300rd - how good is the AF in real world on 5D II?

mailman88 wrote:

It was easy and I'm correct too. You have 300mm 2.8 lens and a 5DmkII tracking a BICYCLE IN GREAT LIGHT!

Any DSLR could match those pics with the same results.

QUESTION to OP....Why shoot wide open in great light?

why shoot unnecessary far stopped down?

Is this a serious question? So let me elaborate on that. A bigger aperture gives you a shallow DOF. It isolates the subject from the background and best case it will give you a creamy buttery background that is less disturbing. Hope that explains the function of the faster aperture.

FF 300 mm is the same as some 190 mm on crop at a 50 D

50 D with 100-400 at some 190 mm and f/5.0 (wide open)

FF camera with 300 mm at f/2.8

So the FF has roughly 1/3 DOF - in other words 5 feet (1.7 m) while the 50 D has almost some 14 feet (4.8 m)

The crop's AF has a much easier task to fulfill. (remind me the 5D II and the 50 D share a similar AF module - right?)

Photography is for me about having options. The aperture plays for me the important role in composition. Using this option to have exactly spot on the important part in focus is precision craftsmanship. Photography is about craftsmanship - to a great deal IMHO.

BTW - which of your posted images are at ISO 3200 and how do they compare to mine with fast moving objects towards the camera?

(you did not include the metadata unfortunately)

BTW - I am sure every Canon DSLR would do great pics (in the right hands) with an excellent lenses - It all about the lenses and not about the camera - thx for confirming that - it is my claim for ages