Rodenstock Apo Digital 55mm f4.5 on Cambo Actus G with Fuji GFX50R : not working

[vvince]

Hello,

the setup is in the title.
The Rodenstock lens is mounted on an Actus #0 plate.

Unfortunately it does not work for me : it's mechanically impossible to focus at infinity, even without any shift : the rear lens element barrel comme in contact with the camera mounting plate.
The farthest achievable focusing point is about 3m ...
Shifting makes thing even worth (of course).

This surprises me because Cambo, in his lens compatibility chart for the Actus, says the Rodenstock 55mm is compatible with Fuji GFX (with limited movements, but I at least would expect focusing at infinity with no movement).
And if I remember well some user reported the use of the 55mm on an Actus and with a GFX camera...

I don't thing I am missing something, because mounting the lens is pretty straightforward, but if somebody managed to have this setup working, I'd be glad to hear about it.

Cheers
Vincent

 

[vjbelle]

That is very odd. The FFD of the Rodenstock 55mm is 67.6mm and the FFD of my Schneider 72mm Digitar is 68mm. I can focus to infinity with my Schneider 72mm and Actus G with either a GFX 50s or 100 with movements. Make sure you have the lens mounted properly.

Victor B.

 

[rdeloe]

Can you put up some pictures of how you mounted it?

 

[vvince]

here are some pictures...

On picture 02, the reining ring has a notch with a smaller outer diameter. This notch goes into the #0 hole of the plate.
On picture 05, the lens is mounted, and there is still some spacing between the rear element of the lens and the retaining ring.
I do not know if this is normal but the rear element cannot be screwed any further.
The last picture is with the bellow removed, lens as closed from the camera as possible, achieving max focus distance at about 3 meters.



Cheers
Vincent

 

[rdeloe]

Pics are helpful.

It looks to me like the lens is mounted correctly. The rear cells should tighten down by hand firmly (but don't overtighten).

See the red arrow in this picture? It goes from the front face of the mount on the GFX 50R to the inside face of the Actus mount plate. What's that distance? Infinity is at 40.9mm.

EDITED: Will caught a dumb error -- should be 40.9mm as shown here

 

[Shashin]

Pics are helpful.

It looks to me like the lens is mounted correctly. The rear cells should tighten down by hand firmly (but don't overtighten).

See the red arrow in this picture? It goes from the front face of the mount on the GFX 50R to the inside face of the Actus mount plate. What's that distance? Infinity is at 67.6mm.

View attachment 182420

The flange focal distance is 67.6mm, which is from the lens plate to the focal plane index on the camera--the little zero with the line through it on the top plate on the GFX camera. The flange distance for the GFX is 26.7mm and it is 32mm from the face of the copal shutter to the rear of the rear element. So there is 8.9mm for the Actus camera mount thickness. Tight...

 

[Alan]

Going by Rodenstock's dimensions, it doesn't seem like it should work. As Will showed, there's less than 9mm between rear of lens and body flange. Then you have to fit the Actus body/bellows mount - not gonna happen...

 

[rdeloe]

The flange focal distance is 67.6mm, which is from the lens plate to the focal plane index on the camera--the little zero with the line through it on the top plate on the GFX camera. The flange distance for the GFX is 26.7mm and it is 32mm from the face of the copal shutter to the rear of the rear element. So there is 8.9mm for the Actus camera mount thickness. Tight...

Oh my goodness, of course. That was dumb. I really need to stop doing three things at the same time. Good catch Will.

So for the red line, Vince, if you can get to 40.9mm that should be infinity.

 

[vvince]

Thanks to all for the constructive and helpful comments!
Well, I was hoping I mounted the lens in a wrong way...
The measured minimal distance between the lens plate (inner surface, with which the retaining ring comes into contact) to the sensor plane (the little zero with the line through it) is about 66-67mm (with measurement imprecision, at least 1mm...), this giving a 3m focusing distance.
The red arrow on the picture above is about 40mm.
And the Actus camera mount is about 9mm thick (from the camera flange to the inner surface of the mount).

So it all fits with calculation Will made above.
It seems that it's just too tight to fit the 55mm on the Actus with the GFX.

Regarding the comparison of Victor above, with the Schneider 72mm Digitar having almost the same Focal Flange Distance than the Rodenstock 55mm and working well with the GFX, the 72mm seems more compact, with a shorter rear element which will not contact the camera plate when the lens plate is at the FFD from the sensor.

However I still do not understand how Cambo indicated this setup to be compatible, neither how people could report successful of this lens with the Actus/GFX.

Cheers
Vincent

 

[rdeloe]

Thanks to all for the constructive and helpful comments!
Well, I was hoping I mounted the lens in a wrong way...
The measured minimal distance between the lens plate (inner surface, with which the retaining ring comes into contact) to the sensor plane (the little zero with the line through it) is about 66-67mm (with measurement imprecision, at least 1mm...), this giving a 3m focusing distance.
The red arrow on the picture above is about 40mm.
And the Actus camera mount is about 9mm thick (from the camera flange to the inner surface of the mount).

So it all fits with calculation Will made above.
It seems that it's just too tight to fit the 55mm on the Actus with the GFX.

Regarding the comparison of Victor above, with the Schneider 72mm Digitar having almost the same Focal Flange Distance than the Rodenstock 55mm and working well with the GFX, the 72mm seems more compact, with a shorter rear element which will not contact the camera plate when the lens plate is at the FFD from the sensor.

However I still do not understand how Cambo indicated this setup to be compatible, neither how people could report successful of this lens with the Actus/GFX.

Cheers
Vincent

Vince, that's disappointing. Have you contacted Cambo about this? Their chart put an open circle next to Apo Sironar Digital 55/4.5 for the Fuji G mount, which means "restricted movement". That does suggest it should reach infinity (but not be able to shift much or at all). I had a copy of this lens for a very short time on my VX23D and I was able to focus to infinity, but movements were limited to a mm or two.

 

[vvince]

Yes it is, I will return the lens, what a pity.

I'll notify Cambo about it.
I read the chart the same way : restricted movement but at least focus at infinity, which it fails to achieve.
I even had Cambo confirm by email that this lens would work, with the Fuji GFX, and that shift would be available. Only tilt was restricted according to them.
Well...

Thanks to all for the help.

I was looking for a wide/normal lens with shift capabilities. I guess that was it for the large format lenses, nothing wider than 60mm should fit.
The other way to go seems to adapt MF lenses, like the Mamiya RB/RZ67 50mm. My next try then.

Cheers
Vincent

 

[stevev]

Hi Vincent,

That must be very disappointing. I was really looking forward to seeing your results. I agree that the mounting of the lens looks right. It is identical to how I have mounted my 55 APO SIronar Digital on the Cambo Copal #0 lens plate.

And like you, I also thought I had seen somewhere that the GFX50R had been used successfully with this lens on an Actus. Maybe not.

The Mamiya RZ67 50 (make sure you get the ULD version!) sits well ahead of the camera and there are no limitations when using it, at least for me with a Z7.

Good luck with getting this sorted.

Cheers,
Steve.

 

[rdeloe]

I'm a bit hesitant to suggest this option because it does require some irreversible custom conversion to work... But you should know that the Mamiya G 50mm f/4 is an extremely good option. I showed this example in another thread about shifting, but you might have missed it because the conversation was around full frame. This image is +/- 15mm of shift at f/11 using my Mamiya G 50mm f/4 on a Fuji GFX 50R.



This is a test shot from a location I use for evaluating infinity performance. The point of focus is a cell tower in the centre of the frame, 4.28km away. This is a near-symmetrical lens designed for a rangefinder camera, so I was expecting strong lens cast. Happily, there's none that I can detect. Light falloff was noticeable in the shifted images. I used the Flat Field Correction tool in Lightroom to tidy that up. A full resolution JPEG version of the frame is here if you're curious. Because it's a near symmetrical lens design, there's effectively no CA, and distortion is minimal..

You have to adapt the mount because there are no adapters for Mamiya G lenses, and you have to get someone to lock the shutter open (which requires disassembly). The shutter operation is not expensive (I paid $150). The machining required to replace the mount is simple work. I did it in my basement in about an hour (and I'm by no means a skilled machinist).

The flange distance on the Mamiya G lenses is even shorter than the Rodenstock Apo-Sironar Digital 55/4.5: 56.65mm. However, the rear end of the lens doesn't stick out as far, and it's not as wide, so I easily get the full 15mm of shift that takes me right to the edge of the image circle needed to cover 6x6 film.

 

[vvince]

I'm a bit hesitant to suggest this option because it does require some irreversible custom conversion to work... But you should know that the Mamiya G 50mm f/4 is an extremely good option. I showed this example in another thread about shifting, but you might have missed it because the conversation was around full frame. This image is +/- 15mm of shift at f/11 using my Mamiya G 50mm f/4 on a Fuji GFX 50R.

View attachment 182432

This is a test shot from a location I use for evaluating infinity performance. The point of focus is a cell tower in the centre of the frame, 4.28km away. This is a near-symmetrical lens designed for a rangefinder camera, so I was expecting strong lens cast. Happily, there's none that I can detect. Light falloff was noticeable in the shifted images. I used the Flat Field Correction tool in Lightroom to tidy that up. A full resolution JPEG version of the frame is here if you're curious. Because it's a near symmetrical lens design, there's effectively no CA, and distortion is minimal..

You have to adapt the mount because there are no adapters for Mamiya G lenses, and you have to get someone to lock the shutter open (which requires disassembly). The shutter operation is not expensive (I paid $150). The machining required to replace the mount is simple work. I did it in my basement in about an hour (and I'm by no means a skilled machinist).

The flange distance on the Mamiya G lenses is even shorter than the Rodenstock Apo-Sironar Digital 55/4.5: 56.65mm. However, the rear end of the lens doesn't stick out as far, and it's not as wide, so I easily get the full 15mm of shift that takes me right to the edge of the image circle needed to cover 6x6 film.

Thank you Rob,

looking at the full resolution picture : the Mamiya is amazingly sharp, for sure!
I had followed your posts regarding this option for the Fuji GFX, however I am not sure it would work for me : I would not know where to have the shutter blocked open (I live in Europe), and I have no machining option (living in a flat...).
I guess this too far DIY for me, but I am happy this works so well for you.
I guess the simplest, out of the box, option would be to follow the advice of Steve and mount "the other Mamiya 50mm" on the RB67 plate sold by Cambo.

Cheers and thanks again for your help

Vincent

 

[rdeloe]

Thank you Rob,

looking at the full resolution picture : the Mamiya is amazingly sharp, for sure!
I had followed your posts regarding this option for the Fuji GFX, however I am not sure it would work for me : I would not know where to have the shutter blocked open (I live in Europe), and I have no machining option (living in a flat...).
I guess this too far DIY for me, but I am happy this works so well for you.
I guess the simplest, out of the box, option would be to follow the advice of Steve and mount "the other Mamiya 50mm" on the RB67 plate sold by Cambo.

Cheers and thanks again for your help

Vincent

Vincent, I got the idea to do this from a German photographer who had the shutter work done by Mamiya Germany. Unfortunately, they don't do it anymore. The person who did mine is in Las Vegas, Nevada, in the US. It is indeed a hassle to send it that far. The machining side could actually be quite simple. A local machinist where you live could attach the lens directly to a suitable Actus plate. That would require drilling four holes in the Actus plate. I don't have an Actus so I don't know if the Copal plate has room for the lens to sit flat.

Anyway, your plan to try the Mamiya 50mm for the RB67 makes a lot of sense given that Cambo sells the plate. No machining necessary. I hope it works out for you.

 

[Alkibiades]

On the Arca Swiss compatibility website Fuji GFX and roddy 55 mm is working...

lens compatibility

www.arca-shop.de