Digital capture retrofit for a film camera ? Is this possible ? Read on.

There have been various attempts to create a digital back for a film camera body. Most have been large kluge like devices, that may work but essentially turn the film body into an unwieldy brick.

What I envision is a marriage of phone and digital technology in a film form factor.

Open a film body and you see three sections, 1) a compartment on the left for a film cartridge 2) a press plate in the center to create a pressure source to keep the film surface at a consistent distance from the lens. 3) an open space on the right to spool film as it is used. I see the above and I see the possibility of a self contained cartridge that fits all 3 spaces, and includes a digital sensor located where the film is held and exposed, along with enough space on either side to accommodate necessary processing electronics.

I envision something that looks like a 126 cartridge but sized for a 35mm body. There would not be a way to mechanically change ISO or other capture settings while the cartridge is in use, but wifi or bluetooth can be used to virtually connect the cartridge to phone or tablet app for on the fly changes. The cartridge would have a micro usb port for download connection.

The trickiest part is creating a digital sensor that will fit in the very limited space where film is held during exposure. Current flat sensor technology may be advanced enough to create a digital sensor the size and thickness of 35mm film. I have no doubt that the necessary electronics can be installed into the right and left compartments. When you look at a phone, the biggest piece is the screen, remove it and you are left with a handful of circuit parts you can hold in the palm of your hand...or install into the sides of the cartridge.

Thoughts ?

Not this old chestnut again!

If and when a robust full-frame digital sensor the same thickness as film can be made, and for less than the price of a complete digital camera; then and only then, might this become feasible. That day isn't yet here.

You've also forgotten to include a battery. In most modern phones, that's the largest single component.

The sensor also has to be synchronised with the shutter, and not all 35mm cameras are the same size.

Forget using the take-up chamber. The space there is already, er, taken up. Unless you're going to rip those parts out of the camera.

Sure, by throwing enough time and money at it, you could build a digital back for one particular make and model of 35mm camera. Would it work as well as an off-the-shelf DSLR or MILC? Doubtful. Would it cost you less? Almost definitely not.

"Something rigid like a sensor carrier would not need the film pressure plate - that's usually easy to remove, and would give more space."

- No, but the sensor plane would need to sit flush with the film guide rails. That means no IR filter can be fitted, and I'm not sure if the microlens and Bayer filter array can be made thin enough not to move the focal plane.

Perhaps you can persuade the people behind the Foveon sensor that there's mileage in this idea? I won't be holding my breath for it to come to market though!

I agree upon the battery issue + the flexibility challenge to adapt to various cameras.

Sorry, I see little value in a due to small production runs / other economic hardships most likely $4000+x device, that is fragile as heck and needs to be pulled out after most likely less than 100 frames to get recharged (for how long, which way?) and collects dust on the sensor during that time.

Yes, it might be nice for proof of concept purposes or to cross system compare your 35mm camera collection.

I also agree upon electronic parts shrinking towards a size making the thing more possible now than back in the days of DMR or Kodak / Fuji modified Nikon film SLRs.

Keep in mind that by now a consumer market for this should not exist any longer. A professional market is even way unlikelier to exist anymore. All the joy provided by once again operating a reasonable shutter speed wheel or winding lever that sounds better and less noisy than the gears in my digitals will be compensated by the annoyance of using an Android device to access other settings.

I am no expert on Bluetooth and WLAN but to me it seems that they'd take a heavy toll on the anyhow most likely too small battery of your dream and also would be challenged if the entire thing has to operate inside a metal camera. Maybe somebody has data what it takes contemporary digitals to operate all their "radio bling" WLAN, GPS etc. energy wise. All I know: Internal antennae were the reason to introduce plastic bodies for them.(Example EOS 5D IV compared to earlier versions).

Sorry, I'd love to get hold of rugged parts that handle nicely. SD cards are already on the flimsy end of the rainbow in my book. shooting micro SDs can't be fun. And while replacing button cells once per year was OK, 4x/day will get annoying.

I don't mind taking an elderly computer apart but putting a new impressive one together still scares me. - Why? - Price of the components, unknown sensitivity to statics, chance to make mistakes. For the same reason I 'd rather buy an off the shelf "classic compromise" camera like a Df or anything M or cope with contemporary interfaces.

Maybe imagine shooting a punk rock concert with your device and switching to film in the same body while "dancers" push you around and there are beer and stage divers above you to get my point about fragility.

Another huge issue: It is unlikely the device would hit the market with competitive specs. So it 'll have to compete against affordable used digital gear, limiting it's target group to the wealthiest inner children.

All great comments. At present, the largest single part in a smart phone is the screen, followed by the battery. The screen requires a specific shape and interface to be effective, limiting what can be done to reduce size. A battery on the other hand, can be made into just about any size or shape, meaning it becomes less of a factor when trying to fit it into a confined space. I suspect the largest part of the cartridge (other than the housing) would be the sensor itself. The sensor has to be strictly designed to fit into the space between the pressure plate and film rails, and have a way to respond when the shutter is opened. Points made about preventing dust on the screen are well taken and are another factor to consider. Power requirements for wlan and bluetooth are not to be taken lightly and are more demanding than the power needed by the actual processing circuitry. I view phone app control (android and iphone) as crucial to this design as it would avoid the need to access the cartridge to change settings. On the other hand, the image processing and storage circuits can fit onto a small very efficient chip, contained in the cylinder located where a 35mm cannister would reside.

Some bodies had removable take up spools, some had integrated spools and and take up mechanisms. The later would of course prevent all or most of the take up space from being used by the cartridge. Regardless of body design, what is common to both is the grooved spindle used to advance film a specific distance. I suspect this action can be used to prime the screen for use. One would have to use the advance lever to turn on the sensor and prime it for use. Subsequent advances would reset the sensor, with auto power down after 1min (adjustable setting within the app ?).

Lots of questions remain. Power on-off when not in use ? USB port for download, or microSD slot ? How many MP and what size of the sensor pixels ? Protection of the fragile sensor ? Making the insertion, design and user interface "fool proof". Etc Etc.

What prompted all of this is seeing the current state of the art in phone technology, and realizing that the limit of phone photography is not sensor quality, or processing chips, it is the lens. The lens is limited by the form factor of a phone, and the need to fit a lens the size of the nail on your pinkie into a space no thicker than a pack of matches. What if you combined the processing technology of a phone, with the lens technology of a real camera ? What if instead of producing a whole camera, with lens etc, you only produce what is needed to produce the image- a "sensor cartridge" designed to fit into the body of an existing manual body? What if the sensor cartridge were designed so that it takes on the size and shape of a 35mm cannister and the plane traveled by the actual film?

Other companies are thinking along these lines. Most in the direction of a digital capture attachment (such as the above). However the MOTO Z line of phones is designed to accommodate external accessories to expand the feature set of the phone. One of the attachments is a Hasselblad branded mechanical zoom lens that promises true photo quality images, with the actual reach achieved by a mechanical zoom lens.

As to price, I would not expect a $100 price, nor would I expect a $1000 price. This range is wide enough to drive a truck through..... Remember this would be just a digital sensor and processing technology- without a shutter, LCD monitor, viewing prism etc. Given the ever declining cost of technology, I suspect this could be produced in enough volume for a retail price of around $500. Not cheap. But it is low enough to be justifiable. Potential customers are hipsters (of course), and anyone with a 35mm film camera who laments the unavailability of film, but loves the convenience of digital. Would people respond ? Look at the robust size of the used market for 35mm film cameras, as evidenced by Ebay and the marketplace of enthusiast sites (like photo.net). I am surprised at the prices now routinely commanded by mid level and relatively common classic cameras. Imagine being able to make your Leica III / M, Contax II/II, Nikon F and other iconic bodies daily use cameras !

Like I said, lots to think about.

"Remember this would be just a digital sensor and processing technology...."

- Yeah, just!

Good luck finding kickstarter backers.

USB port for download, or microSD slot ?

Ain't no question, since the answer has to be: "Both!" You wanna charge somehow, right? - These days folks buy aftermarket USB chargers for their cameras to reduce bulk for travel. And internal hard wired memory won't sell outside the iCrowd.

How many MP and what size of the sensor pixels ?

"Secondary" in my book. Unfamiliar with the real world market I suggest: Look for (other) specs for the buck. - You probably don't really need a Canon 50MP sensor. - Surplus strain on your processor, write speed and everything else later. - Who wants such resolution probably already stocked up with Canon Sony A7 R variants and maybe Pentax. If the odd heritage "gem" of a lens is capable of providing it is questionable. - About 24MP might be the sweet spot of sanity.

Rather ponder "color or speed?" - I'd prefer the latter.

I suspect this could be produced in enough volume for a retail price of around $500

I always thought the camera elements of a DSLR might be cheap enough, to be barely relevant at all. - What used to be MSRP for K1000s X300s and Ricoh KR5s and all those Cosina made budged bodies?

To me the telescopic elements between cartridge and sensor & sensor and take up chamber clutter remain the biggest mechanical challenge for your project.

just a digital sensor and processing technology...."

 

- Yeah, just!

Processing technology is of course the next elephant in the room... I paid fortunes for my 1st gen 6MP and was content shooting RAWs and tweaking the heck out of each and every one of them. - SOOC JPEGs were crap those days.

What about now & them hipsters? I'd suspect contemporary customers to demand acceptable SOOC JPEGs and fear your software techs will have to sit through at least 1 pair of trousers, to get those right.

I don't want to start any "RAW vs. JPEG" discussion. I consider *ist D JPEGs unbearable and admit being impressed enough by Fuji's to occasionally delete RAWs I shot along with them.

Stakes are high.

OK, so I've got my smartphone in one hand, my old fully-manual, digital sensor-equipped 35mm camera in the other hand and held up to my eye. Now, which appendage do I have free to focus with?

The phone could be strapped to the back of the camera, but then it would interfere with getting my eye to the viewfinder and have my nose pressed to its screen. No viewing through the phone would be possible, because the camera shutter stays closed until exposure.

Controlling the camera from the phone is a non-starter without radically modifying the camera.

Maybe with a bit of practise I could learn to juggle phone and camera without dropping either or both. However, putting myself in the mind of the sort of hipster that might be attracted to such a setup, I've given up and moved on to the next piece of technological nonsense, long before I put myself to the trouble of actually learning a new skill.

And BTW, have you any idea what the R&D and production costs of a super-thin full-frame sensor might be? My guess is you could add at least a couple of zeroes to whatever figure pops into your head.

Again, Thanks for all followup comments. I think some clarification is needed. App control would be for settings such as resolution, ISO and white balance. Exposure settings would be in the camera. The digital sensor should be as film like as possible, with minimal custom features. Once set, your phone goes in your pocket and you focus, set exposure etc on the camera body. Future versions could include wifi file transfer to the phone or another smart device. Removable micro SD may be feasible and attractive. Micro usb for charging.

24mp may be the sweet spot for such a device. Enough resolution to make people take notice, not too much as to be overkill for the application.

I don't think processing technology will be the issue. Cheap, fast, small, and highly capable chips are available now. The issue will be sensor design. Once that is solved, everything else should fall into place.

"The issue will be sensor design. Once that is solved,everything else should fall into place."

- OK. We'll check back on this thread in, say, 2025 then.

Don't throw them rusting old 35mm cameras away yet folks. Hermetically seal 'em and save 'em for future use. That full-frame silicon film is just around the corner!

Sensor design is far from the only issue. Apart from the engineering issues, there are economic issues: who is going to do the investments to overcome the considerable engineering hurdles, to end up with a product with a small niche appeal? The companies having the technological skills are invested in digital cameras, so they have zero incentive.

The solution to continue to use your prefered camera already exists, and turns out a growing niche market with improving availability. It's called film.

Just looking at a few cameras I have lying around, neither the shutter position nor the length of the film path are consistent. Both of these would be issues for the "cartridge" solution originally presented.

In fact, when I switched from Canon FD to Nikon, one of the things I noticed was that I could consistently get 37 exposures on a roll whereas my Canons would rarely make it quite there(I'd usually get about 3/4 of an advance stroke). After looking at them side by side, I realized that Canon FD cameras have the shutter roughly centered in the film path, while Nikons place it to the left somewhat.

When you consider the number of popular cameras that people might want this for, the "cartridge" concept becomes a logistic nightmare.

Looking at Nikon, for example, I could see folks wanting one for F2s, F3s, and various cameras in the FM and FE series. Those of course aren't the ONLY choices, but I could easily see them being the most popular choices. The FM and FE series I think have a shorter film path than the F2 and F3.

Add in other popular choices-the Canon A-series, Canon F-1, New F-1, FTb, Pentax K1000, and Spotmatic and you easily have a half dozen or better variations. I'd guess that to be successful, you'd want AT LEAST to offer this for the more popular Nikon, Canon, and Pentax models and probably a few others that I've missed.

Just looking at a few cameras I have lying around, neither the shutter position nor the length of the film path are consistent. Both of these would be issues for the "cartridge" solution originally presented.

Hi, I think the original Silicon Film (or whatever the name) people had a workaround method for this. They had published a short paper, at one time, describing the main issues along with their solutions - it was published by SPSE or IS&T. I had personally met with some of their people at a trade show, and had scheduled a test shoot the next day; unfortunately their only "working unit" then "failed" before that came to pass. Allegedly, per trade information, the units had been dummys and they had been "pretending" to take demo photos - if you use the same models, same clothing, and same rehearsed poses in a sequence, few people would catch on that the actual images had been taken a day prior. (In my case, on behalf of my employer, I wanted some estimates of "shutter delay," and would have caught on, so I guess that perhaps a "failure" of the prototype had to happen.)

At any rate, I don't know if actual working prototypes were ever built or not. Internet lore says it was all a scam; I'm not convinced that this was the case. We (my company) didn't follow up with them for several reasons; mainly their sensing area was too small, and pixel count too low for us. (We were on a mission to get a digital option for our studio film cameras; the idea was to have a digital back that would be swapped out with our film magazines.)

I personally think the scheme was doable, and the thing that killed it for them was the rapid price drop in digital cameras. Once the price of digital SLR cameras fell below $10k US or so, the digital inserts didn't seem like such a deal anymore.

I still think it's doable, but I'm skeptical that it would be profitable. The big issue was to get the imaging surface of the sensor to the film plane. With the optical package on the front of the sensor, it would ideally be inserted slightly into the camera body. So it would take a special sensor format, etc. We went through the gyrations ourselves, looks at all the apparent options - a relay lens system, a fiber optic image-transfer plate, etc. We concluded that our best option was to machine off the back of our studio camera, making a reversion to film magazines impossible. Without that possibility, we abandoned the existing camera body and went with a ground-up digital camera design.

I am very doubtful that film camera users, as a whole, would be willing to pay enough for a manufacturer to come out ok on the deal. To get an idea of what they would need to be profitable, just look at prices for existing digital backs. $500 per unit is just a pipe dream, I think.

Some people have built digital backs for 35mm cameras. These homebrews are huge and bulky but they do function. With full manufacturing it's probably possible to build a digital back system that only increases the thickness a portion of an inch but the economics are just impossible.

First of all there's the development and material costs. Even APS-C sensors are expensive parts, so every prototype is gonna be the better part of a grand just in the Bill of Materials, before assembly. At this kind of size were talking the same many layer PCB tech used for smartphones instead of tablets, so there's $500 per unit or something right there on top of whatever the sensor costs. Then you'd have to build light-tight back shells to adapt to cameras, and that probably means metal instead of plastic which will require hydraulic press stamping tooling for each camera supported. So expect to see support for like the AE-1 and whatever the next 4 most selling cameras are and nothing else.

And then the film camera market isn't even in maintenance, it's shrinking. The profit margins aren't even there for rescuing SLRs from thrift stores and refurbishing them. Most people shooting film cameras want to shoot film, and for shooting digital a device with the actual UI for shooting digital is a better experience. We've already had things like the Epson RD1 series and the Olympus Pen which probably take a huge chunk out of the retro experience market. And Mirrorless's take a huge chunk of people who want to shoot old lenses with price ranges from full frame Sonys to cheap discarded EOS-Ms.

All great comments. At present, the largest single part in a smart phone is the screen, followed by the battery. The screen requires a specific shape and interface to be effective, limiting what can be done to reduce size. A battery on the other hand, can be made into just about any size or shape, meaning it becomes less of a factor when trying to fit it into a confined space. I suspect the largest part of the cartridge (other than the housing) would be the sensor itself. The sensor has to be strictly designed to fit into the space between the pressure plate and film rails, and have a way to respond when the shutter is opened. Points made about preventing dust on the screen are well taken and are another factor to consider. Power requirements for wlan and bluetooth are not to be taken lightly and are more demanding than the power needed by the actual processing circuitry. I view phone app control (android and iphone) as crucial to this design as it would avoid the need to access the cartridge to change settings. On the other hand, the image processing and storage circuits can fit onto a small very efficient chip, contained in the cylinder located where a 35mm cannister would reside.

 

Some bodies had removable take up spools, some had integrated spools and and take up mechanisms. The later would of course prevent all or most of the take up space from being used by the cartridge. Regardless of body design, what is common to both is the grooved spindle used to advance film a specific distance. I suspect this action can be used to prime the screen for use. One would have to use the advance lever to turn on the sensor and prime it for use. Subsequent advances would reset the sensor, with auto power down after 1min (adjustable setting within the app ?).

 

Lots of questions remain. Power on-off when not in use ? USB port for download, or microSD slot ? How many MP and what size of the sensor pixels ? Protection of the fragile sensor ? Making the insertion, design and user interface "fool proof". Etc Etc.

 

What prompted all of this is seeing the current state of the art in phone technology, and realizing that the limit of phone photography is not sensor quality, or processing chips, it is the lens. The lens is limited by the form factor of a phone, and the need to fit a lens the size of the nail on your pinkie into a space no thicker than a pack of matches. What if you combined the processing technology of a phone, with the lens technology of a real camera ? What if instead of producing a whole camera, with lens etc, you only produce what is needed to produce the image- a "sensor cartridge" designed to fit into the body of an existing manual body? What if the sensor cartridge were designed so that it takes on the size and shape of a 35mm cannister and the plane traveled by the actual film?

 

Other companies are thinking along these lines. Most in the direction of a digital capture attachment (such as the above). However the MOTO Z line of phones is designed to accommodate external accessories to expand the feature set of the phone. One of the attachments is a Hasselblad branded mechanical zoom lens that promises true photo quality images, with the actual reach achieved by a mechanical zoom lens.

 

As to price, I would not expect a $100 price, nor would I expect a $1000 price. This range is wide enough to drive a truck through..... Remember this would be just a digital sensor and processing technology- without a shutter, LCD monitor, viewing prism etc. Given the ever declining cost of technology, I suspect this could be produced in enough volume for a retail price of around $500. Not cheap. But it is low enough to be justifiable. Potential customers are hipsters (of course), and anyone with a 35mm film camera who laments the unavailability of film, but loves the convenience of digital. Would people respond ? Look at the robust size of the used market for 35mm film cameras, as evidenced by Ebay and the marketplace of enthusiast sites (like photo.net). I am surprised at the prices now routinely commanded by mid level and relatively common classic cameras. Imagine being able to make your Leica III / M, Contax II/II, Nikon F and other iconic bodies daily use cameras !

 

Like I said, lots to think about.

I can bet you nobody can make such a thingy for $500. I would think rather $5000. Also why do you want such a thing?