Some thoughts on the design of a lightweight 4x5

[banana_legs]

Just weighted my old MDF 5x4 I made a few years ago: 748g including a viewing screen (no lens). The camera has a folding tailboard and much of the weight is in the bellows as they were made from fairly heavy curtain blackout fabric. Not quite at the 500g but easy to carry though. The camera has full front movements and back tilt when in the landscape position (back swing when portrait). I will hunt out a picture.

Best regards,

Evan

[Neil Barnes]

I'd be interested to see it, Evan.

I've had a long conversation today with my CF guy; some of the ideas I wanted to use can't be done, but he's suggested alternatives which should work with a slight redesign - it's the U-carrier for the front standard that's the issue. He did suggest that a complete moulded section could be made, but at eye-bleeding prices!

Scored an interesting vintage lens on the bay last week: a Primar (no, I've never heard of them either and my google-fu is not good on this) Anastigmat F4.5 13.5cm which I believe came off something similar to this: http://cgi.ebay.co.uk/1920s-Compur-Cont ... 0655326001 - though I'm not sure about the 6x45 format that advert claims. That would date it to just after WW1 - 1920 or so - and it seems to cover 4x5 quite nicely. It needs a mounting ring, and it's none of the standard sizes - about 39mm - but I can live without that. I've just taken a couple of approximately identical shots with this and the Xenar (1950) for comparison... unfortunately I forgot to mark which was which; hopefully it will be obvious! Anyway, that'll do for the first prototype!

btw - want a Fresnel brightening screen for a 4x5? Got as little money as me? http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0602633159 - just needed an eighth of an inch off each end to drop into the MPP.

Neil

[dave_whatever]

I'd be interested to see it, Evan.

btw - want a Fresnel brightening screen for a 4x5? Got as little money as me? http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0602633159 - just needed an eighth of an inch off each end to drop into the MPP.

Neil

I used a similar thing off ebay for ages, pretty good for the money but they do tend to get scratched up by the loupe really quickly, so buy a handful.

[Neil Barnes]

Heh. I did...

[Robert J Fallis]

Neil.
I've got a simlar lens and shutter,mine came off a voightlander, and it does cover 5X4 ok, but it's not coated
so I've never tried it with colour film, But Black and white reformance is ok.

bob

[banana_legs]

Neil,

I have found a few pictures of the 4x5 in action, and also some images of my 6cmx9cm MDF camera that weights 504 grams (without lens, but has tripod mount and screen). The first image shows the screen from the rear with a 'spring back' (elastic) however I often fit the screen/ film holder on with velcro.

From the rear, portrait operation.

DSC_4556.JPG (42.06 KiB) Viewed 7693 times

The second image is in landscape mode; to reduce size and weight, the bellows are rectangular (and glued in on the 4x5) so the entire camera needs to go on its side. I have a similar MDF 4x5 with a reversible back and interchangeable bellows, but that weighs 1046 grams (with bag bellows). You can see the wooden clips on the bottom to hold the focussing bed stable when it is unfolded.

Landscape operation

DSC_4548.JPG (64.79 KiB) Viewed 7693 times

This is the 6x9 in a folded configuration. The bellows (made from black paper) are interchangeable on the 6x9.

6x9 folded

DSC_8848.JPG (30.38 KiB) Viewed 7693 times

I will see if I can find more pictures of the cameras in operation.

Best regards,

Evan

[banana_legs]

Here are some more of the 6x9.

DSC_8851.JPG (41.56 KiB) Viewed 7693 times

The lens is salvaged from an old folder and is mounted into interchangeable 3mm MDF plates. All the focussing and shifts etc. are done using M6 bolts and wing nuts. I now use a tripod mount that is an M6 bolt welded to a steel plate so that I can move it along the camera bed, with a 1/4" nut welded on the underside of the plate to fit to the tripod. That way I can balance the cameras (I also have an 8x10 of similar design) and also move the tripod holder right to the back so I can compress the bellows very tightly for pinhole work. In the picture, the tripod mount can just be seen right at the back of the bed.

My 5x7 with removable bellows and reversing back weights in at 1676g without a lens; as the size goes up I had to go to 6mm and 7mm MDF and also reinforce the bed.

Best regards,

Evan

[Neil Barnes]

I like the look of that 6*9, Evan - though it's apparent that there are only a few ways of doing any particular job. The rear focus on the larger camera is an interesting approach that I hadn't considered, but is there a 'fine tweak' - perhaps a rotary - on the lens?

My design is getting closer. I'll probably make a prototype using model aircraft beech ply in various thicknesses and spruce, to prove it all fits together before getting the not-cheap CF machined. I want to use professional bellows but there's an eight-week delivery; perhaps some home-made bellows will make an appearance.

Neil

[banana_legs]

Neil,

Yes, the only way you can raise the lens is with the front rise as the rear standard has limited movements. For the 4x5 I did make a 'fine adjustment' device that allowed one to adjust the focus based on screwing a threaded rod. It worked well, however I found by tightening up the rear standard wing-nut to give a bit of friction, I can make very fine adjustments without the device. For the 6x9 it does get tricky as the screen is so small and there have been a few times when shooting wide open, my focus was a tiny bit out. Much of my work is using the movements to control the plane of focus and exploiting bokeh effects. Generally I am happy with the 4x5 at shooting with an aperture of f/8 or above and can focus satisfactorily; I also often shoot at f/4.5 with no problem too. Some of my lenses that I have recovered from old folders have a focussing front element that can help.

I forgot to mention that all of the screens are 'sanded plastic' rather than ground glass and all have fresnel lenses fitted. I mount the fresnel on the camera side with the grooves touching the ground side of the screen; the loupe does not scratch it that way and dust does not collect in the grooves but it still works fine. I have ground glass screens for the 4x5 and 6x9, but as I usually remove the screen completely to fit the film holder (when strapping the screen/film in with velcro), I have dropped a glass screen and cracked it!

Best regards,

Evan

[Robert J Fallis]

Evan,
I really like that little 6X9 camera...I've just one question.. What do you use to hold the film? did you make your own holder .. or Buy one??


bob

[Neil Barnes]

Evan, where did you get the tripod mount nut? I'm having difficulty locating 1/4 whitworth spike nuts...

Neil

[banana_legs]

Bob,

I have a few old wooden 6x9 film holders, also some '2x3' 6-shot graflex magazines. I have designed the back so that it also fits an RB67 roll film holder. I just remove the screen and then use velcro straps to hold the film holders in place. The graflex magazines were from Ebay in the states; as I was the only bidder, it was worth the postage and import duties. The small holders are not common here in the UK but they do appear occasionally. I waited until I managed to pick up some holders cheap, and then made a camera to fit.

Neil,

Luckily my local traditional hardware shop has a nut and bolt section that has 1/4" nuts and threaded rod too. They are getting pretty rare in the UK now as far as I can tell and all the big chain DIY stores seem to have stopped doing them. I notice you mention making bellows in your previous post; I had a look back through my notes and it took longer to make the bellows for the 6x9 than it did to make the rest of the camera! The total cost of the 6x9 was under £15, including a lens off an old folder from Ebay; not including the cost of film holders of course!

Best regards,

Evan

[Neil Barnes]

Thanks Evan,

I'm having difficulty finding nice bushes, but I have located both 1/4-20 Whitworth nuts and also 1/4-3/16 adaptors, which might be usable.

I have started construction - with a wooden model to test the design before I spend on the CF. Today I bought material to make the bellows, since Camera Bellows in Birmingham don't seem to want to answer the phone. On the grounds that red bits on an engine make it go faster, and red bits on a wing make a model plane fly higher, and A Red Piece Somewhere gets you into a royal society, the bellows will be.... red. Planning the geometry of the bellows has taken me several days...

John Lewis were highly amused as I wandered around their fabric department with a very bright LED torch - it looks as if their (white) blackout curtain lining will do the job!

Neil

[banana_legs]

Neil,

Sounding good. A note of caution: I had some white blackout fabric and dyed it a mahogany red; I now have a folding pinhole camera with Barbie pink bellows! Try dyeing a test piece before you commit yourself to the whole batch of cloth! There is a picture of the camera here:

http://www.f295.org/Pinholeforum/forum/ ... rbie/#num2

Best regards,

Evan

[Neil Barnes]

I have the blackout fabric for the inside and light-proofing, and some 'Panama' red for the outside; paper stiffeners in the middle. I'm keen to see how this will work! I'll probably spray the inside of the blackout fabric black to stop diffuse reflection.

I'm considering whether velcro can be used to attach the bellows to the backplate and front standard.

Neil