Is samsung nx mount large enough for full-frame

[OneGuyKs]

Is Samsung NX mount large enough for FF sensor? Or would it be physically impossible?

What about Fuji X mount?

[Greg Beetham]

I would have to give that a no if using the entire frame is desired, looking at the dimensions they both seem to be primarily designed for APS-C sensor size, if live ‘on sensor’ stabilization is used with a larger sensor then both mounts could use a larger sensor fitted into the body but actually only using a crop of it.
For example the throat diameter of the Samsung NX is 42mm, compared to the throat diameter of the A-mount at 49.7mm and the E-mount at 46.1mm which itself is marginal when allowing for physical design limits and a FF diagonal of 43.3mm. (Sony APS-C diagonal is 28.4mm)
The Samsung NX flange distance of 25.5mm (Fuji X is 17.7mm) allows plenty of scope for adaptors to fit FF lenses just like the E-mount does at 18mm (for comparison A-mount flange distance is 44.5mm) but there is a likelihood that the E-mount would suffer corner shading using a FF sensor with some FF lenses with fast open apertures and an adaptor, and if that’s true than it would certainly be true for the Samsung and Fuji mounts with their even smaller throat diameters.
They both won’t have any problem using FF lenses with adaptors as long as they remain APS-C format.
Greg

[OneGuyKs]

I would have to give that a no if using the entire frame is desired, looking at the dimensions they both seem to be primarily designed for APS-C sensor size, if live ‘on sensor’ stabilization is used with a larger sensor then both mounts could use a larger sensor fitted into the body but actually only using a crop of it.
For example the throat diameter of the Samsung NX is 42mm, compared to the throat diameter of the A-mount at 49.7mm and the E-mount at 46.1mm which itself is marginal when allowing for physical design limits and a FF diagonal of 43.3mm. (Sony APS-C diagonal is 28.4mm)
The Samsung NX flange distance of 25.5mm (Fuji X is 17.7mm) allows plenty of scope for adaptors to fit FF lenses just like the E-mount does at 18mm (for comparison A-mount flange distance is 44.5mm) but there is a likelihood that the E-mount would suffer corner shading using a FF sensor with some FF lenses with fast open apertures and an adaptor, and if that’s true than it would certainly be true for the Samsung and Fuji mounts with their even smaller throat diameters.
They both won’t have any problem using FF lenses with adaptors as long as they remain APS-C format.
Greg

Then why can Leica M 39 throat and 28.8 flange distance host FF sensor?

[Greg Beetham]

Then why can Leica M 39 throat and 28.8 flange distance host FF sensor?

I don't know much about Leica, in fact almost nothing, I don't know what the throat diameter is for the M39 mount, as far as I can tell the real M39 is a screw thread not a bayonet mount and that might give it some extra clearance perhaps.
In any case one of the Leica sensors is a special with sensels progressively point inwards at an angle the further you get from the centre, (helps with corner shading) but I don't remember which camera it was mounted in.
Do you have any actual information on the subject?
Greg

[Bob Janes]

Then why can Leica M 39 throat and 28.8 flange distance host FF sensor?

The extra depth allows a throat smaller than the sensor itself as long as the rear element is near to the mount (if it is deeply recessed into the lens you might get vignetting). Another thing to consider with the new mounts is the position of the electrical contacts, which encroach on the inside of the 'throat'.

Even if there is physical room, lenses designed for APS-C would be unlikely to reach the corners - although MF lenses on adapters might be OK.

[Greg Beetham]

Some A-mount lenses withdraw the rear element back up towards the front element during focusing or zooming.
I doubt they would have made the A-mount the size it is just because that seemed like a good size, they would have made it that size for a reason, quite possibly not obstructing the light cone from the collection of A-mount lenses available; that could be a good reason.
Greg

[bfitzgerald]

I see a few issues one being IBIS not enough room to move the sensor around (probably why we'll never see IBIS FF with the ILC type bodies) hey if I'm wrong I'll eat some of that pie they call humble though.

Vignetting was def an issue on rangefinders and many compact 35mm bodies no doubts there scanned enough film to see what was going down there.
If you look at some previous 35mm designs the lens can sit very close indeed at times to the film plane. Subject to sufficiently good sensors (ie offset lenses etc) it is probably possible to fit a FF sensor to all these mounts.

The problem is it causes some headaches and whilst software can correct things here, not a single one of the current ILC models offers lenses anywhere near as compact as the many M mount lenses (considering they cover full frame) There are significant advantages to the SLR design as these issues are far less severe than on rangefinder/ILC bodies.

[Greg Beetham]

Yes Barry I’m sure they could put a FF sensor in the NEX E-mount (they’ve already done it as you know with the VG900…well put it this way it fulfills both criteria, it’s FF and its behind an E-mount) and then just do correction for any problems via firmware like they already do for lenses that aren’t up to scratch, also fill in the missing information that the on sensor focus and exposure didn’t record, that’s the most likely course they’d take at a guess.
Greg
Ps I prefer corner shading, its cause is quite different to vignette, there would be some double-up if the lens & filter also produced vignette which was then added onto the corner shading, a double whammy in effect.

[David Kilpatrick]

The issue with the Leica mount is that with a 41mm bayonet (39mm screw) diameter and the full frame being 43.26mm diagonal there is a risk of vignetting when non-telephoto lenses longer than about 250mm are used, or faster apertures are used for lenses over 135mm. That's why Leica does not 300mm f/2.8 etc.

This issue is present with Samsung too, but not with NEX. That I guess is the big difference between the E-mount and the NX mount. The E-mount is large enough to allow every DSLR/SLR lens made to work without vignetting (thought not necessarily with IBIS, as stated).

There is no reason why lenses should not be very close to the sensor. This is the case with the RX100 and also with the RX1. The 16mm for NEX is about 5mm further away from the sensor than a straight design would achieve. This is to improve overall coverage and corner quality. But it would be possible to design a very different type of lens if they wanted.

David

[Greg Beetham]

I’m not sure if moving the rear of the lens closer to the sensor achieves much except to take advantage of the inverse square law (half the distance equals quadruple the light) but that increases the likelihood of corner shading, or of increasing the difference in light between the centre and the corner.
The difference in light (angle and distance) between the centre and the corner of the sensor only gets worse as you increase the size of the sensor as well as move the lens closer. Not that there are any FF E-mount lenses to worry about anyway (so far). Using FF A-mount lenses with a longer registration should improve the distance/angle relationship from centre to corner, but there still would be the remaining physical blockage of the E-A adaptor masking off the corners internally or at the very least causing some interference and shading on a FF sensor with some existing A-mount lenses.
Here is a good article discussing the variation of illumination between the centre and the corner with two different lens design, one lens is five times brighter in the centre than the corner. http://toothwalker.org/optics/vignetting.html
It would not matter as much using that high fall off lens if it was used on a smaller sensor as compared to a large one. I suppose they could make the centre pixels a lot less receptive or sensitive perhaps and do some adjustment in the internal processing automatically as well, but all those kinds of things would need to be individually lens specific on a camera that uses a range of existing different lenses…one would think.
Greg

[David Kilpatrick]

Greg, the position of the rear element is completely unconnected with the nodal points and rear exit pupil position, which determine the issues you mention. For example, the zoom lens in the KM A2 effectively almost makes contact with the sensor, and the rear element of the Minolta TC-1 is positioned just mm from the film but is very large. Simple fact is that with the E-mount, all optical restrictions are removed and they can design pretty much any types of lens they want - which is not the case with the A-mount, Leica M mount, and many others.

The position of the rear lens element has no relationship to inverse square law calculations and is not responsible as a primary factor for any light fall off. The iris position and other aspects of design affect this most, beyond fixed optical laws which apply to anything - including a pinhole camera, no lenses needed.

There is an adaptor LA-EA3 which has no internal baffles and removes the problem with the adaptor itself causing any mechanical vignetting. It's designed for the VG-900.

David

[Greg Beetham]

Well ok, I’m almost a convert David, but then the A2 had a very small 2/3 sensor http://www.cambridgeincolour.com/tutori ... r-size.htm and the lens appears quite bulky in size for such a small sensor. If for example you maintained the same lens design and just made it large enough to give the same light transmission for a FF sensor how big would the lens need to be? 6 inches wide, 8 inches?
In that case the A2 sensor/lens analogy might not be transferrable to FF in a practical sense.
The rear element (I’m guessing) has to be there for some reason otherwise why have it? My guess is it focusses and flattens the image field, therefore one would think it has to be involved to some degree in light variation between the centre and the edge of the image field, I get the impression you are saying that the light distribution within the image field occurs before the light reaches the rear element, I’m not an optician so I have to believe you on that score.
I don’t care how baffle free the adaptor is, the FF sensor corner almost touches the edge of the E-mount with nothing mounted on it so at least one of my FF KM lenses would have to almost see around corners at some focus and zoom positions to give shadow free corners, that’s the way it looks to me anyway.
And to be convincing to all and sundry of the need for such a thing as a FF E-mount, the current lens library it has to work well with belong to a different mount, it has no inventory of lenses itself, unless Sony starts bringing out a whole new range of lenses that is.
I suppose when Sony brings the world that new range of FF E-mount lenses we will know then that the real future lies with the E-mount, or the E-mount MkII.
Greg

[Dr. Harout]

... Simple fact is that with the E-mount, all optical restrictions are removed and they can design pretty much any types of lens they want - which is not the case with the A-mount, Leica M mount, and many others...

David

In case of mirrorless A-mount cameras, that would be more than possible: if you have to stick the lens deep in the "mirror" chamber, it would be possible (e.g. Nikon had that fish-eye lens, which when mounting it on the camera you had to lock up the mirror).
So eventually you have a better design and possibilities for the A-mount than the E-mount. After all, I don't think IBIS would be possible for E-Mount (mechanically, at least, and talking all the way for FF E-Mount), and if compensated with electronic on-sensor stabilization, then you loose part of a FF format.

[Greg Beetham]

I don’t think Sony wanted SSS in the NEX at all because it adds weight, cost, battery consumption and heat to the sensor not to mention I don’t think it’s a really wonderful stabilization system for video, that’s the impression I got anyway. The current NEX E-mount lenses have IS and that is supposed to be better for video. A-mount lenses were never designed with video in mind, noisy screw drive focus system and noisy aperture linkage operation so if Sony are intending to wow everyone with a FF NEX type camera you need to have a range of video compatible lenses for those who are keen on the crop video aspect of the whole thing.
High class video compatible lenses that have silent operation and IS as well tend to be very expensive so it’s difficult to guess how Sony is intending to get around all those hurdles. Maybe they won’t bother with the video compatible lenses, maybe they will rely on adaptors for existing crop video lenses, (you will still have to hock the house though) and just let everyone dabble with the existing A-mount lenses via the no3 adaptor, after all there are some quiet-ish motorized A-mount lenses, but none have silent aperture operation.
Maybe they won’t do that either, they could bring a new mount altogether with an adaptor for A-mount, along with some spoofy new lenses, but that one is doubtful-ish I think.
Greg

[classiccameras]

I think the A3000 is a test the water camera, very low spec to keep costs to a minimum and see how the public react. If sales look promising then I suspect higher spec bodies will appear.