Film and Darkroom User

Film and Darkroom User (http://www.film-and-darkroom-user.org.uk/forum/index.php)
-   Cameras - Pinhole (http://www.film-and-darkroom-user.org.uk/forum/forumdisplay.php?f=84)
-   -   messing around with a pinhole (http://www.film-and-darkroom-user.org.uk/forum/showthread.php?t=13290)

CambsIan 1st July 2020 08:04 AM

messing around with a pinhole
 
I've been messing around and created a pinhole camera from scratch for my 12x9 dark slide, out of foam board and black duct tape, not pretty, but I'm hopeful it will work OK, hoping to give it a test run later today.

Not overly hopeful as I don't know the size of the pinhole, so have no idea of exposure times, going to start on the assumption of f224 (0.3mm hole and 67mm focal length as that's what I built it around) and see what happens

If this proves successful, might like to try build one out of MDF for a "prettier" camera and maybe for a 5x4 DDS so that I can use positive paper in it.

Can anyone tell me if all the 5x4 DDS's are the same size ? and can anyone tell me the external sizes of them ? Just so I can tinker about on paper before I go ahead and buy one.

Being really cheeky, anyone got a set of plans for a 5x4 pinhole ?

As usual, any advice, observations, tips and tricks welcome.

Ian

P.S will buy a professionally made "hole" if the project goes ahead

photomi7ch 1st July 2020 03:30 PM

If you google pinhole camera project you will be spoilt for choice.

Svend 2nd July 2020 05:42 PM

Ian, not 4x5, but I did convert a couple of dead 6x6 and 6x9 folders to pinhole. One conversion worked very well, whereas the other (the 6x9) still needs improvement :rolleyes: If you want some insight into these, let me know. Sorry I couldn't help more. Good luck with the project. Sounds like a good one.

JOReynolds 3rd July 2020 08:10 PM

pinhole imaging
 
It's a long time since I played pinhole, but I remember that my one attempt was quite successful. I had access to 1/4 plate (3 1/4 x 4 1/4") Ilford N5 30 (about 2...5 ASA, I think) ordinary film then, so exposure times were quite long.

I was at a school of photography and our theory lecturer filled in many of the blank spaces. As I recollect, the first problem was calculating exposure time. To get reasonable resolution the hole diameter had to be no more than 1mm. But if I used a 1mm nail or needle to pierce a hole in some aluminium foil, it would consist of a short reflective tunnel, which would bounce light everywhere. So I drilled a 1mm hole in some black Formica and used another bit of it to make a pivoted vane shutter. The camera body was a cardboard carton with black electrical tape to seal light leaks. I held the film in place with dots of double-sided tape. The body had to be dismantled to remove the exposed film.

I have read of experiments with negative-working paper negatives and various methods at achieving a translucent with FB paper base.

I think the depth of the box was about 6" or 150mm, so if the numeric aperture was 1mm, the effective aperture was f/150. You wouldn't find that on the scale of a Weston IV but it works out at 2 1/3 stops past f/32.

The resulting (single) negative was of the pavement of Regent St, London, looking towards the BBC. It was more or less correctly exposed but I made the exciting discovery that folk that hung around got imaged, whereas rapidly-moving objects such as cars and walking pedestrians disappeared!

I've never tried it with children but pinhole photography is said to be a favourite topic in school. But it's actually quite involved, requiring some skill with:
- a Stanley knife (to fabricate the camera body).
- duct tape (to hold it together - more knife stuff).
- handling film in the dark (look out for the notch).
- dish processing of film in the dark (it tended to float).
Although it would be fun, I'm not sure it qualifies for 'photography classes'.
By the way, the film I used, Ilford N5 30, was 'ordinary' and could be handled in safelighting intended for bromide paper.

JOReynolds 3rd July 2020 08:52 PM

Quote:

Originally Posted by CambsIan (Post 134347)
Can anyone tell me if all the 5x4 DDS's are the same size ?

Yes, all 5x4" double dark slides are the same size, dimensions standardised in the US before 1914. Those intended for glass plates are thicker but the emulsion plane is in the same position, with respect to the darkslide flange. Adapters were available to put sheetfilm into darkslides intended for glass.
Quote:

P.S will buy a professionally made "hole" if the project goes ahead
You are wise to get a good hole, perhaps etched from thin steel, because that defines the image quality. Some textbooks suggest piercing cooking foil - bad idea! You could try melting a hole with a hot needle in a black polyethylene bag such as used for packing photographic paper.
I remember, now - I made pinhole cameras for the solar eclipse in the late 1990s. But the best one had a 10mm diameter hole and a 1 dioptre spectacle lens. The box was 1 metre long, of course, and had a matte drafting foil 'screen'. You could see the furry bits around the moon's shadow.

CambsIan 4th July 2020 12:52 PM

Hi All, many thanks for the replies, as usual great info

Things have not gone quite to plan as not got round to testing the first camera yet. Even with staying at home as much as possible, don't seem to have enough hours in the day to do everything.

I had considered tray developing, which seems to be the way forward to me

I have managed to find a set of plans for a 5x4 on the net, which don't look to complicated, but as 5"x4" is not a lot bigger than my 9cmx12cm, I am now wondering if bigger is better, maybe go for a 7"x5". As all in the planning stage, I guess now's the time to change my mind.

Not going to be able to do anything for the next week or so, but will post any updates as things progress

Ian

JOReynolds 4th July 2020 08:17 PM

Quote:

Originally Posted by CambsIan (Post 134438)
I am now wondering if bigger is better, maybe go for a 7"x5".

On reading about large-format pinhole photography, the high cost of sheetfilm is a constant topic. FB paper, treated with something to make it translucent, is a popular alternative.
Direct-positive paper, formerly made by Ilford's Swiss partners, would have been ideal but it hasn't been available for several years.

CambsIan 4th July 2020 08:57 PM

My thinking is that I would use Harman direct positive paper, as I can only print from neg's up to 6x6, and anything bigger will have to be contact printed.

https://www.ilfordphoto.com/amfile/f...9/product/720/

If I have read it right it can also be loaded into the film holders under a red safe light, maybe making that a bit easier

I've loads to learn, but reckon it might be fun, mixing both construction and photography.

Ian

Terry S 5th July 2020 11:49 AM

Quote:

Originally Posted by JOReynolds (Post 134444)
Direct-positive paper, formerly made by Ilford's Swiss partners, would have been ideal but it hasn't been available for several years.

Yes, I too wondered if this paper was still available, and according to Ilford's site, it's still is, at least from them directly but I presume also from certain stockists, although you might have to order it in:

https://www.ilfordphoto.com/harman-d...e-paper-sheets

Then of course there is also the option of making positives with 'normal' darkroom paper; for which there are a number of sites on youtube explaining how and is something that I want to have a go of.

Quote:

Originally Posted by CambsIan (Post 134445)
If I have read it right it can also be loaded into the film holders under a red safe light, maybe making that a bit easier

Ian

You are correct about the safelight Ian, which is very helpful when loading and processing; but also check out the idea I've mentioned above. :)

Also note that Ilford's 5" x 4" paper needs to be trimmed by about 1/8", on it's width, to fit into a standard 5" x 4" dark slide.

Terry S

CambsIan 5th July 2020 04:20 PM

The paper is also available from at least a couple of the forum sponsors as well, although not sure how long for as I understand the Harman factory has shut down during the current outbreak.

Reckon I need to make some decisions sooner rather than later if I want to go down the positive paper route.

Thinking cap on !


All times are GMT. The time now is 10:06 AM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.