Digital back for M film cameras

That's how I was thinking it too. It doesn't need to be connected to a light meter (if equipped) or to the aperture dial either. It just needs to receive the image when the shutter opens, just like a roll of film. This would mean one ISO, unless we put a switch on the canister maybe and you could change the ISO when you put it in, or drop the bottom to change it.
 
To put photos onto a computer would you take the whole thing out, exposing the sensor to dust? Perhaps a small bluetooth chip with a dongle could solve this?

ISO changing could be implemented on a lot of the M bodies by hijacking the contacts that lead to the ISO dial (although this would only work for some models, and would probably be too complex regardless).
 
Speaking about the Sony NEX-5, why not use the internals of a NEX-5 or 3, the cameras are extremely small, and not overly expensive. You also have ISO 12,800, pretty good image quality, and the possibility of HD video.
 
Pirate said:
That's how I was thinking it too. It doesn't need to be connected to a light meter (if equipped) or to the aperture dial either. It just needs to receive the image when the shutter opens, just like a roll of film. This would mean one ISO, unless we put a switch on the canister maybe and you could change the ISO when you put it in, or drop the bottom to change it.
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Your film M-Leica, including the M7, is not connected either. The camera assumed you did not lied and dial in ISO truthfully. [I lied all the time because I rate Tri-X @ ISO 250.]

A CCD has a native ISO @ ~100, with a 4 stop under-exposure latitude [Leica M8/9 say pulled ISO @ 80, normal at 160]. Sunny-16 works more than fine. A built-in light meter like an M6 won't hurt. If you must, set ISO between 100 to 1600 [minus 4 stops]. Post-processing in auto-level would equalized the result.

This is one of the point that caused much debate. In essence, some argued for auto-everything in-camera processed to perfection. Others know better.

The Leica high-priests essentially say whatever Leica cannot or did not do, no one else can or should do either.
 
Roberto V. said:
Speaking about the Sony NEX-5, why not use the internals of a NEX-5 or 3, the cameras are extremely small, and not overly expensive. You also have ISO 12,800, pretty good image quality, and the possibility of HD video.
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I have also posted elsewhere that the NEX contains all components needed in an APS-C retrofit...@ $600.
 
Roberto V. said:
Also, I guess you could even make the screen interchangeable with the door on the back of the leica if you're not going to shoot film for a while.
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Actually, I couldn't care less about the LCD. When there is no live-view possible, the LCD is useful only in accessing the menu. Anything else is after the fact. A plug-in iPod worked fine for post-shooting reviews.

Speaking of menu, why would you need it? The ISO is sunny-16 or set in the meter however you want. The WB selecting could be none...as in 16-bits B/W only; or a simple 2-way toggle between Daylight and Tungsten; or simply Automatic...and let post-processing do its thing.

All of the above have been debated to death elsewhere also. Check into my posts and see.
 
Ok, I can really see this working now. On an M4 it would be a little more difficult- any model with the take-up spool permanently in position would be in the way. A removable spool is the way to go.

I'm picturing actually having two parts mounted onto a baseplate with the sensor being held in the middle so you would take the film base off and stow it while using digital. The whole assembly would go in, taking up both film spaces on the sides and the sensor would slide into position behind the curtain.

I'm thinking simple. For the model I would build, I would have a couple dip switches on one of the canisters to select maybe 4 ISO ratings, 50, 100, 400, 1600. Do we really need more than that? Honestly?

Changing the back door is an idea also. A new door that would stick out from the back only a couple milimeters would be sufficient. This way, the pressure plate assembly could be changed to have more room, more movement. A thicker digital sensor assembly could then be used (and we're only talking an extra couple milimeters here) and the door could be left in place for both film and digital without being annoying. No screen, this is not needed.

For memeory, I'm thinking of a mini USB type port to plug into. No removeable card. This would cut down on needed space. The digi assembly could be taken out or left in, and a cable simply plugged into the bottom for downloading. At this same time, you would use your computer to wipe or reformat the memory area, thereby not needing controls on-camera as a normal digi does.

Battery power. I don't know how much power this would take up. Would a AAA battery last any descent length of time? Since my idea is to use a baseplate with the components mounted on it, the battery may have to go in the baseplate. A very thin battery.

The assembly mounted on the take-up spool side would also have to include a mechanical connection to the crank assembly at the top, this triggering a sensor telling the chip that a new picture is coming up. This also would be the initial sensor making things ready for the first picture. Just like loading a roll of film and advancing to the first shot. This will tell the assembly it's ready to go when it's freshly installed into the camera.

"The WB selecting could be none...as in 16-bits B/W only; or a simple 2-way toggle between Daylight and Tungsten; or simply Automatic...and let post-processing do its thing. "
Yes, I agree with this. If anything, there would be a switch for Daylight and Tungsten, but nothing more. Post-processing is part of the digital workflow so it may be cleaned up there.

"I don't hold out much hope for this idea. But while we're wishing, let's wish for a ttl matrix meter option, too."
Absolutely not. This is for a photographer. If you need a computer to tell you how to shoot, don't buy a Leica.
 
This is a quick mock-up of what my system would look like, all parts being on a new baseplate. Stow the original base until you go back to film. The sensor would be suspended in the middle - stiff suspension so it doesn't flop all over the place, and when loading everything with the door opened, you can make sure it sits properly in place and close the door on it, securing it down with the pressure plate on the door.

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Another option I'm thinking of....

Also a replaceable baseplate model, but a thicker base plate to house a proper battery, removeable SD or micro-SD card. A base of about 3/4 inch thickness that would attach just like the original base yet give you all the room needed for extra electronics. The two film spool areas would still be utilized for the main components as in my first idea, but now the base would let us add anything we want without adding much weight to the camera.
 
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Frankie said:
My blasphemy was much denounced by the Leica experts.
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I'm neither a Leica expert or a priest, but as long as all I see is discussions and not silicon, I would tend to agree with them.

And the best way to convince them otherwise is not by styling oneself as a rebel or blasphemer, but by actually producing something.

For the time being, I'd be inclined to put my money with the "it may even be technically doable but nobody will do it" crowd.
 
Pirate said:
The sensor would be suspended in the middle - stiff suspension so it doesn't flop all over the place, and when loading everything with the door opened, you can make sure it sits properly in place and close the door on it, securing it down with the pressure plate on the door.

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How thick do you think a sensor is? A custom door replacement is the bare minimum you'll have to do.
 
I have thought about this idea at great length - the M camera offers 3 areas to build upon - the film take up spaces (i.e the place the film roll goes and the place the take up spool sits in, the removable back door and the baseplate box.

why not use the film spool spaces for batteries. you could have a tiny readout on the baseplate that tells you what the little LCD on top of the M8 did - frames and battery life.

no LCD, no fancy sockets, nothing - just an SD card a spinning ISO setter on the back of the back plate where they normally are and a readout - i would pay good money for that if it was full frame. if it can be done then sign me up!

the biggest problem i can see is getting the electronics to recognise when a frame is being fired and when it's over so that it can begin writing to the card immediately. i think you'd have to hook some kind of sensor up to the shutter release. or depending on how quickly the ccd can act, have some kind of sensor at the beginning edge and the finishing edge of the shutter aperture. however you start the reading process the sensor will need to read the finishing edge of the second curtain to give you complete control over shutter speeds. it's no good having a light sensor because you could fool the CCD into shutting down by putting your hand over the lens, and long exposures in near darkness won't be possible.

as far as i can see, slapping the sensor in to the camera is the easy part. i thought that this kind of venture may end up being something that would have to be set up as a service to modify cameras that would involve getting into the top plate as well as all of the rest - then you could think about having displays in the viewfinder and readouts up there too. modifications should be possible in this manner without destroying the camera it's self - i think there's money in the idea of building a kit to supply to our beloved CLA guys that they can then charge to fit. if someone does that then everybody's happy!! 😀
 
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"How thick do you think a sensor is? A custom door replacement is the bare minimum you'll have to do."

I don't know how thick a sensor is, that's part of my ignorance in this project, but I bet ya I'll learn pretty quick.

"the biggest problem i can see is getting the electronics to recognise when a frame is being fired and when it's over so that it can begin writing to the card immediately."

My thinking was that with a sensor on the take-up spool sprocket, inside, it would trip the chip to say "Hey, stand by and be ready for a shot". It waits in total darkness until the shutter is fired, then, when the sprocket is moved again it will write to the card and again stand by for the next shot.
Does that sound doable?
 
I have bought an RD-1 for experimentation, an M2 and recently an M6 for playing...

One thing I learned is that the underexposure side of a CCD is rather forgiving. The post-processed pictures often turned out OK even if I didn't set a matching higher ISO to begin with.

A micro-SD reader, available cheap and tiny...it is the entire electronic package one needs to house the micro-SD.

An adapter is available for the iPod or iPhone where the device LCD displays images from other devices' memory card. Use it for reviews...later.

Third-party RD-1 battery at 1800mAh and good for 250+ pictures will fit in the film cartridge space...if the internal prong is removed. The interesting thing here is: such a retrofit will have no motor drive and manual shutter cocking is needed. The battery only powers the camera-CPU...RD-1 style. A 3 cell AAA battery holder also fits in the chamber...but a few mm longer.

The mechanical shutter closing or shutter cocking actions can tell the CPU to start dumping files to buffer...take less time than you think.

The Leica M back door if removed, provides a box dimension of 45 x 90 x 7mm. Perhaps a couple mm added to the thickness is not excessive. Typical CCD have extra length pins for mounting onto circuit boards...the whole unit, front cover glass to pin end, is usually ~8mm. The cover glass/Bayer-UV filter portion is <2mm and fits within the film-rail-to-shutter-curtain depth...leaving ~6mm to be dealt with.

If the on-board CPU does nothing more than to grab-frame, write-to-buffer and dump-to-SD, how big must it be?

The rewind knob on the M2/3 is easily converted into a 2/3 position toggle switch.

Forget the frame counter. A 1 or 2Gb memory card will hold ~40 16-bit FF Raw files...same as the film counter. So use it.

I have written volumes in previous posting on this project. The above is only a sampling.
 
Pirate said:
My thinking was that with a sensor on the take-up spool sprocket, inside, it would trip the chip to say "Hey, stand by and be ready for a shot". It waits in total darkness until the shutter is fired, then, when the sprocket is moved again it will write to the card and again stand by for the next shot.
Does that sound doable?
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i think that would work - i think the camera could do with a main on/off switch as well then so that your 'ready and waiting' CCD isn't just eating your batteries.
 
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