Pinhole Camera Question...

[Capocheny]

Hello Emmanuel,

Thank you... math makes my head hurt!

I'll just have to play with the design and see what comes out of it. I must admit I'm really quite excited about the prospects of seeing my first image.

The reason for this intrest in pinhole photography is that I went to a gallery opening a few weeks back. I was absolutely stunned by the beautiful images I saw and how much depth of field there was in those images. The photographer is Diane Bos and she shot the image of the gargoyle figure for the UPS ads that you see on television and in newspapers every so often. I'm not sure if the exhibition is still on at the gallery or not but you may be able to see some of her images online at www.kostiukgallery.com

Again... thanks kindly for the information. It's greatly appreciated.

Are you still shooting with a pinhole camera? I do use a Sinar X 4x5 but it's really not all that conducive to carrying around out in the field. Hence, I thought I'd give pinhole LF a try. After I succeed with the 4x5 version... I want to move ahead with an 8x10 version using photographic paper instead of film.

Cheers

[Emmanuel BIGLER]

I gave a try to pinhole cameras a long time ago but did not continue, attending this local pinhole conference recently made me think again to the physics of the device and I'm considering to practise it again with my children.

Using B&W photographic paper instead of film works fine except for two points
- classical graded B&W paper is blue-sensitive and not panchromatic ; variable contrast papers have a somewhat extended sensitivity to green but I do not know the results on the actual contrast of the image. Allow an exposure index of ISO 1 to ISO 10 in daylight. In artificial light actual sensitivity is smaller because there are much less blue rays emitted by a tungsten bulb. Papers are now rated with and ISO-P (like P-aper) sensitivity index which is roughly 100 times the value of the film ISO sensitivity. an ISO P 500 paper has roughly an ISO 5 sensitivity if used like a film in a camera.



- the image will be.. a negative of course and will be left-right reversed except if you add a mirror in front of the camera. this point is very minor ; you can scan the image with a flatbed scanner and do both the negative/positive 'reversal' processing as well as correcting the left-right symmetry by simple digital image post-processing. But you may of course prefer to work like Fox Talbot and make paper-to-paper contact prints, the final print will be a positive and will be left-right corrected like the original ;-)

[Emmanuel BIGLER]

Information about the World Pinhole Day
www.pinholeday.org

The Worldwide Pinhole Photography Day is held each year on the last Sunday in April.
The next Worldwide Pinhole Photography Day is on Sunday, April 24, 2005.

[Capocheny]

Ennanuel,

Good to hear that you're considering getting back into pinhole photography again... did you, per chance, take a peek at the link I posted for Diane Bos's images? IMHO, they were simply beautiful images and that's what is inspiring me to experiment.

According to some exposure tables I've seen from the internet...they recommend using classical graded paper at an ASA rating of 6 on a handheld meter (and adjusting for reciprocity failure.)

I'm hoping to get my pinhole camera designed and built for the next Worldwide Pinhole Photography Day... it should be great fun.

Cheers

[Rob Hale]

Hi Emmanuel

Am I completly up the creek or are these hole sizes and f numbers back to front
i.e. should the larger pinholes not be a smaller f number or is it a relationship to the focal length?

“I've been told that using a #8 needle produces a diameter of .023" (061
mm) providing a Normal (7") focal length and an f-stop of 330. So, if I
wanted to obtain the sharpest image with the least amount of distortion...
this sounds like the way to go then. Would I be correct in this
assumption? I'm under the impression that the smaller the hole, the
sharper the image. Therefore, perhaps, a wide-angle is the way to go?

I was also told that using a #10 needle to produce a diameter of .018"
(0.46 mm) would produce a wide-angle (5") focal length with an f-stop of
280. According to the discussion above... can I expect a fair amount of
distortion at the edges then?”

Regards Rob.