Nikon D700 versus
Each is the best on Earth for many things. Determining which is better depends on what you want to do with it.
Comparing the two is like comparing the best car from Ferrari to the best car from Porsche. Each is the best in the world, but each is a different car designed for a different kind of driver. It's the same between the D700 and the 5D Mark II.
The Canon 5D Mark II got much better in 2010 when newer v2 firmware was released as a free upgrade. The Nikon D700 has always been excellent, while the 5D Mark II lost the rough edges it had at introduction and has become an extraordinary camera.
The D700 is sturdier but heavier, while the 5D Mark II is lighter, but flimsier. I prefer lighter carry weight; while other people prefer a tougher-feeling camera.
The D700 works better in low light, since the 5D Mark II's AF system flounders in conditions where the D700 keeps on focusing. The 5D Mark II's center AF sensor is swell, but its side sensors are less accurate and less sensitive in low light.
The 5D Mark II has more resolution, but it also had more noise in its shadows, even at normal ISOs, than the D700. The extra resolution doesn't really matter unless you're hanging gallery-sized exhibits with prints at least three feet (1 meter) wide and are standing too close. The 5D Mark II's shadow noise doesn't matter, either, unless you're looking too close.
The 5D Mark II is easy to reset for shooting completely different kinds of subjects with just one click of its mode dial, while the D700 requires too many button pushes to repurpose from, say, shooting landscapes to photographing kids. With Nikon, I have to use two bodies so I can keep each set for one kind of subject: I use my D3 in my studio and a D40 for family and travel. With Canon, the 5D Mark II does all of this at the same time with a flick of a knob. See Canon 5D Mark II Total Recall Memories. The 5D Mark II makes it easy to flick between complete sets of every camera setting, while Nikon's sloppy settings banks take too many button pushes, they don't recall everything and they don't stay set, and thus I still forget things.
I prefer the 5D Mark II for its higher resolution and lower weight for nature and landscape photography. I prefer the 5D Mark II for travel with family if I also intend to do serious shooting on the same trip, because its Total Recall Memories let me swap among all the settings I need for one kind of shooting or another, and the 5D Mark II weighs much less than any full-frame camera from Nikon so it's easy to carry everywhere. I never get tired and leave the 5D Mark II back at the hotel.
For low-light, the D700 focuses better, and in any light, it has less noise in its shadows than the 5D Mark II. The D700 also has a superior AF system in any light to the 5D Mark II, and has a faster frame rate.
For action, news and sports, the Nikon D3s is still the king, but in a completely different speed and price class than either the D700 or 5D Mark II.
The D700 and 5D Mark II are as popular as they are because of their great prices, too, which are much less than two years ago when they were released. Nikon and Canon's professional cameras cost two or three times as much, and haven't gone down in price, either. The D3s and 1Ds Mark III have about the same technical image quality as the D700 and 5D Mark II (respectively), simply in bigger, heavier, faster and more expensive packages.
Comparison Charts top
I've already covered the important differences above; here are simply more details.
I'm skipping all the obvious and meaningless specs, like ISO and numbers of custom functions. What I am tabulating below are real-world observations of things that really matter to photographers.
Ergonomics: Usability and Shootability top
Technical Image Quality top
Technical quality doesn't matter if you missed the shot due to an ergonomic problem above, like the 5D Mark II's defective power switch or an inability to reset the D700 for a new shooting scenario.
Summary Recommendations top
For news, sports and action, get a Nikon D3s.
If choosing between the D700 and 5D Mark II for news, sports and action, the Nikon D700 is better because of its superior autofocus system and higher overall speed.
If you're shooting in low light, the D700's autofocus system works much better than the AF system of the 5D Mark II.
If you have to carry it all day, the 5D Mark II weighs much less.
If you need to swap quickly between banks of settings to grab different kinds of shots, the 5D Mark II's C1, C2 and C3 Total Recall modes are years ahead of anything from any Nikon.
If you need insane resolution for huge prints to be seen too close, the 5D Mark II easily wipes the D700 off the map. Heck, even the old Canon 5D, available used for half the price of a new D700, gives results technically superior to a D700.
If you're bothered by lateral color fringes, the Canon 5D Mark II has no ability to correct them, condemning you to having to use DxO software and modules to fix these common lens defects, while all the second-generation Nikons, including the D700, automatically correct this from any lens. Color fringes just don't happen on modern Nikons, while most Canon wide and zoom lenses are loaded with this defect if you're looking for it.
If you need the highest optical quality with wide zoom lenses, Canon makes no zooms anywhere near as good as Nikon's extraordinary 14-24mm f/2.8 AF-S and 16-35mm f/4 AF-S VR. Canon's newest 17-40mm f/4 L and 16-35mm f/2.8 L II are still only as good optically as Nikon's previous-generation 17-35mm f/2.8 and 18-35mm f/3.5-4.5 D. To get all the performance of which the Canon 5D Mark II is capable with wide lenses, you need to be looking at lenses like the Zeiss 21mm f/2.8. Even so, even with the limited performance of Canon's newest 16-35mm f/2.8 L II, when used at moderate apertures, the 5D Mark II's extra resolution still gives sharper results than the lower resolution D700 with Nikon's superior wide zoom optics.
So what do I shoot as of June 2010? My D3 stays locked-up in my studio, mostly because it has selectable 4:5 aspect ratio. For my style of shooting in the field, I prefer the Canon 5D Mark II because it weighs less than any other full-frame DSLR, and it's Total Recall modes let me shoot anything fast without the fiddling required by my Nikons. If I'm shooting something special, like a kid's birthday party in low light, I'll pull out the D3 (very similar to the D700 I would have bought if I didn't already own a D3), otherwise, the 5D Mark II wins on resolution and light weight. With its new v2 firmware, the 5D Mark II screams. Size, weight and ergonomics are everything to me, so the 5D Mark II is what I grab for use in the field. It's colors are superior to the LEICA M9, and to me, color is everything. Nikon's colors are as good as Canon's; I prefer Japan's Fujifilm look over LEICA's Kodak Ektachrome look.
When I shoot Nikon in the field today, it's usually today's superior Nikon F6, which sells for the same price and weighs less than the D700. I'd love to own the fantastic D700; the only reason I don't is because Nikon sucked me into buying the D3, which came out a year before the magnificent D700, which has the same technical image quality as the D3 but in a newer, smarter package.
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