Design and Operation
Everything about the comparison of the design and operation of these two cameras points to a generational step, rather than a comparison of similar technology. The first version of the 5D was the first DSLR with a full-frame sensor in a compact body without a side-grip. The 1Ds Mark II and the 1Ds Mark III overlapped the release of the 5D, and with the release of the 5D Mark II, the model again redefined the Pro DSLR category.

(Credit: Canon)

Viewing
The LCD display in the 5D Mark II is the same 3-inch size as the 1Ds Mark III, however, it’s now a much higher resolution. At 920,000 pixels, it is four times the resolution of the previous version and competitive with the Nikon D3 and D300 displays. The 1Ds Mark III works with the older 230,000-pixel, dimmer LCD display. In addition, the 5D Mark II sports a very effective non-reflective coating on its screen, and an auto-adjust feature to automatically raise and lower the brightness of the display to match the ambient light. Again, this is a difference of generations.

Canon 5D Mark II	Canon 1Ds Mark III

Many of the specifications are fairly similar: the Live View feature, interchangeable focus screens, the large and bright viewfinders, and the information displayed on both the viewfinder and the LCD menus are now effectively standardized throughout the Canon DSLR line. The slight difference between the 100% view of the 1Ds Mark III and the 98% view of the 5D Mark II viewfinders may or may not be significant, depending on the requirements of the photographer and the nature of the assignment. 

Canon 5D Mark II	Canon 1Ds Mark III

Autofocus
One of the differences between the two cameras is the autofocus performance. The 1Ds is running an autofocus system that seems more sophisticated and certainly more complex with its 45-point TTL, 19 cross-type points, and 26 assist points than the newer 5D Mark II’s 9-point system. However, autofocus is a fairly challenging and ambiguous feature to evaluate. Autofocus so depends on pattern, type and look of the subject, shooting conditions, as well as simple preferences of the photographer, so it’s hard to objectively compare the performance of two such highly evolved and effective systems. If you had a system that was clearly just bad, and one that was workable, you could make a clear determination. In our testing of the autofocus systems we are hard-pressed to point to a clear winner, in spite of the very strong opinions being posted on various online sources. Our best determination is that, of the two systems, the 5D Mark II may be, by virtue of its overall higher level of development and its simplicity, more effective for more applications, but it really depends on the user to make that determination.
 

1Ds Mk III - AF Configuration

5D Mk II - AF Configuration

(Credit: Canon)

5D Mk II Video Capture

(Credit: Canon)

Of course, this all ignores the most profound generational step of the 5D Mark II - that of the addition of HD video with a full-frame 35mm sensor. Coming just on the heels of the Nikon D90, the first DSLR released with HD video capability, the 5D Mark II brings it to a new level. Beyond redefining the class, the addition of this remarkable feature in a $3000 21-megapixel DSLR has truly created a new class of camera, possibly a new class of photographer - opening up an entirely new medium for the still-image-oriented shooter. It’s impossible to determine how this may affect photographers and the photography and video industry. It’s a true “crossover” tool capable of the highest quality of both still and video photography, and it could feasibly create, or at least enable, an entirely new model for the business of commercial imaging. 

As our tools change, our processes and vision changes, and this technology is poised to change the landscape of the entire industry. In this aspect of the camera matchup between the 1Ds Mark III and the 5D Mark II, there is simply no comparison. Let’s look at the features of the two cameras that we can compare; the key matchup is image quality.