Fresnel screen focus distance is different from ground glass

[nicnilov]

I'm using a Chamonix 45N-1 4x5 camera which comes with a fresnel focusing screen. The screen is set up on the lens side from the ground glass and the grooves are also facing the lens. It is a plastic screen and it has a small round hole in it through which I can see the image on the ground glass itself.

When I focus by the image that comes trough the fresnel I get different focusing distance from when I focus through the small hole in fresnel by the image on the ground glass. From what I gather there should be no such difference, since with a narrow depth of field my focus would be off in one case or the other. I assume the ground glass focus would be more precise and this is what I'm using, but then the fresnel gets in the way of checking the focus throughout the frame.

Is this something expected or am I doing something wrong?

Thanks!

[Alan9940]

I don't use any fresnel lens on my LF cameras, but, since the fresnel does have a focal length to itself I imagine this could affect proper focus. Again, I'm no expert but I always heard that the fresnel should behind the ground glass to avoid this issue. Sure hope someone who knows that actual facts jumps in on this thread.

[Oslolens]

This is reported and was upgraded on the N2, and one of the reasons why a bought a N2 instead. Google it and read the "fix" http://www.chamonixviewcamera.com/cameras/45n2

Sent fra min SM-G975F via Tapatalk

[Bob Salomon]

I don't use any fresnel lens on my LF cameras, but, since the fresnel does have a focal length to itself I imagine this could affect proper focus. Again, I'm no expert but I always heard that the fresnel should behind the ground glass to avoid this issue. Sure hope someone who knows that actual facts jumps in on this thread.

If a camera is designed for the fresnel to be between the gg and the lens then the gg is adjusted to compensate for that position.

If the camera is designed for the fresnel to be between the gg and the user then the gg is adjusted for that.

As an example early Linhof cameras were adjusted for the fresnel to be between the gg and the lens. Later one are adjusted for the fresnel to be between the gg and the user.

Should one have mounted the fresnel in the wrong place then the gg has to be adjusted by a service center to correct the positioning of the ground side of the gg.

[Greg]

Years ago took my Nikon Multiphot apart to seriously clean it. The back on the Multiphot has the fresnel lens placed in front of the GG. When putting it all back together, I put the fresnel lens in front of the GG but mistakenly reversed it. Since I was doing macrophotography and microphotography with the Multiphot and depth of field being practically non-existant, this caused my 4x5 chromes to be ever so slightly out of focus. Fortunately diagnosed my mistake with the first batch of processed chromes and corrected the orientation of the fresnel lens. If this reversal of the fresnel lens would matter with general photography, I don't know. Would be interesting if someone else could pipe in on this.

[Oslolens]

there should be no such difference
There is only three things that are crucial, the same plane of focus between film and ground glass, darkness, and no moving of camera from focusing to exposure. Time to to repair. Ask them (Chamonix) what to do, and check the result afterwards before doing something important ;)

Sent fra min SM-G975F via Tapatalk

[choiliefan]

IIRC the later Speed Graphics had the grooved side of the fresnel facing the ground glass.

[cowanw]

I suggest you arrange a yard stick or metre stick up on a 45 degree angle fairly close to your camera and at a wide open f stop focus first one option and then the other. Develop and see your negatives. Is one or the other sharp or both or neither.

[nicnilov]

This is reported and was upgraded on the N2, and one of the reasons why a bought a N2 instead. Google it and read the "fix" http://www.chamonixviewcamera.com/cameras/45n2

Thanks for pointing that out, I was not aware this was a design issue. I contacted the manufacturer and their recommendation is to remove the fresnel and focus on GG.

[Bob Salomon]

Thanks for pointing that out, I was not aware this was a design issue. I contacted the manufacturer and their recommendation is to remove the fresnel and focus on GG.

A fresnel does 2 things:
1 brightens the gg image
2 even outs the illumination on the gg edge to edge.

Ask the manufacturer how they propose that you do these 2 things?
Or
What they will do to your camera to achieve those 2 things?

[Doremus Scudder]

A Fresnel does 2 things:
1 brightens the gg image
2 even outs the illumination on the gg edge to edge.

Ask the manufacturer how they propose that you do these 2 things?
Or
What they will do to your camera to achieve those 2 things?

Bob,

The Chamonix N-1 was designed poorly; the addition of the Fresnel lens was not taken into account and adding it, while brightening the image and evening the illumination, threw the focus off. The easy fix is to remove the Fresnel and use the camera with the ground glass only, similar to many other models of view camera that do not come with a Fresnel. Sure, the image is a bit dimmer, but focusing is more precise. Many prefer the standard ground glass to a screen with a Fresnel lens added.

Best,

Doremus

[nicnilov]

Originally I wasn't aware the issue is specific to this camera model so I was looking for a general confirmation of whether this is not an expected behavior. Turns out this topic has been discussed here quite a lot so I don't think I can add much to it at this point. The issue was fixed in the revised model which is commendable. I'm fine with using the camera without fresnel as I wasn't expecting one to be there in the first place.

[Bob Salomon]

Bob,

The Chamonix N-1 was designed poorly; the addition of the Fresnel lens was not taken into account and adding it, while brightening the image and evening the illumination, threw the focus off. The easy fix is to remove the Fresnel and use the camera with the ground glass only, similar to many other models of view camera that do not come with a Fresnel. Sure, the image is a bit dimmer, but focusing is more precise. Many prefer the standard ground glass to a screen with a Fresnel lens added.

Best,

Doremus

Or mount the fresnel, groove side down, on top of the gg.

The factory should be easily able to provide a means of doing this, it only involves a clip on each end of the gg.

[cowanw]

In any case after you have made your modifications check for sure with real film.

[Bob Salomon]

In any case after you have made your modifications check for sure with real film.

If you mount the fresnel on top of the gg there is no change to the positioning of the ground side of your gg. So focusing will be just as accurate as long as you focus your loupe on the ground side of the gg.

[cowanw]

Won't the GG be allowed to fall forward to the position where the Fresnel is presently? And be a few mm closer to the lens position? Or is the lens held in position even if the space the present Fresnel occupies is vacant.

[Bob Salomon]

Won't the GG be allowed to fall forward to the position where the Fresnel is presently? And be a few mm closer to the lens position? Or is the lens held in position even if the space the present Fresnel occupies is vacant.

Not if you have his camera that was never designed to have anything, other then a film holder, under the gg!

[nicnilov]

Not if you have his camera that was never designed to have anything, other then a film holder, under the gg!

Well, despite the fact it wasn't designed for fresnel screen, there are two separate steps in the back wall, a pair of vertical and a pair of horizontal. The horizontal ones are deeper than vertical. The fresnel rests on the horizontal and does not affect the position of the ground glass which rests on the vertical steps. So yes, moving the fresnel to the other side of the ground glass works, but the fresnel needs to be fixed in its new place in some way for which there is no ready-made provision.

[Bob Salomon]

Well, despite the fact it wasn't designed for fresnel screen, there are two separate steps in the back wall, a pair of vertical and a pair of horizontal. The horizontal ones are deeper than vertical. The fresnel rests on the horizontal and does not affect the position of the ground glass which rests on the vertical steps. So yes, moving the fresnel to the other side of the ground glass works, but the fresnel needs to be fixed in its new place in some way for which there is no ready-made provision.
Not difficult, Linhof added a simple rectangular bar to the middle gg hold down bar screw. Push them to one side, drop the Fresnel on top of the gg and swing them back. Very simple and works extremely well!

http://linhof.com/wp-content/uploads/2015/03/Montage_Fresnelscheiben_4x5-600x734.jpg

[cowanw]

Here is an interesting thread, that seems to answer the question.
https://www.largeformatphotography.info/forum/showthread.php?56287-Chamonix-camera-45N-1-focusing-error
I particularly like Bob's answer then on page 3.
"If a Fresnel, under a gg is causing incorrect focus then the gg position is incorrect. Simply placing the Fresnel on top of the gg or throwing the Fresnel away will not be an automatic cure as someone earlier noted, the thickness of the Fresnel has an effect on focus as any piece of glass or plastic in the optical path shifts the focus by about 1/3rd the thickness of whatever is placed there.

The first thing that you want to check is the focus on and inclined yard stick, with the Fresnel and gg in the factory position. Put a vertical flag pin on the yardstick at the point you are focusing on and focus with a loupe of 4 to 6x power whose eyepiece is adjusted to bring the grain of the gg into sharp focus. Focus on the point where the flag pin is inserted into the ruler. Make an exposure wide open and at f22. Make sure that the lens is within the optimization range for the magnification you are using. Testing with a lens corrected for 1:20 at this range won't tell you much as the lens will not perform optimally.
What is the result? The focus spread on either side of the flag pin will tell you what is happening."
I still think testing it now would at least be reassuring.

[neil poulsen]

For exacmple, Arca Swiss cameras are one of the few designed to have the Arca Swiss Fresnel between the ground glass and the lens.

I've always felt that this arrangement gives a nicer visual experience.

[Tin Can]

Here we go again! I have found fresnel all over the place, front, back, adjusted for both, and not. Removeable or not.

Not picking on Chamonix! Everybody is guilty!

Long old thread...

Chamonix camera 45N-1 focusing error (https://www.largeformatphotography.info/forum/showthread.php?56287-Chamonix-camera-45N-1-focusing-error&p=530867&viewfull=1#post530867)

[Dan Fromm]

Here we go again! I have found fresnel all over the place, front, back, adjusted for both, and not. Removeable or not.

Not picking on Chamonix! Everybody is guilty!

Why do you believe this?

[Tin Can]

What is your exact question?

I have 2 Horseman with fresnel front or back. The thread i linked has a vast discussion of what is what, years before i got here. You are in it.

I didn't see a definitive answer. My Sinar has a removable one on outside.

My Speed has it on the inside.

On my SC11 I just slap a book reading fresnel up and look at it, but focus without it.

I have 2 Cycle Camera Premo with GG ground side facing out.

What do you know believe?

and I can barely believe what I see with my old untrustworthy eyes

Working on a 11x11" point and shoot fixed focus box camera with 14" lens right now, perhaps it will be a solution for me...

or not




Why do you believe this?

[Dan Fromm]

What is your exact question?

Why do you believe that all camera manufacturers make their cameras so that the film plane is not in register with the ground glass?

Chamonix blew it, that doesn't mean that other makers did too. Graflex in particular took pains to make sure that Pacemaker Graphics supplied without fresnels had GG and film plane in register and that Pacemaker Graphics supplied with fresnels had GG and film plane in register.

It isn't fair to blame manufacturers for idiot owners who installed aftermarket fresnels in the wrong place.

[Tin Can]

I don't believe I blamed anyone

I also have never moved a fresnel from factory position

I do try to figure out why things are made the way they are and if working, why

I have a lot of experience taking apart brand new expensive things, changing the parts, per factory orders without manuals. Very good at that. Paid well for decades. I was in Product Testing.

Not cameras, nor lenses, nor shutters. I try to use them as designed and assembled when I get the usually well used LF gear

So far so good, I do suspect a lot of used gear being sold...I made the guy who sold me my first LF camera, a Press camera, fix it. He paid a pro to do it. I talked to the pro in person. All good.

What I want to know is what is the 'theory' behind any machine, a camera is a machine

Peace




Why do you believe that all camera manufacturers make their cameras so that the film plane is not in register with the ground glass?

Chamonix blew it, that doesn't mean that other makers did too. Graflex in particular took pains to make sure that Pacemaker Graphics supplied without fresnels had GG and film plane in register and that Pacemaker Graphics supplied with fresnels had GG and film plane in register.

It isn't fair to blame manufacturers for idiot owners who installed aftermarket fresnels in the wrong place.

[Bernice Loui]

IMO, fresnel adders with the belief this "aids" viewing brightness and "aids" focusing ease is a Farce. There are specifics as to how a Fresnel helps and where it becomes a serious problem. If GG viewing is limited to a specific camera with a GG & Fresnel combo specifically designed together as a unit-system, it works for wide-normal to tele lenses. Once a really wide angle lens is applied to this combo system, expect double imaging between the Fresnel and GG due to the ray angles involved. Then we have the problem of the way a Fresnel lens works, which has much to do with the grooves used to make a Fresnel. These grooves become a focusing hinderance rather and aid.

IMO, skip the Fresnel and learn-adapt to using a plain very fine GG. This simplifies the entire viewing, GG to film holder distance, problem with wide angle lens viewing, groves in the Fresnel issues in many ways. At the beginning of learning how to use a VC, every possible viewing aid was tried from Sinar reflex viewer, Arca reflex viewer, all variations of Fresnel, brightest advertised GG-Fresnel combos and more. Each and every one of them had trade-off issues. After years and much $ wasted on these "viewing aids" it all went back to the plain Ground Glass and dark cloth. One more item to consider, brighter image on the GG does not make focusing easier, faster or "better".


Bernice

[Tin Can]

Good advice Bernice

I have made at least 5 GG, all ground by hand, very fine. I prefer them to my 50's Linhof which are rather coarse

I recently bought a 9X loupe made in USA, Edmund Scientific. Best loupe for me now. It's adjustable.

I also check 'T' on some holders and a few suspect cameras. My Deardorff SC11, 11X14 GG frame was way off when I got it. First and repeated advice here on forum was, "Don't worry about that." I didn't listen but sent the whole back to Richard Ritter to fix, install his bail back and make holders to match.

Then I checked his work. OK!

The two Horseman 8X10 GG frames are actually Cambo with Horseman OE GG and fresnel. Not happy yet. Next year!

[Bob Salomon]

Why do you believe that all camera manufacturers make their cameras so that the film plane is not in register with the ground glass?

Chamonix blew it, that doesn't mean that other makers did too. Graflex in particular took pains to make sure that Pacemaker Graphics supplied without fresnels had GG and film plane in register and that Pacemaker Graphics supplied with fresnels had GG and film plane in register.

It isn't fair to blame manufacturers for idiot owners who installed aftermarket fresnels in the wrong place.

When we were the a Rollei distributor I received a very irate phone call from a well known wedding photographer who was irate because he shot 2 weddings one weekend with his 6008 cameras and virtually every shot was out of focus. He was going to sue me, my company, our service center and the factory!
We made an appointment and he drove to our office in his brand new Jaguar with all of his cameras and 2 proof books of out of focus images.
After looking at the images I looked at his cameras and asked him “when was the last time he cleaned his focusing screen”?
He said the night before the first wedding. I then pointed out to him that the rangefinder/micro prism circle in the center of the screen had a raised circle on the top of the screen. But when he replaced the screens he put them back into the camera upside down!
He then very quietly repacked all of his equipment, said oh and asked if there was anything new for the system. Then left in his Jaguar.

Then there was Mary Ellen Mark who had a similar problem with her a Rolleis. We went to SoHo and looked at her cameras, left her with loaners and brought them to service who couldn’t find a problem. Her complaint was that they were sharp head on but soft when angled.
Service sent them to the factory in Germany and they sent them to Zeiss in Oberkochen and they discovered a third party focusing screen was improperly positioned in the camera!

Lastly there was Avedon’s assistant. He complained that when Avedon shot with his Rollei 3.5 F cameras the field of view was different then when he shot with the assistant’s Mamiya and that with the Rollei the images had flare on one side.
So back into the city to Avedon’s studio and the set was all white. White floor, white walls, white ceiling, white background. There was a pole holding multiple strobes on either side lighting the background and a huge soft box over the subject’s head. Sure enough, on one side, with the Rolleis there was flare. Not with the Mamiya. With both Avedon and the assistant watching I pointed out that one strobe head was pointing slightly back at the camera and adjusting it back towards the background eliminated the flare.
But the assistant still was irate that it showed on the Rollei but not on the Mamiya and Avedon should switch to Mamiya.
After pointing out to him that the 3.5 F had a 75mm lens and the Mamiya an 80mm lens Avedon thanked me and left. He stayed with Rollei!

[Tin Can]

Good story Bob and I believe every word of it!

Artists, can't live with them, can't live without them or their assistants...

[Bernice Loui]

Many years ago when Hasselblad introduced their Acute Matte focusing Screen, there were other aftermarket brands of focusing screens available. Much hemming and hawing happened over the cost of the Acute Matte. We decided to try out the others in camera one day. Using a Hasselblad 2000FCW body, 100mm Planar lens, A12 film back one roll was carefully test exposed with the Acute Matte, another identical roll was exposed as in as much the same as the first roll. Color transparency results indicated the after market focus screen was slightly off focus while the Hasselblad Acute Matte was spot on and brighter using a PME prism as a viewing aid. That was the first and last time any deviation from OEM focusing screens was tried.

This is also why the insistence on the genuine original focusing screen during the Master Technika days and same instance on using only Sinar fresnel GG on a Sinar camera. Sticking to this Orthodoxy has produced zero focusing problems over decades of using these cameras.

All it takes is one wasted roll of film or wasted sheet of film due to what appears to be a simple thing, but the results are not worth the risk or believed-perceived improvement. Stay with the OEM when possible and respect the folks who designed and built the focusing system. More often than not. they really DO know what they are doing.


Bernice






Then there was Mary Ellen Mark who had a similar problem with her a Rolleis. We went to SoHo and looked at her cameras, left her with loaners and brought them to service who couldn’t find a problem. Her complaint was that they were sharp head on but soft when angled.
Service sent them to the factory in Germany and they sent them to Zeiss in Oberkochen and they discovered a third party focusing screen was improperly positioned in the camera!

[Tin Can]

Gotta Agree

If possible I strive to restore anything to stock or OE as possible

Not a fan of Modders, who butcher OE, our old joke was, 'I can make it better...'

2 hours ago I got a NOS porcelain lamp socket that exactly replaces a damaged one in an Elwood enlarger. I will rewire with new cable.

[Bob Salomon]

Many years ago when Hasselblad introduced their Acute Matte focusing Screen, there were other aftermarket brands of focusing screens available. Much hemming and hawing happened over the cost of the Acute Matte. We decided to try out the others in camera one day. Using a Hasselblad 2000FCW body, 100mm Planar lens, A12 film back one roll was carefully test exposed with the Acute Matte, another identical roll was exposed as in as much the same as the first roll. Color transparency results indicated the after market focus screen was slightly off focus while the Hasselblad Acute Matte was spot on and brighter using a PME prism as a viewing aid. That was the first and last time any deviation from OEM focusing screens was tried.

This is also why the insistence on the genuine original focusing screen during the Master Technika days and same instance on using only Sinar fresnel GG on a Sinar camera. Sticking to this Orthodoxy has produced zero focusing problems over decades of using these cameras.

All it takes is one wasted roll of film or wasted sheet of film due to what appears to be a simple thing, but the results are not worth the risk or believed-perceived improvement. Stay with the OEM when possible and respect the folks who designed and built the focusing system. More often than not. they really DO know what they are doing.


Bernice

The Master Technika is decades old. Over that time span Linhof has changed their gg and their Fresnel. The ones supplied in the last few years are much brighter and even then the older ones. But their positioning in the back has not changed.

The Acute matte screen was a Minolta product and was sold by both Hasselblad and Rollei under license for medium format.
Again the screen position in the cameras was identical to their other screens.

As for focus aberrations and Fresnels Nikon made a series of K screens that were optimized for different focal length ranges. Wista offers 2 different Fresnel screens. One for the normal range of short to portrait lengths and a second for long focal lengths.

[europanorama]

199006
Ron Wisner has a very precise statement about Fresnel and Groundglasses. see pdf above.
Link at the end here is dead. got the pdf from archive. its also stored in filesection of FB Largeformat Photography.
Viewfinder screens GG fresnel 4x5 back

https://www.largeformatphotography.info/gg.html letzter link wisner tot/last link wisner dead:

https://web.archive.org/web/20080228204452/http://www.wisner.com/viewing.htm
no need to download- pdf attached here. see first line.
What is the Proper Placement of the Fresnel?
One subject which comes up often is the correct position of the fresnel lens. In years past, several arrangements have been used, including placing the fresnel behind the ground glass, in front of the ground glass, and incorporated into a ground glass made of plastic. However, there is only one correct arrangement. The ground glass surface should face the camera lens, and the fresnel is placed behind it, on the outside of the camera, toward the photographer. The textured surface of the fresnel should be placed against the ground glass. There is a particular reason for this arrangement. In manufacturing cameras and film holders, one overriding concern is the correct position of the focal surfaces of the respective parts. In the film holder this is the position of the septum, against which the film rests, and in the camera this is the position of the diffusion surface, or ground side of the ground glass upon which one focuses the camera. Nothing is more important than the proper registration and agreement of these two elements. If the fresnel were placed in front of the ground glass, interposed between the lens and the ground glass surface, even if it were still physically in the same position occupied by the film plane, a lack of registration can occur. This can be explained by considering the effect of a parallel sided glass plate such as a glass filter upon a beam of light (fig.?). Rays passing through such a plate are displaced by about one third the thickness of the plate, and depending upon the angle when passing through the plate, will be displaced laterally. .Furthermore, the greater the angle, such as in a wide angle lens, the greater the effect, resulting in an apparent curvature of the image when no such real curvature exists. The result will be erroneous focusing of the edges of the image.
------
https://www.photo.net/discuss/threads/fresnel-lens-for-tlr.105798/
Depending on the way the orignal screen is mounted your TLR viewing lens will need readjustment. If the original screen lies flat on a frame under it and you can mount the fresnel screen above it without lifting the original screen this will not be necessary. On the east german Reflekta II TLRs the original screen is mounted with four brackets UNDERNEATH its frame. The brackets are just long enough to hold a fresnel lens, too, but of course the original screen will be in a somewhat lower position.

[europanorama]

not really LF but anyway interesting since the same problems.

1. have both brightscreens by rick oleson.
http://rick_oleson.tripod.com/index-175.html
bought for kiev 60. its 1.56mm(micrometer measured) same thickness like HB-V without fresnel ontop of GG. for K60 its needs shim 1.7 minus 1.56mm. I mention this since its a microprism -fresnel-combination, one version with split.
And its sensational to focus. But i have got problem when using as GG. see next

2. was checking and comparing Mamyia Universal Press/Super 23 cameras with calibrated 150mm blue with new Dora Goodman Zone Z1(light and 200series bodies). i used multiple Groundglasses. on Super 23-G the original. in Filmbacks a 57 x83mm standard GG. Tony Sansone advised to use one back with GG permamently attached. on the other hand the original Rightangle viewfinder with fresnel is sensational.
2b.I was checking Zone Z1 for correct focus. 200series is 0,84mm too short needs shim. 3m distance was 2.8m on scale.
then i tried to use rick olesons brightscreen. it seems too tiny to mount in 6x7-back. i am not sure if this fact led to misfocus. it was laying flat but angled. and i had misfocus. beside that i had this problem: distance set with macroslider and laser. focus checke with helicoid. was fantastically working with brightscreen. best focussing aid i had. seems sort of acumatte. But: when trying to finefocus with macroslider it was not possible. couldnt see a difference. with GG i could.

3. Here is an interesting statement by Tony Sansone: The Mamyia Universal Press/Super 23-guru- we discussed this camerasystem:

"Beware of adaptations with fresnel lens. Remember the incidence of refraction. The focused image is somewhere inside the plastic fresnel, not on the surface. Person who makes the fresnel focus screen with glass at rear must understand this and compensate for it. Very . very few do that".
maybe someone could explain refraction further.

4. Brightscreen can be cut to a larger size than 6x6 but the origina not to 4x5:
Oleson: "And finally, if you need a larger screen, the largest that I can make is 68mm x 78mm for either the BrightScreen MP or the BrightScreen MPD (the cost of these is $80 including shipping). If you need something larger than that, I do have a small number of 103mm x 133mm BrightScreens with no focus aid in the center, which can be cut down to fit larger cameras.... if you need one of those larger special sizes the cost is $100 including shipping."
The question is if it has also a hole in center to see GG underneath. will ask him. see 5.

5. got a special chinese 4x5-fresnel 100 x 122mm with 15mm hole by 3s-krpc ebay. want to use it ontop of Groundglass of Polaroid MP3(made ready for outdoors). since GG there must anyway be replaced i will get it from the same seller(18°, Cosmos Circle and more stuff)

6. Mamyia Quick Roll Graflok 23-4x5 sliding back. When i had no good groundglass i removed the 6x9-GG from this sliding back. it is sandwiched with fresnel and focussing is a joy. old HB-V-GG is very bad then(is also a sandwich but very coarse). I also check focus by moving it to filmholder. then i forget where i had to put Fresnel. i remembered surface was glossy so eighter glossy GG or Fresnel(structure towards lens then. After reading through all the discussions i was unsure. didnt recheck in camera till then. nobody answered in FB.
But i am sure Fresnel is inbetween lens and GG. GG ontop.
On the other hand: Mamyia Universal Press Groundglass-rightangle viewfinder here-has fresnel ontop. i could focus without loupe. its the same construction like the chinese one cosmos circle/3s-krpc. So we can expect really high quality there and its made of very solid material-cannot be cut. he told.

7. Since Tony Sansone already offered and wanted to recreate 4x5-adapter for MUP: Aaron Smith can already deliver 4x5-adapter for Mamiya Universal Press. I have his G-adapter which is not only very precise but better than the original or Super 23-G. no problem using Mamiya RB 67 Pro S.Slit must be prolonged. We adjusted blades for M RB67/70 back and Horseman 16EX should also work-will be verified.
Smith can also deliver universal GG-holder-blade-mounted not slipped in hooks. but original G-GG will work(must be taped since no hooks on the adapter)