Custom Handheld 4x5

[Ben Syverson]

Hey all,

CAD is coming along nicely on my 4x5 design... I figured I'd use this new thread to post periodic updates on the status of the project.

To get it started, I've attached a 3D render of the film back. The strips at top and bottom of the film aperture are for flocked light seal material. There will also be overhangs at the top and bottom to house springs to keep the film holder in place, but those overhangs will not be part of the mold -- they'll most likely be bonded with epoxy.

I know, I know -- no graflok. I'm following a strict regimen of "KISS" -- keep it simple, stupid. No graflok, but one less part that could potentially break in the field...

Anyway, more soon.

[Gordon Moat]

Very nice. Have you considered making the sides wide enough to allow threaded mounts? Those could be use for accessory shoes holders, or some form of grip.

Ciao!

Gordon Moat
A G Studio (http://www.allgstudio.com)

[Ben Syverson]

Gordon, I think you're right. I'll make the left side wall a bit thicker to accommodate threads for a handle.

Accessory shoes will go on top of the plastic "L" that will hang down and retain the film holder. Easier to draw than to describe:

(shoe)
______________
|
|
|

[Ben Syverson]

Here's a revised render.

[Gordon Moat]

So I am curious how the other side looks. Also, it seems to me that even on a CNC producing rounded corners, edges, and slots would be simpler for maching. I think you might want a felt strip area on the left too, which would mean another slot.

Would the ground glass be a slide in for this concept? That would seem to be the simplest way to implement that.

Ciao!

Gordon Moat
A G Studio (http://www.allgstudio.com)

[Ben Syverson]

Hmm, maybe it is a good idea to have another felt strip on the left.

The ground glass would be sold separately, since the camera will ship with a helical focus mount and won't feature any movements. The top-mounted brightline viewfinder is actually extremely close to what is captured on the film.

You're definitely right about beveling the corners, but I'm going to save that for the last stage of design, since it's easier to work with 90° corners while measurements are still in flux.

[Gordon Moat]

Since you are still at the planning stages, though considering machining and ideas, I thought you might like to see this:

http://www.youtube.com/watch?v=jljr6AYETZ8

Obviously way more complex that what you would need to accomplish. However, perhaps there are some ideas that you might want to try incorporating.

Ciao!

Gordon Moat
A G Studio (http://www.allgstudio.com)

[Ben Syverson]

Wow, that's cool. I didn't know Michael had a YouTube stream! Ha. :)

The camera is extremely impressive -- clearly his focus was on providing ultimate flexibility. Obviously I'm sort of at the other end of the spectrum -- my camera only supports one focal length and no movements! :)

If the initial 90mm model sells a few copies, maybe I'll make another camera from the same basic design, for a different focal length...

In the meantime, I'm tightening up the design, and starting to add bevels. Here are some recent renders. I've included a shot of the front, but it's not very exciting yet. :)

[Frank R]

With side walls that high, I don't think you would need felt strips at all.

[Gordon Moat]

The 3/4 view really shows a great deal of thought. Now that I see the front, I wonder how the lens board/cone/holder is attached. Is that something you are still working on, or will you adapt an existing design (Fotoman, Gaoersi, Linhof)?

I think keeping it simple would be a good start. Allowing a lever wind rollfilm back (Linhof, Wista, Horseman) to mount would allow one lens to accomodate two different types of scene view (crop) in one camera with fixed lens.

Ciao!

Gordon Moat
A G Studio (http://www.allgstudio.com)

[George Kara]

Will your kit allow pack film holders like the 545i and fuji pa-45? Also a locking back like Dean has on his Razzle Mod is really great for urban shooting.

[Gordon Moat]

The other issue with felt strips is marring of the surface. Unless a sufficiently hard surface, wear of the holder, and/or wear on the camera might happen. Some wear could cause shiny spots.

Another approach would be a fixed holder, though that would be less flexible. I suppose the camera body could be anodized or powder coated, but then there would be the issue of thickness of coatings taken into the design.

A completely different direction might be a wooden body (for non-marring properties) with metal fittings for mounts. Unfortunately manufacturing precision would be tougher, and not as easy to repeat as CNC milled metal. Wood usage might also mean a thicker design, and more weight.

Ciao!

Gordon Moat
A G Studio (http://www.allgstudio.com)

[Ben Syverson]

With side walls that high, I don't think you would need felt strips at all.
Interesting -- do others agree? If so, I'll leave it off. I have some very high quality flocked fabric, but it is possible that some fibers will occasionally be shed, and make it onto the image plane. Besides, I'd rather go for simplicity if I can.



The 3/4 view really shows a great deal of thought. Now that I see the front, I wonder how the lens board/cone/holder is attached.
Thanks, Gordon! The lens cone will be integrated into the body -- in other words, the whole thing will be one contiguous piece. This makes the design simpler and structurally more robust. I've attached an image showing a rough mockup of what the lens cone will look like. The cone will terminate with a circular mount for a focusing helical.


Allowing a lever wind rollfilm back (Linhof, Wista, Horseman) to mount would allow one lens to accomodate two different types of scene view (crop) in one camera with fixed lens.

Will your kit allow pack film holders like the 545i and fuji pa-45? Also a locking back like Dean has on his Razzle Mod is really great for urban shooting.
Well, the unfortunate news is that because the camera doesn't have a Graflok back, it won't take every holder out there... You'll notice that Dean's solution is to have a standard film retention device (Razzlok :) ) and a separate adapter for the Horseman lever wind holders. My take is a bit different, and I'm curious what you guys think...

I've attached an image depicting the overhangs which would be attached to the back. Those overhangs would house steel springs to retain the film holder. The top overhang drops out a bit early, to theoretically allow clearance for the winding knob on the Guohua 6x12 roll and the Horseman wind lever.

What I'm not sure of is the clearance necessary for the Horseman roll holders. If someone has one of these, they can tell me for sure. What I'm looking for is the measurement from the absolute front surface of the holder (the surface that is placed against the camera) to the first surface of the film winder. By eyeballing it, it looks like it's at least 20mm, which means that it'll just slide over the retaining clips. If it's under 18mm, I'll need to do some extra tricks to accommodate it.

Other than the Horseman, most holders should be fine. I shoot with Fuji QuickLoads a lot, so I'm making sure that fits. I think that should mean that the Polaroid holders will fit as well.


A completely different direction might be a wooden body (for non-marring properties) with metal fittings for mounts.
The whole body will actually be very hard polycarbonate. I know some people are averse to plastic cameras, but plastic gets me extremely fine precision, great durability, light weight, and low production cost. It will also ensure that the camera won't scratch or wear on film holders. The master for the body mold will be produced with Fused Deposition Modeling (FDM) (http://www.alphaprototypes.com/FDM-Fused-Deposition-Modeling.aspx). Check out this cool video of FDM in action (http://www.alphaprototypes.com/videos/FDM-Video.wmv)...

[Dean Jones]

Polaroid made backs of die cast metal......they had strong springs to exert pressure on the 545 holders and standard double darks, but roll film holders could not be accommodated because the sides were too high and the springs too wide......I used three or four of these over the years, but I found the springs seemed to continually loose tension which may have led to light leaks :eek:

[Dean Jones]

Here's another shot of the Polaroid spring back with lens cone. I'm not sure what it was used for. I thought a lot about the potential of this device, before cutting the rear section off and attaching it to a Polaroid 110B. I guess it resembles what you have in mind, but the retention of the holder and the necessary light tightness is where the problem begins. :)

[BradS]

Polaroid made backs of die cast metal......they had strong springs to exert pressure on the 545 holders and standard double darks, but roll film holders could not be accommodated because the sides were too high and the springs too wide......I used three or four of these over the years, but I found the springs seemed to continually loose tension which may have led to light leaks :eek:


Dean, I'm unclear at what were looking at here...is this a rearview of your camera? or, is it an unmodified polaroid camera?

[Ben Syverson]

Dean, it looks like those springs aren't even touching the film plane... I plan to use steel strips attached to the bottom of the retaining clips I posted a picture of. Based on some initial testing, I believe they should be strong enough to secure even fairly heavy holders.

[Bruce Watson]

Gordon, I think you're right. I'll make the left side wall a bit thicker to accommodate threads for a handle.

Don't do that. If you intend for handholding, then keeping the weight down is paramount. Add some lands for the threads, but keep the weight down by not making the entire wall thicker. In fact you could use a sheet metal technique -- make the sides very thin and turn flanges to create the back to get your stiffness. You'd end up with a "pocket" for the film holder. This would give you a place for springs to hold the film holder up against the front and in the slots as well.

Just a thought. Do with it what you will.

[Gordon Moat]

Since it will be plastic instead of metal, that brings up a question of how strong this camera will be. A 90mm lens on the front is not really light weight. Carrying a camera around by the handle puts a great amount of stress on the mounting point too.

Thanks for posting the front cone assembly. You probably posting this once, but were you planning on adding a Fotoman helical? That would be an easy solution.

I'm familiar with your construction technique, having seen a few demonstrations. It would be fairly simple to change cone length in the design to accomodate other focal lengths. Probably a bigger issue is weight and balance, which can be really important for a handheld camera. If the lens outweighs the body, or if a handle would alter the balance, then a front or side heavy camera might not be that easy to use.

Ciao!

Gordon Moat
A G Studio (http://www.allgstudio.com)

[Ben Syverson]

Don't do that. If you intend for handholding, then keeping the weight down is paramount.
Believe me, I know. :) This will be the lightest 4x5 camera you can buy, outside of a pinhole. I think it will be lighter than my DSLR.

Anyway, I don't think an extra 3mm of plastic on one wall is going to make this thing too heavy to handhold. If you're that concerned with saving a gram or two, you can always sand it down. :)

[Ben Syverson]

Since it will be plastic instead of metal, that brings up a question of how strong this camera will be. A 90mm lens on the front is not really light weight. Carrying a camera around by the handle puts a great amount of stress on the mounting point too.
Gordon, the camera is actually designed around the ultra-lightweight 90's like the (regular) Angulon and the Congo. The Angulon is about 130 grams, which is truly featherweight. If anything, the camera will be back heavy if anything larger than a double dark is on the back.

I think the left wall should be fairly sturdy for the handle -- I increased its thickness from 2mm to 5mm, which is pretty substantial.


Thanks for posting the front cone assembly. You probably posting this once, but were you planning on adding a Fotoman helical? That would be an easy solution.
I'll be using a helical from a different Chinese firm. The Fotoman helicals are very nice, but they've recently gone up in price to $200. Using the cheaper helical shaves almost $100 off the final price of the camera, so I figured that would be worth pursuing. :)

[Frank R]

Dean's photo looks like a Polaroid back that came off something like an oscilliscope camera.

You may want to consider making the back fit a 545 holder which is slightly thicker than a standard film holder. If you bend your springs right, it will then be able to hold both securely.

I just noticed that this design will not work with a Polaroid 405 holder since the left side would prevent the dark slide from being removed.

[Ben Syverson]

Frank, it will admit a Fuji QuickLoad holder, so the 545s should be fine.

As for the 405, I've never seen a holder where the dark slide is removed from the left. Unfortunately, that may mean the 405 is not usable.

[Frank R]

Here is another idea that may simplify your design while meeting all the needs of accomodating different types of film holders and roll film backs.

The picture shows the two slide clips that hold the back onto a Nagaoka. Note that the clips have slots that are milled on a slight angle and are held in with two screws. Underneath those two screws are spring washers that prevent the slides from moving once they are in position. Tension on the washers can be adjusted by tightening the screws. Not shown too well in this shot is that the end of the clips bend up so you can move the clip easily with your fingers.

I have one of these cameras and I am surprised at how tightly the back is held in place and how the slides do not move at all.

You may want to try a larger modified version of this clip. Maybe a single one on both top and bottom. Depending on how far you slide it, it will adjust to the different thicknesses needed.

BTW I snagged this photo from here:
http://www.vanityforgotten.com/ebay/viewcamera.htm

The camera pictures were posted for an ebay sale of this camera which has now been sold.

[Frank R]

As for the 405, I've never seen a holder where the dark slide is removed from the left. Unfortunately, that may mean the 405 is not usable.

Yeah, the 405 darkslide comes out of the left side. Many people like to test their exposures with the pack film because it is so much cheaper than 4x5 Polaroid film. This should not be overlooked.

My last post idea would allow for all holders if the light trap walls were reduced in depth.

I really like the idea of a light plastic LF point and shoot.

[Dean Jones]

Dean, I'm unclear at what were looking at here...is this a rearview of your camera? or, is it an unmodified polaroid camera?

The first pic is one of the rear section mounted to a 110B, the second pic is one of the Polaroid 'whatever' camera housing, exactly how it was purchased.
I think there are two very important points that should be given consideration when designing a compact 4x5.....firstly it should fold up as flat as possible so you can store it easily in a back pack and the second point is the weight factor, which will obviously not be a problem here.
Having said that, I agree that a camera should still be well balanced and weighty enough to overcome the tendency for camera shake, a problem that applies to the lightweight digicams. Pick up a plasticky cheaper compact digital camera...it doesn't feel as good as a more solid metal bodied camera with better balance.;)

One more important factor of a hand held 4x5 is the method of focusing.....unaided by any kind of coupled rangefinder it can be rather dicey, especially at wider apertures.
Smaller apertures to increase DOF only results in longer shutter speeds resulting in the inability to hold it still, which in turn means we need a monopod or tripod.
Then the whole concept of being hand holdable has gone. :eek:

The only way for a rigid style camera is by using a 90mm or similar wide angle, this results in a more compact body and less worry when it comes to exact focus. Once you go longer in focal length, no end of problems arise. Focusing close in with anything around 150mm definitely requires some form of accurate focusing system.
It ain't as easy as it looks........

http://homepages.ihug.com.au/~razzle/

[Ben Syverson]

Frank, thanks for the idea about the clips! I have some time before the helical arrives, so maybe I'll do some thinking and see what I come up with. I definitely would like to be able to support as many holders as possible.

If anyone has any more tips or ideas about holder retention mechanisms, I'd love to hear them -- the simpler and more flexible, the better.

[Ben Syverson]

I think there are two very important points that should be given consideration when designing a compact 4x5.....firstly it should fold up as flat as possible so you can store it easily in a back pack and the second point is the weight factor, which will obviously not be a problem here.
This camera won't fold, but I've put the prototype in a small side bag, and it fit well. Basically any bag that you would take your MF gear in will work fine for this camera.


The only way for a rigid style camera is by using a 90mm or similar wide angle, this results in a more compact body and less worry when it comes to exact focus.
My thinking exactly. This camera is specifically designed for the 90mm focal length. If I sell a few copies, I may produce 75mm or 65mm versions. It would be extremely easy to modify the design for different focal lengths, but I'd prefer to go shorter rather than longer.

That said, I've used a cheap Lomo-made "Blik" external rangefinder with some of my cameras, and it works great, especially when you're focusing close at wide apertures.

[Dean Jones]

I guess I'd like to design and build a 4x5 camera that folds into itself, slips in your pocket, fitted with a coupled laser rangefinder.

Ideally it should have a 65mm-210mm f2 zoom lens that also folds into itself. It should weigh no more than a pound, cost under a $1000 and come equipped with a full frame 4x5 digital sensor with wireless transmitter.

Of course it would have full front and rear movements, be built of materials that are not affected by water, sun, solvents, acid rain or nuclear fallout.

It should also be tough enough to support the weight of your car when changing a tyre and be able to stop a bullet.

Now you know my most inner thoughts.........:p

[Ben Syverson]

Dean,
Sounds great, but I don't think you'll sell many if you limit it to 4x5. If you could make the same camera with an 8x10 sensor while keeping the size and price the same, I'd buy one.

[Frank R]

Hey Dean, I would like to see a 4x5 version of a Patent Etui. But with the door folding down instead of to the side. Real bare bones but with front rise and tilt.

[Paul Droluk]

The whole body will actually be very hard polycarbonate. I know some people are averse to plastic cameras, but plastic gets me extremely fine precision, great durability, light weight, and low production cost. It will also ensure that the camera won't scratch or wear on film holders.

We've looked into using a number of plastic materials to mold a lower cost version of our 45PS camera... so far without success. Polycarbonate, while providing high tensile strength and a low wear surface, will fracture quite easily if subjected to impacts... don't bump into things or put it down on hard surfaces without taking care. ABS, PC/ABS blends, and Nylon/ABS blends were also investigated... unfortunately they simply aren't strong enough. Also, most plastics don't hold up very well to UV radiation, and coatings do not adhere very well. The only method we found structurally sound was a polycarbonate internal structure with an overlay molding of soft touch synthetic rubber... by then, costing became prohibitive.

[Dandy97]

We've looked into using a number of plastic materials to mold a lower cost version of our 45PS camera... so far without success. Polycarbonate, while providing high tensile strength and a low wear surface, will fracture quite easily if subjected to impacts... don't bump into things or put it down on hard surfaces without taking care. ABS, PC/ABS blends, and Nylon/ABS blends were also investigated... unfortunately they simply aren't strong enough. Also, most plastics don't hold up very well to UV radiation, and coatings do not adhere very well. The only method we found structurally sound was a polycarbonate internal structure with an overlay molding of soft touch synthetic rubber... by then, costing became prohibitive.

If you are having problems with polycarbonate fracturing with impact stress then your molder is not properly molding the material and degrading it. Polycarbonate is a very difficult material to mold properly, as it does not have a very large processing envelope. When molded properly and with a small amount of glass content it has very good impact qualities. I have taken polycarbonate parts and jumped up and down on them without any adverse effects, and I am not lite. One test we have performed on parts in the past is to go onto the roof of our building and toss polycarbonate housings onto the concrete below. If they are properly molded, they will not break or crack. This is actually a test outlined by one of our customers.

Another material that you may want to look at is mineral and glass filled nylon. This material is used for, among other things, molding engine parts like: cam covers and intake manifolds. It is equally indestructable as polycarbonate and is much easier to mold.

[Ben Syverson]

If you are having problems with polycarbonate fracturing with impact stress then your molder is not properly molding the material and degrading it.

I agree. The Mamiya 7 has a plastic body, and I've dropped it from 4 feet onto concrete, due to a faulty strap ("quick release" indeed). It came away with a few scars to boast of, but no fractures.

That said, if someone buys one of my cameras and cracks it, I can replace the body for free or very cheap. That's the beauty of plastic.