If you've been following along, you know that I got my start on Nikon cameras. As a kid, and for a good while after that, it's safe to say that I was a pretty major Nikon fanboy, to the extent of bashing other camera brands and flaunting my ignorance about them. I think there are many people out there who fall into this category, and not just with cameras, but with computers, cars, sports teams, religion... Fortunately, as I got older and more experienced, my perspective broadened, and I became more open-minded and accepting of the other brands.
These days, I like to consider myself relatively impartial, choosing only to "hate on" something if it has truly proven itself to be worthy of hating. I still have strong opinions about things mind you; I'm just more inclined to spend more time giving something new and unfamiliar a chance.
That all said, these are my personal opinions, so take this all with a grain of salt.
It's pretty safe to say that in the world of professional photography, if your'e shooting with a 35mm camera, it's going to be either a Canon or a Nikon. There are definitely some nice underdogs in the running, but if you go to any kind of press event and take inventory of what the throng of shooters have in their hands, it's gonna be one of the two biggies.
That fact right there should tell you something - when you can look at a large group of people and see that there is that kind of natural selection happening, it's significant. Humans have a tendency to want to use the best tool for the job. If you see a photograph that you like, or someone says to you "hey, can you make me one that looks just like that?", the first thing you do is determine "how did they make that?". You do some research, and you figure out how that thing was made. What tools did they use? How did they use them? And chances are, assuming that you're skilled enough and good at figuring things out, once you've equipped yourself with those same tools, you should be able to get something that looks pretty close to what you were going for.
The other, shorter, version of this is showing up to a place where the guys that are doing what you want to be doing are hanging out, and just watching them do their thing, while you jot down notes about what they're using and how they're using it. This happens all over the place. I can remember as a kid, learning to play the drums, scouring every inch of every page of any magazine article and photograph of my favorite drummers, trying to figure out "what's he using to get that sound?". And of course, I'd run out and buy whatever that thing was (for better or worse).
My main point here is that on a certain level, you need to have the right tools for the job. How you use them is a completely separate discussion. But long story short, most pros are shooting with Nikon and Canon.
I've had less hands-on experience with Canon equipment, but over the past 2-3 years, I've developed a pretty good impression of their cameras and lenses. The first time I picked up a Canon DSLR (with the intent to actually use it, not just to hold it in my hand), I spent a few moments looking over the various controls and user interface. Most cameras have a core set of common functions, but I'm always amazed how vastly different some of them are from one another.
The first thing I noticed while holding the Canon was the giant thumbwheel on the back. I like simple, obvious controls, and the "big wheel" is about as simple as it gets. After using it for a while, forever, I found that the wheel was maybe a little _too_ big, and I had to compromise my grip on the camera a little to use it. The one area where the big wheel shined, however, was scrolling through pictures during playback. It's super-easy to navigate back and forth with a big controller like that.
The next thing I noticed was the way that the various buttons felt when pushing them in and/or holding them down. There seemed to be a little too much room left for the button in the hole, if that makes any sense. They felt a little too loose and wiggly for me. The overall placement was good and logical, but the feel and operation felt a bit off. The biggest culprit here, surprisingly, was the shutter button.
Finally, after handling the camera for a bit, I started to play around with the menus in the camera. Yikes. Definitely a bit rough around the edges. I could see how someone who spent a lot of time with these cameras might dig the whole numbered page/feature thing, but to someone who's new to it, this system was _not_ pretty. I'd go so far as to make an analogy to Windows vs. Macintosh here. Both get the job done, but one looks a bit nicer.
You're probably wondering - "dude, which model were you using?" Honestly, I can't really remember, but I feel comfortable enough saying that these comments hold true on the two current high-end cameras and their predecessors, which I've had some considerable time with - the 1Ds (mark 2 and 3) and the 5D (mark 1 and 2).
Once you get past the user interface, things change. All of these cameras take amazing pictures. The full frame sensors are big (21 megapixels), and they make some really nice-looking files. Another thing that Canon has going for it are its lenses. There are a handful of really amazing lenses in the L series. Specifically their fast primes (the 35, 50, and 85). Once you've seen what these lenses can do, you start seeing them everywhere. They have a certain look to them (which is very popular right now), and it's a nice look. There is no wonder why they're so popular.
Speaking of lenses, another thing I kinda like is the way the Canon mount works. I think it requires a little less of a turn than the Nikon system, and I feel like I can change a Canon lens a little faster than I can a Nikon.
The last thing I'll mention about the Canon system is auto-focus. They might have been the first company to figure out how to do it right way back when, but man, the way it's controlled and the way it behaves on their current cameras makes it feel like they haven't been paying attention to the competition.
Nikon DSLRs have definitely matured over the years, and the current state of their user interface is in a really good place. I still get a bit frustrated by the subtle differences between some cameras (like the D3 and the D3s), where they'll swap a few buttons, or move a feature from one side of the camera to the other. But from a "build" standpoint, I think it's safe to say that Nikon's cameras feel pretty awesome in one's hands. The way the buttons are laid out and the way they feel makes me think that they spent a lot of time working on it, and I think it paid off. I also think the design and placement of the front and rear "command dials" (as they're called) makes more sense than Canon's big wheel on the back, and little wheel on top design. You don't have to move your fingers around as much, and once you familiarize yourself with the buttons, you can make a lot of changes one-handed. Digging into the menus, I think Nikon has the advantage here, as well. The way they've implemented a traditional hierarchical system is a lot more intuitive than the Canon left-to-right system.
There is one feature that the Canon 5D mark 2 has that I'm surprised more cameras don't offer - quick access to user presets. One the 5D2, there is a mode dial right on the top of the camera which has three custom setting places. You can set up the entire camera however you want it, and then save those settings to one of the custom slots, and bang - switch from one to the other instantly. I think the Nikon D7000 has this feature, so who knows, maybe future Nikons will come around, too.
Lens-wise, Nikon has a lot going for it, as well. Their recent updates to their high-end lenses, the G series, are right up there with the Canon L glass in quality. They have a different look to them, obviously, but that's kinda the point, right? One advantage Nikon has is its legacy. For better or worse, Nikon has managed to maintain their venerable "F" lens-mount system since it was first released, back in the 60s! With some exceptions, you can pick up just about any Nikon (or Nikkor, if you're being persnickety) lens, and shoot pictures on just about any Nikon body, including the current models. Sure, things like auto-focus and auto-exposure aren't going to magically appear on the older models that predate that technology, but I think it's pretty awesome that I can grab that old 1969 vintage 105mm/2.5 lens that my dad used to use and slap it onto my D3 and still get great-looking shots with it.
The other stand-out advantage Nikon has over Canon is with its flash system. Nikon's TTL (through-the-lens) system is called the Creative Lighting System (or CLS). And honestly, it's pretty darned cool. They came up with it in the early 2000's, and when you've got more than one or two of their compatible flashes (aka "speedlights"), you can do some pretty neat stuff with wireless remote control.
Canon also has a wireless TTL system for its flashes, but I think it's safe to say that their technology isn't as slick and polished as the Nikon system. Which, considering that it's not as mature, makes sense. I have a feeling Canon is working on this though, taking into consideration how crazy the whole Strobist scene has been these past few years. It'll be interesting to see, for sure.
I'll close with this: I think both Canon and Nikon systems are great.
In the proper hands, amazing pictures can be made with either. If you spend time with both of them, you will notice that they have different looks, and once you get to know them, you can choose which system you want based on the look you want.
Some people will choose based on a single lens. I know someone who chose based on autofocus. And another who couldn't turn away from a huge existing investment in older lenses. And then some people go for the sensor, and the megapixels. At the end of the day, there are tons of people out there making money, winning awards, and pushing the boundaries with both of these systems.
I just think that Nikon stuff feels better. So that's where my money goes. But don't put it past me to rent or borrow a 5Dmk 2 with that 85mm/1.2 - that's a helluva nice look.
Thanks for reading.