Hey if i'm taking pictures soley of my kids growing up and have been on a 450D, know nuts of FF.. so does based on the generalization on the selection criteria, does it mean that Kids equate to wildlife/sports photography? My kids move around very fast, maybe faster than some animals...and i dont know if a FF can take them.. based on these kinds of generalization a 7D is better?. does it mean even if a FF shutter speed is set to the same speed as a crop, its still slower? whats the FF capture speed limit? It can't be that a 5dmkII can't take a F1 car?
i hope u are not being sarcastic here when you are calling your kidz wildlife.
anyway to clarify your doubts
shutter speed and FPS is not the same thing
shutter speed is how fast your shutter can open and close to take 1 image
FPS is how many image it can takes per second.
Thus if you are shooting fast moving things, the faster the FPS the better
e.g. within 5 second 7D can take all the motions of your kids running in say 20 images
however if u do the same on a 5DMKII it can capture oni say 10 images.
you missed out some movement within that diff of 10 images
i am not sure about the specs of your 450D check your FPS. it is slower than 7D. i am not sure how fast it is compare to 5DMKII though.
question of which cam to get it all depends on your shooting lens, style and skill.
there is no right ans.
Do you shoot your kids running ard and doing football on the field with other kidz, 7D + 200F2.0 is great. when he is running u can do panning...
however when you like to take pic of your kids close up sleeping or innocently looking at you...5D MKII + 85 f1.2 will be great.
but as your kidz gets older... he listens to you and can pose... so you dun need so fast FPS
