2026-03-16- Light Diffraction

When light rays pass the edge of an opaque material, they tend to bend slightly around the edge of it. This bending, known as diffraction, is due to light acting not as a series of straight rays, but as waves.

The amount of bending is dependent on the wavelength and is different for different colours, as shown in the drawing below. Light passing through a very fine slit appears on a screen a short distance away as a white line with a band of colours on each side. Diffraction also is responsible for the ‘halo’ around the moon and the star-shaped patterns seen when you look at a distant bright light through a window screen.

In photography, diffraction around the edges of a lens diaphragm opening is responsible for the limitation of sharpness improvement when stopping down. Beyond a certain point, the use of smaller aperture no longer increases the sharpness of an image; instead the image actually becomes less sharp. In the same way, the image sharpness of a pinhole camera cannot be improved by making the pinhole smaller beyond a minimum diameter.

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2026-03-14 - History and Evolution of the Kodak Logo

While working as a junior clerk at the Rochester Savings Bank, George Eastman first began commercial production of dry photographic plates in a rented loft of a building in Rochester, New York in April 1880. In the next few years, Eastman became very successful and expanded the company several times. His company started as the Eastman Dry Plate Company in 1881, later became the Eastman Dry Plate and Film Company in 1884, and soon after the Eastman Company in 1889. The last name change occurred in 1892, when the Eastman Kodak Company of New York was organized. The company has been called Eastman Kodak Company ever since. The word "Kodak" was first registered as a trademark in 1888. The letter “K” had been a favorite of Eastman’s, he is quoted as saying, "I devised the name myself. The letter 'K' had been a favorite with me; it seems a strong, incisive sort of letter. It became a question of trying out a great number of combinations of letters that made word...

2026-03-20-Manfrotto monopods

Sometimes collecting is a matter of persistence. The Manfrotto “GRUPPO” 434SSB monopod (shown top) showed up one day at my local thrift store. They had a price tag of $25 on it. I had bought the lower Manfrotto Compact MMC3-01 monopod at the same thrift store for $3. So I asked, “Why so much?” They answered their “expert” had found it sold for $200 on the internet. I find experts—who almost never clerk in the thrift store, so are unreachable—hard to deal with. There is also the matter someone might actually pay them $25 for a 2.27 kg (5 pound) aluminum pole, so I decided to let the Gods-of-Collecting decide if I was going to ever own it. For weeks I would pick it up, check the price tag to see if they had come to their senses, and return it to the shelf. I did try various clerks to see if they would lower the price, but they said they were not authorized to change prices. I plodded on, week after week without much hope. ...

2026-06-23 Olympus Camedia D-535 Digital Camera

The Olympus Camedia D-535 digital camera is a cute little camera, introduced September 16, 2004. It was modestly priced at about $175 list. It had the motto, “one button/one function.” There were four scene modes available, as well as movies (QuickTime / 320x240 at 15 fps for as long as the memory held out) and “Program-Auto” on the rotary dial. A four direction with a center “OK” allowed rapid access to (starting at 12 and going clockwise)— EV adjustments plus and minus 2EV in ½ EV steps Macro (including Super-Macro allowing shooting down to 2 cm (0.79”) Reset Self-timer (12 seconds) The three buttons under the 1.5 inch (130,000 dot) screen (from left) are delete, menu access and flash modes. The two buttons to the right of the screen are camera (top) and playback. There is a rocker switch for zooming that doubles as a magnification /file views switch on playback. The power-on button is inset into the top at the middle of the camera, with the shutter button ...

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