Cambo Actus + Canon EF Lenses (TS to be precise)

[Kuky]

Hello all,

I am just testing a Cambo Ultima 35 which is for sale. I plan to upgrade it to an Actus-XL and also motorise the rear standard with the Stackshot kit.
My back camera is a Sony A7 RIV. I also have the Canon 90 and 24 TS lenses and my plan was to use them on the Actus, after buying the Canon front lensplate.

But to my biggest surprise Cambo says in one of the docs - https://www.cambousa.com/wp-content/uploads/2019/09/Cambo-Actus-lens-compatibility-table-2019-V1-1.pdf

that Canon EF lenses are not compatible when you have a Sony E mount on the back. I really don't understand why???

I remember reading here -- https://captureintegration.com/seeing-sideways-with-the-cambo-actus/ that one of the solution for using wide angle lenses on Actus was the Canon EF - TS lenses.

What am I missing here?

Regards,
Cristian

 

[Shashin]

It is simple. The flange distance between the Sony and Canon systems is not enough to allow the Actus front and rear standards to have enough space for infinity focus. However, digital backs have a smaller flange distance than the Sony E-mount and so allows this. The Sony E-mount is 20mm.

 

[Audii-Dudii]

It is simple. The flange distance between the Sony and Canon systems is not enough to allow the Actus front and rear standards to have enough space for infinity focus. However, digital backs have a smaller flange distance than the Sony E-mount and so allows this. The Sony E-mount is 20mm.

Alternatively, one might argue this problem arises from the fact that the smart Actus lens panel for Canon EF lenses is ~12.15 mm deep (as measured from the lens mounting surface to the top of the plastic bump on the back that houses the electrical contacts) whereas the dumb Actus lens panel for Cactus EF lenses is ~7.25 mm deep, a difference of ~4.9 mm. (FYI, in addition to those two lens panels, I also have a custom Canon EF lens panel made from a Copal No. 1 mount lens panel and it measures just 4.50 mm deep from the surface of the lens mount.)

To compensate for the additional thickness of the smart lens panel so the lens still will focus at infinity, it's necessary to push the standards closer together by ~4.9 mm and there simply isn't enough room to do so, hence Cambo's warning.

BTW, there's a similar issue with the Nikon F&G-mount lens panel with the built-in mechanical aperture control device, as it's deeper than the original Nikon F&G panel without any aperture control. Which is why I use a custom Nikon F&G lens panel that consists of a Fotodiox Canon EF to Nikon F&G lens mount adapter with a mechanical aperture control that I screwed onto another Copal No. 1 lens panel -- Yes, I probably have too many Actus lens panels on hand ... lol -- which is a total of ~5.8 mm deep as measured from the surface of the lens mount and this works out to 1.5 mm less than the gen-u-ine Actus lens panel at ~7.3 mm.

Anyway, I have sympathy for you, as I had similarly hoped I would be able to use my Actus smart adapter with my A7R and a Contax N 17-35/f2.8 lens that was converted to a Canon EF mount by Conurus, but no such luck. Worse, I don't recall Cambo having ssued any warnings about this conflict at that point in time, so I had no way of knowing about it before I bought mine and discovered it for myself.

As an aside, I have tried a couple different approaches to making the electronic aperture of that lens work on my various FrankenKameras, including my Actus, ultimately with no luck. The latest one had me disassemble a Kipon Sony to Contax N smart adapter and remove its guts from its body, in turn connecting them to my A7R body and Contax N lenses with the guts outside the adapter (which was necessary because I planned to use the lens with movements) and had it working on my kitchen counter.

Alas, I wasn't to get this setup working when I tried to install it on my cameras because the circuit board inside the modified Contax N macro tube I was using as a lens mount was so flimsy that it warped and completely fell apart after I removed the original wires and tried to replace them with the wires from the Kipon adapter. <sigh>

P.S.: The FFD for the Sony E-mount is 18 mm, not 20 mm.

 

[Shashin]

Alternatively, one might argue this problem arises from the fact that the smart Actus lens panel for Canon EF lenses is ~12.15 mm deep ...

Didn't I just say that? The lens panel is the front standard. Hence you cannot bring the lens and camera close enough to reach infinity focus. Basically, the difference between the lens to camera flange distance is too great.

 

[Kuky]

Thank you for your answers!

1. I was aware of the flange distance problem but in my mind I still have different calculation

Canon EF-mount = 44 mm
Sony E-mount = 18 mm
Hence we need 26 mm between the metal ring on the Sony mirrorless camera and the rear of the Canon EF lens.

Dumb Actus Canon EF Lens panel (ACB-CM) = 7.25 mm (as measured by Audii-Dudii)
Back mount holder thickness = 11 mm (I assumed that from this link which describes a similar problem -- https://www.laszlopusztai.net/2017/04/17/choosing-lenses-for-the-actus-g/

So both panels together have around 18mm, well below the 26 mm needed. I still don't understand. Maybe the metal rings on the bellow add so much thickness?

2. What drives me crazy is the following link from the official Cambo website -- https://www.cambo.com/en/news/cambo-actus-canon-eos-lens-adapter/
Quote from that link:
"This ACB-CA lens adapter is designed to work with most mirrorless camera bodies, such as the Sony A7 series, Fujifilm X series and Canon M series. Mounted on the Actus it allows for tilt, swing and shifts with any mounted Canon lens, be it within the limitations of the used lens' image circle."

Now I am not a native english speaker but that quote suggested me it should work even with the thicker smart Canon adapter.

3. How was mr. Steve Hendrix been able to do this -- https://captureintegration.com/seeing-sideways-with-the-cambo-actus/

Quote from that link:
"Challenge #1 is that thicker camera bodies prevent wider lenses from focusing because the built-in flange distance requires a greater buffer between the optic and the imaging plane. If you mount a Canon 35mm/1.4 lens to the front of a Cambo Actus with a Canon 5DS mounted to the back, the grand total of your focus will be about 3/4″ in front of the lens. It becomes the weirdest, most limited macro lens in history.
Yet with that same stingy lens, if you swap the Canon 5DS for the Sony A7R-II, you can focus to infinity. Just the (approximately) 25mm difference in camera depth results in an attainable focus of either 3/4″ or infinity. Amazing. That is why mirrorless cameras are the ideal snugglers for any wide angle photography with the Cambo Actus – the flange distance requirements are a limiting factor, depending on the camera body being used."

At the end he recommends Canon EF-TS lenses as an option for wide angle. But according to Cambo they should not work on the majority of the cameras.

4. First image on this link shows a Canon EF lens mounted with a Sony E back. -- https://captureintegration.com/first-look-cambo-actus-ef-aperture-controller-for-canon/

5. Someone using exactly this combination Sony A7R + Canon 16-35 + Actus -- https://www.fredmiranda.com/forum/topic/1412676/0#13412640

6. I didn't plan to buy the smart Canon lens plate. For me it's too expensive for what it does. There are much cost effective solutions even if you have a Sony back (Sigma MC-11 - 250 USD which I already have) to change the aperture on Canon EF lenses.

Regards,
Cristian

 

[Audii-Dudii]

Didn't I just say that? The lens panel is the front standard. Hence you cannot bring the lens and camera close enough to reach infinity focus. Basically, the difference between the lens to camera flange distance is too great.

I apologize if I unintentionally stepped on your toes with my comment -- it was not my intention, I promise! -- but strictly speaking, you blamed the Sony to Canon flange distance being too short, not the Actus smart lens panel being too deep, which is what I pointed out.

The Sony-Canon flange distance differential (18-44=26 mm) is obviously the same for both the smart and dumb Actus lens panels, one of which does, in fact, allow Canon lenses to focus at infinity, so that factor by itself cannot be the cause of this problem.

It's only because the smart lens panel is ~4.9 mm deeper than the dumb lens panel (hence the need for more space between the front and rear standards than exists, as you correctly pointed out) that it doesn't allow Canon lenses to focus at infinity when used with Sony bodies.

As I read your comment, you dismissed this conflict as simply being "the nature of the beast," so to speak, whereas my comment pointed a finger at Cambo for a lens panel design that is severely compromised and to my knowledge, at least initially sold without any warnings about the existence of this issue.

And if you sense I was / am somewhat annoyed by this, then you are correct. Unfortunately, I bought mine used, so had no ability to return it after I discovered it wouldn't work for my purposes. As it happened, this was also the reason the person I bought mine from was selling it shortly after he bought it, because he wasn't aware of this fundamental incompatibility issue, either.

Caveat emptor, I know, but still ... grrr.)

 

[Kuky]

@Audii-Dudii

So are you saying that the dumb lensplate (ACB-CM) works? And the smart lensplate (ACB-CA) doesn't work because it's 5 mm thicker?
Cambo advertise the ACB-CA to be working with Sony A7 backs. This is so confusing for me.

You don't need the smart lensplate to change aperture on Canon lenses. Unless you're doing field work and change aperture several times per hour then it might have a value.

See my previous comment.
Regards,
Cristian

 

[Kuky]

More confusion. Cambo USA says Canon EF lenses are not compatible with Sony E mount backs on Actus.
But their biggest dealer describes how it works -- https://captureintegration.com/first-look-cambo-actus-ef-aperture-controller-for-canon/
Even with the thicker smart lensplate. They seem to say though that you should use the wide angle bellows.


@Audii-Dudii
Did you try with the wide angle bellows? They say is essential for reaching infinity focus.

 

[Audii-Dudii]

So both panels together have around 18mm, well below the 26 mm needed. I still don't understand. Maybe the metal rings on the bellow add so much thickness?

You didn't include any allowance for the thickness of the compressed bellows, which I just measured at ~8.5 mm between the metal mounting rings.

Now, in all fairness, a portion of the lens panel and camera mounting bracket thicknesses do end up inside the bellows, so just adding all these numbers together will double-count a portion them to some extent.

So to sidestep this, I just now measured the depth of my Actus camera mounting bracket, compressed bellows (as pushed firmly against my kitchen counter) and smart Actus lens panel, and I arrived at a total thickness of 23.8 mm.

In theory, this should just barely allow the lens to focus at infinity, but in reality, it's impossible to compress the bellows as fully as I did with it off the camera when it's mounted on the camera and the pressure to compress it is applied via the focusing knob and focusing rail, so this measurement will increase somewhat when the bellows is relaxed.

But as a practical matter, with the bellows compressed to this extent, zero movements are possible -- no rise/fall/shift nor tilt or swing! -- which sort of makes a camera whose raison d'être is its ability to provide movements rather pointless, eh?

2. What drives me crazy is the following link from the official Cambo website -- https://www.cambo.com/en/news/cambo-actus-canon-eos-lens-adapter/
Quote from that link:
"This ACB-CA lens adapter is designed to work with most mirrorless camera bodies, such as the Sony A7 series, Fujifilm X series and Canon M series. Mounted on the Actus it allows for tilt, swing and shifts with any mounted Canon lens, be it within the limitations of the used lens' image circle."

Now I am not a native english speaker but that quote suggested me it should work even with the thicker smart Canon adapter.

There's also this disclaimer: "The practical use of lenses may be limited to those that can move freely in front of the bayonet of the used camera body, due to the recessed position of the chip in certain bodies."

Which I read as "the only movements available with some lenses focused at infinity will be those that are designed into the lens, because the Actus itself will be bound up so tightly that none of its movements can be used."

3. How was mr. Steve Hendrix been able to do this -- https://captureintegration.com/seeing-sideways-with-the-cambo-actus/

Quote from that link:
"Challenge #1 is that thicker camera bodies prevent wider lenses from focusing because the built-in flange distance requires a greater buffer between the optic and the imaging plane. If you mount a Canon 35mm/1.4 lens to the front of a Cambo Actus with a Canon 5DS mounted to the back, the grand total of your focus will be about 3/4″ in front of the lens. It becomes the weirdest, most limited macro lens in history.
Yet with that same stingy lens, if you swap the Canon 5DS for the Sony A7R-II, you can focus to infinity. Just the (approximately) 25mm difference in camera depth results in an attainable focus of either 3/4″ or infinity. Amazing. That is why mirrorless cameras are the ideal snugglers for any wide angle photography with the Cambo Actus – the flange distance requirements are a limiting factor, depending on the camera body being used."

At the end he recommends Canon EF-TS lenses as an option for wide angle. But according to Cambo they should not work on the majority of the cameras.

He was using the dumb adapter, not the smart adapter. The ~5 mm difference in depth between them makes all the difference!

4. First image on this link shows a Canon EF lens mounted with a Sony E back. -- https://captureintegration.com/first-look-cambo-actus-ef-aperture-controller-for-canon/

5. Someone using exactly this combination Sony A7R + Canon 16-35 + Actus -- https://www.fredmiranda.com/forum/topic/1412676/0#13412640

Again, I have no problem using Canon lenses with my A7R on my Actus provided I use the dumb adapter or my custom-made one. And as coincidence would have it, I bought my Actus from cdavis324, along with the custom lens panel made by S.K. Grimes he mentioned.

And just to clarify, no camera is perfect, especially not the Actus. But for what it is and does, it's a very useful tool for many photographers and my grumblings aside (both in this and other threads) I've enjoyed using and have recommended it to several other photographers, who all seem quite happy with their Actuses (Actii?).

It's just frustrating at times when its quirks and shortcomings -- Yes, it has several of both! -- make their existence known and interfere with my photographic process, that's all. <shrug>

Which is why I've created several "FrankenKameras" over the past few years in an effort to come up with a better solution for me and my purposes. And while it's still under construction as I write this, I think I may have finally turned the corner with my many DIY solutions, as my latest effort is on track to weigh right at 1.5 lbs (with both a lens board and camera mount!) and will be both rigid and precise enough that it won't -- can't, even! -- drift out of alignment the way many Actuses do, resulting in various tilts and swings being applied unintentionally and photos being ruined accordingly.

But I digress and this really isn't the place for such a discussion in any event...

 

[Audii-Dudii]

More confusion. Cambo USA says Canon EF lenses are not compatible with Sony E mount backs on Actus.
But their biggest dealer describes how it works -- https://captureintegration.com/first-look-cambo-actus-ef-aperture-controller-for-canon/
Even with the thicker smart lensplate. They seem to say though that you should use the wide angle bellows.


@Audii-Dudii
Did you try with the wide angle bellows? They say is essential for reaching infinity focus.

No, I haven't tried it, but I wouldn't be at all surprised if it solves the problem or at least substantially ameliorates it. Perhaps I should have bought one -- and if it does solve the problem, then it's probably unfair of me to criticize Cambo about this issue (but if that's the case, then why don't they sell the two together?) -- but I decided long ago the Actus was only going to be temporary solution while I worked on a camera of my own design that would be a better fit for my personal preferences and needs, and I didn't want to spend / waste the money for it.

Needless to say, I never imagined that several years would pass and I'd still be using my Actus, but that's the way things work out sometimes, eh? <blushes>

FYI, I don't have any Canon lenses on hand at the moment, so I can't actually refresh my memory about using them, but I do have the three Actus lens panels I've mentioned -- the smart and dumb ones Cambo sells, plus a custom-made one that came with my camera when I bought it used -- and the only time I recall ever having issues focusing at infinity was when using the smart adapter.

 

[Kuky]

@Audii-Dudii

Thank you very very much for your thorough explanations!!!
Now I am relieved, as you confirm the dumb adapter works. This is consistent with the many links I found and posted on this thread.

As a matter of fact I don't care too much if the movements will be somewhat restricted as the main reason to invest in this camera was to use focus stacking with rear standard only (motorised via Stackshot). This is the kind of work I do -- https://goo.gl/photos/NSt7XfxudP55ajKR7 (actually as a hobby) and I intend to do more complicated stuff, ie focus stacking with wide angle lenses. In this case if you focus stack moving the whole camera, because being close to subject (1:87 scale locomotives) and using wide angle the movement creates perspective distortion which are insurmountable for any focus stacking software or any amount of retouching. So the solution is to keep the lens fixed and move the rear standard only.

Regarding the smart adapter it is elegant but I find the price to be outrageous regarding it's value. Ofc if you buy second hand that may be a different story. I see it of being of a somewhat value if you do much field work and like to change aperture a lot. In my case I change the aperture very rarely.

The link posted previously seems to imply that is mandatory to use the wide angle bellows in combination with the smart adapter in order to reach infinity focus and benefit for some movements. I am just curious, did you try this?? It makes sense for you to invest in the wide angle bellows if you already burned some cash for the smart adapter.
Later edit: nevermind I see you already answered )

TL DR the whole thread
So in the end the literature from the Cambo USA site is wrong in the case of Canon EF lenses not being compatible with Sony E mount mirrorless.

 

[Kuky]

Went to the Cambo dealer today.
front lensplate + wide angle bellows + bayonet holder = 18mm
So it should work.

 

[rdeloe]

As a matter of fact I don't care too much if the movements will be somewhat restricted as the main reason to invest in this camera was to use focus stacking with rear standard only (motorised via Stackshot).

Before you dive in, I suggest you investigate whether or not focusing the Canon 24mm TS-E lens by the rear standard will work. It will "work" in the sense that you will be able to focus it... but will you be happy with the results?

I mention this because that's what I wanted to do with a wide angle lens I'm using (SMC Pentax-A 35mm f/3.5). That lens uses floating elements that become engaged when I focus on anything closer than approximately 1 metre. They are not engaged when I focus by rail (because the lens is set to infinity when I'm doing that). As a result, the corners are soft compared to how they are when I focus using the lens.

I have no experience with the Canon lens, so my concern may not apply.

 

[Kuky]

Before you dive in, I suggest you investigate whether or not focusing the Canon 24mm TS-E lens by the rear standard will work. It will "work" in the sense that you will be able to focus it... but will you be happy with the results?

I mention this because that's what I wanted to do with a wide angle lens I'm using (SMC Pentax-A 35mm f/3.5). That lens uses floating elements that become engaged when I focus on anything closer than approximately 1 metre. They are not engaged when I focus by rail (because the lens is set to infinity when I'm doing that). As a result, the corners are soft compared to how they are when I focus using the lens.

I have no experience with the Canon lens, so my concern may not apply.

Interesting, I was planning to get exactly that Pentax lens. What happens if you focus the Pentax with the ring on the lens?
I have no idea if Canon 24 TS-E has a floating element.

 

[rdeloe]

Interesting, I was planning to get exactly that Pentax lens. What happens if you focus the Pentax with the ring on the lens?
I have no idea if Canon 24 TS-E has a floating element.

When you focus with the ring on the lens, it's superb especially for the money. Apparently the D FA version is better, but it also costs 3-5 times as much. I'm using the SMC Pentax-A 35mm f/3.5 with a Fuji GFX 50R and cannot complain about the results. I get about 8mm of good quality shift with that outfit. However, to get the best image quality in the corners when I'm not tilting, I have to put it at the flange focal distance it was designed for, and then focus with the ring on the lens. (Central image quality is the same regardless of whether or not I focus by rail or by lens ring; the floating elements seem only to help in the corners.)

Where things go weird is tilt. For a typical scene where I'm looking to tilt the plane of focus to maximize the in-focus area in the picture, I start by positioning the lens the distance from the sensor that it would be on a Pentax 645 camera. My camera uses base tilt and I use the "focus far, tilt near" approach. Before too long, I find myself at infinity on the lens, and then in order to get everything in focus, I have to start moving the sensor back using the rail. Paradoxically, the near corners are still good even though I am definitely not using the floating elements because the lens is at infinity on the ring. I can't explain why this works, but it does -- reliably.

I get the same behaviour with my Pentax 67 45mm lens, which is not quite as sharp as the P645 35mm, but still excellent. It also has floating elements and behaves exactly the same.

 

[Kuky]

Ok, so assuming I have subject close to Pentax 35mm lens, lets say 40cm. I put the lensplate at flange focal distance for Pentax 645 mount (70.87 mm) then I focus with with the ring on the lens to a point on the nearest point on the subject. Image quality should be the best possible. Then I begin to shoot the focus stacking by moving the rear standard only. Are you saying that the quality will degrade?

 

[rdeloe]

Ok, so assuming I have subject close to Pentax 35mm lens, lets say 40cm. I put the lensplate at flange focal distance for Pentax 645 mount (70.87 mm) then I focus with with the ring on the lens to a point on the nearest point on the subject. Image quality should be the best possible. Then I begin to shoot the focus stacking by moving the rear standard only. Are you saying that the quality will degrade?

That I don't know empirically (meaning I haven't tried it myself). However, I'm happy to speculate!

The floating elements are clearly designed to be in a specific place for a specific distance. So in theory, when you move the sensor further back, you're messing with that relationship. However, I think you'd still be OK (maybe). I try my best to position the lens the correct distance from the sensor, but there's no way I'm getting it to exactly 70.87mm from the sensor. It's impossible except by chance. And yet I've not noticed any ill effects from being a bit off. Furthermore, as far as I can tell, some use of the floating elements if vastly better than none. Thus, if you managed to get the lens at exactly the right FFD, focused perfectly at 40cm, and then started moving the sensor back in tiny increments, you might have to move it a long way before image quality degrades noticeably. Remember too that the image quality will fall apart in the corners, not the centre.

How important is this to you? It's not a huge deal for me to set something up at 40cm and fire off a bunch of shots.

 

[rdeloe]

OK, @Kuky, I couldn't resist.

Click here to download 6 files. https://drive.google.com/open?id=1sykdFsQCMrEAN_Gupbk3gmlBngNY1mzR

These are full resolution 100% JPEG images exported from Lightroom. They were shot using the SMC Pentax-A 35mm f/3.5 lens, my Toyo VX23D and a Fuji GFX 50R. The Toyo is a rail-focusing camera. The lens was set to what I judge to be flange focal distance from the sensor. As noted above, I could easily be off by a mm in either direction, or more. (I don't think it matters though.)

The six files make two sets:
* The ones labelled 'Focus by lens' are all focused by lens. There's one "top" shot (focus on the number 44 in the CM scale in the ruler), and two "bottom" shots (focused on "U.S.A." at the bottom of the ruler).
* The ones labelled 'Focus by rail' are focused as follows: the "top" shots are set up the same as the 'by lens' version; I provided them as a baseline. The "bottom" shots are focused by rail after setting the focus by lens on "44". They're also focused on "U.S.A." on the ruler, but using the rear standard focus mechanism.

There are two bottom shots in each set because I wanted to double-check that what I was seeing wasn't simply focus differences.

The ones to compare are all the bottom pictures. When I put them side-by-side, this is what I see:
* The central part of the image (the ruler at bottom) looks about identical in all the bottom shots. Any differences are likely due to minor differences in focusing. This shows that the floating elements are not doing their work in this part of the image.
* The extreme corners of the 'by lens' version are clearly better than the 'by rail' version -- but only right in the extreme corners. Here's where the floating elements hit their stride.
* Move out of the corners a bit, in the areas still in focus, and you can see that the impact of the floating elements is greatly reduced; they seem more comparable.

So, I think you'd be OK doing what you want to do, if you're willing to live with reduced image quality in the very extreme bottom corner of the images. BUT I don't know how this manifests as you get closer. Maybe the impact of the floating elements is stronger. The lens will focus closer -- lots closer once it's on a rail. But is this really the best choice for extremely close focusing?

Hope this helps.

 

[Kuky]

Thank you very much for taking the time to test it! Quite interesting results.
There is a clear difference in the corner. I may get away with it in most of the cases, as I shoot 35mm (Sony A7RIV). Also it is possible if subject is closer that this problem gets bigger.
Well I will invest the money and see what I get. This Pentax lenses are quite cheap, I think the lensplate from Cambo it's more expensive (!) than the 35mm.

Thank you again for the test.

 

[rdeloe]

Thank you very much for taking the time to test it! Quite interesting results.
There is a clear difference in the corner. I may get away with it in most of the cases, as I shoot 35mm (Sony A7RIV). Also it is possible if subject is closer that this problem gets bigger.
Well I will invest the money and see what I get. This Pentax lenses are quite cheap, I think the lensplate from Cambo it's more expensive (!) than the 35mm.

Thank you again for the test.

My pleasure, and good luck with this. You're quite right that the Pentax 645 lenses are (mostly) inexpensive.