CNC Machinist learning with medium format camera build

[jaedog]

Thanks Godfrey! Do you think you could annotate a side view of the lens and confirm which part of the lens would be the "mount seating surface"? I also wanted to share an update on the progress of my imitated graflok mechanism. Taking my time to perfect this because once I do, the body model should come together really quick.

 

[Godfrey]

...Do you think you could annotate a side view of the lens and confirm which part of the lens would be the "mount seating surface"? ...

Sure, easy.







I measured from that part of the camera flange to the focusing ground glass.

 

[TimoK]

I was looking your graflock. Couple of points came in my mind. In use you push that plate horizontally and same time it moves up. But not straight vertically but in a small angle to tighten the film back in it's place. There is some black velvet-like stuff to keep the light not leaking in camera. I took couple of pictures of a little bigger Graflock in my 4x5" Cambo.

 

[jaedog]

Hey everyone its been a little while so I wanted to share a probably unimpressive update! Work has been busy and the angling and packaging of the graflok mechanism proved to be really challenging. Still not sure if my model will fit in to the film back but Ill be 3D printing a prototype soon to see about it. (Also the angle should be a fun machining challenge as well along with the two holes which need to be drilled normal to that plane). Thanks so much for pointing this out TimoK and Godfrey for the confirmation on the flange mounting surfaces.

 

[TimoK]

Your model is improving!
If You compare Your picture Capture.PNG to my lock.JPG , that part in your picture is dark grey is a little curved in my picture. It's made of piece of steel I'd call spring, but I don't know the right English term. It is pressing that lock plate but also lets it move. Also those bolts should not be too tight.
Also You have turned that lock plate 90 degrees on the long side. I don't see any reason to it. You should turn the short end because You are pushing that plate horizontally and You need something against your thumb. Look at my pictures, it's visible in those and You'll see it if You think how the lock is working.

 

[jaedog]

Thank you! I'm planning to purchase some spring steel (you got it right) from McMaster-Carr and laser it out on the fiber laser at work. I'm not sure if I will need to add the curves as are shown in your lock.JPG. I intend to use a thread locker and try to find the perfect tension on the bolts since I'm not equipped to form spring steel post production. If all else fails I'm sure I can use some normal sheet stainless steel, add some bends and be okay. And good catch on the turned lock plate, I actually had it as you described initially but chose to add that flange in order to mount a little block I can move horizontally with my thumbs, I've attached a photo of that, let me know if I misinterpreted anything!

 

[jaedog]

I think I can call my Graflok mimic a success! Fits in to the backing well and should provide the proper force on it at an angle that pulls it into the camera body. Next step is the lens mount..

 

[TimoK]

Yes! This looks good. I hope Godfrey will help You with the lens mount.
But there's something between the rear and the front end of the camera body. I think the tripod mount. You'll need at least one female tripod screw ,3/8" or 1/4". I recommend you to make tripod screws in two or three sides of the camera body. You have 6x4,5 roll film back. If your tripod mounting is where it used to be in the old cameras you are taking portrait shots most comfortably and must turn the tripod head to take landscape shots or use a L-bracket to mount the camera on tripod. But you are making a brand new camera, so you can also improve the design. If I was You I'd make tripod screws and also Arca Swiss compatible dovetails on three sides of the camera body, maybe on four sides.

 

[jaedog]

Thanks for the Info! I will definitely integrate tripod mounting point(s) into the body's design. Maybe a round clamping section that would allow me to rotate the camera to any angle. I think I will avoid making the Arca Swiss mounts just to keep things simple for now (only a couple weeks left before Christmas!). The challenge now will definitely be perfecting the Lens mount, and I will definitely be reaching out again here if I hit a brick wall in that design process. If anyone has some sort of 3D model for the Lens mounting system it's more than welcome!

Also, bonus video of the graflok in action! (sorry for the horrible gif quality, it was the only way it would load up)

 

[jaedog]

The CAD is just about finalized. Managed to extract some dimensions for the lens interface out of some open source press lens adapters. Thinking of adding a locking mechanism to keep the Graflok from backing out, and maybe some extra mounting for a future strap loop, side grip, etc. Those features aside, anything obvious I seem to be missing?

 

[Alan]

Cool - elegant.

Looks like you skipped a light trap lip for the left side of the film back. Was that done for compactness? You could get light leaks there under certain conditions. If you don’t want to extend the body for a lip, you could try a recessed strip of felt/velvet.

Inside, you might have reflection problems with the straight tube shape. Some baffling and/or serrations of the inside surfaces would help with that.

 

[jaedog]

Hey Alan, thanks for bringing that up! I'm thinking of lining the whole inside with thin, black adhesive back felt which I suspect will mitigate any internal reflections from the walls. I also want to make some thin felt cutouts for the part to part interfaces as well. Does that sound like it would be enough?

 

[TimoK]

It's looking better all the time!
But...
I agree Alan in both of his comments.
I don't see any reason to skip the left trap lip. It's only calling for problems with light leakages.
Hard to avoid in any other way.
And Yes, Your' design inside of the camera will make bad reflections. I don't believe the black adhesive is the best solution to kill those reflections. All cameras I have been looking inside have been painted black, matte black. But also black surfaces, painted or other, are reflective. So the form of those reflective things are important. And your tube form design inside the camera is not a good form to avoid reflections.
For some reason the old camera houses are like empty boxes, Shorter or longer tubes in quadrat or rectangular form. In every case this is a little wider than the picture size. The reason is taming those light strays coming out the lens in wider angle than needed for the picture.
What I recommend is to divide the camera in three pieces: the front end with lens mount, the rear end with film back mount and the box between those. If I understand You have allready done this in the rear end.
That kind of modular design makes it easier to fine adjust the construction later.
Btw. I found an old drawing about the light stray reflection in the camera body in an old book. I hope I'll find same kind of drawing in Internet ( or maybe You self )

 

[jaedog]

Introducing.. the Hsu100, my first camera body designed and built from the ground up! Thanks so much to everyone on this amazing forum. Without the help of so many smart and experienced people here I doubt I would have been able to get through this project. I've attached a google drive link to showcase the (almost) final product. I am sending the parts out to get black anodize next week and when they return I will add light seal foam, glue in the wood panels, and finish off the inside.

Here is the link to the google drive folder

(P.S to TimoK, I took into account your last reply and redesigned the internals to be a box shape, but did not add the second light trap on account of the original mamiya RB67 not having one. I did do a few experiments adding some light seal foam to the interface of the film back and body and I could not detect any light leak there or anywhere else on the camera, but only a field test will tell for sure!)

In a few weeks after my girlfriend has had time to test it out and we can get the film developed and scanned I will share some of the resulting photos.

Thanks again to everyone, and happy holidays!

Jaelen

 

[buildbot]

Introducing.. the Hsu100, my first camera body designed and built from the ground up! Thanks so much to everyone on this amazing forum. Without the help of so many smart and experienced people here I doubt I would have been able to get through this project. I've attached a google drive link to showcase the (almost) final product. I am sending the parts out to get black anodize next week and when they return I will add light seal foam, glue in the wood panels, and finish off the inside.

Here is the link to the google drive folder

(P.S to TimoK, I took into account your last reply and redesigned the internals to be a box shape, but did not add the second light trap on account of the original mamiya RB67 not having one. I did do a few experiments adding some light seal foam to the interface of the film back and body and I could not detect any light leak there or anywhere else on the camera, but only a field test will tell for sure!)

In a few weeks after my girlfriend has had time to test it out and we can get the film developed and scanned I will share some of the resulting photos.

Thanks again to everyone, and happy holidays!

Jaelen

This is absolutely beautiful, how impressive!
I’m so jealous you have access to what looks like 5 axis mill?!

Also heads up you may want to re-upload the .heic files in your shared folder without the exif data

 

[jaedog]

Hey buildbot, thanks! I went ahead and reuploaded those photos as .JPEG's. Also the machines we have at my work are 3 axis, and I'm definitely super lucky to be able to drop in whenever there's down time and use them. We have a rotary add on for the other HAAS mill we have but it doesn't get much use.

 

[TimoK]

That's my bad English! I'm sorry. Trap is a wrong word here. In RB67 camera body there is something like walls at three sides of roll film back.
Look at this photo

 

[TimoK]

I tried to add that missing "wall" at the left side of your picture with blue color.

 

[jaedog]

Hey guys!

It's been a little while since I last shared an update, and I've also run into some oddities and imperfections in the developed photos taken on the camera. I've attached the photos here so you can see. For those who have followed along I hope this is exciting for you to see as it was for us! Initial excitement aside, however, there appear to be several ghosty pale streaks and some weird smile shaped marks around the center of the image. Is this a kind of light leakage? I'm unsure as I would suspect a light leakage to cause much more damage as it pours in over time. If this is anything anyone recognizes I'd love to know what it is exactly and if possible where the problem is most likely to lay!

Jaelen

 

[Boinger]

I think you are seeing internal reflections. I cnc'd an adapter for my tech camera using aluminum and when I didn't line it with a black coating of some kind I got similar ghosting or casts of color. Depending on what you shoot. From the pictures it seems like reflections of the main color in the given image clouding the capture.

Is your camera black internally or raw aluminum / reflective? Even a small bit will cause reflections. It should be completely black.