The GetDPI Photography Forum

Great to see you here. Join our insightful photographic forum today and start tapping into a huge wealth of photographic knowledge. Completing our simple registration process will allow you to gain access to exclusive content, add your own topics and posts, share your work and connect with other members through your own private inbox! And don’t forget to say hi!

Anyone using Cambo Actus Mini

JeffK

Well-known member
I don't know if Rich hangs out here, but he uses one of these with Sony A7... cameras. He posts over at DPReview and FredMiranda. Just today we were exchanging some thoughts about his new Laowa 20mm that he's using on his Cambo Actus setup. https://www.fredmiranda.com/forum/topic/1774231/2#16074627
I'm trying to see if anyone has used the a Copal 1 lens with a large flange on the Actus Mini. The Rody 180 I mention in another thread has a large flange, seemingly larger than is meant for the Actus Mini. I don't know enough about lens design to understand how that would make an impact?
 

rdeloe

Well-known member
Cambo sells the ACB-1 Lensplate for Copal 1. Presumably that means you can put a Copal 1 shutter on the board, and therefore on the Actus. The rear cell of the HR Digaron-S 180/5.6 seems large, but not enormously large.

I get the sense I'm missing something here Jeff. What do you mean by it has a "large flange, seemingly larger than is meant for the Actus Mini"? Are you talking about the flange focus distance of the lens, or the actual diameter of the lens flange, which mates to the ACB-1?
 

JeffK

Well-known member
Cambo sells the ACB-1 Lensplate for Copal 1. Presumably that means you can put a Copal 1 shutter on the board, and therefore on the Actus. The rear cell of the HR Digaron-S 180/5.6 seems large, but not enormously large.

I get the sense I'm missing something here Jeff. What do you mean by it has a "large flange, seemingly larger than is meant for the Actus Mini"? Are you talking about the flange focus distance of the lens, or the actual diameter of the lens flange, which mates to the ACB-1?
I did some more research. I confused flange with image circle. Actus mini recommends a flange no bigger that 70mm. Found a note on B&H that's is only 60mm for the 180mm. So now I just need to put an offer on the 180 and get a Cambo Actus mount for Copal 1.
 

rdeloe

Well-known member
I did some more research. I confused flange with image circle. Actus mini recommends a flange no bigger that 70mm. Found a note on B&H that's is only 60mm for the 180mm. So now I just need to put an offer on the 180 and get a Cambo Actus mount for Copal 1.
Ah, that makes sense.

I know that Jim Kasson over at DPReview Medium format has one of those 180s and says it's one of the best lenses he owns. He also owns a Coastal Optics lens, so his bar is very high. Good luck grabbing one.
 

TimoK

Active member
I'm using Actus mini with Sony 7RIV. I'm also using 180 mm Rody Sironar-S (an older analog lens - very good) with it. I made my own DIY mounting for it. If you are going to use Cambo standard parts, at least you'll need longer bellows for Actus.

I did some more research. I confused flange with image circle. Actus mini recommends a flange no bigger that 70mm. Found a note on B&H that's is only 60mm for the 180mm. So now I just need to put an offer on the 180 and get a Cambo Actus mount for Copal 1.
I don't understand this. Maybe you should download Lenses for digital photography pdf from https://www.rodenstock-photo.com/service#download_center . Look drawing at page 5. Lenses flange focal distance ( d ) is measured from the lens plate to the sensor.
In 180 mm Digaron it is ~178 mm when focused at infinity and longer when focused closer. The length of Cambo Actus from lens plate to sensor is about 148 mm. Not enough.
You can add 45mm to this by turning swing 180 degrees. Now you have ~193 mm flange. It is long enough to focus 180mm lens from infinity to 2,5 meters or a little closer ( it's hard to measure with my equipment). But the standard bellows isn't long enough. You'll need this or AC-215.
 

vjbelle

Well-known member
'MINI' could be used for any Actus series that utilizes the short rail. All of the front and rear standards utilize the same positions when attached to the rails. The current production Rody 180mm lens cannot be used with the short rail as posted above - at least with a GFX or Sony 7RM4. I have never adjusted the front swing 180 degrees but that would add the needed distance to reach FFD. As also posted above the short bellows is 'too' short for longer lenses and longer would be needed and are available.

I have two complete Actus systems and have been using them for the last 6 years with various DB and mirrorless cameras with great success.

Victor B.
 

TimoK

Active member
The current production Rody 180mm lens cannot be used with the short rail as posted above - at least with a GFX or Sony 7RM4. I have never adjusted the front swing 180 degrees but that would add the needed distance to reach FFD.

Victor B.
The 180 degrees swing would add the needed distance to reach FFD and it really does! I know. According to the manual of Actus it adds 45 mm. And so did I also measure.

Btw. FFD of current Rody 180 mm and the old one are almost the same 178 mm. Look at pdf I linked.

Trading both the bellows and the rail to longer ones is very recommended. https://www.cambo.com/en/actus-series/actus-b-mini-view-camera/ac-330/
 

vjbelle

Well-known member
Anyone considering the Actus (or any bellows system) should be aware that the front and rear standards must be parallel to each other IF the intended goal is focus accuracy across the frame. Engraved numbers should not be relied upon unless proven to be reliable. The accuracy needed is in the 1000th of a degree range and a cavalier approach will result in inferior images. Live view at 100% pixels is an invaluable aid in the field for checking parallelism. I have developed a quick in the field check for parallelism that has proven to be repeatably accurate.

The benefit of the Cambo Actus series is that it is truly portable and easily transported.

Victor B.
 

asnapper

New member
I have an Actus Mini, which I use with a Sony A7rIII & a variety of lenses, Digitars, Canon T/S & Pentax 645 & 67. The longest digitar I have is a 120 but its in a Copal 0. I swing the front standard 180deg when using this lens, so that the focus scale is set to infinity. I see no reason why a 180 Rody wouldn't focus at infinity if you swung the front standard, though I believe you can get a longer rail & you may also need the long bellows. If you want to be 100% sure you could always email Cambo
 

rdeloe

Well-known member
Anyone considering the Actus (or any bellows system) should be aware that the front and rear standards must be parallel to each other IF the intended goal is focus accuracy across the frame. Engraved numbers should not be relied upon unless proven to be reliable. The accuracy needed is in the 1000th of a degree range and a cavalier approach will result in inferior images. Live view at 100% pixels is an invaluable aid in the field for checking parallelism. I have developed a quick in the field check for parallelism that has proven to be repeatably accurate.

The benefit of the Cambo Actus series is that it is truly portable and easily transported.

Victor B.
I enthusiastically echo Victor's point. In fact, I would say that you can't rely on the labelled indicators, and you might not be able to rely on the detent if one exists. Sometimes the detent is not accurately located, and sometimes it's worn from use so there's a bit of play. This makes it very important to check for parallelism. These kinds of cameras should all be user adjustable, but not all are.

Edit: After posting I thought of a couple friendly amendments I wanted to add. First, closing down the aperture can cover up some imprecision. Where we really notice standards out of alignment is at wide apertures where image quality should be good. Second, I don't have the tools to measure 1/1000th of a degree. I doubt the people who built the camera can measure 1/1000th of a degree. That doesn't mean we don't need to be precise, but we can be realistically precise.
 
Last edited:

JeffK

Well-known member
wow, great feed of info. Thank you everyone. Looks like I need to add a longer base and bellows to leverage the lens.
 

vjbelle

Well-known member
Rob..... thank you for pointing out that my reference to 1/1000 of a degree may be a tad too small but probably only by one zero. I had re-read Togers excellent review of the Linhof Techno (a camera I would not own for various reasons) where he set up an example of swing parallelism accuracy to be acceptable if 0.1 degree tolerance L/R could be achieved. He was, at the time, dealing with 6um pixel pitch which now is significantly smaller (3.76) so more than likely to achieve the same accuracy L/R a tolerance of 1/100 degree should be the goal and more than likely if off by that amount can be seen at 100% pixels. I also don't have any type of equipment to come close to that type of measuring capabilities but I'm sure they exist. Regardless - parallelism is critical but adjustable. More importantly is that once set is only good for that lens at that time. Each lens can have a slight tolerance difference that requires a little tweaking of the front standard - but the Cambo is capable of achieving that accuracy.

Victor B.
 

rdeloe

Well-known member
Rob..... thank you for pointing out that my reference to 1/1000 of a degree may be a tad too small but probably only by one zero. I had re-read Togers excellent review of the Linhof Techno (a camera I would not own for various reasons) where he set up an example of swing parallelism accuracy to be acceptable if 0.1 degree tolerance L/R could be achieved. He was, at the time, dealing with 6um pixel pitch which now is significantly smaller (3.76) so more than likely to achieve the same accuracy L/R a tolerance of 1/100 degree should be the goal and more than likely if off by that amount can be seen at 100% pixels. I also don't have any type of equipment to come close to that type of measuring capabilities but I'm sure they exist. Regardless - parallelism is critical but adjustable. More importantly is that once set is only good for that lens at that time. Each lens can have a slight tolerance difference that requires a little tweaking of the front standard - but the Cambo is capable of achieving that accuracy.

Victor B.
Thanks for the extra info Victor, and I hope I didn't come across as being overly picky here. I was worried someone interested in using the tools would run away at the thought of needing such tight tolerances!

This has always been a struggle for me. I can remember when I discovered how to adjust my Toyo, and all of a sudden a lens that I thought was only good at f/8 became good two stops sooner! The lens was fine; it was the camera that was misaligned.

As Geoff said, in the other thread about this that started today, you need to check each time.
 

TimoK

Active member
Ok, I made it off a Hasselblad 16 mm extension tube and an old tech cam #1 lens plate. I already had the Cambo lens panel for Hasselblad lenses. My DIY was installing the lens plate into that extension tube. Then I mounted the lens in the lens plate's #1 hole as usual. Very probably there is misalignment more than 1/1000 of a degree, maybe more than 1/10 :oops:
If You don't have Hasselblad lens plate, it's not cheap either. https://www.cambo.com/en/actus-series/actus-b-mini-view-camera/acb-ha/

So, I think longer rail and bellows is the best way to go, if you can accept those.



180 mm Sironar-S with couple of 16 mm extension tubes (different generations!)180mm_in_actus.JPG
 

JeffK

Well-known member
I have an Actus Mini, which I use with a Sony A7rIII & a variety of lenses, Digitars, Canon T/S & Pentax 645 & 67. The longest digitar I have is a 120 but its in a Copal 0. I swing the front standard 180deg when using this lens, so that the focus scale is set to infinity. I see no reason why a 180 Rody wouldn't focus at infinity if you swung the front standard, though I believe you can get a longer rail & you may also need the long bellows. If you want to be 100% sure you could always email Cambo
The 180 does indeed work with rotating the front standard!
 
Top