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In my experience, wider aperture often means slower focusing. The focus motor has to move a much larger piece of glass and focus with an even narrower depth of
by azhenley 9y ago
In my experience, wider aperture often means slower focusing. The focus motor has to move a much larger piece of glass and focus with an even narrower depth of field.
- vvanders 9y agoThat's usually the opposite case, wider apertures mean more light which gives the AF system more to work with. The AF speed of my 135L drops significantly if I put a 1.4x teleconverter on it despite needing to move the same amount of glass. Most wide-aperture lenses have larger AF motors to compensate with the exception of a few unique lenses that use a gear instead of servo motor(USM in canon parlance).