This camera is amazing. It is fast and takes great images. I was suprised at how easy it was to learn and operate. It makes me want to purchase another one for my second body and give my 5D a rest. Once you use this camera, you won't go back to your old one, promise you that! I don't have any cons right now, I mean yeah it's heavy but this is what I want from this camera, this camera is strong!

Having previously owned a MKII this camera is a definate step up. While the camera has the same overall 'feel', Canon has done an excellant job of redesigning a great camera and making it better. Focusing is quicker, and there is better vertical focusing when using fast lenses. The ability to not have to hold a button while making changes such as ISO are two of the many things canon addressed.

MY WORK IS 75% BLACK & WHITE AND I LOVE THE COMPARISON OF BLACK & WHITE TO COLOR AFTER DOWNLOADING. WE ALL KNOW WE CAN'T GET THAT EXACT POSITION WITH COLOR AND BLACK & WHITE... NOW YOU CAN! MONOCHROME IS MY TOP NEW FEATURE. THE MARK III IS A BIG HIT AT RUNWAY SHOWS FROM NEW YORK TO PARIS...ACTION AND BEAUTY!

Comparing to the previous 1D models in the Canon line that I use: 1DmkI (since 2002), 1DmkII (since 2004), 1DmkIIN (since 2006), and now 1DmkIII (2009). The cameras are all used for outdoor field sports using the Canon 300f2.8, 400f2.8, and 600f4 lenses. I was worried about the mkIII focus issues, but having shot 1/3 of my season so far, I couldn't be happier with the mkIII. The AF in general seems to lock faster and the AI modes seem significantly more intelligent than the earlier models. Pros - the button layout compared to the older 1D versions is different but more functional (I am still not used to it), most key features seem to be one press away - high ISO performance is significantly better than old models - battery life is much improved over previous models (5 level battery meter is useful compared to old models with fewer levels) - 10 frames per second (feels more responsive even when not bursting) - AF point selection much easier using the joystick - dedicated ISO selection button (display visible in view finder as you are selecting) makes it much easier to switch while shooting - no driver necessary when tethered to a Windows computer - takes better advantage of higher-speed CF and SD cards - all of the custom settings are tunable without a computer (no more parameter settings) - more logical layout of the custom parameter menus (grouped into categories by function) - ability to review and scroll through images as they are being written to flash Cons - uses a new battery system (if you are upgrading from old 1D models it means a new set of batteries with charger) - LCD resolution is poor for the size of the screen; the mkIIN had a better balance between screen size and pixel density It is unfortunate that the camera had problems when it originally came out because the version that I have seems to be a very worthy successor in the 1D line.

I shoot mainly sports and this camera is unbelievable.

Great image making machine. Bought mine used for a steal. I thought I bought a bargain and I did - but knowing what this thing can do now, I will gladly pay the asking price for a new one. I look forward to it's successor. For six months now I have had nothing but pleasure. Once you learn how to set up the AF to suit conditions you find yourself in, it just nails whatever you throw at it. Beautiful images with good dynamic range and colours. Just sold my 40D and plan to get the new 7D from BH as soon as they stock it to use along side the 1D3. Have already had people ask why not sell the 1D3 too? Very simple. I doubt the 7D will match the 1D3 in focussing performance- but it will exceed the 40D. It will also not focus F8 lens combinations. IQ will still not match that of the 1D3. 1D3 has a larger sensor than the 7D's 1.6 crop which is nice for the wider end of the spectrum as well as a bit shallower DOF. I use the 1D3 for natural light portraits, birds-in-flight, wildlife, my daughtr's ballet school productions (no flash) etc. Absolute Gem. If you can afford one and you have good Canon lenses and shoot for images A3+ and smaller, don't even think about it. Get it.

While I have had only a few weeks to explore this beauty, I have concluded that I should have invested it a long time ago. I shoot outdoor endurance sports , and the ID is the ticket. Coupled to a 100m-400mm Canon, it beats my 5ds by many a mile. Yes, it is a little heavy, but it is well worth the weight. Its maximum burst speed is breathtaking, almost to much for someone like me who prefers careful timing. Its build and seals relieve a lot of pressure from worries about wet, dirty and potentially damaging conditions. There are many features I have yet to explore, but I can see that once I have played with them they could be valuable. Having both CF and SD capability is a real blessing in fast-breaking situations where memory is consumed quickly. I use the SD as backup memory, so that I don't have to stop and reload. Long battery life also is great. Someone once described this camera as a beast, and so it is. It is powerful and most of all, a pro's beauty.

Initially when I bought this camera, I ran into the focusing problems. Canon was excellent in repair turn around for an winter sporting event I had coming up. Since the repair and firmware upgrades, this camera has run without a hitch. I bought this camera for action and some low light events. During an event, I will run with 2 cameras, one the Mark III and the other the 40D. I also coupled the Mark III with my 5d Mark II, but for low light action at any event where use of flash is limited, the Mark III blows every other camera out the water. There is virtually no hunting for focus and the continuous servo was dead on about 70% during the low light captures. I found the 40d & 5d Mrk II to be out of this areana all together. i'm seriously contemplating he 1d Mark IV to accompany on future event shoots. I used the Mrk III in extreme cold down to -40. Not a hitch and I was surprised how long the battery lasted even at those temps. Great for winter sports and anything you want to through at it. I have used in studio for portrait work, where some of my shots involve action cameo's. The 1D Mark III is the cat's meow. Get it... it will not disappoint.

I use this camera to shoot events, such as, bicycle races and similar events sponsored by NGO's. I like the grips which make it easy to handle. This is important because the camrea is heavy and I find that I tend to carry it by the grips rather than use the strap on my neck which can be rather tiring. Also, the grips and weight add to the ease of handling with the heavier glass With L lenses the quality is there without using too much space on the cards or the computer. I have a 50D which uses more space with the 15 megapixels.

this camera ROCKS. I love it. it's the best. so insted of getting the 1Ds mkIII I got this camera and the 5D mkII now I have the best of both worlds plus, and get this 10 FRAMES PER SECOND. any thing I would need the 1Ds for I can use the 5D mkII on, and things that couldent be done with the 1Ds can be done with the awsome camera.