Somewhat OT: I don't know much about photography but had always known DSLRs as the gold standard for digital photography. I was surprised to learn that there's actually a bit of a shift going on away from DSLRs towards "mirrorless cameras". If you haven't heard about them, the differences are pretty interesting. Basically, DSLRs are still like the one in this article - digital sensors crammed into an SLR. Mirrorless cameras take more liberties, as if they were imagining a digital camera from the ground up rather than starting with an SLR. Eg: http://photographylife.com/mirrorless-vs-dslr
Photography is a hobby of mine. I currently use 2 camera bodies, one is a DSLR (Canon 70D) and the other is mirrorless (Sony A7).
The Sony A7 has a full-frame sensor, which is pretty crazy considering how relatively small it is (much smaller than the 70D body which holds a smaller 1.6 crop APS-C sensor) and under ideal conditions it produces better image quality than the Canon 70D (slightly higher megapixels, but really the physical size of the sensor is what puts it ahead with less noise, plus the Sony sensor technology has better dynamic range).
The Sony A7 is the first camera I've used where the electronic viewfinder is bright enough and fast enough that I can stand using it over an optical viewfinder. And having reached that point it really opens up some great abilities that you can't get with purely optical, like focus peaking (real-time contrast/edge detection to show you which parts of the frame have the sharpest focus) and high zoom in the viewfinder (both of which are really useful especially when using older manual focus lenses which really shine on this camera). Also, just plain seeing the image exactly like the sensor does in terms of depth of field is a real game changer... and yes, you could previously do these with liveview cameras on a bigger LCD attached to the back, but the high-res, bright viewfinder is a really big deal for me as I hate holding the camera away from me while looking at an LCD since it is much harder not to cause sharpness-killing movement that way than when using your face and arms as a sort of bio-tripod.
All that aside, DSLRs still currently win for fast autofocus. Pure phase detect autofocus is just so much faster than the contrast autofocus used by mirrorless cameras. For a lot of photos this doesn't matter, but for some it does. See, eg:
That is a photo I took last weekend with my Canon 70D. I often carry both bodies (70D and Sony A7) with me when hiking, but there's no way I would have gotten those hummingbird photos with the A7 (regardless of which lens I was using on it) unless I was using manual focus and got really lucky with my timing.
Even with analogue SLRs there were times when rangefinders (also mirrorless) had advantages. You didn't have the massy mirror to move, just the shutter, so there were timing and noise benefits.
In the past, the DSLRs sensors were quite sensitive to long exposures. As I remember it, during long exposures the sensor could get so hot that it could actually burn the color filter - so the color accuracy decreased over time. This was why you could not use live-view on a DSLR camera when all the P&S cameras could do it. The new sensors use less current, so they don't get that hot during a long (live view, movie mode) exposure.
The DSLRs still have a few advantages over low-end mirrorless cameras: faster reaction time, faster focusing time (usually because they use phase-detection and not contrast-detection focus sensors), better ergonomics. But they are bulky and have more things that can break (the mirror box is quite complex). We will probably continue to see DSLRs in the professional usage, but a mirrorless camera looks better for the consumer market.
Interesting! I always wondered why digital "conversion kits" for 35mm SLR bodies never became more common -- I would have loved to convert my old Nikon FE to digital.
The problem isn't that it's impossible - the article demonstrates otherwise - but that it's very difficult to pull off aesthetically well. Consider that what you'd want to add, to be comparable to a conventional DSLR, would be the sensor, LCD, image processor, additional controls, card cage(s), battery - it'd all take up extra space, and all on the back of the body, rather than integrated into the overall space of the body.
So, a fairly substantial engineering task, and that's only for a back which would be designed for either a specific model of body, or a small number of identically sized bodies.
Then consider the numbers you'd be likely to sell, versus competing with the units rolling out of Nikon, Canon, et al.
Which is not to deny the geeky appeal of doing it anyway. =:)
Most of the investment in cameras are in the lenses, and I believe you could use your old Nikon lenses on new DSLRs (not sure about other brands), so the pressure was just on upgrading the body, which is relatively inexpensive.
I have been thinking about this for months. It would result in something a bit bulky, but would love to try it on my FM2. In fact, given more time and knowledge I would love to get my hands dirty on this. Main problem: get a hackable full frame 35mm CCD, (or even the full board of a camera) and download raw files to a medium at reasonable speed. That assuming the flash or the bottom output of the camera will sync nicely with the shutter (mostly yes).
Another thing I always wondered is why digital SLRs do not come with CCD "cartridges" and slots. I know that camera bodies are the cheap part of an SLR, but that's the reason I would love this. People would be willing to invest on a good camera body if they were not going to throw it away after 5 years. Things like the Leica M Monochrome would be more of a commodity and less of a luxury.
Wow, this brings back some memories! I worked with Jim at Kodak on the later DCS cameras; I was part of the team that wrote the Photoshop plugin, Camera Manager and Photo Desk.
My company actually built one of the first fully digital aerial mapping systems (commercially at least) using the slightly newer and publicly available Kodak DCS's (~94). They were very nice cameras, especially for the time. I cant even imagine doing this kind of work with film, it would be so tedious. The speed to process the data was incredible when going all digital. This made up for the loss in detail compared to film for most jobs, especially since our costs were quite a bit lower.
Also interesting, is if i recall correctly Kodak actually made about 100 colour infrared versions too which was nice... until we couldn't reliably source them out! We ended up having to burn the filter off of the CCD of the standard RGB cameras systems with some sort of acid solution turning them back into their natural CIR mode.
On an 8.98 x 7.04 mm sensor, about the size of the largest compact camera sensors today (2/3" size, used in a few Fujifilm compacts, is 8.80 x 6.60 mm).
A sensor that size would give a crop factor of over 2 (2.45 horizontally, 2.27 vertically), which would make taking pictures with it embedded in a 35 mm system a bit of a pain. I wonder if they marked the outline of the sensor's frame on the viewfinder screen?
I might be wrong, but I think adding color information would not be _that_ hard. Basically you could filter each sensor cell for one of the RGB colors and just interpolate the results for each color channel. See https://en.wikipedia.org/wiki/Demosaicing
