#Arkive SQ: Thoughts about a smart FD adapter

Started Apr 16, 2019 | Discussions
SQLGuy
SQLGuy Forum Pro • Posts: 10,390
#Arkive SQ: Thoughts about a smart FD adapter
2

Canon FD mount allows for communications and actuation from the body:

1. There's a pin whose length is read by a sensor in the body so that the body will know the maximum aperture of the lens.

2. There's another sensor in the body that senses the position of the aperture ring, so it knows the currently set aperture or whether the lens is in program mode.

3. There an aperture stop down lever in the body that closes down the aperture when getting ready to release the shutter, so composition and focusing can be done wide open.

I think it would be really cool to build an E mount adapter that implemented these features. Besides making FD lenses easier to use, it would also make them easier to mount (no Open/Close nonsense).

It's certainly feasible. The LA-EA3 has such an aperture lever, as does the Nikon smart adapter. Zeiss Loxia lenses have aperture rings, so E mount does support the lens telling the camera the aperture.

The main missing piece would be the focal length(s) of the lens. One option that occurred to me is to allow the adapter to be programmed (probably over Bluetooth or BLE) to recognize specific lenses by max aperture. For people that only have a few FD lenses to use on the adapter, this could make use really easy - e.g. the 2.0 is 35mm, the 1.4 is 50mm, the 2.8 is 24mm... However, if there are multiples at the same aperture, then things get trickier, and a button and maybe an LED or two on the adapter may be needed to switch between lenses. For zooms, I think the best behavior would be to disable IBIS (configurable through the programming).

One other option that occurred to me is little bar code stickers for the breech ends of the lenses and an optical reader in the adapter, ala Leica's 6-bit encoding, so that the lenses could be recognized unambiguously. This would still require configuration of the adapter for the lenses a particular user has, but it would get rid of the need for buttons and LEDs on the adapter. In fact, it could obviate the need for the aperture pin reader.

What do you guys think? Would an FD adapter that allows lenses to work like they do on an FD body, plus EXIF and automatic configuration of IBIS, be a compelling product? I don't think there's enough market for this to be a money maker, but it would be something I'd like to have.

As for my skills in this area - I'm a developer by trade - mostly Java these days. I have some experience with custom solutions based on Cypress PSoC and PRoC microcontrollers. My formal training was avionics and computer engineering. I have a mini lathe and some fabrication skills... some of which come from a hobby in watch repair and restoration. I know nothing about the E mount protocols. Clearly they have been made available or reverse-engineered by Techart and Conurus, but I don't know how available this information is. The FD side of things should be pretty easy to figure out, just by measuring lenses, even if the details are not available somewhere.

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Alan WF
Alan WF Senior Member • Posts: 2,964
Re: Thoughts about a smart FD adapter

This is likely to be in the realm of the possible, but I think the justification is weak.

The original justification for shutter-priority mode adjusting the aperture was that film ISO is fixed, so if you want to keep the shutter at a given speed, the only variable is aperture.

However, modern digital cameras have widely variable ISO. This means that manual mode (selecting the shutter speed and aperture explicitly) with auto ISO can, to a large degree, serve in the place of shutter-priority mode.

Better yet, probably, is aperture-priority mode with "Intelligent ISO" on recent Panasonics. This  analyses the video feed and selects a shutter speed to reduce subject and camera motion to a reasonable degree and then selects the ISO based on the exposure. (I had this on my GM5s and miss it on my Sony a6000. I don't know which other bodies implement something similar.)

Or am I missing something?

Regards,

Alan

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SQLGuy
OP SQLGuy Forum Pro • Posts: 10,390
Re: Thoughts about a smart FD adapter

Alan WF wrote:

This is likely to be in the realm of the possible, but I think the justification is weak.

The original justification for shutter-priority mode adjusting the aperture was that film ISO is fixed, so if you want to keep the shutter at a given speed, the only variable is aperture.

However, modern digital cameras have widely variable ISO. This means that manual mode (selecting the shutter speed and aperture explicitly) with auto ISO can, to a large degree, serve in the place of shutter-priority mode.

Better yet, probably, is aperture-priority mode with "Intelligent ISO" on recent Panasonics. This analyses the video feed and selects a shutter speed to reduce subject and camera motion to a reasonable degree and then selects the ISO based on the exposure. (I had this on my GM5s and miss it on my Sony a6000. I don't know which other bodies implement something similar.)

Or am I missing something?

Regards,

Alan

I think I'm missing something in your response.

A Canon FD body, like my new F-1 or A-1, sets the lens aperture mainly so composition and focusing can be done wide open. This allows a brighter image and a clearer distinction of where the plane of focus is. Focusing at taking aperture, as is done when these lenses are adapted, is desirable under some circumstances - and works because of the light gain of the EVF, but can make things difficult in dim environments, or with large DOF. In addition, It's not just S mode (Tv on Canon) when this is done. Full program uses both shutter speed and aperture as variables when determining what exposure to use. A modern body that knows the focal length of the lens will be able to do this even better.

Loxia lenses are native to E mount. I would like adapted FD lenses to work pretty much like Loxia lenses do. I.e. you can set the aperture (on the lens or on the body) in A or M modes, with or without auto ISO. Or you can leave the lens in P mode, and have the camera determine aperture in S or P modes, again with or without auto ISO. All with the camera gaining EXIF and IBIS data automatically.

Or are you saying that the Loxia lenses are unnecessary and not compelling for some reason?

Of course, if this can be implemented for FD lenses, it could also be done for Nikon F mount, and other stop-down-at-shutter-release manual lenses.

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Alan WF
Alan WF Senior Member • Posts: 2,964
Re: Thoughts about a smart FD adapter
2

Ah, you want this for focusing wide open in aperture-priority mode, not to implement shutter-priority mode. I misunderstood.

You can do that now, albeit manually. Many dumb FD adapters have "open/lock" dials. In one position, the aperture is wide open. In the other, the aperture is whatever is selected by the aperture dial.

Regards,

Alan

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Rol Lei Nut Veteran Member • Posts: 5,331
Re: Thoughts about a smart FD adapter

SQLGuy wrote:

Loxia lenses are native to E mount. I would like adapted FD lenses to work pretty much like Loxia lenses do. I.e. you can set the aperture (on the lens or on the body) in A or M modes, with or without auto ISO. Or you can leave the lens in P mode, and have the camera determine aperture in S or P modes, again with or without auto ISO. All with the camera gaining EXIF and IBIS data automatically.

Or are you saying that the Loxia lenses are unnecessary and not compelling for some reason?

Loxia lenses, as far the the aperture is concerned, are no different from "dumb adapted" lenses (apart from EXIF and the aperture being shown in the viewfinder). The diaphragm cannot be changed through the camera body, nor does the lens remain open and then stop down when the shutter is released.

Years ago I thought of inventing adapters with solenoids, so that the lenses could be focused and the image composed at full aperture, then automatically closed down to the chosen stop for shooting. But that idea was for use with Canon DSLRs, which were practically the only option then for mounting my legacy lenses.

Now, with good EVFs, I rarely have any complaints about having to focus or compose with the lens closed down to its working aperture. And P mode is something I never want to use anyway.

What I would like is an EXIF settable adapter, mainly for setting the camera's IBIS. A Leica M=>FE adaper (so other mounts could be adapted down to M) with a dial for quickly setting the FL. Conceptually not so different from the Techart Pro, but smaller, lighter and with the FL which could be changed in in a instant.

SQLGuy
OP SQLGuy Forum Pro • Posts: 10,390
Re: Thoughts about a smart FD adapter

I often find myself opening the aperture on my FD 15/2.8 Fisheye to focus, and then stopping down again to take the photo. It's easily usable at F8 under most lighting conditions, but focusing it, magnified, or with peaking, is pretty difficult when stopped down.

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SQLGuy
OP SQLGuy Forum Pro • Posts: 10,390
Re: Thoughts about a smart FD adapter

Alan WF wrote:

Ah, you want this for focusing wide open in aperture-priority mode, not to implement shutter-priority mode. I misunderstood.

You can do that now, albeit manually. Many dumb FD adapters have "open/lock" dials. In one position, the aperture is wide open. In the other, the aperture is whatever is selected by the aperture dial.

Regards,

Alan

Sure they do. That's what I was calling nonsense in my original post. A pain to remember to set it to open when mounting and removing the lens, and also potentially a pain to remember that you've locked an FD (not nFD) lens that you are using between adapters and real FD bodies. I do lock down my FD lenses, though, since I use them more often on adapters.

And that still doesn't get you EXIF or setting of IBIS. You can manually set IBIS, and you can, on second gen A7s, manually set EXIF with the lens corrections app. I'd like to have smarter behavior than that from the adapter.

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SQLGuy
OP SQLGuy Forum Pro • Posts: 10,390
Re: Thoughts about a smart FD adapter

Rol Lei Nut wrote:

What I would like is an EXIF settable adapter, mainly for setting the camera's IBIS. A Leica M=>FE adaper (so other mounts could be adapted down to M) with a dial for quickly setting the FL. Conceptually not so different from the Techart Pro, but smaller, lighter and with the FL which could be changed in in a instant.

Why a dial instead of reading the 6-bit?

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Alan WF
Alan WF Senior Member • Posts: 2,964
Re: Thoughts about a smart FD adapter

I don’t think the real problem with this manual mechanism is difficulty in mounting. Just twist one way to make sure the lever is engaged and then twist the other to mount the lens. It becomes natural  after a couple of days. I think the real problem is that they often open up the aperture when you don’t mean to; that’s  why I fix mine closed with epoxy

You want communication of the focal length, communication of the aperture, and control of the stop-down lever, in order of increasing difficulty. There’s no law against dreaming.

Regards,

Alan

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Tons o Glass 0 Class
Tons o Glass 0 Class Contributing Member • Posts: 770
My adapter+app proposal

Let's assume aperture sensing/control is all worked out along with all the E-Mount, L-Mount, RF-Mount, and/or Z-Mount protocols.

Imagine having a Bluetooth-enabled smart adapter with built-in memory, a LCD/LED display, a control ring, and a Bluetooth on/off switch. Now imagine having an app that interfaces with it to push simple app-made or advanced community-created lens profiles and EXIF info to the camera (in-camera corrections for improved SOOC JPEGs with vintage lenses, anyone?). You'd specify which lens you're using via the app.

  • One would use the control ring to select the focal length (if necessary - it would be quite necessary for manual zoom lenses, for example).
  • The current focal length would show up on the display.
  • The aperture would be chosen in-camera - hopefully one would be able to choose between open-aperture metering/focusing/composing or stop-down m/f/c by toggling Live View Effect in the camera menu.
    • I would also hope the adapter would still allow you to "change the aperture" even if the aperture mechanism isn't properly coupled with the lens (in the case of doubly-adapted lenses [Nikon F -> Smart FD -> E, for example]) so that proper EXIF info can still be fed to the camera.

If you increased the memory and added a button to the adapter, you could arrange your kit and push it to the adapter via the app, and take your phone out of the equation for however long it suits you. The button would cycle through your kit and would temporarily display the [customizable] name of the current lens as you cycle through them.

I can only guarantee everything is much more complex than it sounds, and I'm sure things don't work like I think they would, but I would love to have an adapter/app combo like this. I can also assume, as you did, that the adapted lens community is a bit small, and that the percentage of them that would pay for the added build complexity/functionality is rather small

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If this is combination never comes to fruition and you're looking for a project, how about a perfectly universal M42 adapter with a spring-loaded foot that presses the aperture pin (much like an M42-mount camera) with a dial or a lever. It would be pretty amazing to get all the functionality your proposed FD adapter would bring for M42 (and other mounts), but this is more realistic and could likely be achieved at a much lower price-point.

Pentax's later S-M-C and SMC lenses have tabs/protrusions that fowl things up when the adapter has a stop-down ledge.

  • Since these lenses have A/M switches, they don't need the ledge, so the solution has been to use two adapters; one with a ledge for lenses without A/M switches, one without. However, It's also possible to machine the ledge to just the right diameter to allow all the extra bits on these lenses to be unobstructed. Such an adapter is more universal, but not quite perfect*.

Fuji M42 lenses have a tab around the edge of the aperture ring that can fowl things up when the mount is machined too wide.

  • This has an easy solution - simply machine the outer diameter of the M42-mount side smaller, but somehow plenty of adapter makers ignore it.
  • Another solution is to file the tab off on every lens, but then they won't work as Fuji intended on Fuji film bodies. No no, that's not a solution for me.

*Some various M42 lenses in my collection work quite right on an adapter with a fixed stop-down flange regardless of whether or not they need one.

  • One main issue is that the aperture pin length or how far it needs to be depressed is not standard across all M42 lenses.  If the ledge is too far away, the aperture won't stop down accurately at all.  If the ledge is too close or if the pin is too long, some lens designs can get jammed up near infinity focus.
    • The solution is to have an aperture stop-down mechanism modeled after an M42-mount camera instead of a fixed stop-down ledge (or no ledge at all).
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ProfHankD
ProfHankD Veteran Member • Posts: 7,603
Smart adapters

The TechArt Pro LM-EA7 is a really good starting point for thinking about making a smart adapter. Not only does it provide autofocus (or at least auto tweaking of manual focus) for any lens that can adapt to M mount, but it also understands the basic E mount protocol. It also has wireless programming, and can use the body to select between pre-programmed lenses (via a kludge using dummy exposures with smaller aperture settings).

Here's what I think one would want to add/change from the LM-EA7:

  • Provide a way to select which lens is mounted directly on the adapter. This could be as simple as a thumb wheel and a little display. Alternatively, it would be nice if it could read the M mount optical codes, or some other easily user-configurable interface (e.g., RFID), and select based on that. It isn't unreasonable to assume each lens is used with its own dedicated adapter to M, so you'd just have to code the M adapter for each lens.  (If Sony hadn't discontinued the PlayMemories camera app interface, it would have been possible to have an OpenMemories camera app provide a cleaner interface for camera control of the adapter configuration.)
  • Make smart adapters to M mount that can read and/or control lens aperture with a pass through the LM-EA7-ish adapter. The pass through could be as simple as reading analog resistance, detecting aperture position using a Hall sensor, or a wired connection to the LM-EA7-ish adapter. Prime candidates would be Minolta MC/MD and Canon FL/FD/FDn lenses, which all have mechanical aperture couplers that wouldn't be difficult to read: that's how they worked with the bodies they were designed for. Mounting an aperture-control motor in the M adapter is also a possibility, but there's not much space for it and it might draw too much power from the Sony E body.
  • Replace the wireless programming interface with a standard USB connection. It's less sexy, but more reliable and offers the ability to power the unit via USB while configuring.
  • Make the adapter a bit larger to accommodate all the above.

The biggest problems are (1) that there is a limited market for adapting old lenses and (2) none of the body/lens communication protocols are open -- they must be reverse engineered and hence could break at any time if the manufacturer decides to change or add new features to the protocol.

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Rol Lei Nut Veteran Member • Posts: 5,331
Re: Thoughts about a smart FD adapter

SQLGuy wrote:

Rol Lei Nut wrote:

What I would like is an EXIF settable adapter, mainly for setting the camera's IBIS. A Leica M=>FE adaper (so other mounts could be adapted down to M) with a dial for quickly setting the FL. Conceptually not so different from the Techart Pro, but smaller, lighter and with the FL which could be changed in in a instant.

Why a dial instead of reading the 6-bit?

So all kinds of lenses can be adapted to it.

I already have many X=>Leica M adapters, which I use with the Techart Pro.

For example, I could take multiple lenses in Leica R, Rollei or CY mount with me and quickly set the FL, without having to have a coded X=>Leica M adapter for every single lens.

Though I get your argument that coding would make setting the FL fully automatic. My logic is that each X=>Leica M adapter weighs around 75 grams and I'd like to share them between lenses, when possible.

How about a model which can read code (if present) andhas a FL setting dial as well?

Seriously, I'd buy one.

E Dinkla Senior Member • Posts: 2,245
Re: My adapter+app proposal

Waiting for the third party Sony FE chips to glue to my lenses converted to FE mount;

https://www.dyxum.com/dforum/emount-electronic-protocol-reverse-engineering_topic119522_page1.html

Till then the lenses adapted/converted to EF mount and used on the MC-11 adapter + Sony camera have an EMF chip for the same function;

https://www.ebay.com/itm/Pixco-EMF-AF-Confirm-chip-for-Canon-EOS-EF-camera-7DII-5DIII-5DII-5D-7D-100D-40D-/142599309474

They do nothing to set the lens aperture but enough for the IBIS setting and I know which lens I used from the Exif report. Aperture priority mode + Auto ISO + 1/125 up to 135mm focal lengths is enough. Less light and faster lenses let me select a slower shutter speed for that occasion only.

Some native EF and FE lenses for more action and faster changing conditions.

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E Dinkla Senior Member • Posts: 2,245
Re: Thoughts about a smart FD adapter

There are good reasons in this digital photography era to add the aperture preset mechanism to new and old manual lenses.

https://www.dpreview.com/forums/thread/4188321

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Heritage Cameras
Heritage Cameras Senior Member • Posts: 1,765
Re: Smart adapters

ProfHankD wrote:

  • Make smart adapters to M mount that can read and/or control lens aperture with a pass through the LM-EA7-ish adapter. The pass through could be as simple as reading analog resistance, detecting aperture position using a Hall sensor, or a wired connection to the LM-EA7-ish adapter. Prime candidates would be Minolta MC/MD and Canon FL/FD/FDn lenses, which all have mechanical aperture couplers that wouldn't be difficult to read: that's how they worked with the bodies they were designed for.

Canon FD and FDn lenses certainly provide the information required to read (or, more accurately, deduce) the actual aperture set. So do Contax Yashica AE/MM, Fujica X (most), Miranda EC, Nikkor AI/AIS, Rollei/Voigtlander QBM IV and probably others. These have mechanical couplers that transmit the lens's maximum aperture and the deviation actually set. FD and AIS lenses can even provide a ballpark focal length (granularity unknown for Canon's "reserved pin", short/long only for Nikon).

Unfortunately Minolta MD, Pentax KA and Ricoh XR-P lenses only supply this information when the aperture is set to its smallest setting (Minolta) or A/P (Pentax/Ricoh). These (and others where the maximum aperture is unavailable such as Canon FL, Minolta MC, Olympus OM, Pentax K, Praktica B, Rollei/Voigtlander QBM II/III, etc.) would work if the maximum aperture could be set on the adapter. This approach has been used before in the Minolta MC-V1 adapter for MAF lenses on Vectis APS cameras. Konica AR lenses provide the maximum aperture, but no information on what manual aperture is set – only whether it's on EE/AE or not. It might be possible to fake this using the A/M tab, however. Most other manual SLR mounts work like one or other of these types.

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Suave Senior Member • Posts: 2,216
Re: Thoughts about a smart FD adapter

It would be useful to have an adapter that can report the aperture back to the camera, but that's about it.

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SQLGuy
OP SQLGuy Forum Pro • Posts: 10,390
Re: Thoughts about a smart FD adapter

Suave wrote:

It would be useful to have an adapter that can report the aperture back to the camera, but that's about it.

Really? Knowing and setting the focal length for EXIF and IBIS isn't helpful?

Well... I didn't think this project would have that much appeal anyway. I would have thought focal length would be more useful than aperture, though.

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SQLGuy
OP SQLGuy Forum Pro • Posts: 10,390
Re: Thoughts about a smart FD adapter

Alan WF wrote:

I don’t think the real problem with this manual mechanism is difficulty in mounting. Just twist one way to make sure the lever is engaged and then twist the other to mount the lens. It becomes natural after a couple of days. I think the real problem is that they often open up the aperture when you don’t mean to; that’s why I fix mine closed with epoxy

With FD lenses? The only adapter I've heard of that works that way is the Ciecio7. With others, if mounting a new FD lens, or an old FD lens that's not locked down, the aperture lever will end up on the wrong side of the adapter's actuation pin if the lens is mounted while the adapter is in "closed" position. If the lens is unmounted while the adapter is in the closed position, you can hear and feel the aperture lever snap back as it comes off of the adapter's pin.

You want communication of the focal length, communication of the aperture, and control of the stop-down lever, in order of increasing difficulty. There’s no law against dreaming.

I don't think it's dreaming. I've built things like a PSoC 5 based unit to allow memory expansion and SD card read/write for a Sharp PC-1500. This is by emulating memory so the PSoC MCU can make its data appear in the memory space of the LH5801 and can also "read" data from the LH5801 bus.

I also converted my 1982 Yamaha Seca 750 to multi-point fuel injection using junk yard parts and fabricating my own fuel rail and intake manifold. I did use an off-the-shelf ECU for that (Microsquirt), but had to replace their VR conditioner, as they had problems with the initial batch of these (I bought one of the first 10). I made my own 36-1 crank position wheel, for that, too, and adapted coils from a Saturn SC.

I'm quite good at soldering, including surface mount, and have a lot of electronics experience, including having worked for a while at a Sony authorized service center where I repaired everything from monitors (flat panel and the old tube types) to camcorders.

For something like this, a PSoC 3 BLE device would be my choice, because I'm familiar with Cypress' tools, and it would be more than capable. The PSoC devices include on-chip PAL type circuitry, so you can program digital logic into it (TTL/CMOS type gates) without having to add other devices to the solution. For my PC-1500 project, all of the address decoding and chip enables for the RAM expansion is done using this on-chip logic. A PSoC 3 has built-in UART capabilities that can interface with the E mount serial connection, and can easily read a potentiometer for aperture lever position and an array of phototransistors for 6-bit-ish coding. I don't know off-hand if it could directly drive a stepper motor, but it could easily drive a stepper motor driver IC.

There is a decent amount of information about the E mount protocol here: http://camera-wiki.org/wiki/Sony_E_mount_reverse_engineer

Regards,

Alan

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Suave Senior Member • Posts: 2,216
Re: Thoughts about a smart FD adapter

SQLGuy wrote:

I would have thought focal length would be more useful than aperture, though.

I'd like to see set aperture because with modern EVFs in aperture priority the picture you see at f/2 will be the same as at f/22, and it would have been convenient to see the setting without turning the camera over.  All that other stuff I do not have much use for.

I totally agree though that the manufacturers should have menus for registering manual lenses, like Nikon DSLRs do.

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SQLGuy
OP SQLGuy Forum Pro • Posts: 10,390
Re: Thoughts about a smart FD adapter
2

Suave wrote:

SQLGuy wrote:

I would have thought focal length would be more useful than aperture, though.

I'd like to see set aperture because with modern EVFs in aperture priority the picture you see at f/2 will be the same as at f/22, and it would have been convenient to see the setting without turning the camera over. All that other stuff I do not have much use for.

I totally agree though that the manufacturers should have menus for registering manual lenses, like Nikon DSLRs do.

What camera are you using?

On the A7 series, it's quite obvious what the DOF is when you're composing and in the shot. They're full frame cameras, so F2.0 is F2.0, and quite clearly shallow.

I'd like to know in EXIF what aperture was used, but I wouldn't have any difficulty telling the difference between wide open and completely stopped down.

Remembering to switch IBIS focal length, though, is a common problem for me.

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