Q It seems like there have been a lot of cameras introduced in the last year or so, and while it seems like they’re different than previous years, I really wonder. I’ve wanted to stop renting and buy, but I’m a bit nervous of my timing—2K, 4K, 8K—when will it stop or at least slow down enough so I can hop on this merry-go-round?
A The last few years have been exciting times for camera introductions, and I know that it can be difficult with any technology purchase to determine the right timing. It often seems that the day you place your order, the next "latest and greatest" is announced.
Rapidly changing technology also leads to an expectation that current models are easily upgraded. But when you decide on a camera, you have to evaluate whether it does the job for you now; don’t count on an upgrade to take care of any shortcomings.
I would like to comment on your merry-go-round analogy. You mention 2K, 4K and 8K, but don’t mention anything about sensor size. Some might be confused about that previous sentence, but using terms like 2K or 4K doesn’t really say anything about sensor size. If you only consider image-sensor size, there really hasn’t been a merry-go-round of camera introductions. A digital cinema camera’s image-sensor size has been pretty constant: Super 35. Aside from some SLR cameras, the majority of cinema cameras use this sensor size.
The term Super 35 comes from 35mm motion-picture film. While the width of the physical film is the same as 35mm, Super 35 captures a wider area than 35mm (24.89mm versus 21.95mm). It can accomplish this because it does away with the sound-track space that was added to 35mm.
If you look at cameras like the ARRI ALEXA, RED EPIC and Sony F65, they’re based on the Super 35 format. Even lower-priced cameras, like the newly announced Canon EOS C300, RED Scarlet-X and Sony F3, are based on the Super 35 format. And although the Canon EOS 5D Mark II and EOS-1D X use a larger-sized sensor, most other SLRs, like the 7D, use a sensor size that’s close to Super 35.
Why hasn’t the sensor size changed? It has to do with optics. Moore’s law says transistor density on an integrated circuit doubles every two years. That might work for chips, but it doesn’t work for the physics of lenses. Although camera manufacturers may be able to create cameras with larger image sensors, they would still need to build lenses capable of presenting light to the full size of that sensor. While not impossible, it’s difficult, and by "difficult," I mean expensive.
So for the time being, since there’s a plethora of rentable and purchasable lenses that meet the needs of S35 sensors, that’s the sensor size you’ll see for the near future. Of course, there’s more to a camera than the size of the sensor. That part of the merry-go-round is turning fast, but with speed come amazing improvements in picture quality.