Digital Photography from 20,000 Feet
by Wesley Fink on September 25, 2006 12:05 AM EST- Posted in
- Digital Camera
Why the Digital SLR?
SLR cameras have been around for more than 50 years, but it is remarkable how many of those shopping for a digital camera have no idea why the market is moving to the SLR or Single Lens Reflex. Up until the late 1940's the world of hobbyist photography was ruled by 35mm point-and-shoot and rangefinder cameras. These cameras were not really that different from the point-and-shoot cameras that we have today in digital photography, except that they did not have the benefit of all the electronics that are part of today's digital cameras. The cheap point-and-shoots used a fixed focus lens, which meant the lens always shot a certain range (depth-of-field) in focus - no matter whether the subject was in that range or not. The better of these cameras used rangefinders, which were two images from two optics superimposed in the viewfinder. When these two images merged in the viewfinder your subject was in focus. As you can imagine the optics to allow focusing were pretty complicated and expensive to build. However, with a fixed lens that never changed it was possible to design and manufacture some very reliable and affordable rangefinder cameras.
The top end of the amateur photography market, which had embraced 35mm as the "miniature" film standard, then introduced a brilliant idea. Why not manufacture cameras that could use multiple lenses. This would allow the photo hobbyist to use the lens that was best suited for what they were photographing - like a wide-angle lens for interiors, or a telephoto for sporting events and far away subjects. Companies like Leica and Contax pioneered these interchangeable lens rangefinder cameras in the 1930s. After World War II, German camera companies resumed camera manufacturing. Japan, which had manufactured quality optics for a more limited market before WWII, also began making quality interchangeable lens rangefinders. Japanese companies like Canon, Aries, and Nikon championed cameras with changeable lenses.
The ability to change lenses was a great idea, but the execution was anything but simple. Viewfinders started having multiple frames engraved for the different focal lengths like 35mm, 50mm, 85mm. The user had to remember that the tiny square was 85mm. Leica and others had accessory viewfinders that mounted on the flash shoe so you could see about what the lens saw. The problem with the rangefinder is that the viewfinder and the lens never see the same thing. This was not a huge issue with a fixed lens, since the viewfinder could be matched reasonably well to the lens. There were even complicated mechanics that adjusted the viewfinder for "parallax error" on rangefinder close-ups. But with interchangeable lenses the situation became very complicated.
The first popular solution to this problem was the German Exacta, fist produced in 1936. The Exacta had a waist level-finder and a flipping 45-degree mirror. With a flipping mirror, you could look through the lens for composition and focusing - seeing the same view as the lens. You looked at the image from above the camera (5), the image was backwards (as in a mirror image), and the mirror was either manually reset or later reset automatically when winding the film, but the view on the ground glass was the same as any lens (1) mounted on the camera.
In the 1950's the Japanese pioneered further development of the SLR design. A roof pentaprism first appeared on an East German Contax S announced in 1949, but the Japanese camera industry refined and perfected the idea. Asahi developed the Asahiflex in 1952, and in 1954 the Asahiflex IIB. In 1957, Asahi Pentax introduced the fixed pentaprism and the right-hand thumb wind lever. Minolta introduced their first SLR, the SR-2, in 1958. Nikon, Canon and Yashica introduced their first SLRs in 1959 (the F, Canonflex, and Pentamatic, respectively).
The diagram shows how the light passes through the SLR lens assembly (1), is reflected by the mirror (2) and projected on the matte focusing screen (5). Using a condensing lens (6) and internal reflections of the mirrored roof pentaprism (7) the image appears in the eyepiece (8). When an image is taken, the mirror flips up as the arrow indicates, the shutter (3) opens, and the image is projected onto the film or digital sensor (4) The image at the film or sensor is exactly the same as on the focusing screen. [Image from Wikipedia.]
By the early 1960s the basic form of the SLR had evolved to what we know today, as you can see in this photo of the original Nikon F SLR.
Refinements have continued to expand the usefulness of the SLR design. The Topcon RE Super and Asahi Pentax Spotmatic pioneered through the lens metering in the early 60's. Auto exposure was first seen in the Pentax Spotmatic F in 1971, and it was popularized with the Canon AE-1 Program in 1976. Pentax made a limited attempt at autofocus in 1981 with a 35-70 f2.8 lens for the Pentax ME-F. A few years later, Minolta brought out the first real autofocus camera, the MAXXUM 7000, in 1985. The autofocus auto-everything Maxxum 7000 was wildly popular and made autofocus a virtual requirement on future SLR designs.
SLR cameras have been around for more than 50 years, but it is remarkable how many of those shopping for a digital camera have no idea why the market is moving to the SLR or Single Lens Reflex. Up until the late 1940's the world of hobbyist photography was ruled by 35mm point-and-shoot and rangefinder cameras. These cameras were not really that different from the point-and-shoot cameras that we have today in digital photography, except that they did not have the benefit of all the electronics that are part of today's digital cameras. The cheap point-and-shoots used a fixed focus lens, which meant the lens always shot a certain range (depth-of-field) in focus - no matter whether the subject was in that range or not. The better of these cameras used rangefinders, which were two images from two optics superimposed in the viewfinder. When these two images merged in the viewfinder your subject was in focus. As you can imagine the optics to allow focusing were pretty complicated and expensive to build. However, with a fixed lens that never changed it was possible to design and manufacture some very reliable and affordable rangefinder cameras.
The top end of the amateur photography market, which had embraced 35mm as the "miniature" film standard, then introduced a brilliant idea. Why not manufacture cameras that could use multiple lenses. This would allow the photo hobbyist to use the lens that was best suited for what they were photographing - like a wide-angle lens for interiors, or a telephoto for sporting events and far away subjects. Companies like Leica and Contax pioneered these interchangeable lens rangefinder cameras in the 1930s. After World War II, German camera companies resumed camera manufacturing. Japan, which had manufactured quality optics for a more limited market before WWII, also began making quality interchangeable lens rangefinders. Japanese companies like Canon, Aries, and Nikon championed cameras with changeable lenses.
The ability to change lenses was a great idea, but the execution was anything but simple. Viewfinders started having multiple frames engraved for the different focal lengths like 35mm, 50mm, 85mm. The user had to remember that the tiny square was 85mm. Leica and others had accessory viewfinders that mounted on the flash shoe so you could see about what the lens saw. The problem with the rangefinder is that the viewfinder and the lens never see the same thing. This was not a huge issue with a fixed lens, since the viewfinder could be matched reasonably well to the lens. There were even complicated mechanics that adjusted the viewfinder for "parallax error" on rangefinder close-ups. But with interchangeable lenses the situation became very complicated.
The first popular solution to this problem was the German Exacta, fist produced in 1936. The Exacta had a waist level-finder and a flipping 45-degree mirror. With a flipping mirror, you could look through the lens for composition and focusing - seeing the same view as the lens. You looked at the image from above the camera (5), the image was backwards (as in a mirror image), and the mirror was either manually reset or later reset automatically when winding the film, but the view on the ground glass was the same as any lens (1) mounted on the camera.
In the 1950's the Japanese pioneered further development of the SLR design. A roof pentaprism first appeared on an East German Contax S announced in 1949, but the Japanese camera industry refined and perfected the idea. Asahi developed the Asahiflex in 1952, and in 1954 the Asahiflex IIB. In 1957, Asahi Pentax introduced the fixed pentaprism and the right-hand thumb wind lever. Minolta introduced their first SLR, the SR-2, in 1958. Nikon, Canon and Yashica introduced their first SLRs in 1959 (the F, Canonflex, and Pentamatic, respectively).
The diagram shows how the light passes through the SLR lens assembly (1), is reflected by the mirror (2) and projected on the matte focusing screen (5). Using a condensing lens (6) and internal reflections of the mirrored roof pentaprism (7) the image appears in the eyepiece (8). When an image is taken, the mirror flips up as the arrow indicates, the shutter (3) opens, and the image is projected onto the film or digital sensor (4) The image at the film or sensor is exactly the same as on the focusing screen. [Image from Wikipedia.]
By the early 1960s the basic form of the SLR had evolved to what we know today, as you can see in this photo of the original Nikon F SLR.
Refinements have continued to expand the usefulness of the SLR design. The Topcon RE Super and Asahi Pentax Spotmatic pioneered through the lens metering in the early 60's. Auto exposure was first seen in the Pentax Spotmatic F in 1971, and it was popularized with the Canon AE-1 Program in 1976. Pentax made a limited attempt at autofocus in 1981 with a 35-70 f2.8 lens for the Pentax ME-F. A few years later, Minolta brought out the first real autofocus camera, the MAXXUM 7000, in 1985. The autofocus auto-everything Maxxum 7000 was wildly popular and made autofocus a virtual requirement on future SLR designs.
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wheel - Tuesday, September 26, 2006 - link
Thanks for your reply.Regarding the Canon 50mm 1.8, I think most people would agree that the 1.4 is better since it has full time manual focus and also a silent USM motor, plus 8 aperture blades instead of 5 for nicer, smoother looking bokeh (out of focus areas in an image). Of course when you consider the cost differential most people choose the f1.8 and for many it is the smarter choice! However I still believe your sentence in the article suggesting that it happens to be the sharpest lens in the lineup a little misleading. Not a big deal I guess.
If I can make some comments on the following paragraph:
There are plenty of Digital Camera Review sites out on the web, so you may ask why AnandTech is re-launching a Digital Photography section. It appears that current sites are rarely on target with what computer enthusiasts want to know about digital cameras. Some sites make the assumption that the reader knows a lot more about photography than our average reader, which often leads to much of the review being gibberish to a non-photographer. Other sites dwell on tests of things like "start-up times" that were important in early digital, but have become all but meaningless in today's digital SLR market. Still other sites, which are very well-grounded in traditional photography show an obvious lack of knowledge about computers and computer tools that make digital photography so flexible today. It is our sincere belief that we can do it in a better way for our readers and computer enthusiasts everywhere, but please help us as we try to reinvent this wheel. Some of our readers may not like AT delving into Digital Camera Reviews, and to them we say you just can't ignore digital photography any more. Today's digital imaging is nothing more than an optic stuck on a computer, and there is very little left of the mechanical gems that once ruled the world of photography.
A few points:
"Some sites make the assumption that the reader knows a lot more about photography than our average reader, which often leads to much of the review being gibberish to a non-photographer."
So a 'non-photographer' will find a technical review on the big digital camera sites gibberish? I don't think that is a problem, because such reviews aren't really aimed at non-photographers. I would guess that non-computer users are going to find articles on Anandtech about ram timings difficult to understand too!
Other sites dwell on tests of things like "start-up times" that were important in early digital, but have become all but meaningless in today's digital SLR market.
See my comments re: sports / action photography in my previous post. Start up times, shot to shot times and file flush times are quite important to me! Other sites have (very comprehensive) standardised tests that include these timings. I wouldn't say they dwell on the subject though, unless a particular camera is unusually bad at it. If it is not something that is relevant then a reader can easily skip it.
Still other sites, which are very well-grounded in traditional photography show an obvious lack of knowledge about computers and computer tools that make digital photography so flexible today.
In my years of reading the major photo review websites, I haven't encountered this. Without asking you to be specific, can you mention general examples of what you mean?
Cheers,
Ian
tagej - Tuesday, September 26, 2006 - link
The reality is that most computer geeks (myself included) are not photography experts, but are overall tech-savy and interested in things like digital SLR cameras.Sure, I can go to sites like dpreview and the like, and they do an excellent job of reviewing cameras from a pro or prosumer perspective. I could sit and read a bunch of stuff on those sites and educate myself to the point of becoming very knowledgable about cameras... Most of us don't want to do that, or we would have already done so. Instead, AT hit it right on the head with this article, it's a look at digital photograhpy for the tech savy who are not photography experts.
arswihart - Tuesday, September 26, 2006 - link
I totally agree with "wheel." If you feel the need to review cameras, go ahead, but thats not what I come to Anandtech for.aeternitas - Monday, September 25, 2006 - link
" The artistic types distrust turning their vision into cheap Adobe Photoshop tricks, and the tech-savvy are so enamored of technology and editing that they often don't have a clue about what makes a good photograph and what lens to use in a given situation. "I stopped reading there. If you want respectable people to respect you, its a good idea not to be a fucking jackass and insult the readers in the second paragraph. Get some common sence.
Resh - Tuesday, September 26, 2006 - link
Have to side with Wes on this one. Nothing in his words are offensive. He is simply stating the view point of two extremes of the population who both hold very valid positions.Wesley Fink - Monday, September 25, 2006 - link
These are comments from discussions I have had on Forums and in emails with readers. They were not meant to offend, but to point out the fact that the art and technical don't always mix well. This is particularly true when the market, and not the people affected, is forcing changes in the way people work.ksherman - Monday, September 25, 2006 - link
since we have had a camera review on AT! Kudos!To those that say no, I also like to read reviews from multiple sources. AT- dont try to be dpreview, make your reviews a little less technical, easier to understand. Not to fault them, but you need to have some pretty serious photography knolwedge to get their reviews. I would welcome an easier to understand set of reviews. (I do still enjoy reading about my level :-))
On another note, on the last page, you called canons new camera the Rebel XT1, its actually the XTi.
Also, take a gander at the Panasonic Lumix DMC-FZ50, its a sort of pre-digital SLR camera. It basically is a digital SLR, but with an attached lense. Its looking to be my next camera purchase since I am too poor to afford the "real" DSLRs.
saiku - Monday, September 25, 2006 - link
I am a hobbyist photographer (Canon 350D) who likes to do macros/scenery when I can. What I'd love to see are guides for people who want to get into DSLRs and don't know which camera system to buy into. For example, if a person is interested in macros, should he buy into a Nikon system? What about the guy who wants to shoot lots of indoor shots of his baby? Lens choices are very tough for newbies to make and a hefty dose of attention to what lens to pick would be great.PokerGuy - Monday, September 25, 2006 - link
Wes, thanks for the great article. I'm a grizzled vet when it comes to PC tech, but when it comes to photography I'm pretty much a noob. I appreciate the article and look forward to reviews, especially since I'm about to purchase my first digital SLR camera.One dumb question: are lenses for SLR cameras "standard" in terms of connecting to the camera body? ie, can I take a Canon EOS Rebel 2000 SLR lens and hook it up to some other digital SLR camera?
Resh - Monday, September 25, 2006 - link
Also, Canon EF-S lenses only fit certain cameras (Digital Rebels, 20D, 30D), but EF lenses work on all current Canon bodies, digital or film.Third party manufacturers like Tamron and Sigma will make lenses for both Canon and Nikon.