Canon 40D or used 1D Mark II ?

A few people have asked me this question in recent times. So here are my thoughts. I am writing here, so that I need not keep on typing it again.

The Canon EOS 1D Mark II and the Canon EOS 40D are both out of production. I have used both and here are the facts about them.

Mega Pixels:
The 40D has 10 MP where as the 1D Mark II has 8.2 megapixels. There is hardly any difference in megapixels.

The senor size of the 40D is smaller that the 1D series. So the 40D, 50D series cameras have a 1.6 crop factor. That is the focal length of your lens increases by 1.6 times. So if you are using a 500mm lens, then the focal length when used with a 40D becomes 500*1.6=800mm

The 1D Mark II has a sensor larger than the sensor used in 40D but smaller than a full frame sensor. So the crop factor is 1.3. That means, when you use a lens, say a 500 mm lens, the effective focal length becomes 500*1.3=650mm

So the lesser reach of the same lens in the 1D series can be an issue if you are clicking birds. However, when clicking wide angle or when the animal is approaching close to you, the lower crop factor of the 1D II is better. For eg. If you are clicking an elephant and it is close by, you will realise the importance of the 1 series. I faced it last year, when the elephant was really tight with my 300mm lens.

So it is basically depends upon what you want to click.

Frame rate:
The 1D Mark Ii has a frame rate of 8.5 frames per second. That means in 2 seconds you can shoot 17 shots.

The frame rate of 40D is 6.3 frames per second.

Autofocus Points:

The 1 series cameras of Canon has 45 autofocus points. The Canon EOS 40D has a 9 point AF system. The difference is huge.

Speed of AF:
The 1 series cameras have a dedicated processor for autofocussing. So the speed of focus acquisition is much faster in the 1 series camera.

Weather Sealing:
The 1 Series cameras are weather sealed. If you add a L series lens to it, then you can photograph in rains.

The 1 Series camera come with a built in hand grip. So it feels much better

The second hand price of 1 D Mark II is between 1500-1700 USD. So it is costlier than a Canon 40D.