Confused about lensless photography and 4x5 camera

[pdh]

Haven't f295 forums been shut (or are at least slated to) ?

(see http://www.f295.org/main/showthread....l=1#post129979
)

[Barry Kirsten]

Sadly f295 is no longer being maintained and presumably will die away, however people are still managing to post there. It is still possible to access the site and its marvelous archive.

[tonyowen]

Sadly f295 is no longer being maintained and presumably will die away, however people are still managing to post there. It is still possible to access the site and its marvelous archive.

I tried to register, but was informed that it was no longer possible - which means some of the infrrmation will not be available to me.
regards
Tony

[Maris Rusis]

It is possible to see a ground-glass image using a pinhole. But you may not want to do it. With my Tachihara 8x10 camera I can see sunlit scenes at f600 by using a really light-proof focussing cloth and staying under it for upwards of a minute to let my eyes dark adapt. Holding the breath limits condensation on the ground-glass. When the sense of heat and suffocation becomes too much I have to get out and gasp for some blessed air.

[photonsoup]

Using pinholes made from aluminum soda cans and a sewing needle, I can view the image on the glass with a wide angle field of view. The narrower the view the dimmer the image. Most of my pinholes wind up being about 1/2mm, so I measure from the glass to the pinhole in mm and multiply by 2 to get an approximate f-stop for calculating exposure. So far with B&W negative film I've done pretty good.

[Jim Jones]

Since much pinhole photography is done with the camera mounted on a tripod, Replacing the ideal pinhole with a larger one just for framing becomes practical with most large format cameras. The image with an oversize pinhole will be unsharp and dim, but perhaps adequate for framing. Replacing the pinhole with a suitable simple lens will provide a brighter and sharper image. Many such lenses are sold by http://www.surplusshed.com/. Unlike a pinhole, this lens will require focusing. These lenses and extra pinholes can be mounted in lens boards. For many large format cameras, lens boards can be improvised from foam core or mat board. Two screw-in filters with the glass removed can be the basis of another way of changing pinholes. One filter is mounted to a lens board, and the other used to retain a disc with the pinhole centrally mounted. Also, a slide-in pinhole holder can be mounted to a lens board.

[Barry Kirsten]

I tried to register, but was informed that it was no longer possible - which means some of the infrrmation will not be available to me.
regards
Tony

No, you won't be able to register, but I don't see why the various threads and posts would be closed to viewing.

[tonyowen]

No, you won't be able to register, but I don't see why the various threads and posts would be closed to viewing.

The option to view the threads and post is very limited (ie can't open thumbnails) albeit some information is accessible
regards
Tony

[tonyowen]

It is possible to see a ground-glass image using a pinhole. But you may not want to do it. using a really light-proof focussing cloth and staying under it for upwards of a minute to let my eyes dark adapt. Holding the breath limits condensation on the ground-glass. .

Thank you for the GG solution - I have a very dense changing bag that I used to focus. While temperature is not a problem here in the northern hemisphere though claustaphobia might be.
regards
Tony

[tonyowen]

camera mounted on a tripod, Replacing the ideal pinhole with a larger one just for framing becomes practical with most large format cameras. Two screw-in filters with the glass removed can be the basis of another way of changing pinholes. One filter is mounted to a lens board, and the other used to retain a disc with the pinhole centrally mounted. Also, a slide-in pinhole holder can be mounted to a lens board.

Brilliant (pun intended) why are the obvious and simple solutions often missed.

regards

Tony