Fixed focus camera?

[jb7]

Thanks Dave, and Steve-
Badass- what a good word...

Steve, it's the Olympus mount that causes the vignette when the lens is rotated out.
I found I had to file it to accommodate the image corners.

There isn't a lot to remove by thinning out-

Yes, the rear element only just fits-
I reckon there's only 1mm clearance, so centering the lens becomes important-

I could do with a finger jointed box for my next camera...


joseph

[Alan Clark]

Steve and Joseph,

What's all this "finger joint" malarky? Shame on you both!
Nothing beats nice hand-cut dovetails!!

Joseph, seriously, how is the film holder clamped to the back of your camera. I looked at the pictures on the other site, but they don't show this.

alan

[jb7]

Ooh, sounds like a challenge to learn proper skills Alan-

Not having the time or inclination to do that,
and not having access to numeric control, other than my own digits,
I'm afraid I have to design within the limitations of what I can accomplish myself-

I suppose I could farm bits out, but it can get expensive,
and there's usually another way to do things.

Perhaps not the best way, but it gets things done.

The back-
yes, that's a weak link- in one regard, it's less than a positive lock.
On the other hand, it's an advantage-
having literally nothing holding the backs in place is a lightweight solution,
and keeps the form factor to the minimum dimensions possible.

This camera was designed to be hand held,
so just holding the camera keeps the back in place.

That, and friction- the back is rebated by 5mm, and it's a tight fit.
I've used it with the 545 back pictured, a Polaroid 550, Horseman 6x9 and 6x12 roll film backs, and an assortment of 4x5 film holders.

Of these, the newer 4x5's, the Polaroids, and the Horseman 6x9 backs are a perfect fit, and are gripped just enough.

The 6x12 back is slightly larger, and is a tight fit, but works. I don't like using it though,
in case it stresses the camera, and stretches it.

The older 4x5's are slightly smaller, and wobble-
one of them is much too small, and fell out the first time I used it.
A metal tabbed Lisco Regal. So they don't get used anymore-

It isn't a perfect solution, and is open to criticism,
but since I'm the only one using it, it suits me just fine.
the interior rebates are lined with velvet tape around the edges...

I also made a ground glass that mounts like a film holder, for critical composition-
but it kindof defeats the point and shoot idea-

I've shot quite a lot of film with this camera in its previous iteration-
with a plastic 50mm lens-
you can see some of them on my flickr-
they're most of the recent ones-

http://www.flickr.com/photos/joseph-jb7/

I could have used a graflok style back,
but that would have made the camera much bigger,
and much less of a point and shoot.

The next one will have a proper back, along the lines of this one, but smaller-

http://photographyireland.net/viewtopic.php?t=25732

[Steve Smith]

What's all this "finger joint" malarky? Shame on you both!
Nothing beats nice hand-cut dovetails!!

I can do hand cut dovetails but CNC cut finger joints look much better than my not so nice dovetails.... And I refuse to use one of those router jig thingies to cut them!

Actually, as I am a guitar player I like my fingers so I try not to use any hand held power tools if I can help it.



Steve.

[Steve Smith]

Steve, it's the Olympus mount that causes the vignette when the lens is rotated out.
I found I had to file it to accommodate the image corners.

So far, I have only tried this with a 6x6 format so obviously I have missed out on the vignetting. I am hoping that with 6x12 format it will be o.k. too but I'm not sure yet.

I can see from your pictures that you have filed out the corners of your lens plate but did you have to file away any of the Olympus part as well?

If I make a 5x4 version to take the same lens mount then I may have to do some filing.

On the subject of canabalising lenses to use as focusing mounts. I did look at one of my Bronica ETRS lenses for a while but managed to resist taking it apart. I think a broken one would make quite a good focusing mount and is probably wide enough not to cause vignetting.


Steve.

[Alan Clark]

Joseph,
Thanks for your comprehensive reply. I wondered if you were just holding the back in place by hand. My 5 x 4 box camera, which is intended for tripod use, has a back that is rebated on three sides to almost the full depth of the film holder. Two strips of wood, at top and bottom, mounted on bolts that stick out, overlap the rebate. The film holder slides in behind them from the open right side, and is locked in place by tightening knobs down on the wood strips. Very simple and easy to make. For first composing the picture I have a sheet of ground glass mounted in a wooden frame that has the same external dimensions as a film holder. So it slides in first, and is replaced by the film holder when I am ready to take the picture. I fully appreciate that you are using your camera in a different way.

About the dovetails. Judging by the very nice wood shaping on your camera, I think you are being too modest...

Steve. Do you really need all your fingers to play the guitar? How many did Django Reinhart have?

Alan

[jb7]

Thanks Alan-

Yes, if I was to use only sheet film it could be sorted relatively easily-
but the backs I mentioned are four different thicknesses-

It works ok as it is, better than I might have expected really...

I think this one is probably finished now,
time to move on to the next one...

[Steve Smith]

Steve. Do you really need all your fingers to play the guitar? How many did Django Reinhart have?

Well - I do occasionally play Django type stuff but even with all of my fingers, I'm nowhere near Django's competence!


Steve.

[Dave Dawson]

Well my fixed focus camera project hasn't got off to a very good start I haven't been able to find an old 5x4 international back or a #0 shutter at a reasonable price I keep getting outbid)

Has anyone got iether of the above please? The back doesn't have to be pretty and can have a broken/missing gg screen. The shutter doesn't have to be anything fancy either.

HELP please..........Cheers Dave

[Steve Smith]

Well my fixed focus camera project hasn't got off to a very good start I haven't been able to find an old 5x4 international back or a #0 shutter at a reasonable price I keep getting outbid)

Has anyone got either of the above please? The back doesn't have to be pretty and can have a broken/missing gg screen. The shutter doesn't have to be anything fancy either.

I don't have a proper International back but I do have one which I made: http://stevesmithstuff.blogspot.com/ (first picture).

It's been sitting around for a couple of years so if it's of any use to you whilst you are in an experimental stage, you can have it. Then replace it with a proper back when you get one.


Steve.

[Matt Sampson]

I've come a bit late to this discussion but I can't resist passing on a few of the things I've learned/discovered while making cameras which might be useful which I can't see have been covered so far.

It is worth using something like the Schneider helical focus mount if you can, yes they are expensive but they are easy to attach to your camera because of the external flange they have but most importantly they are easy to adjust for perfect focus. Simply make your box/body slightly shorter than the flange focal distance and 'tune' it by adjusting the helical. It beats shimming or trying to make a box accurate to a tenth of a millimetre if you don't have a CNC machine. They have about 4mm of adjustment on them. You shouldn't be using all of the adjustment but you shouldn't need to. The helicals are all the same regardless of focal length, only the scale varies and these are available as a spare from Schneider. You need some one who can actually order spares from the factory ...try Robert White. So if you need a 90mm and can only get a 72mm don't worry too much. The helicals are calibrated for 6x9, which gives you a margin for use with 5x4 and they are only available with Copal 0 holes. A ready made scale saves a lot of work. Getting into depth of field tables and circles of confusion, unless it really interests you will drive you insane. Before you know it you're photographing garden canes stuck in the lawn with measurements on them and going slightly round the bend.

The Fotoman helicals are a good alternative to The Schneiders if you can find one anywhere now and they made ones with No1 holes and even some with extra throw on them.

Matt.

The flange focal distance is basically the back of the shutter/outside of the lens board, to the inside of the ground glass no more complicated than that as the frosted side of the GG is in the plane where the film sits when you put it in.

Remember that lenses project a curved field onto the film. With 5x4 and 6x12 with a 90mm lens there is unlikely to be a problem but if you get into larger formats or wider lenses... I made a 4x10 that used a 90XL lens, you will drive yourself mad trying to get the image sharp across the GG with a loupe. Stopping down helps to correct this of course which is one reason we do it but you may find it helps to set up your infinity point using a loupe on the ground glass slightly off centre. This area of field curvature is a big deal in lens design and something else you want to avoid worrying about unless you really are keen.

I am full of admiration for anyone who wants to make a roll film back but a good alternative are the old Mamiya press S shaped backs. They are capable of great film flatness and canb be found relatively cheaply. If you plan on 6x12 you need the old green ones with the red window to accurately wind the film... every other 6x6 frame. It is possible to cut a 6x12 film gate in one of these ... just.

Your home made camera will almost certainly leak light... this may well drive you mad and next to filling it with water to see where it runs out.. not recommended... you will end up messing around with a torch the dark.. a fact of camera making.

If anyone's interested there are some 6x12 on my website http://www.mattsampsonphotography.com. The camera uses a 65mm lens from an old Mamiya press which doesn't cover 6x12 but I rather like the vignetting, it suits what I do. I wouldn't mind building a Mark II with a Nikkor 65/4 SW though.

[dave_whatever]

Thats some useful info there Matt. Some nice panos on your site too.

Do those Mamiya press backs have a pressure plate long enough for 6x12 then?

I'm also thinking there aught to be a cheaper option to those expensive purpose-made helical mounts - for example if you could find something like this with a fine enough thread pitch to give a useful range of focus. Although plastic it aught to be study enough. And cheap, which I guess is one of the motivators behind this type of DIY project.

[Steve Smith]

Matt, do you have any details of your camera anywhere? I apologise if they are on your website but I couldn't find anything.


Steve.

[Matt Sampson]

Thanks Dave. Hopefully I'll get some more pictures up there over the weekend. The old Mamiya Press backs only have pressure plate to match their format, so 6x7 or 6x9 therefore you need to make one. It isn't that hard. I used aluminium sheet from a model shop, made by KS. Replacing the old one isn't too hard, it's a fairly simple mechanism they use. It ought to be anodised black but the backing paper on 120 film prevents any reflection problems so there's no need to worry. You can start heating buckets of acid in your shed if you like to do your own anodizing, people do, it's a fairly straight forward process... apparently! Something like that Screwfix thingy would probably work but the thread does need to be suitable, not to coarse or loose. Pentax made an adjustable extension tube for their 6x7 which may have its uses but I have never seen one... it might vignette. I agree these projects ought to be cheap wherever possible. Part of the joy, apart from actually making something like this, is making it for as little as possible. I already had a helical. The finder is a little grand but I found it cheap here in Hong Kong and MXV happened to have a used 65mm mask for it amazingly. The lens was of a trashed camera I found at a country auction... GBP 20 for a box full of bits including the back. The accessory shoes, strap lugs etc all came from the same cameras. The rangefinder cost GBP 8 from a bric a brac shop. The box is simply plywood. The hood is attached to an old Cokin filter ring and just pushes on... this still needs work. Unfortunately the lens filter thread has a ding in it so can't be used.

Steve... there aren't any pictures of the camera on my site but I'll try to attach some here. Since these were taken I made some alterations, the helical is now on an aluminium plate screwed to the box. I forgot to say before that aluminium tape is extremely useful stuff for light proofing and I resorted to this to get the camera running so it isn't pretty but it works. It's dark here at the moment so I'm a bit stuck for taking new pictures. There should also be a pic of the 4x10 I made. You may notice some common parts! The handles on the front are drawer handles from BQ that just happened to be exactly the right colour. I made the dark slides for this too which was ... well... interesting.

[dave_whatever]

Pentax made an adjustable extension tube for their 6x7 which may have its uses but I have never seen one.

yeah, like these:

http://cgi.ebay.co.uk/Pentax-6x7-Helico ... .m63.l1177

http://cgi.ebay.co.uk/Pentax-67-6x7-Var ... .m63.l1177

I'd probably leave the anodizing too! Thems some nicely made looking cameras you made there.