On Facebook, a photographer just asked:
I have a decade old DSLR (Nikon D200) that I have been wanting to upgrade for ages. My heart is set on a D700. I also would like to invest in a Tamron 24-70 and 105mm macro. I feel like the body is holding me back (it’s horrible in low light and noisy over ISO 200), but everyone always says to invest in better lenses then upgrade the body.
It’s true that everyone (including me) says “buy lenses rather than bodies”. But don’t listen to “everyone” without interpreting. Because every four years, bodies take over as the “must spend on” item.
Why? Sensors. That’s why. And that’s the only reason.
Sensors get better every year. In particular, the ability to work at higher ISO values, and the ability to take photos with less “noise”, i.e. with better quality, gets better. Sensors get better according to Moore’s Law. Exponentially. And since ISO is an exponential scale, that’s a good thing. With my last camera I could shoot with reasonable quality at 1600 ISO. Now, 10,800 ISO gives me the same quality.
Generally, better (faster, sharper) lenses are much more important than better cameras for your picture quality. But roughly every four years, sensors are so much better that this benefit outweighs the undoubted benefit of better lenses. So if you have a ten year old camera, replace it, take some pictures at 3200 ISO, and marvel. An order of magnitude better is something to write home about.
And then save the rest of your money for new lenses. Fast lenses: f/2.8 for zooms and f/1.4 for primes. And enjoy those.