Lens for DIY afghan box camera

[Grimm_is_new_to_4x5]

Hi !

My name is Grimm and together with my wife Suvi , we have discovered a new love in our life , large format photography !

For some years , we are fooling around as amateurs with a modern canon eos 60d .
In the past i used to have a old minolta camera that was incredibly charming , but as that one broke , non-digital photography got a little forgotten by us i must admit ..

That was until last summer , when on a holiday in Madrid , we saw a woman on the streets taking pictures and developing them on the spot with a Kamra-e-faoree , also know as the Afghan Box Camera. For those who aren't familiar with this type of 'instant' camera , its a very basic 4x5 camera and development room in one .

After some searching , i found this beautiful project website made by Lukas Birk and Sean Foley: http://www.afghanboxcamera.com/

Following the manual provided on that website , we have been building our own afghan box camera and we are able to take nice and sharp b&w negatives.
As a lens , i obtained a Ilex 210mm f5.6 Acu-Symmetrical.
For a portrait picture , it seems to work best if the subject is 2-3 meters away , as its possible to properly focus and frame the picture on this distance.

The issue we are still struggling with , where i am hoping your tremendous combined expertise could help us out , is to take good positives from the negatives.
With the current lens and setup , i cannot take a positive from the negative that covers the 4x5 paper .
If i focus on the negative , i have a image on the focus plate of 2x3cm , if i try to enlarge that image , it will become too blurry to distinguish anything.
I have been trying all kind of different distances between lens and negative picture and internal focus plate , i just can't get it right

When we saw the woman in madrid take the positive , she would attach a negative holder before the lens , on a distance of around 30-50cm (not sure exactly) , and so do the photographers documented on the afghan box camera website.



Does anyone have any idea what i am doing wrong ? I would think it is an issue of lens specification ?

There must be a way to take positives the same size or slightly smaller as the negative . Currently we are making contact prints at home from our negatives , but as its an 'instant camera' , it would be nice to not rely on a dark room

Greetings
Grimm

[Paul Fitzgerald]

Hi there, if you want to make same size positive/negative you would need 4X the focal length + the size of the lens:
210mm X4 + 75mm = 915mm from the negative holder to the positive holder.
I think you should try a 100mm - 150mm lens depending on you measurements.

[jnantz]

hi grimm

it seems that your fixed focus distance is not set for the type of shot you want to do ...

have you done this simple test ...
make a 3-sided-box, long and bigger than 4x5 ... make a small frame
like a matboard cut out that is 4x5 and put waxed paper on it ... the same waxed paper
you would buy at the grocery store and have it act like ground glass inside the open end of the box
cut a hole in the front of the box for the lens and mount it anyway you can on the front.
get the box (camera) /lens as far/close to whatever it is you want to be the subject
and slide the matboard/waxed paper inside the box until it comes into focus.
note how far ( measure? ) the ground glass / waxed paper frame is.
also note how the lens is mounted on the front of the box.
when you put the lens back on your afghan camera, use the measured distance to so your film / paper plane
is that same distance it took to focus in the box / camera you did your tests on.

are you processing the film and then making an in camera contact print ?
if so ... you might want to have an opaque or white " something" on it so the light that hits
the paper+film is filtered / "bland" and not have an image on it, or you might double expose your paper.

i have wanted to make one of these cameras for ages but make long exposure / retina cameras instead.
much less of a hassle since i don't have to develop the print

good luck with your project!

[Grimm_is_new_to_4x5]

Hey thanks for your replies !

I have a hard time understanding the optical physics behind the lenses (been reading tons but i still find it hard to grasp).
From what i understood , to cover my 4x5 paper, i would need a lens of +165mm ?

The image circle is an important factor to consider whenever buying a view camera lens. Always be sure that the lens you are buying has, at minimum, an image circle that will cover your film size. A lens for a 4x5 camera must have an image circle of 6½ inches, or approximately 165mm, to just barely cover a sheet of 4x5 film

So the 210mm on the Ilex lens refers to the focal length and not to the image circle ?


I haven't tried that 3 sided box technique you mention , but it sounds like the same as my box camera ? ( i am even using waxed baking paper as focus plate on that one ) . At the moment , if my subject is about 2-3 meters away ( im going back out to do some tests today and ill measure exactly the distances ) , the focus plate is about 40cm from the 'back' of the lens to have a sharp full image , whats also almost the maximum i can move the focus plate .
I can try it out as i wouldnt be limited to the dimensions of the afghan camera , to see what the best results would be with this current lens.

At the moment i just take the negatives on the photographic paper with the camera , develop and fix them inside the camera , and when i am back home , i make a contact print in my walk-in closet that has become a darkroom .
I follow this exact technique described here , the positive i get are the same as if i would take a digital picture of the negative and invert it in photoshop , so i think the technique is ok ? I also orderd some Harman direct positive papers to see the results that would give , in the hope it could currently eliminate my issue..

Paul , you recommend a 100 - 150mm lens ? The image circle of such a lens should still cover my paper you think ?
What kind of aperture value would you also look for ? As a poor student , i can't afford a lens with shutter or a copal shutter, so i choose the f5,6 as its slow enough for me to use the lens cap as a shutter (2sec indoors with natural window light seems fine) .

I am thinking about getting a new lens now i am getting a better understanding of the matter , but i have to be sure it's what i need as i can't really afford too expensive adjustable lenses , or another lens that doesn't really do what i want

I do really recommend this DIY project , its easy and fun and costed me (not including the lens) , less than 50€ on materials , and a weekend of work.

[Sevo]

Hey thanks for your replies !

I have a hard time understanding the optical physics behind the lenses (been reading tons but i still find it hard to grasp).
From what i understood , to cover my 4x5 paper, i would need a lens of +165mm ?

No. Coverage depends on the lens design, magnification and on the acceptable resolution and vignetting. And last but not least it will depend on the aperture (there are some lenses where coverage is quite variable and will more than double by stopping down). 165mm was a common figure for 4x5 infinity coverage with the original Tessar design in technical or scientific photography - change one parameter, and you may need more or could do with less focal length to get a acceptably sharp and un-vignetted negative of a given size. At your (portrait) distance 135-150mm Tessars would already do perfectly well.

In any case, you may forget about focal length, if the current lens does well for the primary purpose (group or portrait shots) - depending on the extension you built into the camera it could be hard or even impossible to find a lens that serves both purposes, at least without getting wider than generally considered attractive for portraits. A much easier solution to the re-photographing problem would be to get a 2dpt to 4dpt achromatic accessory lens, which would reduce the infinity distance to comfortable 50 respectively 25cm without racking out the camera. Perhaps the achromat could even be made part of the copy stand affair.

[Paul Fitzgerald]

"Paul , you recommend a 100 - 150mm lens ? The image circle of such a lens should still cover my paper you think ? "

Yes, you're shooting at lifesize, 1 - 1, twice the focus distance so twice the image circle

" What kind of aperture value would you also look for ?"

f/4.5 - f/5.6. At 1 - 1 you need 4x the exposure, 2 full stops, so f/5.6 acts as f/11

"As a poor student , i can't afford a lens with shutter or a copal shutter, so i choose the f5,6 as its slow enough for me to use the lens cap as a shutter (2sec indoors with natural window light seems fine) ."

An enlarging lens(135 - 150mm) would work very well for re-photographing the paper neg. to a paper pos. The manual shows fitting the front of an old rollfilm camera for focusing, one from a 6x9 camera would work well(105mm).

Have fun with it.

[jnantz]

grimm

the problem you are having is your fixed lens isn't fixed at the right distance to the film / paper
to give you a focused image. if you WANT lifesize images sure use a smaller focal length ( as others have suggested ) but you still
have to make sure the image is focused ... and using a smaller focal length lens, focus is more critical ( as a macro lens )
than using the 210 you already have. do the test i mentioned, make sure the distance from your lens to
your baking parchment is the same distance as in your test and if you stop your lens down you will have no trouble with your 210
and paper negatives. as you already know, paper negatives are pretty contrasty, you can use variable contrast paper and a 2-2.5 enlarging filter
so your image won't be as contrasty, or shoot in overcast light, open shade &c.
if you fix the lens so it isn't able to move in and out to focus, tie a string to the right distance to make sure
the subject is the right distance to make things easy for you ... and use the parchment ground glass as a viewer ...
im not sure what developer you have in your tank, but a low contrast developer ( like caffenol c or dilute dektol or ? ) might make things easy for you too.

have fun with your project
john

[Grimm_is_new_to_4x5]

Hey guys , thank you for all your advice , i am a few days on the countryside so i don't have too much time yet to check these things out . Afghan camera project will continue next week ! Cheers !

[Grimm_is_new_to_4x5]

Hey !

I have been busy all morning with the described 3-sided box experiment (uploaded some pictures of it , i hope i interpreted the setup right ? )
So i toke a backpack as 'subject' , where the point to focus on are the quechua letters on the backpack.

If i put the front of the lens on 160cm of the letters , the distance between the 'inside' of the lens and the focus plate is about 36-37cm . The image of the backpack is too large to fit 'on' the focus plate .
If i move the distance between lens and subject to 2meter , the distance from focus plate to the inside of lens stays the same , but i can get more of the backpack on the focus plate.
Sounds logic to me ?

(yup the last one is blurry but i already toke the setup down before i saw )

Thx for the experimental advice , it helps understanding some things better !


For the liquids i am currently using :
-Print NE b&w print developer dilluted 1+7 , seems to be made by Compard KG
-Fixer : Agfa Fix-AG b&w , dilluted 1+7

As papers i have the Ilford Multigrade IC RC de luxe 4x5 and the Harman direct positive paper (didnt had a chance to test that one yet)...


I have been working a lot last week , so i am thinking if it would be interesting to get another lens . I want to go deeper into large format photography , but i think a lens with at least a shutter would be more easy to start with . I will also receive a cheap light meter from a friend , and i think the combination of light meter + fixed shutter times will make it easyer to me to grow experience .. In my understanding , if you got a fixed aperture , you could basically make a kind of helping table with , this amount of light = this shutter time ? Ofcourse its also a matter of looking what you are trying to capture , the contrasts of that image ?

I got a few things on Ebay i was looking at , can anyone 'rate' them to me , or give me a better advice ? At the moment i got a budget until 200€ .
(150mm) f/6.3 Uncoated Helical Focus Rectilinear Lens with Iris Aperture 4x5
Carl zeiss jena tessar 135mm f 4.5 4x5 lens
VINTAGE ICA HELIOS EXTRA RAPID APLANAT 1:8 13cm LARGE FORMAT FUNCTIONAL LENS
LINHOF SCHNEIDER 127mm 4.7 PRESS XENAR large format 4x5 lens SYNCHRO COMPUR
Are any of these lenses suitable ? If so , would i still need a close up lens for making the positive from the negative ?

Last questions i got are about some terms i don't understand , if anyone knows a good links where i can read myself into understanding that would be awsome .
The ratio's 1:1 / 1:8 .. Is that how much the lens magnifys ?
What is meant with a lifesize image ? I suspect it to be this 1:1 ratio , but then you got to understand that too ofcourse :P

Thanks !

[Grimm_is_new_to_4x5]

Today i finished building the camera and the tripod , here are some pictures . Im proud like a new father .
The camera is called Victor (Vic for the friends) , and he's 'best friend forever' , the tripod is called Lucky Louis . (or just Lou for the friends)