Why change?: Main shortcoming with Canon X0D-series (10D, 20D or 30D) in bird photography is autofocus performance. Even for static subjects there may be several exposures needed to get one acceptable sharp picture. Not enough if we consider in that once a lifetime situation in bird photography is measured usually in seconds. For fast moving targets servo mode focusing is much too slow and inaccurate. The rate of in focus shots and slow number of frames per second are working against photographer each and every time with action shooting.

Other benefits for 1-series body like weather sealing, bigger viewfinder and larger capacity battery themselves, as nice they are, would not justify camera upgrade in my situation.

Auto focus: Very soon after launch of MKIII there has been ongoing debate on camera auto focus performance. Coming from 30D I have no insight for how the earlier 1-series cameras are comparing, but here are my conclusions of my MKIII, serial number 517xxx:

I'm using one shot auto focus with center af-point activated (focus recompose style) in most static situations. MKIII performs flawlessly and is locking af spot on correctly and quickly usually with the first frame. A huge improvement over 30D which occasionally refused to lock or misfocused a little on several exposures made. This is utmost important as I'm shooting often at distant locations where it is possible to get one decent shot of a bird specie only once.

Updated 22.10.2007:

For moving subjects I used to select servo mode with all 45 auto focus points activated. For subjects in front of uniform background like sky it was working flawlessly as long as I could keep the subject in focusing area only somehow. But now, for anything else in bird in flight photography I'm recommending single point autofocus with assisting focusing points, more below.

I keep the Custom Functions III settings at defaults, excluding C. Fn III-2 -> slow and C. Fn III-8. I have tried several combinations of other C. Fn III -custom functions but feel the defaults are more suitable.

AF expansion with selected points: For flying birds I am setting C.Fn III-8 to '2' with only center focusing point selected. This concentrates focusing into center with the nearest surrounding points assisting if subject escapes from center point. It helps to lock and maintain focus, but even then tracking has to be smooth operation since autofocus is very fast on everything.

MKIII should, in my opinion, has assisting expansion points set as they are with 5D: when one shot af -mode is set, expansion points are disabled. I would not like to switch that setting too often, but I'm afraid I have to. Please read more at Customization -chapter below.

Two flight pictures on left should be without problems, like the third one. The rightmost picture shows near worst case scenario with distant subject in front of close-by contrasty background. Only center point selected AF with expansion points is working then definitely better.

Ten good megapixels enables some more cropping. I also felt that 1.6x ratio was occasionally too 'tight' when subject moved closer. For my purposes, the resolution given and current set of my optics 1.3 crop ratio is very close to an ideal field of view.

The following example is no masterpiece by any means but demonstrating how you can crop heck out of a quick documentation shot, still ending up with something useful for web or small magazine pictures. Per pixel image quality is clearly better than with, for example Canon 30D.

Unfortunately the in focus area and optics are not identical in the following comparison, but I hope you can get some idea of how close the 1DMKIII is pushing full frame 5D.

First picture with crop: Canon EOS 1DMKIII, 1/60s, 90mm, f10, ISO 100

Second picture with crop: Canon EOS 5D, 1/20s, 90mm + 1.4XTC, f13, ISO 100

Third picture: Example of MKIII 'dreamy look' in spite of challenging dynamic range with some dark and white details. In my opinion this color layout is closer what I can see from viewfinder than the harsh graduations I got from X0D -series.

LCD -display: No bigger complaints but as many have suggested it could have a few extra pixels to show focus more accurately. Anyhow, it is better than the one with 30D or 5D. One little thing nagging me is the color of histogram background: it is a dark grey and it is melting into black Info -view background almost completely. This is very annoying especially when you are inspecting highlights and darks from histogram while shooting outdoors. It should be light grey like in 5D, dark grey is close to a firmware bug in my eyes.

Live View (Updated 23 Aug 2007): Useful feature for certain, but I'm not using this camera much for still life studio so the use is a little limited. I tested Live View by operating camera from tethered computer. Very useful for still life studio shooting, I can check all the minute details before exposure and focusing can be done with great precision. With wireless this could be also used for photographing wildlife remotely. I'm not wondering this feature is in every recently published dslr -mode from Canon and Nikon!

Battery: With my style of shooting I could probably use battery for a long weekend shootout with over 2000 frames. Typically I have over 90% of charge left after a few hours shooting. For any other reasons than back up in rough conditions, like very cold weather or temporary electricity shortage while traveling, the supplied battery is sufficient.

Flash: User manual information here only. Flash X-Sync is max 1/300s, with external studio strobe max 1/60s. Corresponding numbers for 5D are 1/200s and 1/125s. I would like to see X-Sync 1/300s and 1/125s max for strobe if I would use this camera at studio.

Update for flash: A couple of tests I read suggest that max X-Sync with strobe can be as much as 1/300s in real life. Canon states max 1/60s for studio strobes: another overly cautious specification perhaps.

Ergonomics: At 1345g (3lbs) MKIII is approximately 1.5 times heavier and bulkier than 5D. The difference is very significant in practical shooting and camera handling. I prefer lighter cameras but your mileage may vary: big hands, not traveling by air with camera gear and using fast tele lenses hand held is one user scenario into opposite direction from mine.

I feel camera size just right when it is attached to EF 500/4L, but not so much when I am using my 'normal lens' EF 50/2.5 macro for walk-around shooting. With ground level flower and fungi photography on tripod I also prefer the smaller body of 5D. With nowadays flying policies 'the lighter the better' concerns all camera gear. Fortunately Canon has been able to shave off a few grammes from previous model with lighter battery.

Although I have never been using external battery packs, the general layout and shape of MKIII is familiar from earlier Canon modes. I have not found the bigger body size problematic for maneuvering camera operations and settings.

Control buttons and disks have good amount of 'firmness' and I prefer that decisive feel over 5D controls. Shutter button is as responsive and fast as it should be on this price class camera. Once you get auto focus tracking, things are going very smoothly indeed. I have not yet exhausted the picture buffer once but my typical shooting consists of single shots or short 2-5 frame bursts.

Control layout seems to be well designed to avoid accidental change of settings. In 5D the nuisance is viewfinder diopter adjustment knob for those who not use eyecup but are swapping angle finder on and off (me). In MKIII the diopter adjustment is well thought, like the rest of the operations.

Battery and memory card compartments are 'belt and braces' -style with enough cover to keep your cards intact no matter what happens. Common gripe at web forums is the 'flimsiness' of X0D -series memory card door. In my opinion those are very trivial nuances. After years of using aforementioned cameras from jungle to arctic latitudes I'm yet to break one camera body for build weakness.

Sensor cleaning: I'm launching sensor cleaning operation manually around twice a week and use rocket blower occasionally. With the apertures I'm using MKIII, I cannot see dust too often. But same goes with 5D: learn to swap lenses quickly, take care in dusty environments, use rocket blower and you should not have any bigger issues with dust.

Some extra features compared to 5D and X0D -series:

- A/C -adapter included

- Integrated eyepiece shutter instead of gadget in neck strap for long exposures

- Hand strap mount on bottom of camera

- Vertical grip shutter and main dial

- Extra slot for SD card for more storage or backing up

Operations: The button operations are changed from previous model MKII to be more similar with X0D and 5D series. In fact operations are even better overall than in cheaper models, thank's to more options for customization and some improvements in button layout.

The settings like ISO, aperture, shooting mode and auto focus point should be intuitive and easy enough to operate without taking eye from viewfinder. Ideally the selections are toggling between two settings, like how you can now swap center point auto focus into 45 -point af and back by pressing af -selection button and joystick center in sequence

MKIII button layout is advancing from X0D -series in several ways: ISO is the rightmost button on top, focusing mode is on top left and without that extra nuisance AI Focus -mode of smaller Canon models! Shooting and metering mode buttons can be customized so you can for example toggle only between Av and Manual -shooting modes. Typically you tap button and then have six seconds to turn selection disk into desired setting. Interface logic is kind of similar to X0D -models and 5D, but with even less button clutter and more options to customize away unnecessary settings.

Customization: MKIII has several ways to customize settings and operations. You can save all but few settings into memory card, register and apply basic settings, customize some controls via Custom functions, save three sets of Custom functions, customize personal 'My Menu' and so on.

I have found many of them useful, like setting some more frequently used operations (Battery Info, Sensor Cleaning, Mirror Lockup) into My Menu for easy reach. But in my opinion the registered basic settings functionality is not quite far enough. I cannot save ISO -value into setting and applying the setting is cumbersome operation either from menu or then pressing shutter and ae -lock buttons simultaneously. I'm missing C -shooting mode of 5D where you can register all the settings (like you can now save into card in MKIII) and apply all them just by turning the mode dial into C.

There are situations like 'Landscape with tripod': ISO100, mirror lockup, Manual mode, f16 and 1/10s shutter to begin with. Or 'Photograph that flying bird and do it now': ISO640, Av -mode, no exposure correction, f5.6, ai -Servo... I think you got the idea. If I can get one of my setting applied in 5D by simple turn of dial, why could I not get two or three of them with camera costing 1500 euros more?

Room for improvement: Canon should have take more care to not change auto focus too much from previous model. Sure they have worked together with professional photographers, but obviously omitted a few important aspects or camera applications. In 1DMKIII ad they told they have listened the customer. Next time they should listen even harder.

Customization is lacking fast selection switch for all settings, 5D has that in C -mode, shooting mode with all the registered settings, including ISO, activated by one switch of selection disk. Smaller problems I have found so far are mentioned above.

Conclusion: For a keen bird photographer 1DMKIII is the best choice for most of applications. Apart from size (a subjective point) and price camera is so much ahead of 30D there is not even comparison in real life shooting. However, if you are deeply oriented into action shooting, you could also consider 1DMKIIn for less price and 'backward compatibility' with auto focus.