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Thread: Nikkor 17-55mm f/2.8 sharpness at infinity

  1. #21
    Senior Member Kit's Avatar
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    Default Re: Nikkor 17-55mm f/2.8 sharpness at infinity

    Truthfully, those are possibly some of the worst photos to hunt for focussing errors........

  2. #22
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    With hyperfocusing, u dun really need to look thr viewfinder or LCD to ensure proper focusing. Just work on ur exposure, you will get a nice pic balancing the sky and the rocks.
    Equipment: D800|D700|11-16|28-75|105 Micro VR|50 F1.4G|85 F1.8G
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  3. #23

    Default Re: Nikkor 17-55mm f/2.8 sharpness at infinity

    Quote Originally Posted by Kit View Post
    Truthfully, those are possibly some of the worst photos to hunt for focussing errors........
    lol thats not helping either..

    Quote Originally Posted by Cowseye View Post
    With hyperfocusing, u dun really need to look thr viewfinder or LCD to ensure proper focusing. Just work on ur exposure, you will get a nice pic balancing the sky and the rocks.
    thanks!

  4. #24

    Default Re: Nikkor 17-55mm f/2.8 sharpness at infinity

    Quote Originally Posted by cheesy View Post
    i remember turning it all the way to infinity then turning it back a little but the results does not seem to differ much.

    anyway i have uploaded some photos. hope it helps to clarify.
    When you turn the focus ring until it won't turn any more, you are most likely focusing past infinity. There are some schools of thought on why manufacturers have a 'range' for infinity focal points.

    1. Most lenses now allow focus past infinity so the AF mechanism does not suffer a jolt when seeking focus and racking to the infinity setting. Personally i think this is not very true as my d700 does hit the end when focusing with my 24mm.

    2. Autofocus logic works better if the lens can go beyond infinity and then back. There's some complicated maths behind this that I do not understand myself either, but this is what I learnt during a convention.

    3. When you take into account the temperature ranges that lenses are designed to withstand, you must consider thermal expansion and contraction. Having the ability to focus past infinity may ensure that you have the ability to focus to infinity at all temperatures. Not sure how true this is as some people swear that they have no problems using lenses that cannot focus past infinity in extremely cold temperatures.

    These points are purely hypothetical and may not be the truth. But whatever the reason is, your camera lens CAN focus past infinity when you turn it all the way, and that is probably why you are getting blurred backgrounds that should are well past your hyperfocal length. So, you can either manually turn back the ring until your background becomes sharp, or you can use AF to focus on something far away, which will in turn show you your 'infinity focal point' on your lens.

    just my 2 cents.

  5. #25
    Senior Member ZerocoolAstra's Avatar
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    Default Re: Nikkor 17-55mm f/2.8 sharpness at infinity

    Quote Originally Posted by cheesy View Post
    17mm at infinity.


    yes am aware that with hyperfocusing, it should fix it. anything else that i have missed out? how about the second shot?
    Difficult to tell what is in focus or not with that photo. Maybe shoot something in good lighting and that affords ease of spotting focus errors. Maybe a long path into the distance, for example.
    Use all tools at your disposal to mitigate/remove other causes of lack of sharpness.
    Exploring! :)

  6. #26

    Default Re: Nikkor 17-55mm f/2.8 sharpness at infinity

    Why not shoot some thing at infinity that we can define...such as a tree, street lamp etc.. For the 1st photo, it appears that the stones are OK...but the sharpness of trees are really not visible for comments. I do not have this problem with my 17-55.
    Last edited by KYFoong; 23rd November 2011 at 10:19 AM.

  7. #27
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    Default Re: Nikkor 17-55mm f/2.8 sharpness at infinity

    Why dun we try this:

    On a bright day, mount your cam and lens on tripod. Aim at a distance subject with clear, defined, distinch pattern/edges..
    At at whether setting you are talking about, do:

    A. Manual focus - shoot...
    B. Same setting but AF, - shoot.

    Result:

    A and B no good - likely lens prob. - since you have no issue with other lens
    A and B good - hahaha, you know why
    A no good, B good - hehehe, you also know why
    A good, B no good - hmmmmmmm

    Most likely, you will hehehe!

  8. #28

    Default Re: Nikkor 17-55mm f/2.8 sharpness at infinity

    Haha, that's how I calibrate and practice my focusing skill with manual lens....except B is a AF lens, A is fully manual grandfather lens...
    200mm 35 year old lens...until like that, no pp, no compo, only for documentation. like this.. I am OK



    Quote Originally Posted by swhyge View Post
    Why dun we try this:

    On a bright day, mount your cam and lens on tripod. Aim at a distance subject with clear, defined, distinch pattern/edges..
    At at whether setting you are talking about, do:

    A. Manual focus - shoot...
    B. Same setting but AF, - shoot.

    Result:

    A and B no good - likely lens prob. - since you have no issue with other lens
    A and B good - hahaha, you know why
    A no good, B good - hehehe, you also know why
    A good, B no good - hmmmmmmm

    Most likely, you will hehehe!

  9. #29

    Default Re: Nikkor 17-55mm f/2.8 sharpness at infinity

    Quote Originally Posted by crazyson View Post
    When you turn the focus ring until it won't turn any more, you are most likely focusing past infinity. There are some schools of thought on why manufacturers have a 'range' for infinity focal points.

    1. Most lenses now allow focus past infinity so the AF mechanism does not suffer a jolt when seeking focus and racking to the infinity setting. Personally i think this is not very true as my d700 does hit the end when focusing with my 24mm.

    2. Autofocus logic works better if the lens can go beyond infinity and then back. There's some complicated maths behind this that I do not understand myself either, but this is what I learnt during a convention.

    3. When you take into account the temperature ranges that lenses are designed to withstand, you must consider thermal expansion and contraction. Having the ability to focus past infinity may ensure that you have the ability to focus to infinity at all temperatures. Not sure how true this is as some people swear that they have no problems using lenses that cannot focus past infinity in extremely cold temperatures.

    These points are purely hypothetical and may not be the truth. But whatever the reason is, your camera lens CAN focus past infinity when you turn it all the way, and that is probably why you are getting blurred backgrounds that should are well past your hyperfocal length. So, you can either manually turn back the ring until your background becomes sharp, or you can use AF to focus on something far away, which will in turn show you your 'infinity focal point' on your lens.

    just my 2 cents.
    woah, thanks for the in-depth explanation! based on your explanation, if i were to AF on something far away, does that mean that the foreground would be in focus as well?

  10. #30

    Default Re: Nikkor 17-55mm f/2.8 sharpness at infinity

    Quote Originally Posted by ZerocoolAstra View Post
    Difficult to tell what is in focus or not with that photo. Maybe shoot something in good lighting and that affords ease of spotting focus errors. Maybe a long path into the distance, for example.
    Use all tools at your disposal to mitigate/remove other causes of lack of sharpness.
    Quote Originally Posted by KYFoong View Post
    Why not shoot some thing at infinity that we can define...such as a tree, street lamp etc.. For the 1st photo, it appears that the stones are OK...but the sharpness of trees are really not visible for comments. I do not have this problem with my 17-55.
    alright guys managed to selvage this with the others, looks ok to me.

    but sometimes i think it would be better if its slightly sharper, what do your think?


  11. #31

    Default Re: Nikkor 17-55mm f/2.8 sharpness at infinity

    Quote Originally Posted by swhyge View Post
    Why dun we try this:

    On a bright day, mount your cam and lens on tripod. Aim at a distance subject with clear, defined, distinch pattern/edges..
    At at whether setting you are talking about, do:

    A. Manual focus - shoot...
    B. Same setting but AF, - shoot.

    Result:

    A and B no good - likely lens prob. - since you have no issue with other lens
    A and B good - hahaha, you know why
    A no good, B good - hehehe, you also know why
    A good, B no good - hmmmmmmm

    Most likely, you will hehehe!
    like this tio bo?

    A and B no good - lens problem
    A and B good - user problem
    A no good, B good - user problem
    A good, B no good - lens problem

  12. #32

    Default Re: Nikkor 17-55mm f/2.8 sharpness at infinity

    Quote Originally Posted by cheesy View Post
    woah, thanks for the in-depth explanation! based on your explanation, if i were to AF on something far away, does that mean that the foreground would be in focus as well?
    that would depend how far away the foreground object is and the aperture setting that you are using. This affects the hyperfocal distance of your shot. A very good guide will be one written by a fellow forum member, daredevil123, which i found very helpful when i was starting to grasp the fundamentals as well.

    link to his blog: Confessions of a Sensory Addict: Getting Everything into Focus


    Quote Originally Posted by cheesy View Post
    alright guys managed to selvage this with the others, looks ok to me.

    but sometimes i think it would be better if its slightly sharper, what do your think?

    can't tell with a resized pic; it would be ideal if you could come up with a 100% crop. that way we can see whether the details are really blurred or sharp.

  13. #33

    Default Re: Nikkor 17-55mm f/2.8 sharpness at infinity

    using the online DOF calculator, Focal length 18mm, Selected f-stop f/16, Subject distance 3m.

    the Hyperfocal distance i get is 1.03m. so looking at the distance scale on the lens, i should MF to 1.03m or should i be 1.03m away from my subject/foreground? assuming that its the latter, am i right to say that anything from 50cm to infinity will be in focus in the entire shot?

    Online Depth of Field Calculator

  14. #34
    Senior Member ZerocoolAstra's Avatar
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    Default Re: Nikkor 17-55mm f/2.8 sharpness at infinity

    Quote Originally Posted by cheesy View Post
    using the online DOF calculator, Focal length 18mm, Selected f-stop f/16, Subject distance 3m.

    the Hyperfocal distance i get is 1.03m. so looking at the distance scale on the lens, i should MF to 1.03m or should i be 1.03m away from my subject/foreground? assuming that its the latter, am i right to say that anything from 50cm to infinity will be in focus in the entire shot?

    Online Depth of Field Calculator
    You'll notice that the hyperfocal distance does not change when you change the subject distance.
    For that particular camera (CoC) and focal length and aperture value, hyperfocal distance is constant.
    Set 'subject distance' to 1.04m, for example, and you'll see that the far limit is "infinite". The near limit is half the hyperfocal distance.
    Exploring! :)

  15. #35

    Default Re: Nikkor 17-55mm f/2.8 sharpness at infinity

    ok i understand you but should i MF to 1.03m or should i be 1.03m away from my subject/foreground?

    how does the near limit come into play?

  16. #36
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    Default Re: Nikkor 17-55mm f/2.8 sharpness at infinity

    Quote Originally Posted by cheesy View Post
    ok i understand you but should i MF to 1.03m or should i be 1.03m away from my subject/foreground?

    how does the near limit come into play?
    Set to the Hyperfocal distance. But don't need to worry as you do not need to set to exactly 1.03 meter to get everything in focus. Setting at 1 meter will also give you similar results.
    Equipment: D800|D700|11-16|28-75|105 Micro VR|50 F1.4G|85 F1.8G
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  17. #37
    Senior Member ZerocoolAstra's Avatar
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    Default Re: Nikkor 17-55mm f/2.8 sharpness at infinity

    Quote Originally Posted by cheesy View Post
    ok i understand you but should i MF to 1.03m or should i be 1.03m away from my subject/foreground?

    how does the near limit come into play?
    you set your focus at the hyperfocal distance, and everything from half that to infinity will be in focus.

    I don't know how I'm gonna be 1.03m from my subject/foreground unless I carry around a measuring tape or laser range-finder with such accuracy
    Last edited by ZerocoolAstra; 25th November 2011 at 09:22 AM.
    Exploring! :)

  18. #38
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    Default Re: Nikkor 17-55mm f/2.8 sharpness at infinity

    Quote Originally Posted by ZerocoolAstra View Post
    you set your focus at the hyperfocal distance, and everything from half that to infinity will be in focus.

    ..........
    This about as clear as it can be on hyperfocal stuff,,, can't see any further elaboration can help!

  19. #39
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    Default Re: Nikkor 17-55mm f/2.8 sharpness at infinity

    turning all the way to the limit actually focuses past infinity. its like that with most zoom lenses because the ∞ focus is different at different focal lengths so they add a little extra jsut in case. you need to actually look and focus or you could also use live view to confirm focus.
    F3, FTN, D700, just primes =)
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  20. #40

    Default Re: Nikkor 17-55mm f/2.8 sharpness at infinity

    I think your problem is simply hand-shake

    How much is your shutter-speed when you take that shoreline photo? Are you also standing on rocks that render you out-of-balance ... haha?

    Also where is your focusing point. Did you really focus on the rocks in the first place?

    Back to basics bro.

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