E-mount for Nikon MILC, good idea or not?

[snellius]

Maybe there should also be a curved sensor in this camera, with a new series of Nikkor lenses. No old lenses and and for the time being, no other brand lenses.

Curved sensors are not a great idea for an interchangeable lens camera. The lenses need to be designed for whatever is the sensor curve (and it needs to be not so much a 'curve' as a 'dish'. Designing to a specific curve doesn't ease so many of the problems of designing a high quality lens (it makes it easier to mitigate the problems of a very poor lens) and would mean that the camera wouldn't be useable with legacy lenses.

 

[bobn2]

One of the problems a lot of people points out against the use of the F-mount in future mirrorless models is the lens throat diameter that prevents designing/using the ultra-fast aperture lenses and the E-mount wouldn't bring any advantage there as it shows just 2mm more and still far from other competitors.

It's not just the diameter of the mount, it's the register. The E-mount has a register of 18mm whilst the F mount is 46.5mm. It means that the E-mount straddles the exit cone from the lens where it is much narrower, therefore the mount can be narrower. That being said, the F-mount can go down to f/1.2, and there haven't been many faster lenses at FF.

You have this back to front

I really don't.

the actual distance from the rear of a Sony lens to the sensor is approx 12mm taking into account the thickness the lens protrudes into the mount. this makes it harder to cover the sensor than the similar F mount with a 47mm registration distance where you can have a larger cone . Think of it like this, the largest opening in the lens barrel can be about 39mm, move this even closer to the sensor until it is touching and you eliminate the sensor corners completely from the exit cone.

That's a different effect. What we are talking about is what can be the subtended angle of that light cone. Yes, you're right, in that in that extreme, the mount would shade the edges of the frame. However, as a sanity check, think of the Classic Canon 7, which used the 39mm Leica screw mount (register 28.76mm) and came with an f/0.95 lens.

This lens didn't actually mount on the screw mount, but the clear aperture was 39mm.

--
Tinkety tonk old fruit, & down with the Nazis!
Bob

Consider long telephoto lenses, they are in the position with the short registration distance of vignetting caused by the rear element being a good distance up the lens barrel, my 200-400 has the rear element some 80-100mm away from the sensor

Do your 200-400 or 80-100 have an f-number of faster than f/1.4? That's what we were talking about. In any case, pretty much every designed for digital lens has the exit pupil something like 100mm away from the sensor, even if they are wide angles. Just do the geometry, even in the far corners, hardly any of the exit pupil is shaded by the lens mount aperture, probably not enough for the vignetting to be noticed. Here's a diagram to show you what's happening





On the right is the exit pupil of an f/1 lens, 100mm from the image plane (actually the distance doesn't matter, because the light cone always subtends the same angle, in proportion to the f-number). On the right in cyan is the 43mm image diagonal. In green is the 40mm aperture of the lens mount at 18mm register. As you can see the dark green shaded area is the part of the exit pupil obscured, in the end maybe 1/3 of the exit pupil (can't be bothered to do the exact sum), 0.6 stop loss in the extreme corners. And of course, that is using a lens not designed for the mount, if the lens is designed with a positive rear element filling the mount circle, there need be no shading at all.



--
Tinkety tonk old fruit, & down with the Nazis!
Bob

 

[bobn2]

Maybe there should also be a curved sensor in this camera, with a new series of Nikkor lenses. No old lenses and and for the time being, no other brand lenses.

Curved sensors are not a great idea for an interchangeable lens camera. The lenses need to be designed for whatever is the sensor curve (and it needs to be not so much a 'curve' as a 'dish'. Designing to a specific curve doesn't ease so many of the problems of designing a high quality lens (it makes it easier to mitigate the problems of a very poor lens) and would mean that the camera wouldn't be useable with legacy lenses.

--
Tinkety tonk old fruit, & down with the Nazis!
Bob

That's exactly what I mean, everything new without any compromise. The curved sensor as a compulsor to release all the old (and other brand lenses). No mechanical aperture controle and no mechanical AF drive. Everything new and compact.

I don't think making a new system completely incompatible with legacy and third party lenses is a marketing strategy likely to succeed, especially since there are no clear technical advantages to be had.

--
Tinkety tonk old fruit, & down with the Nazis!
Bob

 

[Antonio G]

Ok, fine as I'm not an expert on these matters and never had a Sony E (camera or lens) or information other than the one I could get online*, so I will not dispute your measurements and they even reinforce my opinion about seing no benefit at all for the user if a Nikon mirrorless camera adopts the E-mount and it would most likely be even worse for the company to follow that path.

* I just took as good that so diverse sources indicating 46 or 46.1mm were talking about the inside measurements as per the definition of lens throat diameter.

 

[snellius]

Maybe there should also be a curved sensor in this camera, with a new series of Nikkor lenses. No old lenses and and for the time being, no other brand lenses.

Curved sensors are not a great idea for an interchangeable lens camera. The lenses need to be designed for whatever is the sensor curve (and it needs to be not so much a 'curve' as a 'dish'. Designing to a specific curve doesn't ease so many of the problems of designing a high quality lens (it makes it easier to mitigate the problems of a very poor lens) and would mean that the camera wouldn't be useable with legacy lenses.

That's exactly what I mean, everything new without any compromise. The curved sensor as a compulsor to release all the old (and other brand lenses). No mechanical aperture controle and no mechanical AF drive. Everything new and compact.

I don't think making a new system completely incompatible with legacy and third party lenses is a marketing strategy likely to succeed, especially since there are no clear technical advantages to be had

If Nikon would make the move to a larger format, would you be against it because old lenses do not fit?

 

[bobn2]

Maybe there should also be a curved sensor in this camera, with a new series of Nikkor lenses. No old lenses and and for the time being, no other brand lenses.

Curved sensors are not a great idea for an interchangeable lens camera. The lenses need to be designed for whatever is the sensor curve (and it needs to be not so much a 'curve' as a 'dish'. Designing to a specific curve doesn't ease so many of the problems of designing a high quality lens (it makes it easier to mitigate the problems of a very poor lens) and would mean that the camera wouldn't be useable with legacy lenses.

That's exactly what I mean, everything new without any compromise. The curved sensor as a compulsor to release all the old (and other brand lenses). No mechanical aperture controle and no mechanical AF drive. Everything new and compact.

I don't think making a new system completely incompatible with legacy and third party lenses is a marketing strategy likely to succeed, especially since there are no clear technical advantages to be had

If Nikon would make the move to a larger format, would you be against it because old lenses do not fit?

I'm not 'against' anything that Nikon does. It's their business, they do what they think best. I can't see the point of Nikon moving to MF, since their current lens system can do anything that MF can do. If they want to cater for that market, it would make more sense to have a 100MP FX sensor with a base ISO of 32 made. It would keep the advantages of the current lens system and match anything MF systems can do. If they went to MF they would have to put a lot of R&D developing the infrastructure to no advantage, but that's their decision. I wouldn't be a customer for it, though. As for the FX mirrorless, I can't see how enforced incompatibility by itself is any advantage whatsoever. There are arguments for abandoning both the mechanics and protocols of the F-mount, but that would and should allow adapters. The curved sensor, as I see it, only offers disadvantages. Development would be expensive, it would offer no optical advantages in this context and it would restrict the system to only those lenses Nikon developed. That's one of the things that killed the N1 system.

 

[GodSpeaks]

I heard some people claim Nikon should use E-mount for the new MILC system.

Because E-mount already has plenty of lens and users. Nikon can also make adapter ring for DSLR lens.

The ONLY people saying Nikon should use the E-mount are Sony fanboys.

If you want to use the argument of plenty of lenses and users, then the MFT mount wins, as MFT has the best lens lineup in mirrorless. But that won't happen either.

Nikon will either use the F mount or a new mount and an F-mount adapter. My bet is on the latter.

 

[cosmicnode]

One of the problems a lot of people points out against the use of the F-mount in future mirrorless models is the lens throat diameter that prevents designing/using the ultra-fast aperture lenses and the E-mount wouldn't bring any advantage there as it shows just 2mm more and still far from other competitors.

It's not just the diameter of the mount, it's the register. The E-mount has a register of 18mm whilst the F mount is 46.5mm. It means that the E-mount straddles the exit cone from the lens where it is much narrower, therefore the mount can be narrower. That being said, the F-mount can go down to f/1.2, and there haven't been many faster lenses at FF.

You have this back to front

I really don't.

the actual distance from the rear of a Sony lens to the sensor is approx 12mm taking into account the thickness the lens protrudes into the mount. this makes it harder to cover the sensor than the similar F mount with a 47mm registration distance where you can have a larger cone . Think of it like this, the largest opening in the lens barrel can be about 39mm, move this even closer to the sensor until it is touching and you eliminate the sensor corners completely from the exit cone.

That's a different effect. What we are talking about is what can be the subtended angle of that light cone. Yes, you're right, in that in that extreme, the mount would shade the edges of the frame. However, as a sanity check, think of the Classic Canon 7, which used the 39mm Leica screw mount (register 28.76mm) and came with an f/0.95 lens.

This lens didn't actually mount on the screw mount, but the clear aperture was 39mm.

--
Tinkety tonk old fruit, & down with the Nazis!
Bob

Consider long telephoto lenses, they are in the position with the short registration distance of vignetting caused by the rear element being a good distance up the lens barrel, my 200-400 has the rear element some 80-100mm away from the sensor

Do your 200-400 or 80-100 have an f-number of faster than f/1.4? That's what we were talking about. In any case, pretty much every designed for digital lens has the exit pupil something like 100mm away from the sensor, even if they are wide angles. Just do the geometry, even in the far corners, hardly any of the exit pupil is shaded by the lens mount aperture, probably not enough for the vignetting to be noticed. Here's a diagram to show you what's happening



On the right is the exit pupil of an f/1 lens, 100mm from the image plane (actually the distance doesn't matter, because the light cone always subtends the same angle, in proportion to the f-number). On the right in cyan is the 43mm image diagonal. In green is the 40mm aperture of the lens mount at 18mm register. As you can see the dark green shaded area is the part of the exit pupil obscured, in the end maybe 1/3 of the exit pupil (can't be bothered to do the exact sum), 0.6 stop loss in the extreme corners. And of course, that is using a lens not designed for the mount, if the lens is designed with a positive rear element filling the mount circle, there need be no shading at all.

--
Tinkety tonk old fruit, & down with the Nazis!
Bob

You need to re-draw that Bob the "rear" of the lens exit tube is only 12mm off the sensor, everyone forgets that the lens mount has a bayonette that has a thickness which protrudes into the mount throat, this is about 6mm which must be subtracted from the registration distance, this opening in the lens body is at "best" a max of 39mm, not the 43mm of the lens throat and this for mainly telephoto lenses where the elements are well up inside the lens body, wide angles and normal lenses often have focusing element tubes in this area reducing this diameter further. Only wide angle lenses will have the posative rear element filling the lens mount circle, normal and tele lenses are well inside the lens tube on such a short registration distance, it's these small details that make the difference to how perfect the lens mount can be . Make the lens mount Sony or Nikon 5-6mm bigger in diameter in order that no part of a 43mm diagonal sensor is obscured by any part of the lens material and it does not matter what the registration distance is. Make it slightly bigger still for the movement of the most aggressive IBIS, of course you will never get a new mount that will take a adaptor for Sony or Fuji lenses there simply is not enough room.



--
Mike.
"I say we take off and nuke the entire site from orbit, it's the only way to be sure."

 

[cosmicnode]

Ok, fine as I'm not an expert on these matters and never had a Sony E (camera or lens) or information other than the one I could get online*, so I will not dispute your measurements and they even reinforce my opinion about seing no benefit at all for the user if a Nikon mirrorless camera adopts the E-mount and it would most likely be even worse for the company to follow that path.

* I just took as good that so diverse sources indicating 46 or 46.1mm were talking about the inside measurements as per the definition of lens throat diameter.

The thing is Antonio everyone who owns a camera can simply check the dimensions themselves, but all rely on a website which should present a diagram of a generic lens mount and then give a indication as to which dimensions the stated sizes relate to.

 

[bobn2]

One of the problems a lot of people points out against the use of the F-mount in future mirrorless models is the lens throat diameter that prevents designing/using the ultra-fast aperture lenses and the E-mount wouldn't bring any advantage there as it shows just 2mm more and still far from other competitors.

It's not just the diameter of the mount, it's the register. The E-mount has a register of 18mm whilst the F mount is 46.5mm. It means that the E-mount straddles the exit cone from the lens where it is much narrower, therefore the mount can be narrower. That being said, the F-mount can go down to f/1.2, and there haven't been many faster lenses at FF.

You have this back to front

I really don't.

the actual distance from the rear of a Sony lens to the sensor is approx 12mm taking into account the thickness the lens protrudes into the mount. this makes it harder to cover the sensor than the similar F mount with a 47mm registration distance where you can have a larger cone . Think of it like this, the largest opening in the lens barrel can be about 39mm, move this even closer to the sensor until it is touching and you eliminate the sensor corners completely from the exit cone.

That's a different effect. What we are talking about is what can be the subtended angle of that light cone. Yes, you're right, in that in that extreme, the mount would shade the edges of the frame. However, as a sanity check, think of the Classic Canon 7, which used the 39mm Leica screw mount (register 28.76mm) and came with an f/0.95 lens.

This lens didn't actually mount on the screw mount, but the clear aperture was 39mm.

--
Tinkety tonk old fruit, & down with the Nazis!
Bob

Consider long telephoto lenses, they are in the position with the short registration distance of vignetting caused by the rear element being a good distance up the lens barrel, my 200-400 has the rear element some 80-100mm away from the sensor

Do your 200-400 or 80-100 have an f-number of faster than f/1.4? That's what we were talking about. In any case, pretty much every designed for digital lens has the exit pupil something like 100mm away from the sensor, even if they are wide angles. Just do the geometry, even in the far corners, hardly any of the exit pupil is shaded by the lens mount aperture, probably not enough for the vignetting to be noticed. Here's a diagram to show you what's happening



On the right is the exit pupil of an f/1 lens, 100mm from the image plane (actually the distance doesn't matter, because the light cone always subtends the same angle, in proportion to the f-number). On the right in cyan is the 43mm image diagonal. In green is the 40mm aperture of the lens mount at 18mm register. As you can see the dark green shaded area is the part of the exit pupil obscured, in the end maybe 1/3 of the exit pupil (can't be bothered to do the exact sum), 0.6 stop loss in the extreme corners. And of course, that is using a lens not designed for the mount, if the lens is designed with a positive rear element filling the mount circle, there need be no shading at all.

--
Tinkety tonk old fruit, & down with the Nazis!
Bob

You need to re-draw that Bob the "rear" of the lens exit tube is only 12mm off the sensor, everyone forgets that the lens mount has a bayonette that has a thickness which protrudes into the mount throat, this is about 6mm which must be subtracted from the registration distance, this opening in the lens body is at "best" a max of 39mm, not the 43mm of the lens throat and this for mainly telephoto lenses where the elements are well up inside the lens body, wide angles and normal lenses often have focusing element tubes in this area reducing this diameter further. Only wide angle lenses will have the posative rear element filling the lens mount circle, normal and tele lenses are well inside the lens tube on such a short registration distance, it's these small details that make the difference to how perfect the lens mount can be . Make the lens mount Sony or Nikon 5-6mm bigger in diameter in order that no part of a 43mm diagonal sensor is obscured by any part of the lens material and it does not matter what the registration distance is. Make it slightly bigger still for the movement of the most aggressive IBIS, of course you will never get a new mount that will take a adaptor for Sony or Fuji lenses there simply is not enough room.

Your discussion is based on a whole load of incorrect assumptions The position of the rear element does not matter, for this discussion (I accept the point that when it's far enough back, it will physically shade the frame), it is the size and position of the exit pupil that does. Also, there is nothing making the lens protrude through the mount, if the designers choose not to do it that way. Then, check through what I wrote again. The 43mm refers to the image diagonal, I used 40mm for the lens throat opening. As for 'only wide angle lenses will have a positive rear element', any lens can have a positive rear element if designed that way (a retrofocal lens needs a positive rear group, but that is different from a positive rear element).

As for the rest, sure a bigger mount has advantages, wat we were discussing is whether the E-mount restricted use of lenses faster than f/1.4 - it clearly doesn't.

Loading…

www.parkcameras.com

--
Tinkety tonk old fruit, & down with the Nazis!
Bob

 

[dkyl]

Hi Bob,

how far/close are we to curve on demand sensors?

The curvature can then be 'matched' to a new lens design.

That'd be worth starting a new mounts for whilst maintaining backward compatibility with existing lenses for flat sensors.

 

[cosmicnode]

One of the problems a lot of people points out against the use of the F-mount in future mirrorless models is the lens throat diameter that prevents designing/using the ultra-fast aperture lenses and the E-mount wouldn't bring any advantage there as it shows just 2mm more and still far from other competitors.

It's not just the diameter of the mount, it's the register. The E-mount has a register of 18mm whilst the F mount is 46.5mm. It means that the E-mount straddles the exit cone from the lens where it is much narrower, therefore the mount can be narrower. That being said, the F-mount can go down to f/1.2, and there haven't been many faster lenses at FF.

You have this back to front

I really don't.

the actual distance from the rear of a Sony lens to the sensor is approx 12mm taking into account the thickness the lens protrudes into the mount. this makes it harder to cover the sensor than the similar F mount with a 47mm registration distance where you can have a larger cone . Think of it like this, the largest opening in the lens barrel can be about 39mm, move this even closer to the sensor until it is touching and you eliminate the sensor corners completely from the exit cone.

That's a different effect. What we are talking about is what can be the subtended angle of that light cone. Yes, you're right, in that in that extreme, the mount would shade the edges of the frame. However, as a sanity check, think of the Classic Canon 7, which used the 39mm Leica screw mount (register 28.76mm) and came with an f/0.95 lens.

This lens didn't actually mount on the screw mount, but the clear aperture was 39mm.

--
Tinkety tonk old fruit, & down with the Nazis!
Bob

Consider long telephoto lenses, they are in the position with the short registration distance of vignetting caused by the rear element being a good distance up the lens barrel, my 200-400 has the rear element some 80-100mm away from the sensor

Do your 200-400 or 80-100 have an f-number of faster than f/1.4? That's what we were talking about. In any case, pretty much every designed for digital lens has the exit pupil something like 100mm away from the sensor, even if they are wide angles. Just do the geometry, even in the far corners, hardly any of the exit pupil is shaded by the lens mount aperture, probably not enough for the vignetting to be noticed. Here's a diagram to show you what's happening



On the right is the exit pupil of an f/1 lens, 100mm from the image plane (actually the distance doesn't matter, because the light cone always subtends the same angle, in proportion to the f-number). On the right in cyan is the 43mm image diagonal. In green is the 40mm aperture of the lens mount at 18mm register. As you can see the dark green shaded area is the part of the exit pupil obscured, in the end maybe 1/3 of the exit pupil (can't be bothered to do the exact sum), 0.6 stop loss in the extreme corners. And of course, that is using a lens not designed for the mount, if the lens is designed with a positive rear element filling the mount circle, there need be no shading at all.

--
Tinkety tonk old fruit, & down with the Nazis!
Bob

You need to re-draw that Bob the "rear" of the lens exit tube is only 12mm off the sensor, everyone forgets that the lens mount has a bayonette that has a thickness which protrudes into the mount throat, this is about 6mm which must be subtracted from the registration distance, this opening in the lens body is at "best" a max of 39mm, not the 43mm of the lens throat and this for mainly telephoto lenses where the elements are well up inside the lens body, wide angles and normal lenses often have focusing element tubes in this area reducing this diameter further. Only wide angle lenses will have the posative rear element filling the lens mount circle, normal and tele lenses are well inside the lens tube on such a short registration distance, it's these small details that make the difference to how perfect the lens mount can be . Make the lens mount Sony or Nikon 5-6mm bigger in diameter in order that no part of a 43mm diagonal sensor is obscured by any part of the lens material and it does not matter what the registration distance is. Make it slightly bigger still for the movement of the most aggressive IBIS, of course you will never get a new mount that will take a adaptor for Sony or Fuji lenses there simply is not enough room.

Your discussion is based on a whole load of incorrect assumptions

They are not assumptions but actual dimensions.

The position of the rear element does not matter, for this discussion (I accept the point that when it's far enough back, it will physically shade the frame), it is the size and position of the exit pupil that does. Also, there is nothing making the lens protrude through the mount, if the designers choose not to do it that way. Then, check through what I wrote again. The 43mm refers to the image diagonal, I used 40mm for the lens throat opening. As for 'only wide angle lenses will have a positive rear element"

"filling the rear mount" don't cut up sentences to change the meaning.

any lens can have a positive rear element if designed that way (a retrofocal lens needs a positive rear group, but that is different from a positive rear element).

As for the rest, sure a bigger mount has advantages, wat we were discussing is whether the E-mount restricted use of lenses faster than f/1.4 - it clearly doesn't.

I'm simply correcting assumptions based on incorrect dimensions simply taken off the net.

https://www.parkcameras.com/p/92451...zoks5br8WtLe8nyX_x9BpDT4DYEcher4aAkKcEALw_wcB

--
Tinkety tonk old fruit, & down with the Nazis!
Bob

--
Mike.
"I say we take off and nuke the entire site from orbit, it's the only way to be sure."

 

[olstrup]

Technic aspects aside, it would surprice me if the the E mount wasn't patented by Sony.

 

[bobn2]

Technic aspects aside, it would surprice me if the the E mount wasn't patented by Sony.

 

[bobn2]

One of the problems a lot of people points out against the use of the F-mount in future mirrorless models is the lens throat diameter that prevents designing/using the ultra-fast aperture lenses and the E-mount wouldn't bring any advantage there as it shows just 2mm more and still far from other competitors.

It's not just the diameter of the mount, it's the register. The E-mount has a register of 18mm whilst the F mount is 46.5mm. It means that the E-mount straddles the exit cone from the lens where it is much narrower, therefore the mount can be narrower. That being said, the F-mount can go down to f/1.2, and there haven't been many faster lenses at FF.

You have this back to front

I really don't.

the actual distance from the rear of a Sony lens to the sensor is approx 12mm taking into account the thickness the lens protrudes into the mount. this makes it harder to cover the sensor than the similar F mount with a 47mm registration distance where you can have a larger cone . Think of it like this, the largest opening in the lens barrel can be about 39mm, move this even closer to the sensor until it is touching and you eliminate the sensor corners completely from the exit cone.

That's a different effect. What we are talking about is what can be the subtended angle of that light cone. Yes, you're right, in that in that extreme, the mount would shade the edges of the frame. However, as a sanity check, think of the Classic Canon 7, which used the 39mm Leica screw mount (register 28.76mm) and came with an f/0.95 lens.

This lens didn't actually mount on the screw mount, but the clear aperture was 39mm.

--
Tinkety tonk old fruit, & down with the Nazis!
Bob

Consider long telephoto lenses, they are in the position with the short registration distance of vignetting caused by the rear element being a good distance up the lens barrel, my 200-400 has the rear element some 80-100mm away from the sensor

Do your 200-400 or 80-100 have an f-number of faster than f/1.4? That's what we were talking about. In any case, pretty much every designed for digital lens has the exit pupil something like 100mm away from the sensor, even if they are wide angles. Just do the geometry, even in the far corners, hardly any of the exit pupil is shaded by the lens mount aperture, probably not enough for the vignetting to be noticed. Here's a diagram to show you what's happening



On the right is the exit pupil of an f/1 lens, 100mm from the image plane (actually the distance doesn't matter, because the light cone always subtends the same angle, in proportion to the f-number). On the right in cyan is the 43mm image diagonal. In green is the 40mm aperture of the lens mount at 18mm register. As you can see the dark green shaded area is the part of the exit pupil obscured, in the end maybe 1/3 of the exit pupil (can't be bothered to do the exact sum), 0.6 stop loss in the extreme corners. And of course, that is using a lens not designed for the mount, if the lens is designed with a positive rear element filling the mount circle, there need be no shading at all.

--
Tinkety tonk old fruit, & down with the Nazis!
Bob

You need to re-draw that Bob the "rear" of the lens exit tube is only 12mm off the sensor, everyone forgets that the lens mount has a bayonette that has a thickness which protrudes into the mount throat, this is about 6mm which must be subtracted from the registration distance, this opening in the lens body is at "best" a max of 39mm, not the 43mm of the lens throat and this for mainly telephoto lenses where the elements are well up inside the lens body, wide angles and normal lenses often have focusing element tubes in this area reducing this diameter further. Only wide angle lenses will have the posative rear element filling the lens mount circle, normal and tele lenses are well inside the lens tube on such a short registration distance, it's these small details that make the difference to how perfect the lens mount can be . Make the lens mount Sony or Nikon 5-6mm bigger in diameter in order that no part of a 43mm diagonal sensor is obscured by any part of the lens material and it does not matter what the registration distance is. Make it slightly bigger still for the movement of the most aggressive IBIS, of course you will never get a new mount that will take a adaptor for Sony or Fuji lenses there simply is not enough room.

Your discussion is based on a whole load of incorrect assumptions

They are not assumptions but actual dimensions.

The assumptions aren't in the dimensions, they are in the understanding of optics.

The position of the rear element does not matter, for this discussion (I accept the point that when it's far enough back, it will physically shade the frame), it is the size and position of the exit pupil that does. Also, there is nothing making the lens protrude through the mount, if the designers choose not to do it that way. Then, check through what I wrote again. The 43mm refers to the image diagonal, I used 40mm for the lens throat opening. As for 'only wide angle lenses will have a positive rear element"

"filling the rear mount" don't cut up sentences to change the meaning.

I'm not sure what that means. What I said was 'if the lens is designed with a positive rear element filling the mount circle, there need be no shading at all.'. The reason is simple, a positive element at the rear of the lens provides exit pupil magnification at that point, the lens mount is no longer a restriction. Certainly, there will need to be other elements in front which compress the ray bundle sufficiently, but even with the positive rear element, there is no reason why that rear group cannot overall have a negative power, as would be necessary for a telephoto.

any lens can have a positive rear element if designed that way (a retrofocal lens needs a positive rear group, but that is different from a positive rear element).

As for the rest, sure a bigger mount has advantages, wat we were discussing is whether the E-mount restricted use of lenses faster than f/1.4 - it clearly doesn't.

I'm simply correcting assumptions based on incorrect dimensions simply taken off the net.

Which 'incorrect dimensions' were you referring to. The only one you mentioned was a reading error on your part, not an incorrect dimension.
--
Tinkety tonk old fruit, & down with the Nazis!
Bob

 

[bobn2]

Hi Bob,

how far/close are we to curve on demand sensors?

No idea. It's not a matter of theoretical issues, it's a matter of detailed engineering. It wouldn't be hard to make an actuator mechanism that would provide the curve on demand. Then you'd need to make a sensor with enough flex to do it. Maybe a wafer thinned silicon sensor would work, but how long would it last? Even if the silicon structure survived the repeated flexing, would the CFA and microlens layers delaminate? Ensuring a usable lifetime would be a case of prolonged R&D and evaluation, which wouldn't come cheap. Otherwise, it would need a non-silicon sensor, which is a whole new ball game,

The curvature can then be 'matched' to a new lens design.

That'd be worth starting a new mounts for whilst maintaining backward compatibility with existing lenses for flat sensors.

I can't see that there really is much advantage in a curved sensor for a ILC. The only real advantage is that for very simple lens designs, it might relax the design constraints a little, but for high quality lenses it's a matter of making them highly corrected over some arbitrary spheroid rather than a plane, which isn't any easier. Frankly, it's a solution looking for a problem. Interchangeable lens cameras don't have a problem needing that solution. There is a lot of hype, like for instance this:

Loading…

phys.org

But when you read through it, the claims (in this publicity piece) don't make much sense. I would think that the claims in the reported paper make sense, but they will be about the manufacturing technique for this sensor.

 

[olstrup]

• bobn2 wrote:

Technic aspects aside, it would surprice me if the the E mount wasn't patented by Sony.

 

[Antonio G]

You're absolutely right but as I said before when it comes to the Sony this was my only option as I don't own any of their cameras or lenses.

 

[Ayoh]

One of the problems a lot of people points out against the use of the F-mount in future mirrorless models is the lens throat diameter that prevents designing/using the ultra-fast aperture lenses and the E-mount wouldn't bring any advantage there as it shows just 2mm more and still far from other competitors.

It's not just the diameter of the mount, it's the register. The E-mount has a register of 18mm whilst the F mount is 46.5mm. It means that the E-mount straddles the exit cone from the lens where it is much narrower, therefore the mount can be narrower. That being said, the F-mount can go down to f/1.2, and there haven't been many faster lenses at FF.

You have this back to front

I really don't.

the actual distance from the rear of a Sony lens to the sensor is approx 12mm taking into account the thickness the lens protrudes into the mount. this makes it harder to cover the sensor than the similar F mount with a 47mm registration distance where you can have a larger cone . Think of it like this, the largest opening in the lens barrel can be about 39mm, move this even closer to the sensor until it is touching and you eliminate the sensor corners completely from the exit cone.

That's a different effect. What we are talking about is what can be the subtended angle of that light cone. Yes, you're right, in that in that extreme, the mount would shade the edges of the frame. However, as a sanity check, think of the Classic Canon 7, which used the 39mm Leica screw mount (register 28.76mm) and came with an f/0.95 lens.

This lens didn't actually mount on the screw mount, but the clear aperture was 39mm.

--
Tinkety tonk old fruit, & down with the Nazis!
Bob

Consider long telephoto lenses, they are in the position with the short registration distance of vignetting caused by the rear element being a good distance up the lens barrel, my 200-400 has the rear element some 80-100mm away from the sensor

Do your 200-400 or 80-100 have an f-number of faster than f/1.4? That's what we were talking about. In any case, pretty much every designed for digital lens has the exit pupil something like 100mm away from the sensor, even if they are wide angles. Just do the geometry, even in the far corners, hardly any of the exit pupil is shaded by the lens mount aperture, probably not enough for the vignetting to be noticed. Here's a diagram to show you what's happening



On the right is the exit pupil of an f/1 lens, 100mm from the image plane (actually the distance doesn't matter, because the light cone always subtends the same angle, in proportion to the f-number). On the right in cyan is the 43mm image diagonal. In green is the 40mm aperture of the lens mount at 18mm register. As you can see the dark green shaded area is the part of the exit pupil obscured, in the end maybe 1/3 of the exit pupil (can't be bothered to do the exact sum), 0.6 stop loss in the extreme corners. And of course, that is using a lens not designed for the mount, if the lens is designed with a positive rear element filling the mount circle, there need be no shading at all.

--
Tinkety tonk old fruit, & down with the Nazis!
Bob

You need to re-draw that Bob the "rear" of the lens exit tube is only 12mm off the sensor, everyone forgets that the lens mount has a bayonette that has a thickness which protrudes into the mount throat, this is about 6mm which must be subtracted from the registration distance, this opening in the lens body is at "best" a max of 39mm, not the 43mm of the lens throat and this for mainly telephoto lenses where the elements are well up inside the lens body, wide angles and normal lenses often have focusing element tubes in this area reducing this diameter further. Only wide angle lenses will have the posative rear element filling the lens mount circle, normal and tele lenses are well inside the lens tube on such a short registration distance, it's these small details that make the difference to how perfect the lens mount can be . Make the lens mount Sony or Nikon 5-6mm bigger in diameter in order that no part of a 43mm diagonal sensor is obscured by any part of the lens material and it does not matter what the registration distance is. Make it slightly bigger still for the movement of the most aggressive IBIS, of course you will never get a new mount that will take a adaptor for Sony or Fuji lenses there simply is not enough room.

Your discussion is based on a whole load of incorrect assumptions The position of the rear element does not matter, for this discussion (I accept the point that when it's far enough back, it will physically shade the frame), it is the size and position of the exit pupil that does. Also, there is nothing making the lens protrude through the mount, if the designers choose not to do it that way. Then, check through what I wrote again. The 43mm refers to the image diagonal, I used 40mm for the lens throat opening. As for 'only wide angle lenses will have a positive rear element', any lens can have a positive rear element if designed that way (a retrofocal lens needs a positive rear group, but that is different from a positive rear element).

As for the rest, sure a bigger mount has advantages, wat we were discussing is whether the E-mount restricted use of lenses faster than f/1.4 - it clearly doesn't.

https://www.parkcameras.com/p/92451...zoks5br8WtLe8nyX_x9BpDT4DYEcher4aAkKcEALw_wcB

--
Tinkety tonk old fruit, & down with the Nazis!
Bob

Just wanted to note that the lens you linked to is an APS-C lens.

Regardless there are even faster FF lenses available for E mount such as the Mitakon 50mm f0.95.

 

[cosmicnode]

One of the problems a lot of people points out against the use of the F-mount in future mirrorless models is the lens throat diameter that prevents designing/using the ultra-fast aperture lenses and the E-mount wouldn't bring any advantage there as it shows just 2mm more and still far from other competitors.

It's not just the diameter of the mount, it's the register. The E-mount has a register of 18mm whilst the F mount is 46.5mm. It means that the E-mount straddles the exit cone from the lens where it is much narrower, therefore the mount can be narrower. That being said, the F-mount can go down to f/1.2, and there haven't been many faster lenses at FF.

You have this back to front

I really don't.

the actual distance from the rear of a Sony lens to the sensor is approx 12mm taking into account the thickness the lens protrudes into the mount. this makes it harder to cover the sensor than the similar F mount with a 47mm registration distance where you can have a larger cone . Think of it like this, the largest opening in the lens barrel can be about 39mm, move this even closer to the sensor until it is touching and you eliminate the sensor corners completely from the exit cone.

That's a different effect. What we are talking about is what can be the subtended angle of that light cone. Yes, you're right, in that in that extreme, the mount would shade the edges of the frame. However, as a sanity check, think of the Classic Canon 7, which used the 39mm Leica screw mount (register 28.76mm) and came with an f/0.95 lens.

This lens didn't actually mount on the screw mount, but the clear aperture was 39mm.

--
Tinkety tonk old fruit, & down with the Nazis!
Bob

Consider long telephoto lenses, they are in the position with the short registration distance of vignetting caused by the rear element being a good distance up the lens barrel, my 200-400 has the rear element some 80-100mm away from the sensor

Do your 200-400 or 80-100 have an f-number of faster than f/1.4? That's what we were talking about. In any case, pretty much every designed for digital lens has the exit pupil something like 100mm away from the sensor, even if they are wide angles. Just do the geometry, even in the far corners, hardly any of the exit pupil is shaded by the lens mount aperture, probably not enough for the vignetting to be noticed. Here's a diagram to show you what's happening



On the right is the exit pupil of an f/1 lens, 100mm from the image plane (actually the distance doesn't matter, because the light cone always subtends the same angle, in proportion to the f-number). On the right in cyan is the 43mm image diagonal. In green is the 40mm aperture of the lens mount at 18mm register. As you can see the dark green shaded area is the part of the exit pupil obscured, in the end maybe 1/3 of the exit pupil (can't be bothered to do the exact sum), 0.6 stop loss in the extreme corners. And of course, that is using a lens not designed for the mount, if the lens is designed with a positive rear element filling the mount circle, there need be no shading at all.

--
Tinkety tonk old fruit, & down with the Nazis!
Bob

You need to re-draw that Bob the "rear" of the lens exit tube is only 12mm off the sensor, everyone forgets that the lens mount has a bayonette that has a thickness which protrudes into the mount throat, this is about 6mm which must be subtracted from the registration distance, this opening in the lens body is at "best" a max of 39mm, not the 43mm of the lens throat and this for mainly telephoto lenses where the elements are well up inside the lens body, wide angles and normal lenses often have focusing element tubes in this area reducing this diameter further. Only wide angle lenses will have the posative rear element filling the lens mount circle, normal and tele lenses are well inside the lens tube on such a short registration distance, it's these small details that make the difference to how perfect the lens mount can be . Make the lens mount Sony or Nikon 5-6mm bigger in diameter in order that no part of a 43mm diagonal sensor is obscured by any part of the lens material and it does not matter what the registration distance is. Make it slightly bigger still for the movement of the most aggressive IBIS, of course you will never get a new mount that will take a adaptor for Sony or Fuji lenses there simply is not enough room.

Your discussion is based on a whole load of incorrect assumptions

They are not assumptions but actual dimensions.

The assumptions aren't in the dimensions, they are in the understanding of optics.

The position of the rear element does not matter, for this discussion (I accept the point that when it's far enough back, it will physically shade the frame), it is the size and position of the exit pupil that does. Also, there is nothing making the lens protrude through the mount, if the designers choose not to do it that way. Then, check through what I wrote again. The 43mm refers to the image diagonal, I used 40mm for the lens throat opening. As for 'only wide angle lenses will have a positive rear element"

"filling the rear mount" don't cut up sentences to change the meaning.

I'm not sure what that means. What I said was 'if the lens is designed with a positive rear element filling the mount circle, there need be no shading at all.'. The reason is simple, a positive element at the rear of the lens provides exit pupil magnification at that point, the lens mount is no longer a restriction. Certainly, there will need to be other elements in front which compress the ray bundle sufficiently, but even with the positive rear element, there is no reason why that rear group cannot overall have a negative power, as would be necessary for a telephoto.

any lens can have a positive rear element if designed that way (a retrofocal lens needs a positive rear group, but that is different from a positive rear element).

As for the rest, sure a bigger mount has advantages, wat we were discussing is whether the E-mount restricted use of lenses faster than f/1.4 - it clearly doesn't.

I'm simply correcting assumptions based on incorrect dimensions simply taken off the net.

Which 'incorrect dimensions' were you referring to. The only one you mentioned was a reading error on your part, not an incorrect dimension.

Those taken of Wikipedia . they are correct but do not refer to the same parts of the lens mount so cannot be compared across mounts. the registration distance is from the front of the mounting face to the sensor not the rear of the lens barrel which in the case of Sony is around 12mm. the important dimensions will be the diameter of the exit of the lens and its distance to the sensor when working out light paths.

--
Tinkety tonk old fruit, & down with the Nazis!
Bob

--
Mike.
"I say we take off and nuke the entire site from orbit, it's the only way to be sure."