Using a Petzval lens for potraits

Using Petzval-type lenses for portraits when the subject's face is out of the center of the image requires some care. The article discusses and gives an example of how to decentralize the lens to reposition its optical axis over more peripheral areas of the photographic frame.

Calculator – cost of photographic...

Calculator for easy assessment of photographic formula's cost. You enter quantities, dilution, packaging and price and get right away how much one liter of that working solution costs. Very convenient to compare different formulas, purchased ready to use or homemade, and decide what suits you best...

Mix your formulas – black and white...

Find a compact set of chemical reagents, 8 in total, that will allow you to develop film and print B&W photographies. With instructions about mixing, using and cost considerations. A nice starting point if you are interested in setting up a photography darkroom and make your own chemicals.

Enlarger head using LEDs

Article presents project to build a black and white photo enlarger head, with timer, using LEDs and Arduino platform. The result is high power and excellent contrast control for black and white work.

Using RAW format in photography

Article analyzes a practical case in which the use of RAW file, thanks to its greater depth of color, allows the exploration of areas of a photograph that in format .jpg would be lost.

Color Depth in digital image files

Article explains why and how color-depth concept is necessary to express the array of different colors a digital system can handle. It clarifies why it must be expressed in bits, what that means in terms of color differentiation, when true-color is reached and why sometimes more than true color...

Finding the focal length of a lens

  This is a calculator that will help you in finding the focal length of a photographic lens. The method is about focusing on one or more objects at different distances. Each time, you write down 3 measurements. Only one measurement could do. But the idea is that “averaging”...

Pinhole, where truth, beauty and goodness...

Pinhole is a photographic technique that employs most of the times a home made camera in different degrees of improvisation and roughness. Matchboxes, shoeboxes and whatever boxes and containers are sort of starting point for those projects. The photographer bricoleur may also start from scratch by...

Front raise and horizon line

For a given lens and given film or sensor format, this simulator shows how much it is possible a front raise and where the horizon line will end up in the final picture. Focusing is assumed to be at, or closer to infinity, a normal landscape condition. Observations: 1 – The scheme is...

Refraction, Dispersion and Optical Glass for...

Refraction Refraction is a phenomenon of waves changing direction when passing from one medium to another. In a photographic lens that is the case when passing from air to glass and again from glass to air. It occurs also when passing from one type of glass to a different one. They are not all the...