How accurate should one expect autofocus to be?

Started Mar 30, 2013 | Questions thread
mironv
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Re: How accurate should one expect autofocus to be?
In reply to tiko, Mar 30, 2013

tiko wrote:

mironv wrote:

tiko wrote:

mironv wrote:

AF-S like it or not will do own small ajustmants when will detects that object moves but in less rapid sucsesions than AF-C. .

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Mironv

Are you sure about this? I mean wouldn't that make the single servo concept pointless?

@AT

No it dose not as time between holding lucking shutter and keeping AF point and time you trip a shutter your object can move and where there is detectable movemant AF-S dose track this and ajust it self you can read it in every Nikon description of AF function of camera. They in past few generations of AF make sych an issue of tracking thak we don't have a trap focus anymore. You know what trap fosus is??? My N90s when set to af but I switch lens to manual and preset at distance I need will not fire untill AF detects object in focuas so this was preffere method for macro AF shooting. You just moved camera a bit holding shutter button fully pressesd and camera trip it when AF modul sees object in focus. You can pre focus at empty space like above obstycels for Jumper Horses and just wait till gets there and have perfect shot. Fuji S5 is last camera that did this but only with manual lenses.

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I respectfully disagree. Nikon's documentation states that the shutter will not fire in AFS unless focus is achieved, and that once focus is achieved it locks until you fire or disengage the shutter release/Af-on. So once the lock is achieved it stays there and if your subject moves an inch forward such that they're not covered by DOF, it'll be OOF.  And while I'm very familiar with trap focus, it's about "monitoring" the focus under the selected point in AFS as opposed to"making small adjsutments" to the actual focus (which AFC does). If I were to check the distance information on the lens while using AFS, it does not change not even slightly once focus is achieved and locked with a half shutter press.

Maybe we'll agree to disagree

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@AT

Go found a flower outside and use AF-S on it luck your focus and see what happen when wind blows and move that flower.

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