Solargraph by Pekka Salminen

I’ve done some pinhole camera experiments in my younger days, but Justin Quinell is our age’s master in this technique. Have a look at his collection of multiple-month exposures, which he calls Solargraphs.

He also built a miniature camera, letting you expose from within the mouth. And he even sells those little cameras for next-to-nothing.

And do visit Junstins homepage, where you’ll find lots of other goodies, including instructions on how to build a 720-degree camera out of toilet rolls.

A histogram is basically the lightmeter of the digital age. It is a tool that helps you getting the most out of your camera.

Click here for a nice explanation of what they are and how to use them. You need Power point or similar. Alternatively, you can download a zipped pdf file of the presentation here.

Anyone familiar with photography knows about f-stops. Calculated as Focal Length divided by Diameter (of the front lens element). The smaller the value of the f-stop, the more light passes the lens, the shorter exposure time necessary, the narrower the depth of field, the lower ASA/ISO rating necessary.

Typical f-stop values are f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22 and f/32, but there are lenses with f-stops as low as 1 and as high as 128. With the arrival of automatic exoposure meters, fractional f-stops have also become the norm.

T-Stop

When you start using professional film lenses, you will come across the phrase T-stop. While the f-stop is a mathematically derived value, the T-stop is a calibrated value. Since lenses have optical elements, and each of these elements blocks a (tiny) amount of light, the actual amount of light coming through a lens is always lower than the f-stop value suggests.

Therefore most cine lenses are individually calibrated to give the actual amount of light transmitted, the T-stop (T standing for Transmission.) T-stops are always (slightly) higher than f-stops.