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!

Cambo Actus G with Rodenstock 55mm f/4.5 APO Sironar Digital and Nikon Z. Very soft edges...??

stevev

Member
Hi everyone,

I recently acquired a Cambo Actus G and some Mamiya RZ67 lenses. On the back I use a Nikon Z7 or Panasonic S1R. I have been getting fantastic results with that setup. Sharp across the frame and right into the fully shifted edges albeit with (expected) strong vignetting in the extreme corners at 15mm of rise.

Newly arrived from eBay is a "Mint" used Rodenstock 55mm APO Sironar Digital (Copal 0) and the corresponding lens plate from Cambo. I started testing it this morning on the Actus, with both the Z7 and S1R. I tested at f8, f11, f16 and f22. I tested it on my back fence 3 metres away and on another subject (a line of houses and trees) 150 metres away.

When focused in the centre of the frame, the centre is sharpish but the edges are very soft. Not mush perhaps, but pretty close. This was the case for both near and far subjects, with both cameras and at all apertures, although f22 was slightly better but otherwise to be avoided due to dulling from diffraction. I was surprised and disappointed.

When shifted, the edges are even worse. The focus peaking 'shimmer' clearly shows a circular zone of high contrast/sharpness that widens and narrows somewhat with focus and aperture changes. To me this suggests field curvature, although Rodenstock state that for the APO Sironar Digital lenses "special attention was given to the correction of the curvature of field."

However there are no circumstances in which I can achieve satisfactory focus in the outer third of the frame. This is my first Rodenstock lens.

Electronic shutter, 2 second timer, RRS tripod, zoomed live view focus, with peaking.

Is there something obvious (to you) that I am missing here? Perhaps I have an issue with the lens itself? Perhaps the way I have attached it to the lens plate with the retaining ring is incorrect, but I don't think so. Any advice would be gratefully received.

Thanks in advance,
Steve.

100% crops below, shot at the local park this morning.

First, the full scene.

_1030154entire.jpg

Centre

_1030154centre.jpg

Left

_1030154left.jpg

Right

_1030154right.jpg
 

Alan

Member
Can you focus at the edge and get that area to sharpen up? If so, do both sides sharpen up at the same time? If not, do they require opposite focus direction from center to sharpen?

Maybe try slightly unscrewing the front and/or rear group from the shutter a bit and see if anything changes.
 

stevev

Member
Thanks Alan,

I can focus at either (unshifted) edge and that improves them both slightly, but at the expense of the central area, which becomes less sharp. Focusing on the shifted edges makes hardly any difference and they remain unusable.

I will check if opposite direction is required and will also try slightly unscrewing the back group so it sits 0.5 to 1mm further from the shutter/front group. And report back.

Along those lines, perhaps there is a thicker or thinner retaining ring that I should be using but there was nothing extra that came with the Cambo lensplate (ACB-0 for Copal 0 shutter lenses - here: https://www.cambo.com/en/actus-series/actus-g-view-camera/acb-0/).
 

Will Deleon

New member
Hey Stevev,

I also just received my Rodenstock 55mm 4.5 Digital lens from Ebay lol. I have it on a Rollei X Act 2 camera with a Sony A7rIV. I'm having a kinda similar issue as you but not as bad. Please let us know what you troubleshoot. I did my research on this lens and it should be one of the sharpest in the entire line up :/ .
Thanks!
 

diggles

Well-known member
Are you focusing it at the same aperture you are taking the picture at? Or are you focusing it wide open then stopping down to take the picture?
 

stevev

Member
Will - sorry to hear that. I will update the thread with any solutions.
diggles - I am focusing at the same aperture that I am taking the picture at.
 

TimoK

Active member
It looks like there was a little swing. Did you see the small screw on the Copal shutter. It should be in the small hole of the lens plate. There is two of those in Actus lens plate, one over and other under the bigger #0 hole.
 

stevev

Member
Hi TimoK,

There was no swing indicated, but I will recheck and reshoot. I see a three small screws that seem to attach part of the shutter to the front group and one very small screw hole nearby, but there is no matching screw that came with the lens.

IMG_2058.jpgIMG_2057.jpgIMG_2059.jpgIMG_2060.jpg
 

TimoK

Active member
Sometimes it's there, sometimes it's missing. It keep's the lens not rotating. I think it have been in that hole and screwed away. So that was not the reason.
I also see a little CA's in your park shots in left and right. There should not be CA's even when swinged.
 

vjbelle

Well-known member
There is something radically wrong with your lens. I have an Actus G and numerous LF lenses and use both my 4150 and 7RM4 with it and have never seen edges like that from any lens. What is more alarming is that you are using a significantly smaller portion if the image circle which should yield sharper results. If possible you should send the lens back.

Victor B
 

scho

Well-known member
There is something radically wrong with your lens. I have an Actus G and numerous LF lenses and use both my 4150 and 7RM4 with it and have never seen edges like that from any lens. What is more alarming is that you are using a significantly smaller portion if the image circle which should yield sharper results. If possible you should send the lens back.

Victor B
I agree. Send it back. My copy of that lens is sharp across the frame with no blurry edges. I've used it on an Actus G with FF Sony cameras, Fuji GFX 50, and now Hasselblad 50 CII.
 

TimoK

Active member
Yes, I also agree with vjbelle. Send it back.
I also bough a couple weeks ago the older verison of that lens, apo grandagon 55mm. It is sharp and there is no chromatic aberrations on unsharp areas. Unfortunately I have not used it yet. I only took one serie of test shots and decided to keep it. It looked sharp enought , and quite free from CA's. Different from your copy.
One thing I did check before sending it back is that the front part of the lens is tight at it's place. You don't need to use power when tightening, or must not use. But check it's not loose.
 

Will Deleon

New member
Will - sorry to hear that. I will update the thread with any solutions.
diggles - I am focusing at the same aperture that I am taking the picture at.
Looks like I figured out my issue. I had put the retention ring backwards 😅! Images seem to be nice and crisp now. Hope you resolve you issue!
 

stevev

Member
It seems that the retention ring issue is my last stop before taking everyone's advice and seeing if I can send the lens back.

Will, that is great news. Would you mind either posting some photos or describing the correct arrangement of front group, lens plate, retaining ring and rear group? Including the orientation of the retaining ring i.e. is has a bevel on one side of it.

My setup is in the following order, as seen in the photo below, front left to right:

First the rear group.
Then the retention ring with the bevelled side facing to the right (which prevents the Cambo plate from moving around)
Then the Cambo plate with the word Cambo facing to the right and the magnetic lugs facing left
Then the front group.

Note: When assembled as described there is a gap of about 1.5mm between the rear group and the retaining ring, but it is all tight and solid, with no movement of any components.

*** Should there be two retaining rings i.e. one on either side of the Cambo plate? It looks like that would have the effect of moving the rear group slightly further away from the shutter. And that might position the front and rear groups in a way that solves my problem.

But if I have it assembled correctly then it must be the lens I guess, and I will contact the eBay seller, a US camera shop, to discuss.

IMG_2063.jpg
 
Last edited:

Will Deleon

New member
It seems that the retention ring issue is my last stop before taking everyone's advice and seeing if I can send the lens back.

Will, that is great news. Would you mind either posting some photos or describing the correct arrangement of front group, lens plate, retaining ring and rear group? Including the orientation of the retaining ring i.e. is has a bevel on one side of it.

My setup is in the following order, as seen in the photo below, front left to right:

First the rear group.
Then the retention ring with the bevelled side facing to the right (which prevents the Cambo plate from moving around)
Then the Cambo plate with the word Cambo facing to the right and the magnetic lugs facing left
Then the front group.

Note: When assembled as described there is a gap of about 1.5mm between the rear group and the retaining ring, but it is all tight and solid, with no movement of any components.

*** Should there be two retaining rings i.e. one on either side of the Cambo plate? It looks like that would have the effect of moving the rear group slightly further away from the shutter. And that might position the front and rear groups in a way that solves my problem.

But if I have it assembled correctly then it must be the lens I guess, and I will contact the eBay seller, a US camera shop, to discuss.

View attachment 179623
Hey Steve

This is my set up:



IMG_2361.jpgIMG_2367.jpgIMG_2366.jpgIMG_2365.jpg

Pretty flush to the lens board. Also the Novoflex copal 0 boards are threaded as well. So my issue was two things. I didn't thread the front elements all the way in and also (refer to image 4) I put the retention ring with the step facing out. Once I flipped it, I was able to mount pretty flush to the rear element. (Hope this makes sense).
 

stevev

Member
UPDATE

1) Cambo don't see an issue with how I am mounting the lens in their plate. They suggest it is the lens.
2) Roberts Cameras have agreed to allow me to return the lens.
3) I have ordered another 55mm f/4.5 Sironar from a different eBay store, 'Unused in box.'
4) When that arrives I will retest and report back.

Thanks again to all that have posted ideas and suggestions.
 

Alkibiades

Active member
not the lens or glasses are here the problem but the lack of calibration of the glasselement with the shutter.
Some guys wanted to see a not calibrated lens- here is the best possibility to see it.
This can happen when somebody just put the glasses in a shutter without exact calibration. It doesnt matter if the glasses are new, mint or very old.
 

stevev

Member
Thanks for the information Alkibiades.

I have sent the lens back to the USA and I have ordered an "Unused in box" replacement, which will be here in a few days.

If calibration is the problem, will the replacement lens have the same issue once I mount it in my Cambo Actus G?

Do I need to calibrate the lens first? How do I do that?

Thanks,
Steve.
 

Alkibiades

Active member
Thanks for the information Alkibiades.

I have sent the lens back to the USA and I have ordered an "Unused in box" replacement, which will be here in a few days.

If calibration is the problem, will the replacement lens have the same issue once I mount it in my Cambo Actus G?

Do I need to calibrate the lens first? How do I do that?

Thanks,
Steve.
If you already orded this second lens so just test this lens first.
Maybe you have luck and the lens is well calibrated- as it should if you get a really new and mounted by Rodenstock lens.
The ebay and internet world is big and there are a lot of confused stuff. The old days where you get a lens from a real professional dealer who exactly knows what he sales are over.
So if the lens perform well- there is no problem. If not there are few possibilities.
The first one is that you send the lens to Rodenstock and dicribe them the problem.
The calibration of the 55 mm is not a big deal, usually if you talk with them they make it even for free.
The calibration of the Digaron lenses is complicated and this can be really expensive.
The second possibility is that you know a good and profesional repair station whe they can do it.
If you are new in the large format- middle format stuff i dont think you will be able to do it. You need little small ring for this. You put them on the front element.
Then you can check the edeges. sometimes you need 2 rigs ect...
The reason for that is that all shutters have are different made, they are never the same, the tolerances can lead to these soft edges. This is at all digital lenses as also special analoge lenses with big image angle of 110°-120° as the Apo Grandagons or Super Angulon XL.
 
Top