New LF user needs help understanding backs

hi, im very very new to LF, as in ive never shot one, only held, looked at, and read alooooooottttt about it.

anyways, my dilemma, this summer ive decided my project will be to build a point & shoot 4x5 camera with some wide angle lens on it (37-75mm, havent decided yet). i will be going the route of using an old olympus lens' focusing mechanism and rigging it up with the lens to achieve focusing w/o bellows or sliding box. the camera body will most probably be wood, ill probably make a mockup first, then a version using nice wood, and maybe, if i can get my friend to do/teach me how to use the CNC machine in the architecture lab at school make a body out of exotic wood and a removable cone (fotoman type) out of aluminum.

my problem lies in the back of the camera. im simply clueless as to how LF backs really work. im a MF whore and understand them completely but this is a diff. beast. i have a basic knowledge of 4x5 film holders but my problem is where do they go? if there a "back" persay on 4x5 cameras, or do you just slide the holder into grooves made into the camera. also, i want to be able to use a ground glass/lexan. what do i need to read/learn and buy to do this? are there "backs" available that just accept the GG and film holders? is that even how it works, lol? i dont think so.

(there was a url link here which no longer exists)
that is sort of what i want to do but he did not explain how he went about creating the back of the camera which is my biggest confusion.

and finally, to avoid the usual but necessary questions. i am not doing this because i think its cheaper, LF cameras are extremely cheap now on fleebay which im aware of, this is as much about taking pictures for me as it is designing something and building it (im a photo & architecture major so the designing is normal). this will be expensive and time/labor intensive and i understand that.

with that said, sorry for boring you, i just really need some help

Thanks,
kauffman

Posted wirelessly..

Kauffman, if I understand your question most LF field cameras simply have a rectangular frame that contains a ground glass upon which you compose. This frame is held tightly against the open back of the camera with a spring loaded hinge. When you are done composing on the ground glass, you pull back the unhinged side of the back, slide in your filmholder (or Graflex or other back), making sure the holder. Grooves align with the back appropriately to ensure light tightness,then remove your darkslide and shoot. I hope this is what you were trying to understand. If not, sorry.

I can't answer your questions but I believe some time ago Peter Gowland made a LF camera intended to be hand-held and without a bellows. You might try a search for him and track down more information.

36cm2, thank you for clearing that up, thats exactly what i was looking for. what i need to see now is a detailed image or diagram of it all because at the moment i dont see how the frame w/ GG pulls away and allows the film holder in. you said the "unhinged" side of the back, do you mean the frame w/GG only has spring tension on one side?

I just quickly googled Peter Gowland and clicked on cameras in the topics. There are excellent pictures of the cameras that may give you ideas.

Posted wirelessly..

Exactly. I have a Tachihara, so that's my frame of reference. Google Images the name and you'll come up with something that shows the back. The hinge is attached on the upper and lower edges of the back and on the camera body edges at a point about 2/3 toward one side. You can lift both lateral edges, but one side lifts more easily than the other. On that side there is a bump along the edge of the camera body backside that bumps up against a correlating bump on the film holder (or graflex,etc.) and let's you know when the holder is in the correct position so that when you let go of the hinged back it pushes everything lighttight against the camera again. Sorry if this isn't clear. It's from memory, wirelessly posted from a parking lot (picking up the wife at work).

Posted wirelessly..

To clarify, there are two actual hinges, one on the top side and one on the bottom side. The right and left sides open when lifted to receive a holder.

I am on the same page as you - I figured it out by playing around with things until I understood what has to happen. Moving levers and trying to figure out what lever locks or unlocks the gg to be able to rotate it, pulling on levers to see what moves or not. The key to this is "Be Gentle" and "Don't force anything" or damage to the camera may follow. Those are general good rules for any camera really. But LF is a different beast. I am still playing with the camera, the movements, practicing putting film backs in, taking the slide out, tripping the shutter, putting the dark slide back in (with the opposite side showing so I know if it is "exposed" or not) and then taking the film back out, turn it over, do it again. Practice until you are real comfortable with the movements, the levers that lock the movements, both opening and closing them, double checking yourself each time. It's a slow process for me but it will improve my efficiency when I do start shooting.

One thing I have found about Apug - if you have a question, people here are very willing to help in every way they can. I have learned more here in less time that anywhere else online.

Good luck to you.

If the project is a point and shoot camera, then the complexities of the standard spring back are unnecessary. The film holder just has to be clamped to the back of the camera. The film depth inside the holder with the darkslide removed is standardized. Older technical cameras require that you exchange the ground glass back for the film holder. If you will be using an accessory finder you should only need to worry about attaching the standard holder or a roll-film back, and setting the infinity focus. The rest is a light-tight box with some ergonomic considerations.

I just constructed (built is too grandiose a term) a pinhole camera using a wooden cigar box. The lid accepts the film holder and acts as the clamp to locate the holder. It is not pretty, but it works. Obviously pinhole requirements are less exacting than a lens mount. http://grahampatterson.home.comcast.net/~grahampatterson/grahamp/pinhole/index.html

grahamp, you're completely right for a point and shoot with hyperfocal focusing, which i dont want to use yet. i am going to attempt rigging up the focusing mount from an olympus lens as some have done and being able to focus a certain amount. which means i need a ground glass. im afraid the spring back i will need to source as its a certain standard across the board.

so any suggestions on a cheap spring back with opening for ground glass i can buy and permanently attach to my camera box? preferably one new enough that it accepts all the common film holders. thanks

If you get a Graflock back from a Speed or Crown Graphic, or if you buy a rear standard from an old monorail, things may become a bit simpler- even if you simply use them for models. Then you can use Grafmatic holders to carry 6 shots at a time. A point and shoot that requires using ground glass is going to be a bit awkward at best. Rangefinders set to the lens you choose is the only real way to go unless you're guestimating distance and shooting one shot at a time. If that is your goal, I agree with grahamp- just build the camera to take a film holder solidly attached (clamped?) to the rear, and take it apart after each shot. You could even set up the distance to the film plane for the hyperfocal length of the lens and shoot it as a sort of big, "focus free" toy camera.

You might also think a bit about the projected focal length of this camera. I am certainly not an expert, but finding anything short of 65 mm that will cover 4x5 is going to be a serious challenge.

It would be good if you could look at a large format camera, and all will be much clearer.

A conventional film holder has a lock rib on the face toward the darkslide end that meshes with a groove on the camera side of the back that forms a light trap and also makes it possible to remove the darkslide without pulling the holder out of the back.

The groundglass panel holds the filmholder in place usually with spring tension. The panel on a Graflok/International type back is removable, and there are slides on the inner surface of the back that can hold rollfilm holders or Grafmatic holders or other kinds of adapters in place.

The depth from the surface of the filmholder frame to the film emulsion is generally called the "T" distance. Note that the T distance should be the same as the depth of the inside surface of the groundglass frame to the matte surface of the groundglass, which faces the lens.

A simple kind of system would be to make a back where the filmholder just slides into a groove, and you sacrifice another filmholder to be your groundglass holder, routing out the back side so you can fit a groundglass against the film rails, which assures that you are at the right T-distance without having to do any precision machining of the groundglass frame.

You can sometimes also find entire camera backs for sale on eBay, that are easily adapted to projects like this.

thank you everybody. i wish the large format camera ive seen and touched was a 4x5 because i would understand, instead its a one off peice made to use glass plates.

David, your paragraph on the "T" distance helps me tremendously! i was wondering how one gets the GG distance to lens the same as the film to lens distance. if you look at the link i posted, the OP said he sourced parts from a cambo portrait camera he had, im assuming thats where his back came from? it has GG built in like a couple monorails ive seen which would be my preferred action if nothing else is possible. i found a couple sinar spring backs on ebay but im pretty sure the price for those like some on KEH is going to be out of my range. id much rather spend time and designing on the back rather than money so i can spend the money on a good peice of glass. i like your idea of sacrifcing a film holder as a GG holder, seems simple enough to do and none of the complex measurement are needed. i will def. resort to that when all my complicated, probably not worth it but fun options are exhuasted, lol. seems weird, but i get a kick out of being stumped and facing these problems.

so does anybody want to post a link to a full graflok/international type back that i might need to get, doesnt have to be for sale, i just want to get a look at it and all the components involved. so far, im trying to decipher it by looking at 4x5 camera pics online and thats a little tidious since some dont have the correct viewing angles.

finally, like i said, i will be attempting to rig up a helical focusing mount with the ring from an old 35mm olympus 50/1.8 lens as ive seen before, whichever lens i get will hopefully fit inside pretty snuggly, ill make all those measurements and decisions when the time comes. so point and shoot is a general term. not really a point and shoot, more like a 4x5 camera thats not as heavy as a monorail and is hand holdable, i currently work with an rz67 and it weighs but i hike with it and take it into the swamp. think of my 4x5 as a clyde-o-wide but a bit more refined, with Ground Glass and minimal focusing (no close-up work).

Take a look at Rayment Kirby's site, He's got full drawings there.

The "T" distance is the setback from the camera side of the frame to the GG.
When a film holder is slid into place the film surface displaces the GG backwards.

If you look at your RZ back & pull the darkslide, it's the distance from the front surface to where the film sits. This is an example, the "T" is different on a 4X5 holder.

Regarding using an OM focusing mount, I doubt there's 25mm diameter internally, you're going to need a very small lens/shutter combination to work that out. If you can.
It would be easier with a barrel from a Pentax 6X7 or the like.

For as simple point-and-shoot, leaving the back open, perhaps with guiding ridges around the 3 sides, and simply rubber-banding the film holder and/or ground glass on works very well. Self-adhesive weatherstripping makes for a good light seal.

For a simple point and shoot it's extremely hard to beat converting a Polaroid 110B. There's several guys who offer them commercially, but since self construction is your goal then you can just get a look at what they've done as a beginning guide.

For a P-110 conversion, the advantage is that the RF is already there, the bed is already there, and you can change the lens if you don't like the idea of reusing the Polaroid 127mm that's on it. (Need to make a new cam if you change the focal length of the lens.) Once you get very wide, however, the bed gets in the picture.

I think you're going to be disappointed with the image circle of a short, short lens unless you drop some serious cash into the lens itself. You mentioned 37-75mm. That's like REALLY, REALLY, REALLY wide on 4x5. I know you said you understand this is expensive.

As you get that short a lens, then you almost don't even need the GG or a rangefinder. Your DOF is going to be so big zone focusing is easy. Maybe eve easier. For example, the Online DOF calculator calculates the hyperfocal length of a 40mm lens at f/8 on 4x5 film as 6.69 ft. Basically everything from 3.4 feet to infinity will be in focus. Why bother with the GG for that. For that short why bother making a focus mechanism at all. I know you said you didn't want to use the hyperfocal distance, but you'll have to make some serious gear knobs to tweak those tiny distances using a GG and loupe. How fine is the pitch on this helical you want to use?

Even with 75mm at f/8 the hyper focal is 23 ft with the DOF 11.6 ft to infinity. You'd only need to focus at 12 ft or closer. Again, why not use zone focus at that DOF.

Plus a lens shorter than 75mm with coverage for 4x5 is going to be big on the rear element. And expensive. 75mm on 4x5 is about equivalent to 25mm in the 135 world, and if you shoot a lot of MF then it's about equivalent to a 40mm lens on 6x6. A 40mm on 4x5 is about equivalent to a 25mm on your RB67. That's wide.

Let me offer you a pathway. (Not like I've done this, so take it with a grain of salt. It's easy for me to sit here and tell you what to do, huh? It's not my project.)

I'd find the lens(es) you plan to use, then mock up a simple box to hold a 4x5 film holder to see how they actually work in the environment you expect to try. If the images aren't up to snuff (specifically poor image circle), then don't waste your time building a camera to fit those lenses. Try more lenses. When you find the lens that works good, then figure out what you need to build for it. If you don't need movement, then you may get away with robbing some of the old "good" folders for short lenses with "adequate" coverage. Look for an old 6x6 Agfa with the terrible synthetic bellows that is bad but one of the upscale models with the decent coated lens to steal from it. That should be an 80mm, which is close to your target of 75mm. But the coverage will be lacking.

I know you said you want the construction experience. But just in case you really want pictures instead of the experience of building it yourself, then watch the evilBay for a good Crown Graphics. I consider them pretty much point and shoot, plus all the engineering is already done. And it weighs less than an RB67. The converted P-110B weighs even less than a Crown. I've carried my P-110B in my computer bag with 3 4x5 holders plus enough of the computer junk to actually get work done. (OK, I had to leave my lunch home that day.)

But if you want the challenge and the construction education, then keep us posted on your progress!!

Michael

michael, you bring up very good points, specifically in the focusing of such a wide lens. i am aware of the cost of a good wide lens that has enough coverage, and i cringe, but im willing to do it. i will probably go with a schneider 58, 72, or 90 super angulon xl's. ive ruled out anything wider than 58. im aware its EXTREMELY wide, but im pretty used to shooting 10-16mm on 35mm format.

you're right, i probably dont need a GG or focusing mount, and its probably not worth it for soooo much extra cash, but if im going to build something, im not going to cut corners, if i dont have the money, ill just wait till i do, no rush. i like a GG because i can compose exactly whats going on the film and the focus can be checked via loupe. im not sure of the pitch of the helical focusing mount im going to use, hell, im not sure what focusing mount i will be using. if business goes good this summer i might just pick upt he schneider focusing mount for the lens i get, theyre around $350 on b&h, ouch.

thank you for all your advice, i particularly like your idea of building the camera around the lens, and i will do just that since it will be the most important part of the camera. im really in no rush, so im taking my time, looking for a good condition graflok back, a good solution to focusing, building material, etc. ive sketched a ton as to how i want the camera to look. before i buy a premade camera ill get a 4x5 view camera (monorail) for close-up work (wild orchids and other plants/insects) and just lug it aroung the everglades.

kauffman v36 said:

...i will probably go with a schneider 58, 72, or 90 super angulon xl's. ive ruled out anything wider than 58. im aware its EXTREMELY wide, but im pretty used to shooting 10-16mm on 35mm format.

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10-16mm in 135 format is wide, I'll give you that.

If you happen to settle for 90mm, and cost is an object, then you might just look at the older Angulon instead of the Super Angulon. It's physically much, much smaller, financially much, much easier on the wallet, and mine gives very good coverage with no movements on 4x5. My old Optar WA 90mm also gives excellent results, but 90mm seems to be narrower than you are really looking for.

Frankly, I've never used anything wider than 90 on 4x5, so at the angles you're talking about I'm a little lost. For that matter, I almost never use my 28mm on 135 despite the fact that I paid an arm and a leg for it. If I had a brain in my head I'd sell it, since I tend to think of 35mm as pretty wide for my style. In fact, for my 135 kit I could probably sell everything except the 35mm and the 85mm and be done with it. They're 75% of my use. The others are mostly clutter.

kauffman v36 said:

.... i particularly like your idea of building the camera around the lens, and i will do just that since it will be the most important part of the camera.

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I do think that's your best strategy. Perhaps not the best strategy if you were trying to mass produce something, but despite how much everyone here would like it, I doubt we'll be seeing these beasts at Wal-Mart next spring.

kauffman v36 said:

... before i buy a premade camera ill get a 4x5 view camera (monorail) for close-up work (wild orchids and other plants/insects) and just lug it aroung the everglades.

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I've done a tiny bit of this in the swamps in SC, and my advice there is get a long lens (300mm or so), a good solid tripod that you don't mind getting filthy, and plenty of bellows extension to give you macro capacity. Plan to learn about bellows factor in your experiments with this. Of course, you're a wide kind of guy, so you may want a wide lens and get really close.

I find the perspective effects from a foot or two away better. The pistol and stamen are usually better in relation to the foreground and background petals when all are "about" the same distance. When the background petal is twice or three times the distance from the lens as the foreground petal it "looks funny" to me, like the exaggerated nose on a facial closeup shot on a really wide lens.

MB

ahh yes, the beauty of ultra wide angle distortion. lol. the nose on the facial closeup is classic. if i were going to lug aroung a monorail for closeup work id probably get a lens 150mm or up with a loooot of bellows extensions, and like you said, learn a great deal about bellows compensation.

its funny, on my 35mm system, i shoot 300, 400, and even 600mm at times for nature. then i get down with my 6x7 system and its 50mm which is like 28 on 35mm. hence why i tend to carry 30 lbs of gear. being young has its attributes.

For a back, I would simply take your time and look for a suitable parts camera. B&J Grovers, for instance, or similar cameras, are dirt cheap. Buy one for $50 or $60 (or less), steal the back and bellows, and recycle the rest to aother camera nerd (or the actual recycing bin). However, you can make your own if you are capable of doing precision work with wood or metal.

The simple sliding box idea is a good one IMO. There was a similar camera that one of the Manzanar prisoners had a woodworker in the camp make for him. I believe he kept it under the radar of the guards, though I cannot remember for sure. He used the camera (4x5, I believe) to shoot pictures inside the camp. Can't remember all the details, as it has been years since I have seen the short documentary film about him.

I do, however, suggest sticking with a somewhat more "normal" focal length for your first foray into large format; perhaps something in the 75 to 150 range. There will be a larger variety of things you can try shooting this way.

ive pretty much settled on something in the 75 range, be it 72 or 75. 50mm would be the widest i want to go but thats too wide for now. when i find a relatively cheap 72 or 75 with enough coverage without movements ill be all over it.

kauffman v36 said:

...being young has its attributes.

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Go ahead. Rub it in.

haha, shall i dare go on a limb and say you probably graduated high school before i was born. same goes for the majority of the members here.

kauffman v36 said:

haha, shall i dare go on a limb and say you probably graduated high school before i was born. same goes for the majority of the members here.

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That's not much of a limb to go out on. Be daring young man. Be daring.

haha. good too know you old foggies still have a sense of humor. oops, did i say that out loud?