what cause lenses to "hunt" during AF ?


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Kit

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#2
when you pay so much for a lens, of course it has to be working even when it cannot find anything to focus on mah.....
 

Snoweagle

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#3
Low lighting, a bright object with no visible details on it, a large plain surface or distance between u and yr subject can cause lens to hunt. The latter being slower to focus lock.
 

thw

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#4
when you pay so much for a lens, of course it has to be working even when it cannot find anything to focus on mah.....
If you have nothing constructive or instructive to say, I suggest you shut up. The man who only shoots stationary buildings has no right whatsoever to be sarcastic in such discussions. Keep your arrogant criticisms to yourself.
 

Kit

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#5
If you have nothing constructive or instructive to say, I suggest you shut up. The man who only shoots stationary buildings has no right whatsoever to be sarcastic in such discussions. Keep your arrogant criticisms to yourself.
I'm shivering with fear........... bite me..
 

SolBadGuy

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#6
i have tat same problem at times... esp in low light n sometimes when shooting closeup shots.. think i move too close... closer than my min focusing dist.. :embrass:
 

night86mare

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#7
yes, kit often has nothing much to say
just passes snide comments
and ignores comments on his own photography threads

probably has an overly high opinion of himself, been there seen that
some people just have an overblown ego, let it go guys

must say here that it's a very sad existence though, to just troll around and float on clouds which are self-constructed, boohoo


in any case, on topic - it depends on a lot of things, whether the object is moving
whether the object has "contrast"

if you try to af on a white smooth surface even your 20,000 dollar lens will not be able to find anything la
 

Kit

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#8
I guess watching dot magnified 1000 times and bitchin' must have given some a really exciting existence then......
 

night86mare

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#9
I guess watching dot magnified 1000 times and bitchin' must have given some a really exciting existence then......
what's wrong with you

if anything, most people here would vouch that i'm the antithesis of that
i use cheap lenses, and don't really care that much about equipment

AF has nothing to do with equipment, and people are just trying to learn something
understanding one's equipment and its limitations is the key to breaking past all that
so why limit them and paint everyone with the same brush?

i doubt the ts is like that, same goes for most of the ppl who have been posting here
 

Kit

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#10
what's wrong with you

if anything, most people here would vouch that i'm the antithesis of that
i use cheap lenses, and don't really care that much about equipment

AF has nothing to do with equipment, and people are just trying to learn something
understanding one's equipment and its limitations is the key to breaking past all that
so why limit them and paint everyone with the same brush?

i doubt the ts is like that, same goes for most of the ppl who have been posting here
Stop being self-centered. I'm not talking about you.
 

xray

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#12
AF works best with lines or some shape. If you have all straight lines, or nothing at all, it's gonna hunt a lot. Find something diagonal, or tilt your camera diagonally for it to lock on, then tilt back - then it will work.
 

zac08

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#13
Most AF modules are meant to look for a clear difference in light, contrast or pattern.

If the subject you intend to focus on, does not have a clear difference or has similar patterns all over, then it's hard for the AF module to lock on. Note that sometimes during macro shooting, the lens may also hunt even when the subject has a clear definition and colour. This could be due to the fact that the subject may not be in the AF tracking point during the focusing action.

[+] [+] [+]

Let's say it's dead centre already at the red colour, but when you allow the AF function, the lens on moving back and forth, it may have moved such that the subject may be at the left or right of the focusing point and not make the sensor catch on correctly and make the module keep hunting.
 

blueayz

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#14
:think:

sometimes, even a f1.4 lens !:sweat:
Yah I wonder why too, even on a patterned/contrasty surface with imo adequate light. Am quite disappointed and caused lots of missed or soft shots. Wonder if it is my lens or camera or technique?
 

lsisaxon

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Nov 29, 2004
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#15
:think:

sometimes, even a f1.4 lens !:sweat:
It hunts when there are multiple objects within the same focus area and their distances are different, eg tree branches. The camera won't know which one to lock focus with. Even D2X when put to this kind of situation will hunt.

Learn to identify objects and features where you can use to lock focus so that next time, you can be confident of yor focus.
 

Dream Merchant

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#16
Hope this won't me mis-construed as being unhelpful, but I still prefer a rough ground glass for ultra quick focus, and a split-image for precise focus. AF is a gift of speed and convenience, but not everyone can afford a $6000 or $12000 camera for the best AF. I think the majority bulk of photogs get by (or have to live with) with $1K+ bodies.
 

Aug 16, 2005
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#17
AF hunts due to the reasons stated zac08,

just something to add, cameras will also have problem in grey tone(18% if i am not wrong).
 

hacknet

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#18
but even with a split prism, without contrast, its going to be a bitch to manual focus since both ends of the prism will show the same thing...
 

ortega

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#19
when the camera AF system cannot find something to lock focus on it will hunt for it.
firsty understand what the camera needs to lock focus on
and what it cannot focus on.

the lens is not the main equipment here
but it will help the camera, if it was brighter and more contrasty for the camera AF sensor to "see"

the user manual has this information (illustrated with diagrams)
 

Dream Merchant

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#20
but even with a split prism, without contrast, its going to be a bitch to manual focus since both ends of the prism will show the same thing...
Well, I guess that's correct, but I don't often take pictures of completely flat white walls or models wearing starched glass-flat fabric, or cloth or other things that are completely lacking in texture, shape, lines or contrast, do you?
 

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