Some musings on camera design... [Archive] - Large Format Photography Forum

jb7

8-Jan-2010, 05:59

I'm considering the design for my next camera.
I want something light, that I can travel with, probably 4x5, but I'm also considering 5x7.
Perhaps it's just a question of which one I build first...

Probably 4x5. I know that cameras are cheap,
and that some will consider it insane that I should make one, rather than buy one,
so hopefully we've got that one out of the way.

So far, the parameters for the design are as follows-

lenses- from a 47XL to a maximum of 350mm extension, using one bellows.
Ideally, I'd need to source thinner cloth than the last set I made-

Movements- full movements on the front, undecided about movements on the back-
obviously, a fixed back would be stiffer, and smaller
(and prettier- the less I make, the better it looks)

Maximum rise about 50mm, perhaps a little less shift and fall-

Bed- at least a double extension, perhaps similar to the Ebony SW-
with an extra extension for longer lenses.
I don't think I'd be interested in a folding design...

Material would be American Black Walnut and Aluminium.
A more exotic metal would be preferable,
but a lot more difficult and expensive for me to source-

Lensboards- Technika type-

One largish question I'm asking myself-
rather than making a camera with a square removable back, for easily changing the film orientation,
I'm considering making a fixed one, to the proportions of the holder,
to keep the overall size to a minimum.

This would, of course, mean that the whole camera would need to be rotated when changing from portrait to landscape.
Two (or three) tripod mounting points would make things easier,
and the light weight would help.

I made a point and shoot camera that works like this, and the savings in bulk are considerable-

Another consideration is the focusing system-
helical pinion drives and racks are not at all cheap,
and will probably be the single most expensive part of the camera-
quite possibly more expensive than some lenses...

I've sent an enquiry to SK Grimes about this, and I'm awaiting a reply...
Of course, should anyone have something suitable on an otherwise unusable camera,
I'd be pleased to hear from them-
these things can always be incorporated if you have them in your hand...

Straight cut gears might be a little less expensive,
but wouldn't be as good-

So that's some thinking out loud done-
any thoughts or observations would be welcome,
although suggestions that I should buy a Shen or a Cham less so...

My experience of different types of cameras is limited;
I use a 171 Arca F-Line, and would like something smaller and lighter-
I reckon I'd use it for Architecture and portraits-
perhaps the odd landscape if I found myself in one...

Thanks for listening-

joseph

Dan Fromm

8-Jan-2010, 07:17

http://www.thalmann.com/largeformat/toho.htm Perhaps not exactly what you think you want, but food for thought.

Frank Petronio

8-Jan-2010, 08:40

isn't back tilt more useful than front tilt? I'd put the shifts and rise up front and swing/tilt in the back. The Linhof Technika mechanism seems like a simpler way to accomplish the back movements, although people can swear at them. The Toho rise/shift lensboard is simple and clever....

If you could put up with the slower operation, you could "pin" the gross movements and use a focusing helicoid for fine focusing. That would save weight and complexity, not having a full focusing track.

You might look at this, I think a monorail may well be the lightest and simplest design.

http://www.glennview.com/sinar.htm scroll down to "HALFBREED SINAR/GLENNVIEW CAMERA"

Nathan Potter

8-Jan-2010, 09:46

I might investigate sources of carbon fiber for the material if you really want to push the lightness deal. As Dan points out the Toho reviewed by Thalmann looks like a dandy piece of kit. But if you have construction skills, the challenge of building your own has its own rewards and has nothing to do with cost or time. My first 4X5 was built with surplus parts and walnut standards.

Nate Potter, Austin TX.

csant

8-Jan-2010, 10:24

As far as I have seen camera designs, foldable cameras seem to be less bulky than non-foldable (at least concerning transportability). Why would you go through the hassle of saving on camera size by making a fixed orientation back, and then go non-foldable? (just thinking out loud here - and please correct me if I am wrong)

Eric Woodbury

8-Jan-2010, 10:33

I have some thoughts on this. I've been designing a new camera similar to your specs for about a year. I have started over twice. This will be my third 4x5 that I've designed and built. My use is mostly landscapes and abstracts, so my movement requirements are somewhat different. Also, I want to use lenses from 58 to 450mm. I will get back to you when I have a few more minutes.

Robert Hughes

8-Jan-2010, 10:36

Good thread Joseph, but... next time, can you make it rhyme? I'd like to see it presented as a sonnet.

Jack Dahlgren

8-Jan-2010, 11:18

Good thread Joseph, but... next time, can you make it rhyme? I'd like to see it presented as a sonnet.

Haiku seems suitable for this topic:

lightweight camera
make it from carbon fiber
spidersilk bellows

jb7

8-Jan-2010, 11:44

Good thread Joseph, but... next time, can you make it rhyme? I'd like to see it presented as a sonnet.

Thanks Robert, I'm afraid I can't obey your command-
though describing a camera in 14 lines
(employing the use of internal rhyme) would surely serve to sharpen the mind...
but for now, it's back to the task at hand...

Thanks for the comments and observations- and links-
I hadn't seen that Sinar page before, it's always good to find someone more obsessive than yourself-

I use a monorail already, and I'd like something different.
While there might be some design pointers there, I just don't have the facilities or skills to work with metal-

I've posted a couple of cameras on these pages before,
the Arca Irish 8x10 conversion, and the 4x5 point and shoot camera (The Plank),
and they would better describe the materials and skills I'm stuck with-

I take the point about the swings and tilts to the rear,
as I mentioned, I'm undecided-
I know I can make a better looking, stiffer, camera by keeping it simple,
and the functionality might not be impaired too much.

I do have an open mind though, at this stage nothing is built (well, apart from the front standard).
Though even that isn't finished...

Why would you go through the hassle of saving on camera size by making a fixed orientation back, and then go non-foldable? (just thinking out loud here - and please correct me if I am wrong)

The camera should be relatively short, with no fold out bed-
I'd like to use a 47mm XL, and don't want to get into drop beds to accommodate it,
although the drawings are at a very early 'blocking out' stage.

I'm used to carrying the Arca in a backpack, with a lens attached, so that it only needs to be mounted and focused to be ready for use.
I reckon I'd like a similar arrangement for this one, but in a lighter, smaller package.

There might be a way to wrap it up in a removable shell, I suppose, for protection...

Nathan, I've used walnut before, and it is really quite light-
I'm not going to be trying to break any records with the weight,
and fabricating custom carbon parts might be (will be) beyond me and my pocket...

Thanks again for your comments and observations, already I'm tilting back towards rear tilts and swings-
well, a little bit anyway...

Robert Hughes

8-Jan-2010, 11:53

5 Stars! Jb7 Ftw!

jb7

8-Jan-2010, 11:58

:)

Ftw?

Jack Dahlgren

8-Jan-2010, 12:01

I used to think it was "f*** the what?" but later learned it means "for the win"

jb7

8-Jan-2010, 12:03

"f*** the what?"

might be more poetic...

John NYC

8-Jan-2010, 18:45

By the way, don't ever challenge the Irish to a language smack down... James Joyce, William Butler Yeats... it's in the genes my friends.

athens01

11-Jan-2010, 09:48

Jb7, 4x5 is relatively square, (compared to 5x7), So in my opinion, the slight savings of material and weight of a fixed horizontal 4x5 don't outweigh the flexibility and ease of rotating the back to vertical. A 5x7 is totally different. You only need 5.5-6 inches square for a 4x5 with a rotating back, you'll need 8.5-10 square to allow for a rotating 5x7 back. So building a 5x7 horizontal camera makes sense to me because you can save a significant amount of material and bulk to the camera body, but a fixed 4x5 isn't really that much smaller than one with a rotating back.

I've been thinking about building a 5x7 camera with a "rotating front" A colleague says some French cameras of the late 1800's were designed like this, but I don't know any makes. So basically, make the 5x7 standard and back just big enough for the film holder, or horizontal "only", and to rotate it to vertical you'd basically disconnect the back standard from the camera bed, rotate the back AND the bellows off the front standard, the re-lock the back standard in the vertical position. I suppose you don't need to rotate the bellows off the front standard but you could basically split the bellows in have , 5x7 to square then square to the lens board, put a light trap at the break and rotate the back and back half of the bellows of the mid section... anyway some thought.. Some consideration for the point at which the rear tilts needs to be worked through but I think it would work..

jb7

11-Jan-2010, 14:09

Interesting idea regarding the rotating back and bellows, Peter-

You mention the limited savings to be made by not having a square back-
but you have to consider my chosen material too- wood-

Making an articulated back would require two thicknesses of material-
one, the removable back, and two, the rear standard connected to the bellows.

The Toho that Dan linked to on the previous page has the advantage of being constructed of metal, and the thickness of the rear standard is extremely thin-
I'm not sure I could make something that light in timber and make it durable, and free from the possibility of warping-
and any extra dimension on the standards will take away from the bellows length,
which I'd like to fold quite small, to accommodate the 47mm.

In fact, I think the bellows might have to be the first component I make, to make sure that they'll fold tight enough.

I like the idea of the rotatable back and bellows, but will need a little time to think it through-
it actually adds to another thought that occurred to me, that perhaps a modular camera might be considered, that could have both a 4x5 and 5x7 back-

As I mentioned previously, doing away with the notion of rear tilts and swings would make for a more easily constructed, stiffer, and prettier camera,
and given enough rise, fall, and shift,
rear movements can be implied, so to speak- perhaps not too much of a limitation.

Regarding your point about the squareness of the 4x5 format-
it's surprising how much smaller a 4x5 back can be compared to something that has to accommodate a removable 5x5 back-
at least, that was my experience with the p&s camera I made-

I'd also like to thank Eric Woodbury, who pm'd me with his thoughts on camera design, much appreciated-

And John, of course, from the next parish, for the plámásing...

j

athens01

12-Jan-2010, 07:38

J, You're probably aware of these companies, but if not, they may give you and idea on some focusing parts... in the power transmission sections. and of course they are expensive.. and shipping.. I think the precision threaded rod in the mcmaster-carr catalog leads to some interesting ideas about a focus set up. and just incase anyone's else is interested in this type of thing:

http://www.smallparts.com
http://www.mcmaster.com/
http://www.mcmaster.com/#catalog/115/1091/=5ccj2s

jb7

12-Jan-2010, 07:59

Thanks Peter, yes, I'd seen the MMC stuff-
perhaps a larger module than I'd like-

SK Grimes did get back to me, sent me a search engine, so not much help-

Racks are going to prove difficult-

Threaded rod for rear focus is still a possibility, I suppose-
is that how the Chamonix works?

Thanks again for the links-
will have another look-

Bob Salomon

12-Jan-2010, 09:26

You might want to read this and then rethink back movements.

http://www.rodenstock-photo.com/mediabase/original/Entzerren_am_Computer_A4_e_Druck_7860.pdf

jb7

12-Jan-2010, 09:33

Thanks Bob-

I had a quick look, that article only seems to reference lens movements and digital corrections-
did you post the right link?

Bob Salomon

12-Jan-2010, 09:37

Thanks Bob-

I had a quick look, that article only seems to reference lens movements and digital corrections-
did you post the right link?

Yes, it shows why movements in camera are the best way to correct image shape (back movements) and maintain maximum resolution compared to not doing the movements a correcting in computer.

jb7

12-Jan-2010, 09:47

ok, but those movements could just as easily be applied to the front standard to achieve the same results.
Nobody mentioned using a computer for corrections.

Rear swings and tilts would be useful for plane of focus corrections,
but I find that when shooting buildings with the Arca,
front rise is usually the first movement called upon-
since both standards are usually in the lower position to start off with.

It's a system I'm used to, and it works for me.

As I mentioned earlier, I plan on including full front movements-
it's the rear movements I'm undecided about-

Gordon Moat

12-Jan-2010, 14:46

If your rear standard movements are on the film plane axis, then the change in focus, or need to refocus, is minimal. I have worked on this with my own camera design, though at the moment my emphasis is on rear swing and not shift.

Brian Stein

12-Jan-2010, 15:44

Jb7, 4x5 is relatively square, (compared to 5x7), So in my opinion, the slight savings of material and weight of a fixed horizontal 4x5 don't outweigh the flexibility and ease of rotating the back to vertical. A 5x7 is totally different. You only need 5.5-6 inches square for a 4x5 with a rotating back, you'll need 8.5-10 square to allow for a rotating 5x7 back. So building a 5x7 horizontal camera makes sense to me because you can save a significant amount of material and bulk to the camera body, but a fixed 4x5 isn't really that much smaller than one with a rotating back.

Another consideration in the 45 vs 57 is the widest lens with full coverage on 57 IIRC is the 72mm schneider.
I am a 57 devotee (I love the way a vertical 57 contact looks just like a page from a book) and am reworking my current P&S into carbon fibre with that orientation, but have also considered what you are discussing so will be following this with interest.

In terms of the focussing if you do use the phillips/chamonix type of mechanism this has been done quite inexpensively with threaded rod / nut (of course now I cant find the link), or with what looks like something stolen from a macro setup http://home.online.no/~gjon/tsmith.htm

jb7

12-Jan-2010, 17:26

Thanks Gordon, Brian-

Gordon, I'm not used to axis tilts, they'd be a luxury-
but if tilts and swings were to be incorporated,
I think I'd make them close to the axes-

Brian, the 5x7 is very tempting, but there is no shortage of temptation in photography-
and I think I'd be happier traveling with a 4x5-

True, the 72mm covers 5x7, but I think I might like to use that that large circle for movements on 4x5-
and the 47mm gives a similar view (if a different proportion) on 4x5-

Working the other way, I'd need a new 110mm with a large image circle to match the 72mm on 4x5, if I were to decide on 5x7.
And that's not going to happen-

Also, I've got a 5x7 portrait lens, a large one, so it would make sense to accommodate that, if I were to consider a 5x7,
so that might need to be a different camera altogether- perhaps another Arca conversion-

All this thinking aloud about personal choices must be getting a bit tedious;
but in a nutshell, a traveling 5x7 would be a nice thing,
but I don't have the lens set to match-

I have considered a threaded rod focusing device,
I even have a design for a spring loaded rough focus mechanism that I stole off a height adjusting foot from a projector...
and considering the cost of rack and pinions, I might end up using something like that yet...

I also considered a Macro Rail for focusing, I bought two of them with that in mind a while ago-
not the same one as in your link, but, I don't think it's a solution-
just as in the camera you referenced, it looks out of place, an addition, and not an integrated solution- and I think it should be possible to do better-

Though I always think that before I start chopping things up...

Gordon Moat

12-Jan-2010, 20:09

http://www.mcmaster.com/#gear-racks/=5cm6b0

Those can be much cheaper. You need a pinion gear to drive it, and something to turn the pinion. Where I have been stuck on a camera design is lockdown handles, since all the ones I found on McMaster Carr are simply too big for my needs.

jb7

13-Jan-2010, 05:05

Thanks Gordon-

Yes, the hardware is a problem, particularly the racks and pinions-
or, if you to be serious about it, the paired helical racks and locking pinion shafts-

The Ebony is the obvious case study here,
and from extensive searching of engineering companies on the internet,
I'd have to conclude that the drive trains they use are not cheap to make.

Let's leave out the custom locking pinion shafts for a moment;
two 400mm helical racks, 0.5 mod, stainless, from http://www.hpcgears.com/sitemap.htm
would cost £240 + vat,
and 4 double pinion drives £100 + vat,
and this would only be a start point, basic components.

A custom pinion drive, or preferably two, with locking provision, would be a better solution,
but I would imagine those parts would be hugely expensive to commission.

The problem with the MMC drives you linked to above is that they're quite large-
the drive itself is about 12mm diameter-
and apart from the unnecessary bulk it would add to a small camera,
it would mean a large amount of travel from small inputs-
not the precise travel I'm spoiled with on my own camera, with a drive of around 4mm diameter.

It becomes clear that one of the reasons that the Chamonix is so affordable
is because of the decisions taken about the focusing system-
and it's looking like I'm going to have to choose a similar route.

However, if there are any engineers/machinists out there who could give me some more reliable information,
I'd be very pleased to hear it...

Locking levers, miniature precision ones, are another problem;
I've already given up on them, and have been considering using thumbscrews to clamp sliding parts into position.

So, so far- and this thing is beginning to gel a bit-
focus via a threaded rod mechanism, driven by a wheel to the rear, with a spring loaded quick release for coarse positioning-

Front extension via interlocking sliding beds, clamped into position with a pair of thumbscrews for each bed.

There. I reckon I saved myself 500 quid this morning...
at the cost of some fretting about the loss of a more ideal solution-

Bob Salomon

13-Jan-2010, 05:56

ok, but those movements could just as easily be applied to the front standard to achieve the same results.
Nobody mentioned using a computer for corrections.

Then you don't fully understand the difference between front and rear tilts and swings.

Both will coontrol the plane of focus. But rear movements also control the shape of the subject. Front swings and tilts do not.

Yes you can do the same, if your lens has enough coverage, by using direct displacements (level camera and using rise and fall only. But your design doesn't really have enough to do that on most architecture shots (for example - the Linhof re and GT have 3.3" of front and rear rise which can be extended in 3.5" increments beyond that. The GTL has 7+" of rise in the front). And your design doesn't have rear rise and fall or shift as I read your plans and only a small amount of shift.
That is why I sent you to the computer link because that is one way that you could correct image shape in PP. Only at the cost of image quality.

jb7

13-Jan-2010, 06:12

Then you don't fully understand the difference between front and rear tilts and swings.

Thanks Bob.

Willful ignorance is one of my many failings.

Btw, what wide angle 4x5 lens do you sell that would be able to use 7" of rise?

Colin Graham

13-Jan-2010, 07:14

Hi Joseph, I built a WA design 5x12 last year and kept a general log of the process. It was fairly specific to my own needs, but it might give you some ideas.

http://www.colinflanarygraham.com/cameralog.html

jb7

13-Jan-2010, 07:26

Thanks Colin, yes, I remember that one-
I'm pretty sure I complimented you on it at the time,
very nice looking cameras, and beautifully made-

I had it bookmarked already...

A 4x5 will be smaller, of course, which will lead to its own problems-
when I did the 8x10 conversion, I had expected that my next camera would be bigger than that,
but some recent traveling convinced me that I should really be thinking about making my existing setup less painful to carry around-

Will definitely be having a look at your cameras again-

athens01

13-Jan-2010, 10:58

Yet another (hair-brained) idea for rear movements......It may not be elegant, but if you did design the camera like we talked about earlier.... detachable rear standard, rotating back and bellows for horizontal and vertical options..., you could incorporate different fixed connecting points to enable generalized directional perspective changes (back movements). In other words, fixed tilt and swing positions that buy you just enough angle difference to give the lens and front standard some help. I only say this only in thinking about a design with a detachable standard...if the detachable back is "central" to the design of the camera then why not explore options around that specific design element... hell it may be more irritating to use if you can lock in say a 10 degree tilt but that's all...just an idea..

Gordon Moat

13-Jan-2010, 16:02

http://www.youtube.com/watch?v=MKb4Dkjjmk8

The elegant aspect I find about the Gilde 617 camera is the use of magnets to hold various parts in place. There are also lots of interlocks and movements.

http://www.edmundoptics.com/onlinecatalog/browse.cfm?categoryid=30

You might want to request a catalogue, though if you browse through their Positioning Stages, you might find a few items you could use. Prices are okay if you only want to make one or two cameras, but would be expensive for production.

http://www.edmundoptics.com/onlinecatalog/browse.cfm?categoryid=256

I am looking at production, and not just one camera. What I found with small lockdown handles is that I needed to order over 100 in order to get anyone interested in making them. That means I would need to finalize on one design, and then use it throughout the camera. The process has been quite difficult, though if I manage a large order of handles, then the overall price point would stay within reason on the finished cameras (target under $800 US).

The trick on the rack and pinion, with a courser rack, would be to get a larger pinion, or a smaller pinion. The idea is to translate hand (finger) motion to rack motion, and the diameter gives you finer control. I don't see the advantage of a helical, because some for of lockdown would be your device to prevent slippage.

Ciao!

Gordon Moat Photography (http://www.gordonmoat.com)

JRFrench

13-Jan-2010, 17:07

I have recently finished making my own 4x5 camera, mainly using the CNC mill at my University, as well as the CNC Lathe to make the thumbscrews. I ended up using rare earth magnets for attaching the back to the standard, and most of my movements are a bit different to how you would see them on commercial cameras as I had to design it around the equipment and materials I had available.

The focusing screw is a bit tedious, its very slow and you can't force it by pushing the standard to the rough position like you could with a rack and pinion. Unfortunately I found Rack gears difficult and/or expensive to find over here. If I were to do it again I would try a friction rack and pinion, where a rubber wheel roller on a grippy bar.

At the moment some of the movements require an allen key to unlock, but eventually I will make some lightweight aluminium thumb screws so no tools are required.

Some more photos here: http://www.flickr.com/photos/27441544@N07/sets/72157623205328086/

jb7

14-Jan-2010, 04:01

Thanks again for your continued responses-
JR, that's a particularly robust looking camera-
I'm very jealous of your access to CNC-
Detents are a nice touch too, not sure I'd be up to that-
I'm sure I could make them, but would be worried they'd turn up in the wrong place...

There is a solution to your tedious focusing screw,
involving a spring loaded nut that is pushed out of the way for fast, rough focusing-

It looks a bit heavy, have you weighed it?
What are you studying, is this part of your course?

Gordon, I suppose the advantage of the helical drive is in keeping the bed centered,
and perhaps it might run smoother, with less likelihood of binding against the sides-
The smaller modules might allow for lower gearing, more input, less travel-

That 617 looks good, completely beyond me though-
I like the motor drive, from time to time I wonder about how motors can be applied to movements-
Then I pull myself together-
I've seen pictures of an electrically driven 20x24, but it was huge and heavy looking-

Can't help you on the lockdown handles, I'm afraid-
that's the difference between making something for yourself, and making something for production-
the market is far less accepting of my limitations than I would be-
Did you say you were designing a 4x5 camera?
Look forward to seeing something, sounds interesting-

I had a look at those Edmunds bits, don't think you'd hit your price point by shopping there-

Peter, that rotating rear standard and bellows is giving me something to think about-
but I'm wondering is it overkill-
a simpler solution would be to build a camera without it, and use an 'L' bracket to rotate-

The rotation is a good trick, and I like the look of the camera you linked to,
but it would exclude the possibility of rear movements altogether-

My ignorance of the function of rear movements notwithstanding,
(that's sarcasm, unfortunately)
I'm still not completely decided about which, if any, to include-

I had another look at Colin's camera again last night, it makes good reading-
particularly the musings about interlinked three dimensional thinking,
and how components determine other components-

Although there appeared to be a very strong vision about how things worked together,
and the timeline for building it showed very rapid progress,
it was reassuring to know that even Colin had to make time for some head scratching...

Colin Graham

14-Jan-2010, 04:34

Thanks Joseph. Sorry about the redundant posting, couldn't remember if I'd posted a link to it over here or not. I envy you your project, and look forward to seeing your progress with it.

Gordon Moat

15-Jan-2010, 12:39

Thanks again for your continued responses-
.......

Gordon,
........
Did you say you were designing a 4x5 camera?
Look forward to seeing something, sounds interesting-

My test of all this, and what led me to working on a 4x5 camera, was doing a Polaroid conversion. I made the entire lens block movable front standard on a milling machine. The rear film holder was made from one block of aluminum on the same mill. Everything is as compact as possible, and as thin as I could work with the Polaroid body.

What I discovered was that the milled parts are vastly more robust than the Polaroid parts. It made me realize how limited the Polaroid camera design is as a starting point. So I decided to work on a dedicated 4x5, which will probably use the rangefinder mechanism of the Polaroid, though more likely just a platform allowing regular 4x5 usage. Sketches, mock-ups and using Google SketchUp have allowed me to figure out the dimensions.

First hurdle was the bellows dimensions. While a custom design could be made, that would increase costs, so it was decided to use an existing available bellows. Next was the decision to go with Technika style lensboards, since I already have several. Then with the major detail limitations, I have been polishing the design. Unfortunately, I have yet to solve the lockdown handles, and that might mean more changes before I get to a final product. Realistically, I am aiming at about 10 cameras as the break even point, not counting my time involvement.

What I want out of it is a 4x5 camera that can take rollfilm or instant film holders, and use regular 4x5 holders. I want rear swing movement without focus shift, which would allow for things like selective focus (portraits, still life, etc). Weight needs to be light enough to hand hold, and ergonomics so that it feels balanced. Additional movements on the front, in a manner I worked out on the Polaroid conversion (swing, tilt, rise and fall, shift), using only two lockdown handles. Everything with zero detents using threaded slugs that McMaster sell (M4 x.7 thread with 2.5mm ball). Mostly 6061 and 7075 heat treated aluminum for strength and low weight.

Ciao!

Gordon Moat Photography (http://www.gordonmoat.com)

JRFrench

15-Jan-2010, 13:00