extension of the lens in front of the camera?  Obviously this would probably mean a mirrorless body but crucially retain an APS-C sensor.  Remove the pop up flash, or move it off centre, and you now have a smaller body.


Sounds like the kind of lens Pentax needs for their K-01...

The AF group (and likely also the IS group) would probably still need to be outside the camera body though; I think they'd have an awful hard time squeezing all those electronics into a barrel that fits through an EF mount opening & still maintain an APS-C image circle.  Very different from Canon's existing lens designs, but then again they could probably pull it off given their lens design talent.  Maybe if they went to a G1X-size image circle it would fit...

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Re: Canon EF 40mm f/2.8 Pancake Coming [CR3]
« Reply #81 on: May 24, 2012, 01:26:06 PM »

maxxevv

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Re: Canon EF 40mm f/2.8 Pancake Coming [CR3]
« Reply #82 on: May 24, 2012, 10:28:12 PM »
The reality is that with the 'pancake lens" the size should be the same as other mirrorless with the lens mounted.

On a micro 4/3 camera, the flange distance is 20mm, so with a pancake lens you have 20mm + the depth of the pancake lens (20mm for the Panasonic 14mm pancake).  Flange distance for most SLRs is over 40mm, so regardless of how thin the pancake is, you get a larger package.

It is not fair to use MICRO 4/3 as the size comparision.  I am talking about APS-C or even FF in my suggestion

The idea and physical laws are the same, regardless of sensor size. 

If you extend the logic, it applies to the NEX system too. Why the NEX cameras can be so thin/slim ? Because of their lens flange distance.  The rumoured mirrorless lenses from Canon have a shorter back focus plane distance than the Sony ones. From previous CR citations, supposedly only 1mm distance! So you can imagine how close the flange distances are.

Also, part of the reason with closer flange distances is that it allows the design and use of smaller optics for an equivalent focal plane area of focus. 

Rocky

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Re: Canon EF 40mm f/2.8 Pancake Coming [CR3]
« Reply #83 on: May 25, 2012, 04:32:38 PM »
The reality is that with the 'pancake lens" the size should be the same as other mirrorless with the lens mounted.

On a micro 4/3 camera, the flange distance is 20mm, so with a pancake lens you have 20mm + the depth of the pancake lens (20mm for the Panasonic 14mm pancake).  Flange distance for most SLRs is over 40mm, so regardless of how thin the pancake is, you get a larger package.

It is not fair to use MICRO 4/3 as the size comparision.  I am talking about APS-C or even FF in my suggestion
The idea and physical laws are the same, regardless of sensor size. 

RIGHT, Let us talk about phsical laws. A small sensor will only need a shorter focal length to give the same angle for a bigger sensor.  Micro 3/4 has a mutiplicayion factor of 2.  So the 14 mm Panasonic ancake lens will be equilvalent to a 28mm lens on a full frame.  The 14mm will need a total of 40mm (20mm for the lense, 20mm for the fringe depth). That is a ration of  2.86. Now apply this ration for the 28mm for FF. than it will need 80mm. That is physical Law. Sensor size does not matter???  The bigger the sensor, the bigger the lense for the same viewing angle.

Thr Fringe diatance can be set to anything by the manufacturer to suit the usage. NEX fringe is set so thin for the using of adapter for the OLD range finder lenses,like Leica, Canon etc.  The fringe distance can be set independent of the back focal plane distance.  For mirrorless, the lenses have the luxury of going inside of the body and into the body. Have you look at  the Leica wide angle lenses lately???  As the the rumores 1mm back focal distance lens from Canon, it is going to be huge. In order for it to work, the rear element of the lens MUST cover the whole sensor. What it mean is the lense will ge going inside of the fringe and way into the body. You just cannot make a cmera body with a 1mm fringe distance.

Here comes the phsical law again. the size of the optic is determined by the focal length, speed of the lens and the associated mechanical and electronics part. It got nothing to do wit hthe fringe distance (except for wide angle lens for range finder cameras, that is another story). Just look at the pancake lens from Panasonics. The optics are small, the lens dismeter is large. That is for the mechanical and theelectronis component. It has got nothing to do with the fringe distance.

EOBeav

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Re: Canon EF 40mm f/2.8 Pancake Coming [CR3]
« Reply #84 on: May 25, 2012, 05:12:26 PM »
So...what I hear you saying is, size matters?

RIGHT, Let us talk about phsical laws. A small sensor will only need a shorter focal length to give the same angle for a bigger sensor.  Micro 3/4 has a mutiplicayion factor of 2.  So the 14 mm Panasonic ancake lens will be equilvalent to a 28mm lens on a full frame.  The 14mm will need a total of 40mm (20mm for the lense, 20mm for the fringe depth). That is a ration of  2.86. Now apply this ration for the 28mm for FF. than it will need 80mm. That is physical Law. Sensor size does not matter???  The bigger the sensor, the bigger the lense for the same viewing angle.

Thr Fringe diatance can be set to anything by the manufacturer to suit the usage. NEX fringe is set so thin for the using of adapter for the OLD range finder lenses,like Leica, Canon etc.  The fringe distance can be set independent of the back focal plane distance.  For mirrorless, the lenses have the luxury of going inside of the body and into the body. Have you look at  the Leica wide angle lenses lately???  As the the rumores 1mm back focal distance lens from Canon, it is going to be huge. In order for it to work, the rear element of the lens MUST cover the whole sensor. What it mean is the lense will ge going inside of the fringe and way into the body. You just cannot make a cmera body with a 1mm fringe distance.

Here comes the phsical law again. the size of the optic is determined by the focal length, speed of the lens and the associated mechanical and electronics part. It got nothing to do wit hthe fringe distance (except for wide angle lens for range finder cameras, that is another story). Just look at the pancake lens from Panasonics. The optics are small, the lens dismeter is large. That is for the mechanical and theelectronis component. It has got nothing to do with the fringe distance.
In landscape photography, when you shoot is more important than where.

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moreorless

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Re: Canon EF 40mm f/2.8 Pancake Coming [CR3]
« Reply #85 on: May 25, 2012, 06:24:43 PM »
So would a "super EF-S" mount allowing for lenses with 1mm backfocus on a camera that can also mount EF/EF-s lenses actually be possible?

That does seem like an interesting way to apprach the concept of space saving, rather than making the body thinner you have 4cm of the lens optics inside instead.

Does strike me as a rather "canon like" move aswell since it would make EF/EF-s lenses easier to adapt and balance but not allow for older rangefinder lenses to be used.

paul13walnut5

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Re: Canon EF 40mm f/2.8 Pancake Coming [CR3]
« Reply #86 on: May 25, 2012, 07:29:41 PM »
I really think canon would be wrong to break the 25ish year legacy that EF lenses have.  Anything they make from now on should be friendly towards EF.  EF is their K, Their F.  Their mirrorless should on some level be compatable with EF.  How many folk buy Pentax Q's or Nikon 1s, that would be better buying a system that supports legacy and micro lenses.

It's unfortunate to say, but Sony were the most forward looking in this regard.  But then again, how many minolta dynax lagacy users have an NEX?

   


Rocky

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Re: Canon EF 40mm f/2.8 Pancake Coming [CR3]
« Reply #87 on: May 25, 2012, 08:51:32 PM »
I really think canon would be wrong to break the 25ish year legacy that EF lenses have.  Anything they make from now on should be friendly towards EF.  EF is their K, Their F.  Their mirrorless should on some level be compatable with EF.  How many folk buy Pentax Q's or Nikon 1s, that would be better buying a system that supports legacy and micro lenses.

It's unfortunate to say, but Sony were the most forward looking in this regard.  But then again, how many minolta dynax lagacy users have an NEX?

 
Canon should also be friendly to the EF-S also, if the mirrorless is APS-C sensor. I agree that the NEX is forward thinking about letting the owner to be able to use OLD range finder lenses. But in reality, how many people are doing that ?? When  a range finder lens is used in NEX or any mirrorless, manual focusing is required.  So we need to wide open the lens to get the focusing accuracy from the "lifeview",  then stop down the lens to take picture. By that time the screen will be way too dim to be used. Also it is a slow process. The otherway is to use "zone focusing" to avoid wide open and stop down the lens. But we still have to deal with  the dim screen.
« Last Edit: May 25, 2012, 09:17:21 PM by Rocky »

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Re: Canon EF 40mm f/2.8 Pancake Coming [CR3]
« Reply #87 on: May 25, 2012, 08:51:32 PM »

Daniel Flather

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Re: Canon EF 40mm f/2.8 Pancake Coming [CR3]
« Reply #88 on: May 25, 2012, 10:32:32 PM »
The more I think of this lens the more I want one, but it has to be tiny.  This lens on my 5D3 would be my mirrorless mirrored camera.
« Last Edit: May 25, 2012, 10:34:08 PM by Daniel Flather »
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maxxevv

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Re: Canon EF 40mm f/2.8 Pancake Coming [CR3]
« Reply #89 on: May 25, 2012, 11:21:20 PM »

RIGHT, Let us talk about phsical laws. A small sensor will only need a shorter focal length to give the same angle for a bigger sensor.  Micro 3/4 has a mutiplicayion factor of 2.  So the 14 mm Panasonic ancake lens will be equilvalent to a 28mm lens on a full frame.  The 14mm will need a total of 40mm (20mm for the lense, 20mm for the fringe depth). That is a ration of  2.86. Now apply this ration for the 28mm for FF. than it will need 80mm. That is physical Law. Sensor size does not matter???  The bigger the sensor, the bigger the lense for the same viewing angle.

Thr Fringe diatance can be set to anything by the manufacturer to suit the usage. NEX fringe is set so thin for the using of adapter for the OLD range finder lenses,like Leica, Canon etc.  The fringe distance can be set independent of the back focal plane distance.  For mirrorless, the lenses have the luxury of going inside of the body and into the body. Have you look at  the Leica wide angle lenses lately???  As the the rumores 1mm back focal distance lens from Canon, it is going to be huge. In order for it to work, the rear element of the lens MUST cover the whole sensor. What it mean is the lense will ge going inside of the fringe and way into the body. You just cannot make a cmera body with a 1mm fringe distance.

Here comes the phsical law again. the size of the optic is determined by the focal length, speed of the lens and the associated mechanical and electronics part. It got nothing to do wit hthe fringe distance (except for wide angle lens for range finder cameras, that is another story). Just look at the pancake lens from Panasonics. The optics are small, the lens dismeter is large. That is for the mechanical and theelectronis component. It has got nothing to do with the fringe distance.

You've got your physics a little mixed up and the topic/areas being discussed here too it seems.

When we talk about back focus plane distances and how it affects the size of the lens, we are referring to sensors of the same and equal size, not across different sizes.   When you get one design with a back focus plane at 1mm versus one at 30mm, the optics required for the shorter one is smaller.  Par equal area of focus and within limits of optics diffraction. Which is why Leica comes into such a picture. It was design to use FF (in the film days) but yet for equivalent focal length and aperture lens, they were smaller than say Canon or Nikon designs, even if they were all full manual, non-AF lenses.

In this case of Canon's mirrorless, nobody seems to be certain for sure what's the sensor size. And we can only infer from the back focus plane distance that for the sensor size they are designing for, they are trying very hard to miniaturize the size of the lenses.  And for what ever size sensor they are using. Be it a FF,  1.3x, 1.6x or 1.85x crop, it SHOULD be (within limitations of cost and practicality) smaller than lenses designed for sensors of equivalent crop factor.




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Re: Canon EF 40mm f/2.8 Pancake Coming [CR3]
« Reply #89 on: May 25, 2012, 11:21:20 PM »