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A7xIII release date

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artuk View Drop Down
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Post Options Post Options   Quote artuk Quote  Post ReplyReply Direct Link To This Post Posted: 21 June 2017 at 18:01
Originally posted by kefkafloyd kefkafloyd wrote:

It's not all that different than an a7 body, except the grip is slightly different. The changes in the actual chassis are very mild.


Personally I think the A7ii replacement will use the same or similar body to the existing models - but that's partly on the assumption its cheaper to keep using them than change it (so maybe everything will go to the A9 body... But that somewhat erodes its unique position in the range).
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Miranda F View Drop Down
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Post Options Post Options   Quote Miranda F Quote  Post ReplyReply Direct Link To This Post Posted: Yesterday at 08:22
Originally posted by artuk artuk wrote:


a9 photo

Leica sl photo

In these photos you can clearly see that the corners of the a9 sensor are obstructed by a very tight lens throat, whereas the sl mount gives an entirely clear view of the sensor. It may only be "a couple of mm" but it appears to make what looks like a significant difference.

Don't forget that there has to be some lens hardware *inside* the bayonet too, to lock the lens to the camera, and this reduces the view of the sensor still further. I would expect this to be an issue for wide aperture long focal length non-telephoto lenses, if anyone makes these nowadays ...
A58, 5d, Dynax 4, 5, 60, 500si/600si/700si/800si, various Sony & Minolta lenses, several Tamrons, lots of MF primes and *far* too many old film cameras . . .
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Post Options Post Options   Quote Miranda F Quote  Post ReplyReply Direct Link To This Post Posted: Yesterday at 08:24
Originally posted by artuk artuk wrote:

Originally posted by kefkafloyd kefkafloyd wrote:

It's not all that different than an a7 body, except the grip is slightly different. The changes in the actual chassis are very mild.


Personally I think the A7ii replacement will use the same or similar body to the existing models - but that's partly on the assumption its cheaper to keep using them than change it (so maybe everything will go to the A9 body... But that somewhat erodes its unique position in the range).

Tempted to agree, but suspect that will be driven by the choice to use the larger battery or not.
A58, 5d, Dynax 4, 5, 60, 500si/600si/700si/800si, various Sony & Minolta lenses, several Tamrons, lots of MF primes and *far* too many old film cameras . . .
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Bob J View Drop Down
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Post Options Post Options   Quote Bob J Quote  Post ReplyReply Direct Link To This Post Posted: Yesterday at 08:30
Originally posted by Miranda F Miranda F wrote:


Don't forget that there has to be some lens hardware *inside* the bayonet too, to lock the lens to the camera, and this reduces the view of the sensor still further. I would expect this to be an issue for wide aperture long focal length non-telephoto lenses, if anyone makes these nowadays ...


We need to remember that these body shots are taken from 12 inches or more away, while the rear element of the lens is likely to be under an inch from the sensor... so in practice the rear element gets a peek around the bayonet hardware. E-mount does look tight, but the fact that it works and can even manage IBIS within the image circle suggests it is sufficient (whether by initial design or luck is debatable)
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Post Options Post Options   Quote artuk Quote  Post ReplyReply Direct Link To This Post Posted: Yesterday at 12:13
Originally posted by Bob J Bob J wrote:

Originally posted by Miranda F Miranda F wrote:


Don't forget that there has to be some lens hardware *inside* the bayonet too, to lock the lens to the camera, and this reduces the view of the sensor still further. I would expect this to be an issue for wide aperture long focal length non-telephoto lenses, if anyone makes these nowadays ...


We need to remember that these body shots are taken from 12 inches or more away, while the rear element of the lens is likely to be under an inch from the sensor... so in practice the rear element gets a peek around the bayonet hardware. E-mount does look tight, but the fact that it works and can even manage IBIS within the image circle suggests it is sufficient (whether by initial design or luck is debatable)


Absolutely correct Bob, but the lens design still needs to pass through that narrow lens throat, and therefore any rear elements will always be smaller than that aperture, as they sit inside the body of the lens. Therefore, a non telecentric design with rear element and sensor physically very close. In practice in many E mount lenses I own the rear elements are well recessed into the body of the lens (zooms more than primes, but some primes too). The lens throat plus the lens body makes most lens exit pupils smaller than the sensor, and with such a short flange depth, light to the outer field of the sensor must by design strike at an angle.
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Post Options Post Options   Quote kefkafloyd Quote  Post ReplyReply Direct Link To This Post Posted: Yesterday at 13:30
That's also true of mounts that use digital that are narrower than E-mount. What's the difference between an F-mount lens or K-mount lens (which have a narrower throat than E-mount) that have to pass through a mirror box versus an airgapped E-mount lens? Not much, the exit pupil is limited by the mount in both cases. As long as the image circle projects to a 24x36 box with a little wiggle room for IBIS, that's all you need. People use the Canon TS-E lenses on E-mount with very little complaint, and if any lenses would have trouble with image projection, it would be those. Even with their MF-sized image circles to help, the big tilt-shift movements still work on the body.

Plus, not all optical designs need to have an exit pupil that meets or exceeds the size of the bayonet. There's probably a degree of which off-angle or incident light rays are OK versus a problem, but what that degree is depends on sensor design. A lot of exit pupils are already smaller than the sensor on SLR formats, and in some cases they even get baffled to reduce stray light or reflection.

The bayonet is a consideration in lens design, but there's probably other factors affecting it more.

Adapted lenses are a different kettle of fish, but the fact that you can use all those adapted lenses on E-mount is a benefit, users just have to take in consideration the sensor performance of non-native lenses.

Edited by kefkafloyd - Yesterday at 13:38
 



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