Notes by Dr. Optoglass: Color Bit Depth, Middle Grey and White Balance of the Human Eye

Topics Covered: Color Bit Depth Middle Grey Whiteness and White Balance Colors, like features, follow the changes of the emotions – Pablo Picasso We have already seen that the color space of the eye, as defined by the CIE 1931 XYZ color space, estimates about 10 million colors for our vision. The word size required […]

Notes by Dr. Optoglass: Dynamic Range of the Human Eye

Topics Covered: Contrast Ratio Static and Dynamic Range The Dynamic Range of the Human Eye Contrast Sensitivity By painting colors and lines and forms seen in quickened mood I was seeking to make this mood vibrate as a phonograph does – Edvard Munch The following image has two objects – can you see them? No? […]

Notes by Dr. Optoglass: Sensitivity and ISO of the Human Eye

Topics Covered: Sensitivity ISO The ISO Range of the Human Eye Photography to the amateur is recreation, to the professional it is work, and hard work too, no matter how pleasurable it my be – Edward Weston A camera sensor (or film) is like a sponge: It has the ability to soak in light. How […]

Notes by Dr. Optoglass: The F-numbers of the Eye

Topics Covered: Typical F-numbers for various scenarios How to find f-stop T-stop The F-numbers of the Eye If I could steal someone’s dream myself, I’d have to go for one of Orson Welles – Christopher Nolan We have all the formulas we need to calculate f-numbers at various ISOs based on lux levels. Here is […]

Notes by Dr. Optoglass: How to Read Light for Exposure

Topics Covered: Light meter – Incident and Reflective Lux, EV and Common Scenarios The Inverse Square Law Art is never finished, only abandoned – Leonardo da Vinci Now that we know what an exposure is, we are ready to measure it. There are two ways in which to do this: Using an incident light meter […]

Notes by Dr. Optoglass: Camera Exposure

Topics Covered: Exposure and Camera Exposure Exposure Value (EV) and Stops F-number and Shutter speeds Look and think before opening the shutter. The heart and mind are the true lens of the camera – Yousuf Karsh This is how a camera works: The sensor is a jar that can take in light till a certain […]

Notes by Dr. Optoglass: The Units of Photometry – Part II

Topics Covered: Nits and Lux Footcandles and footlamberts Typical light levels for various scenarios Actually, I’m not all that interested in the subject of photography. Once the picture is in the box, I’m not all that interested in what happens next. Hunters, after all, aren’t cooks – Henri Cartier-Bresson In part I we covered measuring […]

Notes by Dr. Optoglass: The Units of Photometry – Part I

Topics Covered: Joules and Watts Lumens and Candelas Lumens per Watt Counting Photons A beautiful thing never gives so much pain as does failing to hear and see it – Michelangelo Let’s start with some radiometry units: Imagine a light bulb has having a total volume (energy) of light that it can pour out during […]

Notes by Dr. Optoglass: How to Measure Light

Topics Covered: How Light Works Radiometry vs Photometry What is Brightness Light makes photography. Embrace light. Admire it. Love it. But above all, know light. Know it for all you are worth, and you will know the key to photography – George Eastman The full spectrum of light is represented thus: As you can see, […]