fundamentals

Some people argue that you don’t need to know anything about physics or technology in order to take good pictures. They are right. This category is intended only for those who don’t trust their ignorance.

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.

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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...

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Refraction, Dispersion and Optical Glass for photographic lenses

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...

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Focal length and image circle

(image source: wikimedia commmons) You certainly saw already a diagram more or less like this one. It is a standard way to explain what focal length is. This is how camera makers talk about focal length and they have a good reason for that: they want you to learn what focal length means in the...

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What is a photographic lens?

Any scene you can shoot is made up of objects that emit light (own or reflected) and it is from this light that the lens will form an image to be recorded on film or digital sensor. If it were possible to block almost all light coming from a scene, like this one from my apartment window, leaving...

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Light and colors, physics and perception

Yes, light is a wave, and then … Wave, is a phenomenon in which there is energy transmission without transport of matter. It’s like energy traveling in space. It is easier to understand if we think of an example where there is matter transporting energy. For example, to drop a stack of...

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What is a histogram in photography?

  With digital cameras is always good the possibility of checking the result right after the click. Those who never used film don’t know how good it is. But sometimes, a quick evaluation may show that the picture registered is OK and later, on the computer, we realise that shooting it...

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Pixel’s anatomy – logical and physical

At the heart of digital world we find the “bit”. At the heart of digital images we find the “pixel”. The pixel was already know in Antiquity. But as for the want of fine electronics it used to be made out of little stones and “files” were called mosaics. The...

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