The Canon 5Dmk3 and Pentax K-5 (picture to scale)
So, am I going to re-equip to get the 'ultimate' in high ISO shots? Well, no, and for several reasons, which I'm going to run through now...
- Cost: The expense required to swap from one system to another can be considerable, and for me outlay would total well over £13,000, especially once you start adding in a flashgun, new (bigger) bag, vertical grip, remote release. But the main expenses would be the camera itself (£2,999), 500mm f/4 lens (£8,400+) and other lenses in the £300-£600 range. That 500mm for me has serious shortcomings though.
- Weight: Just the 500mm lens weighs about 25% more than all of my lenses and Pentax K-5 put together (it's 3.87kg), so add in the 5DMk3 at 950g, and 3 more lenses, and I won't be wanting to carry that anywhere!
- Flexibility: I shoot lots of pseudo-macro stuff with my 300mm, because it focuses down to about 4 feet. The Canon 500mm focuses to 10 feet minimum, and that would mean not being able to use it for flowers, dragonflies etc.
Pentax K-5, DA*300mm lens at F/6.7, 1/125s @ ISO400, handheld.
- Bulk: All that weight has to take up more space, the 500mm is huge, and I'd therefore need a bigger, bulkier (and heavier) bag for it all.
- The Canon EF 500mm f/4.0 L IS USM and Pentax DA* 300mm f/4 (picture to scale)
The Green Button: Pentax have a green button. It's nothing to do with the green (auto) mode; the Green Button is really useful. Although its function varies depending on the mode you're in, and how you've set it up to work, I find it amazingly useful for quickly setting a manual exposure - I adjust my aperture, hit the Green Button and hey presto, the camera meters and sets the shutter speed. Very quick, very easy, and manual mode would be a lot less user friendly without it. I'm amazed no other manufacturer has something similar to be honest. It also acts as a reset button for exposure compensation, ISO... Just very useful.
- Weather-sealing: Whilst the Canon is 'protected against dust and moisture', my Pentax is truly weatherproof, and I know from experience that includes mud (and the rinse in a puddle afterwards) and heavy rain. 'Dust and moisture' doesn't fill me with confidence.
My K10D out in the rain.
- Ergonomics: With one exception (that I'm pretty much used to now anyway, see below), I love the layout and feel of the K-5, everything's where it should be, wheels turn the 'right' way. Personally I don't like the large wheel on the back of Canons, I don't feel that it sits in the right place for my thumb. The on/off switch on the 5Dmk3 is under the mode dial, it makes much more sense to me to have it around the shutter button. Zooming in and out of a image in playback? Just a spin of the rear wheel with the Pentax, but button presses with both Canon and Nikon, it just seems so much easier and more natural the Pentax way.
I know over time I'd get used to the different layout, and it obviously works for lots of other photographers, but I just don't want to. :-)
- The Future: My K-5 has the best APS sized sensor available at the moment, and when tested by DXOMark the dynamic range (until the release of the D800 it was the best of any camera) and overall quality was so good that they ranked it above every Canon sensor, including the full-frame models. So although at the moment the 5DMk3 is bound to have a better performing sensor than the K-5 (it's full frame, and a year and a half newer), when I come to upgrade from my K-5, I'm sure the sensor in the latest Pentax will be better than the one in the Canon.
Well, I really wish the Green Button and the Exposure Compensation Button were in the same positions they were with my K10D, they've been swapped round on the K-5 and it took me quite a while to get used to it. And I wish the auto-focusing was as good as the Canon/Nikon equivalents, for the odd occasion it really matters. But I still usually get the shot I'm after, so it's not a deal-breaker. And that's honestly it. Everything else works perfectly for me, and suits me and my hands beautifully. Swap systems? No thanks (I'd really, really miss that Green Button for a start!).
So what I'm saying I suppose, is that you weigh up the pros and cons of particular cameras and systems (including considering the lenses available, not how many of them, but whether they're of use to you), think about your budget, try out all the cameras you can afford, and get a camera that suits you, even if it may mean making some compromises on image quality. You should end up with a camera you want to use, want to carry, and enjoy.