4x5 Pinhole

[Toffle]

Just thought I'd post a pic of my attempt at a 4x5 pinhole camera. 40mm f-133. Overall size is slightly larger than a film holder and about 2" deep.

Total investment so far, $2.68. The cost of two t-nuts nearly doubled my cost, and unfortunately, I still have to budget for some black felt for the light trap. It looks like this project is spiraling out of control.

This is yet to be tested, but I figure if a Zero Image can cover 4x5 at 25mm, I should be ok. I'll be taking this on vacation to Arizona next week. If I get anything worthwhile, I will let you know.

(I apologize in advance for the digital picture here, but as I understand it, pictures for illustration purposes are permitted. If this is out of line, the mods may delete as they deem appropriate.)

 

[DWThomas]

Looks good! I have actually been toying with the idea of a wooden box 4x5 pinhole cam myself. I would probably use paper negatives in it for WPPD in April this year. Dunno if I'll get far enough or not. I have a B&J Press 4x5 which I made a pinhole lensboard for, and a pile of filmholders, but I'm thinking maybe it's time to increase the percentage of homemade components!

 

[Ottrdaemmerung]

I'm really tempted to try making a pinhole camera from one of the wooden cigar boxes that my local tobacco store is always giving away. I'd love to make it work with 35mm or 120, but I think 4x5 would be easier to fashion.

 

[Toffle]

I'm really tempted to try making a pinhole camera from one of the wooden cigar boxes that my local tobacco store is always giving away. I'd love to make it work with 35mm or 120, but I think 4x5 would be easier to fashion.

I think two or three cigar boxes stacked would make a great 5x7 camera. That might be my next project. If I had any construction ability at all, I would have built this camera from scratch, as I hummed and hawed for weeks looking for an existing box with dimensions close enough be adapted to accept a 4x5 film holder.

 

[Marco B]

Nice work, have fun with it!

 

[Toffle]

The best part is, I eye-balled a pinhole of .3mm, then took my camera up to the lab, where they put it under a microscope and measured.... .3mm

 

[grahamp]

I made a cigar box 4x5 last year. Details at http://grahampatterson.home.comcast.net/~grahampatterson/grahamp/pinhole/index.html

You need a really good pinhole (thin metal and a clean edge) if you are aiming for a physical depth of 25mm, otherwise the corners will vignette a lot.

 

[RalphLambrecht]

The best part is, I eye-balled a pinhole of .3mm, then took my camera up to the lab, where they put it under a microscope and measured.... .3mm

The optimal pinhole diameter for a focal length of 40 mm is roughly 0.23 mm. So, 0.3 mm is a bit on the larger order, but it will work fine. Most people shoot pinholes for their unique characteristics and not to get optimal sharpness results.

Good luck and don't forget to post some images.

 

[Toffle]

The optimal pinhole diameter for a focal length of 40 mm is roughly 0.23 mm. So, 0.3 mm is a bit on the larger order, but it will work fine. Most people shoot pinholes for their unique characteristics and not to get optimal sharpness results.

Good luck and don't forget to post some images.

Hi Ralph,
Where did you get your figures? (I don't doubt them) My calculations, from the designer at pinhole.cz came to .282 mm, but I figured .3 was about as precise as I could get without specialized tools.

One problem I have found with my design, is that not all 4x5 film holders are created equal. I built my camera around a holder with a pronounced ridge that keeps the holder in place when you pull the darkslide. Without the tension of a spring back, some holders are prone to slipping out of place. I already have an idea or two to fix things; this has been a tremendous learning experience.

 

[RalphLambrecht]

Hi Ralph,
Where did you get your figures? (I don't doubt them) My calculations, from the designer at pinhole.cz came to .282 mm, but I figured .3 was about as precise as I could get without specialized tools. ...

Two optimum pinhole diameter equations exist. One is optimized for resolution d = sqrt(3.66*lambda*f), the other for sharpness d = sqrt(2.44*lambda*f), lambda being the wavelength of light and f being the focal length. In your case, the former returns d = 0.29 mm for resolution and the latter d = 0.23 mm for sharpness, assuming a wavelength of 555 nm and a focal length of 40 mm. Most people, subjectively, prefer sharpness over resolution.

You'll find more here:

http://www.waybeyondmonochrome.com/WBM2/TOC_files/PinholePhotographyEd2.pdf

It's not a big deal, but you may want to experiment with both and see which you like best.

 

[Toffle]

It's not a big deal, but you may want to experiment with both and see which you like best.

Thanks again for the info. I do have WBM II at home and will check the pinhole section out. I don't know if you can tell from my pic, but I have built this so that the pinhole fits into a slot for precisely the purpose you suggest, to try different apertures for the style of photographs I hope to make.

Cheers,