Sorry for the technical hitch - I posted this a couple of weeks ago before disappearing on a shoot and no words showed up! Here's trying again....
First of all, a quick reminder of the headline features:
- 22MP full frame sensor
- ISO 25600
- Improved AF
- 100% viewfinder coverage
- 1040k dot 3.2" LCD
- Dual memory cards
To be honest, when I read the spec sheet they had me at 'improved AF'. While an excellent camera in so many ways, the achilles heel of the 5D mark II has been its autofocus. My EOS 3 film cameras from 1999 had far superior AF than a 2008 mark II, and my cameras were permanently set to use only the central AF point as it was the only one that could reliably lock on to anything.
So I ordered a 5D mark III body the moment I read it included the same AF system as the new flagship 1DX. There are 61 auto focus points spread across a large section of the viewfinder, and they are customisable to your heart's content. You can choose different modes depending on what you are shooting, configure the camera to cycle only through 15 or 9 points for greater speed, choose AF or shutter priority etc.. In this way it is similar to the 7D.
Fortunately there are other things that have been improved too:
Overall build quality feels extremely solid, and Canon claim the weather sealing improved over the mark II. In fact the build quality and control layout are very reminiscent of the 7D. It inherits the same ON/OFF switch located beside the lockable mode dial, the larger buttons and a dedicated movie/live view button to the right of the viewfinder. A new 3.2" screen produces contrasty images. The shutter sound is decidedly tinny however, and makes you feel like you are using a toy camera. I understand this is the price we pay for 6FPS and reduced shutter lag and vibration, so I can live with it but it does sound very cheap!
Two new buttons are the Q "quick menu" button, that brings up all the cameras settings on the rear screen and adjustable using the rear joystick, and a new 'Rate' button that allows you to rate images during playback from 1 to 5 stars. This one seemed pretty useless to me, who rates their images in camera? But my friend Toby who I share a studio with claimed he would use this all the time on his documentary shoots, so YMMV. In any case, many of the buttons are programmable and can be set to other functions if you choose - this is a great move on Canon's part.
Another nice feature is the viewfinder which now has 100% coverage and, like the 7D, incorporates electronic overlays such as grid lines and active AF points. Along the base there is now a +/- 3 stop exposure scale rather than the previous 2. All useful stuff.
The body can now take dual memory cards. You can set the camera to switch automatically when the first one is full, record RAW files to one and JPEGs to the other, or write every picture to both cards simultaneously. But unlike the 1DX which takes 2 CF cards, the 5d mark III takes a CF card and an SD card, which is somewhat less useful unless you have a collection of high capacity SD cards lying around, which I don't. It will take an Eye-Fi SD card however which may replace the need for the WFT wireless transmitter in some cases.
And finally we come to image quality. Like in the 1DX, Canon have resisted the siren call of higher megapixel counts and the 5d Mark III receives a very modest increase to 22MP. In my initial very basic tests high ISO quality is greatly improved, with ISO 6400 shots looking cleaner than ISO 1600 shots from the Mark II. I haven't yet had a chance to test colour rendition and dynamic range, but initial results are very promising. If general improvements are in line with the 1DX I was shooting with last month then I will be very happy indeed.
The new DIGIC 5 processor adds the ability to process RAW files in camera, as well as blend multiple exposures and create HDR images. I would normally choose do do these kind of things on the computer where I have much more control, but can understand that it might be useful to be able to do this in the field occasionally. I haven't yet had a chance to test these functions yet so stay tuned.
Overall the 5D is feels rather like a 7D with a 1DX sensor inside, and that's no bad thing. With improved frame rate, ISO and AF the Canon 5D mark III has truly become a 'do everything' camera. All of the weaknesses of the mark II have been addressed. Unless you need the blazingly fast frame rates of the 1DX then this is all the camera you will ever need.
Retailing at £3000 including VAT the mark III is not cheap - a mark II can now be bought new for half that amount. So is it worth it? If you need good AF, shoot at high ISOs or need higher frame rates then the new camera is a big step forwards. If you are a landscape shooter typically shooting on a tripod at ISO 100 and manually focusing then maybe not. As for me, I've replaced one of my mark IIs and I'm sure I'll replace the other before the end of the year.