That’s a logical question. After all, the APS-C format has already died once—albeit in its original Advanced Film incarnation that was killed off by the rise of digital compact cameras. But unlike their film-based ancestors, which included a handful of APS-C SLR models, the proven advantages found in APS-C DSLRs may give them a reprieve from the same fate. Let’s take a closer look at those benefits, especially as they relate to pros who demand more than improved low-light performance and depth-of-field separation from their camera systems.
For starters, APS-C DSLR bodies can be built smaller and for less than similar-featured, full-frame DSLR bodies, period. That’s because nearly all of the components involved in the camera design and exposure system are larger and more expensive to manufacture in full-frame cameras. Topping the list is the cost differential between the full-frame sensor and APS-C sensor, with full-frame sensors typically priced several hundred dollars more per chip due to the difficulty faced in manufacturing a larger-area sensor. (Approximately 30 full-frame sensors can fit on an eight-inch wafer compared to over 100 APS-C sensors, and defects are more likely in the full-frame manufacturing process.) Obviously, the cost of manufacturing full-frame sensors has come down over the years as resolution has increased or we wouldn’t see affordable 20-plus-megapixel models like the Nikon D600 or Canon EOS 6D. The same can be said about APS-C sensors. However, other component costs for a full-frame camera have remained higher, including the prices for the larger reflex mirror (Canon and Nikon models), SLT mirror (Sony), optical viewfinder, shutter blade, internal AF motor and even the batteries (more power needed to operate the mirror assembly, shutter and AF).
In this increasingly competitive space, manufacturers can’t hide or absorb the cost of building the camera in hopes that photographers will buy more lenses and accessories to make them profitable. So don’t expect the same features and performance between similar-priced APS-C and full-frame HDSLRs. For the same price, the APS-C camera likely will include faster focusing systems, better burst performance, better build, additional manual controls over video, etc. The question pros must ask is whether the increased low-light performance, typically brighter viewfinder and increased depth-of-field separation provided by a full-frame DSLR will be enough to offset the missing features, smaller sizes and lower costs of APS-C models.
Wait! We’re forgetting the other half of the DSLR equation: the cost, size and compatibility of lenses! If you’re moving up from an APS-C-based DSLR, you’ll notice that lenses optimized for use on full-frame cameras are larger and more expensive than their APS-C-optimized equivalents. Again, material costs add up, but manufacturers also know that pros are more willing to spend more for a good lens (or they can blame the higher prices on economy of scale). Sure, a full-frame camera provides a wider field of view for any given focal length than an APS-C camera, but you may not be able to fit as many lenses in your camera bag (or budget), and if you’re a Canon shooter, you also lose backward-compatibility with your existing stock of lightweight EF-S lenses. (You can mount Nikon DX lenses on FX models such as the D600; however, you can’t mount a Canon EF-S lens on full-frame models such as the Canon EOS 6D without an adapter because of differences in back-focus distance and interference from the mirror.)