20 UTTERLY USELESS Facts About Photography

So, here are 20 pieces of completely useless but quite interesting photographic information. What do the millimeters in focal lengths actually measure? So, inside your camera lens are a series of optical glass elements that bend and direct light so that it can be focused onto your sensor. And when this happens, the image is actually projected onto your sensor upside down. And that's because at a certain point all the light rays converge and cross over. And this point is known as the optical center of your lens. Now when your lens is focused to infinity, meaning its focus is set to something as far away as it can possibly focus, the focal length, the number of millimeters, is the distance between that optical center and your camera's sensor. So in a 50 mm lens, that distance is from the point where the light converges to the sensor and that would be 50 mm or 5 cm if you prefer. I think I might start referring to my lenses in centime just to mess with people. Oh yeah, I shot that on an 8 1/2 cm lens. The 12 abandoned Hasselblads. A while ago, Hasselblad sent me an X2D camera and honestly, it's become my favorite camera. And I know some people were a bit jealous that I got sent one for free. But I know where you can get a free Hasselblood, too. There are 12 of them. Medium format, just sitting there, abandoned, waiting to be picked up. And I'm going to give you their location. But surely that sounds like useful information. And this video is about useless information. And don't worry, this is totally useless because those cameras were left abandoned on the moon. NASA astronauts famously used specifically modified Hasselblad cameras during the Apollo missions. They were built to survive the harsh lunar environment and adapted for use with space suits. But when it came time to leave the moon, NASA had to make some tough decisions about weight in order to make sure they had enough fuel to get the astronauts back home to Earth. And NASA decided that their baggage allowance weight would be better used bringing back some rocks instead of the Hasselblad cameras. So they left the cameras behind and only brought the film magazines back. So now there are 12 Hasselbag cameras sitting in the lunar dust littered across the six Apollo landing sites, perfectly preserved in the vacuum of space. So hop over and pick one up. It's yours. So why does bokeh have an H? Bokeh is the aesthetic quality of the blur produced in the out of focus parts of an image. And the word bokeh is Japanese and it translates as blur or haze. It's pronounced bo as in bone and k as in kennith. And you're meant to give equal stress to each syllable. Boare. But the translated spelling is historically b o k e. So where did the h come from? So the answer is from an American magazine photo techniques back in 1997. Mike Johnson, the editor at the time, was getting increasingly frustrated that English-speaking people were incorrectly pronouncing it boke, like joke. So, he started spelling it with an h at the end to help people pronounce it properly. And that just kind of stuck. And now that's become the default for the English spelling of bokeh. The world's largest digital camera is the LSST, the legacy survey of space and time camera, and it's located at Vera C. Reuben Observatory in Chile. It was designed to capture incredibly detailed images of the cosmos at a resolution of 3,200 megapixels or 3. 2 gapixels if you prefer, and it does a pretty good job at that. The camera weighs about 2,800 kg. It's about the size of a small car, and the sensor is over 2 ft wide. So, we all know JPEG as our favorite tried and tested file format. But JPEG is actually a group of people. It's the joint photographic experts group, an actual committee of engineers who designed and developed the image compression algorithm in the late 1980s. The first color photo was made with potatoes. In 1861, a young Scottish physicist by the name of James Clark Maxwell conducted an experiment to show that all colors can be made with the appropriate mixture of red, green, and blue light. And he was able to create a color image of a tartan ribbon using three separate photographs shot through red, blue, and green filters and then layering the three plates together. However, the first commercially successful color photography process, the autochrome, was invented in the early 1900s by French brothers August and Louis Lumiere. They found a way to combine all three colors together onto one single plate via the use of potato starch dyed

red, blue, and green. So, the first color photos were literally made out of potatoes. Why is it called ISO? ISO, the sensitivity a camera sensor is set to, has to be compliant with the standard set by the International Organization of Standardization. But here's the odd part. ISO is not an acronym. The name ISO was taken from the Greek word ISO meaning equal and was deliberately chosen as it needed to be the same in every language. So, this also means that it's pronounced ISO and not ISO. It would be like calling a RAW file an RAW file. F-stops don't actually measure light. When we shoot at an f-stop, while a lot of people might say f1. 4, f2. 8, etc., that's not actually correct. It's f over 1. 4, f over 2. 8 over as in divided by. It's a mathematical formula that gives you the diameter of your aperture, where f is the focal length of your lens. — So a 50 mm lens means that f is 50. So if you set it to f2 or rather f over2 that's 50 divided by 2 which is 25. So the diameter of your aperture would be 25 mm. However, there are many factors that determine how much light gets through your lens. The internal configurations of all the elements, the coatings on the glass, etc. So f over4 on one lens might give you a very different amount of light to f over4 on another lens. The actual amount of light that gets through your lens is measured in transmission stops, also known as t-tops, and that doesn't always match what your f-stop boasts. Most ND filters are lying. A 10- stop ND filter, sometimes called an ND-1000, theoretically reduces light by a factor of 1,000. But in reality, most ND filters reduce some color wavelengths more than others, and this causes color shifts. And that's why the very high-end ones advertise true neutral density, because most aren't neutral at all. They're just density filters. The longest ever photographic exposure was taken by accident. In 2012, Regina Vulenborg, an MA fine arts student at the University of Hertfordshire, placed a sheet of photographic paper inside an empty can of beer and mounted it on a telescope at an observatory to create a pinhole camera and then forgot about it. And in 2020, the cam was found by the observatory's technical officer, still sat there exposing the image, revealing what may be the longest photographic exposure ever taken, capturing over 8 years of sunrails in a single image. The photo shows 2,953 arcs of the sun across the sky, with elements of the observatory's evolving landscape also visible within the frame. And while German artist Mikuel Wesley holds the current official record with a 4-year 8-month exposure, Vulcanborg's accidental artwork does appear to surpass this pigeon photography. In 1907, German apocry Julius Nebron invented pigeon photography. And to be clear, I'm not talking about photographs of pigeons. I'm talking about cameras strapped to pigeons. He fitted homing pigeons with tiny timed cameras in order to get aerial photos. And while the military explored its use for reconnaissance in World War I, rapid advancements in aviation soon made this obsolete. Also, training pigeons to get good compositions was met with uh limited success. Camera flashes used to work by exploding. Unfortunately, I'm old enough to remember when camera flashes actually exploded. My first camera used flash cubes. You'd buy them in packs of three and mount one on top of your camera. Each cube held four tiny single-use magnesium bulbs that ignited with a pop every time you pressed the shutter. After each shot, winding the film on would rotate the cube to the next side, ready for the next miniature explosion of light. The term snapshot comes from hunting. In the early 1800s, snapshot was a hunting term. It referred to a quick instinctive shot fired without taking aim, usually at fastmoving game. But in 1860, British scientist and astronomer Sir John Hershel repurposed the word to describe a photograph taken hastily without much care. And the name kind of stuck and snapshot became part of photography's everyday vocabulary. No part of a 35 mm full-frame sensor is actually 35 mm. So, some

higherend cameras today feature what's called a 35mm sensor, which is also known as fullframe. But the odd part is that a 35 mm sensor actually measures 36 mm wide by 24 mm tall with a diagonal of 43 mm. So, if no part of this is 35 mm, why do we call it a 35 mm sensor? The answer goes back to the film era. 35 mm was the name of the total width of the strip of film, including all the sprocket holes running down both sides. The actual image area was just the bit between them, 36x 24 mm. So, when digital sensors were designed to match the same image area and field of view, the old name just sort of stuck, even though the sensor itself has never been 35 mm wide. What is the most viewed photo of all time? time is estimated to be an image called Bucolic Green Hills by Charles O'Ra, a former National Geographic photographer. And I'm guessing you will have seen it. It's this. It was later renamed Bliss and used as the background for Microsoft Windows XP, which ensured its ubiquitous nature. It was shot on a Mamia RZ67 film camera with Velvia 50 slide film. And what I find very interesting about this image is that it's apparently straight out of camera, just unmodified. This is the original film scan. Microsoft added a bit of saturation and contrast and obviously had to crop it to the desktop background aspect ratio when it was chosen, but otherwise there was no digital enhancement of it at all. How many megapixels can we actually see? If your eyes were cameras, they would have a resolution of 567 megapixels, according to scientists. So, we've had the longest exposure ever taken, but what was the shortest? The raptronic camera was invented by Harold Edertton in the 1940s, someone whose work I talk about in my high-speed photography tutorial video. It was invented to capture images of nuclear explosions just micros secondsonds after detonation. It bypassed the limitations of mechanical shutters by using two polarizing filters and a Faraday cell. And it was able to take exposures as fast as 10 nanose. That's 10 billionths of a second. Victorians were crazy. Because rudimentary Victorian cameras needed such long exposures to work, sometimes up to 30 minutes for one picture, sitters were often held in place with head braces and metal poles, and babies clothes were often sewn into chairs to keep them still. The word pixel was coined in the 1960s by shortening the term picture element. Films have a megapixel resolution. Different film stocks have been measured and have a resolvable level of detail equivalent to different megapixel sensors. For example, 35 mm Fujifilm Velvia 50 and Kodak Ektar 100 have a 20 to 25 megapixel level of resolution. While higher ISO stocks like Kodak Portra 800 or Ilford Delta 3200 can resolve detail at equivalent of around 7 to 10 megapixels. And that concludes my list of 20 utterly useless pieces of photographic information. I'll see you next time.