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Interchangeable Lens Mount for Phones

A standard lens mount arrangement, not one per manufacturer or something stupid like that.
  [vote for,

One of the problems with camera phone photography is that the camera phone lens angle of view is fixed, and is usually fairly wide angle. This is good for scenes that would suggest using such a wide angle lens. This is not good for scenes that dont, such as people portraits, selfies, etc. The usual well-known distortion effects of shooting too close with a lens that has too wide an angle of view will always distort the face to give prominence to the centre area, resulting in pictures of people with big noses and lips.

== History

Over many decades we have seen interchangeable lens cameras, from view cameras, field cameras, press cameras and technical cameras all featuring a bellows arrangement and a lens baseplate upon which a lens is screwed, to the more modern rollfilm cameras with interchangeable lenses, to the even more modern 135 film format cameras with their highly marketed ranges of interchangeable lenses. There was even a short while before the interchangeable lens digital mirrorless camera when camera consumers still thought they needed their cameras to look like film SLRs, with a reflex mirror box and prism and all that.

== Present

Now that all photography, professional and otherwise, broadcast or stills, is done on a mobile phone, it would behoover the phone manufacturers to stop messing about with stupid multiple cameras on the back of the phone and just put a pair of proper identical sensors, and have a specific industry standard agreed lens mount for the lens pair, to allow the field of view and angle of view to be tailored by the consumer by spending more. A pair, rather than a single, is immensely more useful for 3D video, ascertaining depth for fake bokey, and a lot of other uses as yet occluded.

== S mount

There is already a standard that nearly comes close to this - the S Mount, which is a M12x0.5mm thread. Whilst this would technically work, I feel it is asking for trouble if you let the masses loose on this. Changing lenses on a film camera required three hands, or if you've got a table to rest the camera body on, three hands, still. Interchangeable mirrorless lenses are very easy to poke a finger in onto the sensor, although this never actually happens because nobody ever buys a second lens after the kit lens that came with the camera.

== Captive rear element

With a phone camera lens mount, I would suggest a slightly different approach. Split the lens design such that the rear element of the lens is always part of the sensor module. The interchangeable part consists of the remaining elements minus that rear collector element (which in a lot of conventional lenses tends to be a similar shaped element and does the same kind of job across all the lenses) (or put it another way, the differences of the rear elements found across conventional lenses are due to arbitrary design, and if required could have been designed out to meet an identical rear element specification in many cases).

== Not screwed

The mount itself should not be a screw thread, probably not a bayonet either. I suggest a flat rectangle or oblong area as a 'mating plate' that has an easy clip or clamp arrangement. Or alternatively, a sliding in arrangement. It should be not possible to lose the lens by day to day rough treatment. My old Mamiya C330 medium format roll film twin lens reflex has an interchangeable lens arrangement of pairs of lenses (identical pairs as it happens) mounted on an oblong baseboard, which you simply place in place on the camera rack front, and there's a shaped metal rod arrangement that you clip in place that holds it there. That works well for a TLR, but you'd need something a bit more foolproof for a phone. The point is, it doesn't have to be rotary or screw or round.

Not only will this open up a secondary market, but it will also improve the viability of mobile phones as the dominant camera device, for a much wider range of subjects, rather than being restricted to a range of wide subjects.

Ian Tindale, Jul 02 2017

Optical zoom lens for cell phone https://www.theverg...-announced-mwc-2017
[scad mientist, Jul 03 2017]

Simple and Uncomplicated Nikon Compatability https://www.nikonia...-lens-compatibility
To be fair, this charts the evolution of a near 60-year old specification, so you might expect it to be a bit hairy around the edges. [zen_tom, Jul 03 2017]

Jitter camera—baked http://www.cs.colum...ects/jitter_camera/
For [neutrinos_shadow]: // I always thought digital cameras could use "saccades" to improve image quality, by mounting the CCD on a piezo-electric mount (or 2, for both directions...). // [notexactly, Jul 05 2017]


       [+], as long as:   

       (1) It doesn't increase the bulkth of the phone when using a default lens.   

       (2) There is no (2).
MaxwellBuchanan, Jul 02 2017

       // a sliding in arrangement. //   

       Something like the standard flash shoe mount ? There's probably plenty of tooling around that could be adapted.
8th of 7, Jul 02 2017

       Agree with [Max-B] - the 'standard' lens for the phone should be small enough such that it doesn't stick out.
hippo, Jul 02 2017

       I think this is a problem best addressed by using an actual camera. A problem with phone cameras is they have gotten quite good and people have mistaken them for camera cameras when in fact they are phone cameras.
tatterdemalion, Jul 02 2017

       A fair point.   

       That suggests something similar to Google Cardboard.   

       A smartphone is dropped into a carrier which uses the phone's capabilities to deliver additional functionality.   

       The important bits of a camera are the lens(es) and the image sensor. Everything else is just "nice to have".   

       Why not have a frame which carries a top-of-the-line image sensor, a battery, and a lens mount ?   

       Load the app on your smartphone. Insert into "frame". Use the controls on the frame (via USB) to select effects etc., and the phone display as the viewfinder. The captured image is stored in the phone and can be emailed, printed, uploaded etc.
8th of 7, Jul 02 2017

       The point of phone cameras is that they are compact, and they are part of something you carry with you all the time anyway.   

       The fraction of the western population carrying a camera ready for use at any one time has increased from about 1% in 1950 to just short of 90% in 2016. That's a 90-fold increase. And the only good camera is one that's there when you need to take a picture.   

       As sensors become denser and more light-sensitive, the only limit on the optics is the diffraction limit. In turn, that means that lenses can become much smaller and shallower. Add to that the ability to compensate for chromatic and spherical abberations in software, to some extent, and it becomes possible to make very small cameras and lens systems which are excellent. The main barrier is cost; if you could spend as much on the camera of a phone as you would spend on a good "normal" camera, the results would be outstanding.   

       Maybe a compromise would be to have a lens that could telescope, then collapse back into the phone body when not in use. If you have that extra depth to play with, you have a lot more options.
MaxwellBuchanan, Jul 02 2017

       // western population //   

       Could an upgrade of said population be achieved ? This would have a disproportionately positive impact on the quality of captured images, shirley ?
8th of 7, Jul 02 2017

       No, what's needed is an upgrade of the surroundings.   

       Even a gifted photographer with the best technology will find it difficult to produce an appealing image of, say, Basingstoke without using special effects such as, say, a fuel-air bomb.
MaxwellBuchanan, Jul 02 2017

       // Basingstoke ... fuel-air bomb //   

       We can help with that. For free. Please. Go on, you know you want it. Just say the word ...
8th of 7, Jul 02 2017

       It's all yours, [8th]. But you'd best be quick.
MaxwellBuchanan, Jul 02 2017

       //Now that all photography, professional and otherwise, broadcast or stills, is done on a mobile phone...//

Not sure if sarcasm or ignorance...
But this is a good idea. Most importantly, the mount will need to be very strong, because the phone will get put back into pocket/bag with the lens attached, asking for trouble.
neutrinos_shadow, Jul 02 2017

       Only 53% of humans, the ones with two or more X chromosomes, care so little for their digital devices as to mistreat them in such a way ...
8th of 7, Jul 02 2017

       The image sensors seem a fairly cheap component of these things. So, why insist on making the lens removable from them?   

       Better, shirley, would be to have each 'lens' module have its own complete imaging sensor sealed onto it, and just plug into the phone via a standard digital interface, I dunno, say, USB.   

       This would let you add good camera/lens combinations to crap phones.
mitxela, Jul 02 2017

       It'd be a MIPI CSI-2 interface, rather than USB.
Ian Tindale, Jul 02 2017

       [Link] There is a new optical zoom lens for cell phones that reflects the image 90 degrees so the zoom lens doesn't make the phone thicker or stick out. The concept is called a periscope lens and has been commercialized before since it is in at least 1 Sony pocket camera I own.   

       If the periscope zoom lens works out for cell phones and catches on, it may somewhat eliminate the need for this idea. Alternately, if this idea can be implemented using periscope lenses, you might get changeable lenses that don't make the phone any bigger (except for the really big zoom lenses).
scad mientist, Jul 03 2017

       Interestingly, when they say on advertisements than an image was "shot on an iPhone" or similar, it may also say in small print that "additional equipment was used". What this means is that an iPhone was used for the imaging, but it was an iPhone with an expertly mounted top-quality camera lens attached...
hippo, Jul 03 2017

       The "rear collector element" should be able to function as a complete (though basic) lens on its own.
notexactly, Jul 03 2017

       It certainly could, but it would not have the optical advantages of even a basic Cooke triplet design. The main issue is that unlike the eye, which does have only a single element, any attempt we've made at a camera (with the exception of some interesting huge format pinhole cameras made from steel drums) tends to have a flat recording surface, and therefore the requirements placed on the lens are more complex - it has to take a spherical 'out there' reality and place it on a planar 'in here' record of it.
Ian Tindale, Jul 03 2017

       Naturally, the mount specifications should be a Nikon 'F' mount, probably with some kind of AF sub-specification, though to be honest, the whole specification taxonomy gets impossibly complicated (see link, linked) rather quickly.   

       Should other lenses be required, one can simply fork out £80 for a bit of metal to convert from the F-mount to a T or M42 mount - preferably in a way that signals which of these are in play at any particular time.
zen_tom, Jul 03 2017

       Well, I don't think a rotary or circular mount is necessary or desirable. A slide-in lockable flat plate is better (with a very high level of precision to ensure repeated alignment), and because it is only a partial lens, it will form the whole unit with the fixed captive rear element, requiring less bulk and protrusion. It should probably be only about the size of a micro or nano SIM card, and not overly thick (as the rear element is already recessed and up against the sensor). As soon as we want to incorporate a whole range of focal lengths, we're up in bulk, even if we use a periscope, like the old Sony TX range and others (eg, the flat waterproof rugged cams from Pana and Fuji). I think the populace should be educated rather forcefully that they don't want the complication of a zoom, that because they're currently getting by fine with just a lone wide-angle prime. Then if you give them a choice of three (eg, in 135 format equivalents: 28mm; 60mm and 100mm) you'd have a sufficient choice for most general photography.
Ian Tindale, Jul 03 2017

       // It'd be a MIPI CSI-2 interface, rather than USB.   

       A 25 pin RS-232 seems appropriate.
tatterdemalion, Jul 03 2017

       SCSI, shirley? You could then ask people "what sort of phone does your port have?"
MaxwellBuchanan, Jul 03 2017

       // A 25 pin RS-232 seems appropriate //   

       A serial data stream via a "D" connector by all means, but a 20mA current loop at 110 Baud will make it a lot easier to produce hard copies of images on your ASR-33 Teletype ...
8th of 7, Jul 03 2017

       I also wonder, if pixel count continues to increase, how necessary will it be to have multiple lenses rather than just a single wide-angle lens with software deciding how much of the image to use? Cameras already do this to some extent with "digital zoom".   

       If 10MP is enough for a good image, and the sensor has 1000MP and a wide-angle lens, then a small central part of the image (equivalent to a longer lens) would still be good. And yes, I know a cropped wide-angle image isn't the same as a long-lens image, but it meets many of the needs.   

       Or - here's a thought. Suppose you can't make a 1000MP sensor, but you can make it more sensitive (faster). You could have a wide-angle lens with the sensor covering only part of the image. Then you capture several partial images by moving the sensor quickly to tile a full 1000MP wide-angle image; or just leave the sensor in the middle for a single "long lens" image.
MaxwellBuchanan, Jul 03 2017

8th of 7, Jul 03 2017

       Thanks, [8th]. Thought it was a bit drafty.
MaxwellBuchanan, Jul 03 2017

       // how necessary will it be to have multiple lenses rather than just a single wide-angle lens with software deciding how much of the image to use?   

       Many sports broadcasts do this. They use 8K cameras to shoot the action so that they can zoom in tight on action replays without loss of video quality.
tatterdemalion, Jul 03 2017

       //moving the sensor quickly to tile//
I always thought digital cameras could use "saccades" to improve image quality, by mounting the CCD on a piezo-electric mount (or 2, for both directions...).
neutrinos_shadow, Jul 03 2017

       //There's probably plenty of tooling around that could be adapted.//   

       Hehe. So 1970 - 2017.
bigsleep, Jul 04 2017


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