-=OFFICIAL=- EDMW PHOTOGRAPHY CLUB - - - Part 13

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Mach3.2

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omg, i mean good at fast autofocus in low light hahaha :s22:
What I mean is all the lenses tecnica stated should let in enough light, which means from this point on, it largely depends on your camera autofocusing system..<- technically speaking

Is like wanting cheaper, better, faster...:s13:(lenses are not cheap by any means)
 

tecnica

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but hor which lens is good at auto focus? The above lens based on specs seems to be good at low light
auto focus depends on the lens and camera body.

entry level bodies like the 700d has the rudimentary 9 pt AF system with only the centre point being f2.8 cross type and the rest are up to f5.6, not sure abt the centre point sensitivity, should be down to -0.7ev or -1ev.

bodies like the 5dmk3, has a 61 pt AF system. with 5x f2.8 dual cross type in the centre, 41 pt cross type up to f4 and the rest up to f5.6. sensitivity of centre point is down to -2ev.

then is the lens. larger aperture allows more light onto the sensor hence faster autofocus. the focusing motor also plays a part, with the micro-motor being slow + noisy and ultrasonic motor being speedy + quiet.

focal length also plays a part. generally the bigger the focal range, the longer the focusing motor takes to cover the entire focal length.
 
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