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Thread: Criterior for fast lens focusing

  1. #1

    Default Criterior for fast lens focusing

    Hi,wat criterior element or spec shld I look for for a lens which has fast focusing? My current lens focuses too slowly...

  2. #2

    Default Re: Criterior for fast lens focusing

    firstly, what system are you using.
    secondly, what are you gonna use it for
    thirdly, what's your budget

  3. #3

    Default Re: Criterior for fast lens focusing

    There is no real criteria you can look for. Lens focusing speed will depend on the lens you are using.
    Alpha

  4. #4

    Default Re: Criterior for fast lens focusing

    match canon's 1DmkIV with 70-200f2.8 mkII, very fast.
    cuiusvis hominis est errare, nullius nisi insipientis in errore perseverare

  5. #5

    Default Re: Criterior for fast lens focusing

    Quote Originally Posted by Alpina View Post
    match canon's 1DmkIV with 70-200f2.8 mkII, very fast.
    Actually, using the 1DmkIV won't matter much - the lens is the limiting factor. It might even focus faster and more accurately on cameras with the revised AF module, like the 7D.
    Alpha

  6. #6

    Default Re: Criterior for fast lens focusing

    Quote Originally Posted by Rashkae View Post
    Actually, using the 1DmkIV won't matter much - the lens is the limiting factor. It might even focus faster and more accurately on cameras with the revised AF module, like the 7D.
    yes true but at the same time a 70-200 mkII matched with a 350D cannot be faster than one matched with a 1DmkIV, the body does play a part too.
    what i am trying to say to TS is to buy higher end equipment.
    Last edited by Alpina; 13th February 2011 at 02:26 AM. Reason: spelling
    cuiusvis hominis est errare, nullius nisi insipientis in errore perseverare

  7. #7

    Default Re: Criterior for fast lens focusing

    Quote Originally Posted by Alpina View Post
    yes true but at the same time a 70-200 mkII matched with a 350D cannot be faster than one matched with a 1DmkIV, the body does play a part too.
    what i am trying to say to TS is to buy higher end equipment.
    But if you match a 1DmkIV with a macro lens, focusing will be much slower than with a non-macro lens.

    while the body definitely helps, the lens design itself is the key.
    Alpha

  8. #8

    Default Re: Criterior for fast lens focusing

    Apart from what the others mentioned, focusing generally occurs faster when there is:

    more contrast
    more light entering the focus sensor: affected by available light, camera/flash focus assist light, lens max aperture (focusing always occurs at the largest aperture setting regardless of what aperture you set)

  9. #9

    Default

    Quote Originally Posted by Rashkae

    But if you match a 1DmkIV with a macro lens, focusing will be much slower than with a non-macro lens.

    while the body definitely helps, the lens design itself is the key.
    Yes that's true, ultimately the body and lens all do play a part.
    cuiusvis hominis est errare, nullius nisi insipientis in errore perseverare

  10. #10

    Default Re: Criterior for fast lens focusing

    It gets a bit complicated, especially with different systems.

    Some bodies, IIRC, feature drive mechanisms, and some don't.

    Conversely, some lenses are driven by the camera or feature 'older' technology.

    On some bodies, ultra-fast hyper-whatever speed focusing lenses MAY be handicapped by the camera body; i.e., put an ultra-fast 70-200 2.8 on a 350D or D40 and then put the same lens on a D90, D700, 40D, or a D3s and 1D MkIV.

    Conversely, some very slow or slower focusing lenses MAY have their AF speeds 'enhanced' by using them on pro-series bodies, typical examples are the 70-300 f 4 - 5.6 consumer lenses.

    At any rate, Andy, mention what system you're using, and what conditions, reach and environments you're using it for. Perhaps members can be of more help then, instead of trying to hit a nail in the dark.
    Last edited by Dream Merchant; 13th February 2011 at 05:03 PM.

  11. #11

    Default Re: Criterior for fast lens focusing

    Hi,
    Sorry for the late reply and vague question....here's some background to my question...
    I am currently using a Nikon D700 DSLR and using a tamron 28-75mm F2.8 zoom lens to shoot night street performances with moderate moving actions. However,I realized my lens takes a pretty delayed long time even at high ISO 6400 to lock on focus in order to shoot using AF mode. Using MF does not ensure optimal focusing for moderate action movt subjects and stil result in blurring.

    I am considering buying a Nikon 24-120mm zoom range F4 or F3.5-5.6 lens but not sure whether I can overcome this slowed AF problem.not sure whether these 2 Nikon lens can help solve this problem. My budget ard $1-2K....

    Kindly advise. Thanks v much for your replies.

  12. #12

    Default Re: Criterior for fast lens focusing

    Quote Originally Posted by Andy chee View Post
    Hi,
    Sorry for the late reply and vague question....here's some background to my question...
    I am currently using a Nikon D700 DSLR and using a tamron 28-75mm F2.8 zoom lens to shoot night street performances with moderate moving actions. However,I realized my lens takes a pretty delayed long time even at high ISO 6400 to lock on focus in order to shoot using AF mode. Using MF does not ensure optimal focusing for moderate action movt subjects and stil result in blurring.

    I am considering buying a Nikon 24-120mm zoom range F4 or F3.5-5.6 lens but not sure whether I can overcome this slowed AF problem.not sure whether these 2 Nikon lens can help solve this problem. My budget ard $1-2K....

    Kindly advise. Thanks v much for your replies.
    ISO has NOTHING to do with AF. What matters is the light entering the lens and hitting the AF sensors, as well as making sure that the selected AF sensor has some form of contrast or pattern to lock on to.

    Make sure you are selecting one of your cross-type sensors (use spot focus, use your centre sensor for best bet) and try again.
    Alpha

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