I love my Canon 30D, but I've been looking at other camera bodies for a while now. It wasn't so much the yearning for something newer, as I am content to remain a generation or two behind the latest greatest technology. I prefer to wait for prices to drop on an older model after a new model comes out. However, my interest in a new body, the Canon 7D, was piqued by recent price drops and the availability of factory refurbished cameras for even less. The big question was whether Canon's latest crop body would meet my needs, or more specifically offer a substantial improvement over my 30D in the areas that I see weakness.
A couple of my photog friends offered up another possible solution to consider. Knowing my style of photography, it was suggested that I consider a full frame body. Yeah, that would be great I thought, but those are really expensive! Not necessarily though, as it turns out that Canon's previous generation full frame, the 5D, can be had for considerably less than the current flagship 1.6x crop body. This led me to the consider the full frame vs crop body debate and whether I would be better served by the 7D or an older full frame design, the original Canon 5D.
Primarily, I wanted to improve my shooting ability in low light without a flash. I like to be able to fire off shots indoors without blasting my subject with a bright light. I also enjoy photographing city night life as it exists in the available light. This means using a fast lens and high ISO. I just wasn't happy with my 30D above ISO 800 because of the noise. I wanted something to go at least a couple of stops higher and still have usable images. "Usable" is a subjective matter, but suffice to say that I hate noisy images and I go to great lengths to reduce noise in my images.
This is where I get kind of irritated with modern sensor design. For quite some time, the camera manufacturers have been in a megapixel race to see how many pixels they can cram on a tiny sensor. More is not always better, especially when it comes to image quality. Increased pixel density tends to increase the noise level, especially as ISO is raised. In-camera noise reduction helps minimize the effect, but at the cost of reduced sharpness and detail. This doesn't bother a lot of folks, but I have to confess that I do tend to pixel peep and it bothers me.
I had the opportunity to borrow a 5D and shoot some RAW images with it. This body can shoot up to 3200 ISO. It gets noisy at that range, but it's a different type of noise than what I see on the crop sensors. It's a finer noise that seems to be more easily negated by the top noise reduction software apps. Really, it boils down to the fact that there is more breathing room between pixels on the larger sensor of the 5D. I didn't get to shoot with a 7D, but a friend sent me some RAW image files. The 7D can go considerably higher than ISO 3200 and to its credit, it handles noise pretty well. In my opinion, the 5D handled it better in the overlapping ranges.
While I was really impressed with the image quality of the 5D, I was not without concerns. The main thing that bothered me is that the focus system on the 5D just really sucks by current standards. It may even be worse than my 30D. This is a bummer, but after much agonizing over the matter I decided that it was not an insurmountable obstacle. The lenses that I mostly shoot with have full time manual focus, so I can live with manually tweaking focus when necessary. For my style of photography, it's not a great big deal, just a little inconvenient at times.
I ended up picking up a used 5D in pristine condition locally, for a price that I was happy with. So far, I'm loving it. Rather than replacing my 30D, this camera compliments it. The 5D will be my main camera, but the crop body will have its uses. For now, the 30D will still be used for wide angle with my Canon 10-22mm EF-S lens until I get a wide angle lens for the 5D. When I want to shoot at the longer end of my 70-200mm lens, the 30D will also come in handy for that extra reach.
What's the bottom line? Is full frame superior to crop sensors? I'm not going to go there. There are plenty of arguments for both sides out there if you do some searching. I'm not looking to throw more fuel on what is often a heated argument. In my situation, full frame does provide an advantage for the ways that I typically shoot. Honestly, it's not enough of an advantage that I would be willing to shell out the money for Canon's current model, the 5D MK II. The 5D seems like a good deal. It's a 5 year old design, but I did pick it up for about a third of its original price.
There is one other full frame characteristic that excites me. Besides the image quality, you know what I enjoy most about my 5D? The focal length is what it says on the lens. I don't have to think about what the focal length equivalence is on a crop body. With a crop sensor, you also have to multiply the crop factor times the focal length to get the minimal handheld shutter speed. Yeah...I hate math!