Possible ROM Coding of Non-ROM Lenses?

[forestcasey]

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Hi, R-Camera forum:

Longtime reader, first-time poster. Have been the beneficiary of your insight over many years and it has led me to gather a decent R lens collection, which I use with my Leica R3, SL, and SL2-S cameras. It's a great system, some lenses of which are still arguably undervalued for what they are. 

Anyway! Like many of you, I've invested in many R-to-L adapters, finally springing for the first-party Leica adapter with ROM coding. It's great with the ROM coded lenses, but slightly less useful for non-ROM lenses. Flash forward to today, when I learned about the Akara Labs 6-Bit coding for M Lenses: https://akaralabs.com/products/leica-m-mount-lens-6-bit-encoder

Basically, a DIY tool for changing old or non-coded M lenses into lenses that communicate their focal length with Leica's digital M lineup.

My question is this: Would this at all be possible with R lenses with ROM coding? Would love it if this is so. You're the experts, let me know what you think!

[masjah]

The M coding comprises black and white dots which are read optically by the camera (or adapter) and the Akara kit looks like a jig to facilitate marking up black and white dots yourself. The coding on the R system is totally different in that it is an electronic ROM (read only memory) chip (and sometimes actually even a small microprocessor) that has been programmed with the particular lens details (even down to the aperture closing dynamics of the individual lens example). Leica used to offer to convert old lenses retrospectively, at a cost of course, but no longer do so. This is definitely a factory job. It would also involve removing cams 1 and 2 of three cam lenses. Leica sold off all its R series parts, so the specially shaped ROM chips are not available, and you would also need the equipment to burn them (also sometimes called "blow" or "program" them). I would be absolutely delighted to be proved wrong over this!

 

Edited June 6 by masjah

[jaapv]

6 hours ago, masjah said:

I would be absolutely delighted to be proved wrong over this!

I'm afraid that is not going to happen - it is next to impossible to duplicate the ROM coding system. Nor would it be worth the trouble. 

[250swb]

I think it's hardly worth it for the miniscule benefit. The main advantage of ROM is if you use flash with an R8 or R9 body, which is very much a niche. The Akara device you mention appeals to a much wider M lens market, but it's a very, very old idea and has the same inherent problems that using a coding template has always faced, the coding marks rubbing off when the lens is mounted.

Edited June 7 by 250swb

[forestcasey]

Appreciate the info—like I said, I very much respect your expertise!

Slightly disagree with how minuscule the benefit is for modern usage. Being able to have the correct lens coded to EXIF data when using a Leica SL and the first-party lens adapter is really convenient. Having built-in lens corrections that you don't have to manually select is convenient, too. Just my $.02.

Would anyone happen to know where the surplus of ROM chips went after Leica sold off their stock?

Thanks very much again.

[masjah]

1 hour ago, forestcasey said:

Appreciate the info—like I said, I very much respect your expertise!

Slightly disagree with how minuscule the benefit is for modern usage. Being able to have the correct lens coded to EXIF data when using a Leica SL and the first-party lens adapter is really convenient. Having built-in lens corrections that you don't have to manually select is convenient, too. Just my $.02.

Would anyone happen to know where the surplus of ROM chips went after Leica sold off their stock?

Thanks very much again.

I agree that the additional benefits of the ROM chip are sometimes somewhat underestimated. Even with the film R8/R9 it was useful, for example, when using a ROMmed 2X extender, and a variable aperture zoom lens, to have the correct aperture value sent to the camera, and also for example the actual focal length sent on the lens to the Leica R-L adapters for proper IBIS and perspective control on an SL2. There are other small but useful benefits which I won't list. 

 

[jaapv]

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On 6/7/2025 at 10:47 PM, forestcasey said:

Would anyone happen to know where the surplus of ROM chips went after Leica sold off their stock?

 

My guess would be the dustbin.  It is not just a matter of the ROM chip, one would also need the sensors inside the lens and the connections. 

[250swb]

On 6/7/2025 at 9:47 PM, forestcasey said:

Appreciate the info—like I said, I very much respect your expertise!

Slightly disagree with how minuscule the benefit is for modern usage. Being able to have the correct lens coded to EXIF data when using a Leica SL and the first-party lens adapter is really convenient. Having built-in lens corrections that you don't have to manually select is convenient, too. Just my $.02.

 

I guess so, if you can't remember what lens you may have used or be able to correct a lens in ACR isn't too taxing. But how did people do this before ROM, was it so much a different world or perhaps a more intelligent world, not relying on codes to do simple jobs that substitute for photographer skills?

[Helge]

Am 7.6.2025 um 22:47 schrieb forestcasey:

Appreciate the info—like I said, I very much respect your expertise!

Slightly disagree with how minuscule the benefit is for modern usage. Being able to have the correct lens coded to EXIF data when using a Leica SL and the first-party lens adapter is really convenient. Having built-in lens corrections that you don't have to manually select is convenient, too. Just my $.02.

Would anyone happen to know where the surplus of ROM chips went after Leica sold off their stock?

Thanks very much again.

Did you check with Paepke, whether they took over the leftover devices (if there where a lot) once they took over the service for the R system?

If yes, they might be able to provide some conversions…

[jaapv]

Provided they have software to program the chip to the specific lens.

[forestcasey]

 

On 6/9/2025 at 2:03 PM, 250swb said:

I guess so, if you can't remember what lens you may have used or be able to correct a lens in ACR isn't too taxing. But how did people do this before ROM, was it so much a different world or perhaps a more intelligent world, not relying on codes to do simple jobs that substitute for photographer skills?

Hi, Steve --

Really went out of my way to show respect to true photographers like yourself. Love all of your numerous photos of the English countryside, they are really quite stunning! Also love your choice of username, the Ferrari 250 'SWB' is an exceptional automobile.

When I am shooting a professional job (sometimes of fancy cars like your favorite Ferrari), it's usually easy to just grab my 24-90 and not worry about the metadata. But sometimes I'm at home with a shelf full of R lenses and I'll grab a few at random and take pictures. It's tough to remember after the fact sometimes whether I was using a 28mm Elmarit-R or a 35mm Summicron-R, especially when the aperture written on the metadata is basically an estimate. Sometimes I do little fun lens tests just for me between the 50mm Summicron-R and 50mm Summilux-R. How convenient it would be to have that be written into the files? That's all I am saying, thanks for your input.

[forestcasey]

On 6/9/2025 at 10:45 PM, Helge said:

Did you check with Paepke, whether they took over the leftover devices (if there where a lot) once they took over the service for the R system?

If yes, they might be able to provide some conversions…

I have never heard of Paepke, thank you very much for your response. 

The only source I heard of was of a now-retired tech in Canada and that led to a dead end. Can't thank you enough for this suggestion.

[250swb]

12 hours ago, forestcasey said:

 

Hi, Steve --

Really went out of my way to show respect to true photographers like yourself. Love all of your numerous photos of the English countryside, they are really quite stunning! Also love your choice of username, the Ferrari 250 'SWB' is an exceptional automobile.

When I am shooting a professional job (sometimes of fancy cars like your favorite Ferrari), it's usually easy to just grab my 24-90 and not worry about the metadata. But sometimes I'm at home with a shelf full of R lenses and I'll grab a few at random and take pictures. It's tough to remember after the fact sometimes whether I was using a 28mm Elmarit-R or a 35mm Summicron-R, especially when the aperture written on the metadata is basically an estimate. Sometimes I do little fun lens tests just for me between the 50mm Summicron-R and 50mm Summilux-R. How convenient it would be to have that be written into the files? That's all I am saying, thanks for your input.

Just as I don't have a favourite car (my username is simply my initials combined with a jokey reference to my job which is to do with exotic cars) I also don't have a favourite lens or any particular interest in the exact aperture I used. I can make a good guess by looking at the photograph and about knowing myself, and that is a skill which also helps me understand other peoples photographs. And if I ever put camera and lens details next to a photograph, like I often do on Flickr, it's to help other people understand the photograph (if they are interested) and not for myself.

I don't think in over forty years of photography I've ever asked somebody 'what lens and aperture did you use?' because I have over forty years of learned intuition to get me as close to the ballpark as I'm interested in being, not that lens and apertures should be needed to appreciate a photograph anyway. And one of the many advantages of using film is that EXIF files don't exist and I'm all on my own in understanding my own photographs and how they are made. And if I could ban my digital Leica's from making an EXIF file I would, it wouldn't bother me at all. Of course the big elephant in the room is that the main area where R lenses are used commercially nowadays is in cinematography, a very expensive business to be in, and do they need EXIF files, nope.

    

Edited June 15 by 250swb