Converting a Nikon Nikkormat EL to digital with a Sony Nex-5N
Take a vintage film camera that no longer works and convert it to digital.
Many of us love vintage cameras and we don’t find exactly what we are looking for in today’s modern (even retro inspired) SLRs or mirrorless cameras. Today’s digital cameras are amazing, but lets face it, things just used to look better. I started collecting a few vintage cameras and went as far as developing film in my own bathroom. But the advantages of digital photography are numerous and as an infrared enthusiast those advantages multiply quickly (such as actually being able to see what you’re focusing on!). So I set about trying to turn a vintage camera into a modern mirrorless ILC.
Ideas and considerations:
There are 2 ways of going about this that I can think of.
1. Design a digital back for a specific camera so that the digital sensor is placed at the same flange focal distance as the film would be and leave the original film camera intact. This has two major drawbacks. Firstly, the electronics that are necessary for digital photography take up considerable space and that means that the digital back will protrude much further out from the back of the camera than the original film back. Secondly, the firmware for the digital sensor and image processor has to be custom designed to take cues from the existing mechanical film controls. The sensor has to know when to be ready for a picture and when the exposure has finished so that it can process and store the image, and then get ready for the next picture. This is not a simple task.
2. Replace the innards with an existing fully functional digital mirrorless camera, essentially housing the camera in a new enclosure. The main drawback of this is that it is destructive to both the original film camera and the digital camera, as they have to be irreversibly modified. Also, the flange focal distance will be reduced in order to fit the digital camera inside the film camera without protruding as with a digital back. This means an extension tube is required to maintain the correct flange distance for the lens. The effect of not doing this will be to greatly increase the minimum focusing distance of the lens (you would still be able to focus at infinity without the extension tube). This is the method I chose to try.
As a Leica and Nikon S appreciator, I first thought of buying an M3 that was for parts, but even a broken M3 is costly and is still very collectible. So it would be a shame to totally ruin one without even knowing if it is possible to do. I do have a broken Nikon S that may turn in to project no.2.
Instead I had a Nikkormat EL lying around that would be perfect for a first attempt. Its cheap, common and easy to work with. If you decide to attempt a similar project I recommend trying it out on something similar first.
The next important consideration is which digital camera to use. There are 2 main considerations;
1. Dimension of the camera, screen and electronics – will it be able to fit with minimum modification?
2. Layout of the controls – how easy will it be to map the physical controls of the digital camera to the mechanical controls of the film camera?
After careful consideration, the Sony Nex-5N provided a relatively affordable camera that fit the criteria. But it also has a very useful feature for this project – focus peaking. This is when the liveview screen or EVF will highlight exactly what is in focus. This provides a very effective way of being able to focus manually, as the finished camera will not be able to autofocus. The fact that the 5N did not have a built in EVF was a bonus because the EVF in an SLR would be directly above the center of the sensor, rather than to the left like in a rangefinder. I was able to get the sony add-on EVF for the 5N and that will fit very nicely in place of the original prism viewfinder.
As I mentioned before, I’m an IR photography enthusiast and so I will be removing the hot mirror filter, allowing me to use infrared filters on the lens. I have had a couple different infrared converted SLRs, but this was an opportunity to have a full spectrum camera that can use any filter. The problem with this approach is that filters are expensive and sizes vary from lens to lens. This got me thinking, since I have to custom design an extension tube to maintain the flange focal distance, maybe I could design this extension tube to take changeable filters, allowing me to use one set of filters for all lenses. This is still just conceptual as I haven’t got to the stage of designing the extension tube yet. The extension tube will be custom milled, probably from aluminum.
Once the camera has been built I will do my best to restore it with some good looks. The leatherette will be replaced and the black paint repainted. I will try to seal the camera as well as possible from dust and light with some rubber seals and light proofing materials too.
Part 1: Stripping the Nikkormat EL
It’s quite amazing how many moving parts there are in an old SLR camera. There are hundreds of tiny mechanical pieces and screws. I had no prior experience tearing down an SLR so I did it like anybody else would. Just started taking it to pieces and see what I found.
Tools required: Small philips and flathead screwdrivers, spanner wrench, tweezers, cutters
As I started taking the Nikkormat apart I thought about how the Nex 5N would fit. You can already see the first problem. The battery housing in the grip of the 5N is wider than the Nikkormat. In order to fit the battery inside the Nikkormat it would have to be turned sideways, and this means modifying the electronics of the 5N…
I’m not going to give you a detailed step-by-step of taking apart the Nikkormat, because it would be endless. The basic method is, if you see a screw unscrew it! Be very careful to save all the screws in a way that you can identify where they came from. Getting the top plate off is a little bit tricky. There are 3 small screws visible around the sides of the plate. There are 2 screws holding the Nikkormat name plate to the prism housing that have to be removed. Then the ring surrounding the battery charge indicator button to the left of the viewfinder has to be unscrewed. Next the winder and ISO dial on the left need to be taken apart and removed. The ring around the base of the exposure speed dial has to be unscrewed (there are no holes for a spanner wrench). Finally the winding lever has to be removed. Now you can take off the top plate.
The purpose of stripping down the Nikkormat was to clearly see how the Nex 5N will fit and to prepare it for modification by Dremel. So I took almost everything out. You don’t have to take apart many of the individual mechanisms in order to remove them, so try to identify which screws are holding them in. Since there was no turning back on this project I just cut all the wires and removed them as much as possible.
In order to remove the face plate and expose the shutter mechanism, you have to strip the leatherette off to expose 5 screws on the front. 2 more screws on the top where the prism should be also hold it. The shutter mechanism is easy to remove unharmed and can probably be sold as parts. The faceplate with the lens mount has a deep light proof box on it. This would have to be cut off as well as much of the film plate behind the shutter. There would then be enough space to comfortably fit the Nex 5N sensor and electronics.
Part 2: Stripping down the Sony Nex-5N
Instead of removing the sensor and electronics from the Nex, it makes more sense to leave them attached to the Nex enclosure so that they are held firmly in place and then cut down the Nex enclosure to fit snuggly in the Nikkormat. This way you avoid any risk of the sensor and mainboard moving around.
There are already some videos of people tearing down a Nex 5 on youtube so you can follow those if you want a step-by-step. The Nex is very simple and consists of the sensor, shutter mechanism, mainboard, sd card slot, battery compartment and controls. Be careful when pulling out the ribbon cables, they are delicate and some clip in, others dont.
I was concerned that I would have to extend some of the ribbon cables in order to move some components around, but as it turns out none of them will have to be extended. Only a couple of the buttons will have new switches soldered on the board by thin wires in order to move them onto the Nikkormat top plate (the playback and record buttons).
Part 3: Combining the cameras
Using a dremel cutter I cut out the center part of the film plate and the box that is attached to the lens mount, to make enough space to fit the sensor and mainboard.
It takes quite a long time to cut and grind so much of the metal but the metal is quite soft and one cutting wheel was enough to do the whole body
Getting the size right was just a matter of cutting a little bit at a time and constantly comparing the space to the digital parts that I would put inside. You don’t want to cut too much because it’s easy to weaken the structure beyond repair, so cutting small and then enlarging it bit by bit is the way to go.
The casing of the Nex 5N also had to be cut down substantially. I cut it as close as possible to electronics without losing any of the screw holes with which they are secured to the casing. The Nex casing is made of aluminum and is very easy to cut with a dremel. I then was able to place all of the nex 5 parts inside and make some small adjustments to the cuts with a tungsten carbide cutting bit.
The EVF proved to work out extremely well and fit perfectly in the old viewfinder spot, as the accessory connector is dead center of the sensor, just like a hotshoe on an SLR. I did have to remove some the plastic casing of the EVF to make it sit further back but the EVF is still intact. The battery had to be turned sideways as I mentioned before, and it fits very snuggly with some extra grinding, with just enough room for the SD card reader to sit infront
In order to sit the battery in this position, the battery connector has to be removed from the original power ribbon cable (by desoldering) and reattached by wires allowing it to be further away from the mainboard than the ribbon cable will allow.
With everything in place I cut the back door to make way for the screen and the scroll wheel controls
The sensor needs to be as parallel as possible to the focal plane which means some fine tweaking will be necessary. In order to fix the components in their final position I will design and 3D print some small brackets to screw the Nex casing to the Nikkormat structure. Unfortunately it takes about a month to receive a 3D print order and I want to print one piece at a time minimize errors in measurements, so I will print one piece and attach it, then measure for the next.
The first bracket I have ordered is for the top.
This piece was ordered from iMaterialize who are a 3D printer based in Belgium. They provide a good choice of materials and the most suitable for these small parts is brass which unfortunately is relatively expensive. I also ordered a bracket to hold the EVF in place at the same time. These should arrive around the end of Feb 2013.
In the mean time i have some soldering to do and I need to design the pieces that will extend the controls from the Nikkormat to the Nex, such as the winding lever. This will act as the on off switch. When the lever is pulled out slightly to reveal the red dot, the camera should be on. Luckily the on/off switch on the Nex 5N is very similar, so it shouldn’t be too difficult to do. The shutter release is also almost directly on top of the Nex shutter release making it relatively easy to extend down too.
In the mean time please ask questions and leave comments below. Here are some pics of the camera partially assembled
Update 02/09/13: Whilst waiting for pieces to arrive I’ve designed the F Mount attachments ready for my custom extension tube
Finally my 3D printed brass mounting brackets have arrived after more than a month of waiting! The project goes on…One secures the digital components to the Nikkormat body and the other secures the EVF in place. I had these made at i.materialise in Belgium out of brass. They get gold plated by default so I feel like my ghetto camera hack has some gold teeth to match now.
The camera takes its first breaths. Proof that it lives! I know it still looks like crap but the looks will be the final stage. Unfortunately I somehow damaged the accessory port and the camera doesnt recognise the EVF I have a backup 5N that was broken on ebay for parts, but the lcd output on the mainboard on that one doesnt work and the EVF does… cant believe it. Which means I have to find another 5N mainboard from a broken camera that works. Next stage is the transferring camera controls to the Nikkormat buttons.