Cameras as Computers

It's been a bumper week for digital SLR photography. Between the Canon EOS 40D and 1Ds Mk III and Nikon's D300 and D3, there are lots of lovely new toys to look at. Me, I'm still delighted with my 30D. Approaching 30,000 frames on the counter since I got it last October, it's barely let me down. I have a few shots that I would have preferred the camera to have handled better, but not many.

This is the first time that my DSLR has been replaced whilst I was still using it - I upgraded from the 350D whilst that was still a current model - and it got me into thinking about camera upgrading strategies. It struck me that, in some ways cameras are like computers. They essentially are little specialised computers that only do a few things. They're not general purpose computers, and nobody's trying to hack together a Twitter client for my 30D, but they are nonetheless electronics and roughly follow the market forces that other electronica do.

The DPReview links above all contain nice timelines of when the predecessors to each camera was released and their major features. Here's the 10/20/30/40D line from Canon:

Effective pixels
Auto focus
Continuous (JPEG) LCD monitor
EOS D30 Apr 2000 3.1 mp 3 point 3.0 fps, 3 frames 1.8"
EOS D60 Feb 2002 6.3 mp 3 point 3.3 fps, 8 frames 1.8"
EOS 10D Feb 2003 6.3 mp 7 point 3.3 fps, 9 frames 1.8"
EOS 20D Aug 2004 8.2 mp 9 point 5.0 fps, 23 frames 1.8"
EOS 30D Feb 2006 8.2 mp 9 point 5.0 / 3.0 fps, 30 frames 2.5"
EOS 40D Aug 2007 10.1 mp 9 point 6.5 / 3.0 fps, 85 frames 3.0" (Live view)

Which roughly equates to a resolution bump every 2-3 years and a feature bump every 12-18 months for Canon's prosumer DSLR. Nikon's upgrades for the Dx00 line are more leisurely: the D100 appeared in Feb '02 at 6MP, the D200 in Nov '05 at 10.2MP and the D300 in Aug '07 at 12.3MP. A model upgrade every 2-3 years.

Let's just avoid argument and assume here that Canon and Nikon both make excellent cameras that take awesome pictures. That's what I believe to be true, even though I have a strong personal preference for Canon.

My question, then, is this: is it better to update your prosumer model every time it's upgraded, or to buy a high end model and keep it for years?

With film photography, that's a non question. In digital photography, I don't think it's clear at all. The main reason being that camera sensors and onboard image processors are still making dramatic progress in terms of low noise, high sensitivity and increased dynamic range. In resolution too, of course, but I think that's becoming less of a driving factor for upgrades these days. I hesitate to say "12MP should be enough for anybody", but it's certainly good enough for this Flickr junkie.

The 30D costs about £600 right now. The 5D is £1500 and the 1D Mk II is £2600. Let's pick a number out of the air and say one might want to spend £300/year on photography. That's what I pay for my broadband service every year, as a yardstick. Assume, for the sake of argument, that paying up front isn't a problem.

At £300/year, the £600 40D has to serve two years. The 5D has to serve 5 years and the 1D Mk III just over 8.5 years. Is it a better deal to get an update to Canon's latest sensor and processing technology every two years, or to get what's great right now and hold on to it for some time? Maybe you'll never own the 'best' camera at any instant in time but, given such regular and significant advances in sensor technology it might be better for some kinds of photographers to be more current.

Your thoughts?