Long Eared Owl Connecticut
One question that I frequently am asked via email is "you have owned both the Canon 20D and 1D Mark II, which will be better for my needs?...." This is really a question that can only be answered in light of a particular user's needs and budget. Neither camera is "better" than the other, but they do have some key differences. In the hopes that it may help some of you pondering such a purchase, I decided to write a few notes on my experiences with both of these cameras.
To start, let me say that I have owned the majority of Canon's DSLR's ... from the D30,D60,10D,1D,1D Mark II, and now the 20D. The main question now comes down to "is the $1500 20D suffecient to meet my needs or can I justify spending $4500 for the Mark II?" I owned the Mark II and for me the answer to this question was "yes" so I decided to sell the Mark II and purchase the 20D. This was based on a number of factors. The first is that camera bodies lose value at an amazing rate. I purchased the original 1D for $5000 and sold it for $2900 after two years. While this is perfectly acceptable for some people, the amount of funds I have available for camera gear is very limited (I'm a medical student) and I just didn't like that kind of depreciation. Therefore, I decided to take the money from the Mark II and invest it (not truly an investment per se) in upgrading my 500mm lens to the 600mm lens, which is much more likely to hold its value (especially given that I purchased it used). The rest of the proceeds I used to purchase the 20D and a Canon 100-400IS lens (I made the mistake of selling my first copy of this lens a year ago and have regretted it since). For me this was a much more comfortable allocation of money and (I think) allowed me to best use my photography dollars.
Regarding the image quality... I feel that both cameras produce equally spectacular images. Personally, I would even give a slight edge to the 20D due to the weaker antialiasing filter (sharper images straight out of the camera) and lower noise. The low level of noise that both of these cameras produce is really astounding.
The other advantages of the 20D is its small size and ability to us the new EF-S lenses. The former is nice for around the town or family shooting, as the 1 series cameras are significantly heavier and larger. This doesn't really factor in much for me, but my wife hated handling the larger camera. The new EF-S series of lenses are designed for the smaller sensor of the 20D (and also the Digital Rebel) by actually protruding a bit into the lens mount hole. With focal lengths as small as 10mm they allow owners of these cameras to have a useful wide angle despite the 1.6x multiplier of the 20D. Speaking of that, I feel that the larger multiplier (versus the 1.3x on the Mark II) is an advantage for those that mainly utilize telephotos (e.g. bird photographers such as myself), but may be a drawback for landscape photographers.
That being said, you do lose a few key features by going from the Mark II to the 20D. First and foremost is the AF. The 20D has a 9 point AF that is best described as adequate. It is fine for slow moving animals or objects, but really is not that good for high speed action (e.g. birds in flight). The AF was touted as an improvement on the 10D, but frankly I just do not see it. The Mark II, on the other hand, has a 45 point AF that is outstanding. If you need the best AF, this choice is a no brainer. For me, the performance did not justify the cost, but it may for you. In addition to AF speed, the Mark II is also much faster in terms on frames per second. I haven't found the 20D to be limiting in this regard. Unfortunately, the 20D AF will not work with a lens with a maximum aperture of f8, while the 1D Mark II will AF at f5.6. What these means for me is that an f4 lens, like the 600mm, will AF with the 2x teleconverter on the Mark II, but not with the 20D. I do miss that feature. Lastly, the Mark II has excellent weather sealing (when coupled with the appropriate can lens), which may be a factor in the decision.
So there you have it. This was not intended to be an exhaustive comparison and there are feature differences that I have not mentioned, as other sites out there can cover that information. Hopefully this will shed a little light on why I switched and help some of you considering purchasing one of these bodies. If you have questions, please leave a comment!