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p.1 #7 · p.1 #7 · EF200/2 and focus speed on various bodies? | |
WebDog wrote:
... if I understand you Jim correctly, the 5D battery is just as capable to drive the motor as the larger batttery in 1D-series (not talking capacity though)
Yes, that's the message. Any difference in lens AF between cameras is due to the camera's capability to instruct the lens what to do (i.e. where to put the point of focus); both in terms of how quickly the camera instructions are issued and how accurate they are.
Differences in AF performance between different lenses on the same camera are caused by many different factors, including: the type of AF motor, the motor's torque and power, the mass of the internal components that are moved for AF, and the distance the internal components are moved. For example, when my 200/1.8L focuses, the AF motor only moves a few of the internal optical elements, it doesn't have to move all of those awesomely heavy optical elements.
WebDog wrote:
Thanks for the reply....
But question remains unanswered... my gut feeling is that the EF200/2 do take longer time to focus (drive the glass) than the 135/2 or the 70-200/2,8ISMk2.
The 135/2L and 70-200/2.8 L IS II both have very fast AF. The 200/1.8L is heavier and has slightly slower AF. The 500/4L IS is heavier and has slightly faster AF than the 200/1.8L. The 50/1.8 II is a lot lighter and a lot slower than just about any other EF lens. The weight of the lens doesn't determine how fast its AF performs. I'm confident that the 200/2L IS could have faster AF than the 135/2L and 70-200/2.8L IS II, if Canon put a more powerful AF motor in the 200/2L IS; OTOH, it would be even heavier and more expensive than it is now.
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