When digital SLRs started to come into the market, they
essentially replaced the 35mm film camera. In most cases, the lenses that fit
your 35mm camera could now be used on the new digitals (from the same
manufacturer, of course) without the need for any adapters. Sweet.
Those who made this transition noticed something right away.
The 50mm focal length lens that gave a ‘normal’ angle of view on their film
camera now acted like an 80mm lens, or slight telephoto, when attached to the
digital SLR. In other words, the image was now magnified compared to using the
same lens on the 35mm camera.
In some ways this was a benefit, because it meant that the
telephoto lens you bought for your 35mm camera now reached a bit further on the
digital SLR– about 1.6 times further. The downside was that the wide angle lens
that used to work beautifully for landscapes on your 35mm wasn’t so wide
anymore on the digital.
This difference is attributable to the size of the sensor in
the digital camera. Most consumer SLRs use an APS-C size sensor, which is 22mm
x 15mm. Compare that to 35mm film at 36mm x 24mm. Given the same lens
projecting the same ‘image circle’ on the digital sensor and the 35mm negative, the digital sensor only
captures part of what the negative captures. Essentially, the digital image is
magnified (by 1.6 times) since it’s like zooming in on a small part of the
image circle.
For years now, professionals who could afford it have been
using full frame digital SLRs
(example – the Canon 5D) which use a 36mm x 24mm sensor, just like the 35mm
negative size. While the manufacturers could have stuffed more pixels into this
bigger sensor (and did so to an extent), the big benefit is that they can now
make the pixels bigger.
Why? The bigger the pixel, the more light it can gather,
meaning the camera will yield less ‘noise’ in the image in low light
situations. Overall, the image is cleaner and yes, at a somewhat higher
resolution. In fact, Nikon recently introduced the full frame D800 with an
astonishing 36 megapixel sensor. Compare that to the Canon 5D’s 22 megapixel
resolution or 18 megapixels on most consumer SLRs. Of course, file sizes bloom
with higher resolution.
All of this is significant because the prices of full frame
camera bodies are starting to slide below the $2000 price point. While APS-C
and other similar size sensors kick-started the digital photography revolution,
affordable full frames will eventually bring it full circle. The smaller sensors
won’t disappear for a while yet, but those of us who came up through the film
world will once again be able to shoot the way we used to – only with the
immediacy of digital and a moderate size hole in our pocket.
