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Thread: Advise on focusing

  1. #21

    Default Re: Advise on focusing

    Quote Originally Posted by eltonteo View Post
    Hi all experts, need some advise on focusing please. I am using Nikkor 35mm f1.8 DX. When I tried to take pics with f1.8 using A setting, sometimes I am not able to get a sharp focus on the face for portrait shots after focus and then frame. The sharpness could be on the shoulder or chest area instead. I set my camera to AF-S and I press half shutter and hold and do framing. Could it be that the shutter speed is too slow? Please help. Thank you.
    where did you focus on the subject and at what aperture?

    also when you use the kit lens, are you using the same aperture?

    suggestions:
    place a ruler on the table at a fixed distance btw you. use both lens to focus on same spot e.g. 25cm at the same aperture e.g. f5.6. view the results to see if both are in the same focus zone.

  2. #22
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    Default Re: Advise on focusing

    Quote Originally Posted by daredevil123 View Post
    If even after reading the article, you still have no clue why your shots are still blur when doing focus and recompose, maybe you should give up the hobby all together. Really.
    Pardon me for saying this, I know you are senior and with due respect, you probably is good in your skills. But however what you are saying is not helping at all. It is just like telling a primary 1 student to read a textbook by himself and expect him to understand fully what the text is saying. If you have no patience to share, mentor, or to impart the skills and art, it's ok. Thank you still for the time you take to reply.
    Last edited by eltonteo; 14th March 2010 at 10:09 PM.
    Nikon D90 | 18-55mm f/3.5-5.6 | 55-200mm f/4-5.6 | 35mm f/1.8G | 50mm f/1.8D

  3. #23

    Default Re: Advise on focusing

    Likely its because the depth of field at 1.8 is very shallow. Thats why you kit lens at f3.5 is fine. I have used that lens too and at f1.8, certain parts of the face are off focus. So, just use a larger f stop.

  4. #24
    Senior Member madmartian's Avatar
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    Default Re: Advise on focusing

    Quote Originally Posted by night86mare View Post
    .......but your kit lens generally has a smaller maximum aperture.
    Quote Originally Posted by ngodrm View Post
    Likely its because the depth of field at 1.8 is very shallow. Thats why you kit lens at f3.5 is fine. I have used that lens too and at f1.8, certain parts of the face are off focus. So, just use a larger f stop.
    Got some sense here
    Take the shot!

  5. #25
    Moderator catchlights's Avatar
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    Default Re: Advise on focusing

    Quote Originally Posted by eltonteo View Post
    Yup, I have read that multiple times. With my kit lens, no problem. But with 35mm f1.8, the face will not be sharp. Strange.
    the best way to confirm it is to do a series of test.

    set up your camera on tripod,
    stick 5 pieces of $10 note on a wall,

    ====++=================
    |.......................................|
    |... $10.................... $10.....|
    |.......................................|
    | ...............$10...................|
    |.......................................|
    |... $10.................... $10.....|
    |.......................................|
    =======================


    place your camera with tripod aim at the notes on the wall
    with a distance similar your usual distance shooting a portrait
    use center focusing point to focus any $10 note at the four corners,
    once focused, switch to manual focus
    recompose your framing to place the center $10 note at the center
    take a shot

    do a series of test with different aperture, lenses. tell us about your finding.

    nothing beats hand on
    Last edited by catchlights; 14th March 2010 at 10:02 PM.
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  6. #26
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    Default Re: Advise on focusing

    Quote Originally Posted by catchlights View Post
    the best way to confirm it is to do a series of test.

    set up your camera on tripod,
    stick 5 pieces of $10 note on a wall,

    ====++=================
    |.......................................|
    |... $10.................... $10.....|
    |.......................................|
    | ...............$10...................|
    |.......................................|
    |... $10.................... $10.....|
    |.......................................|
    =======================


    place your camera with tripod aim at the notes on the wall
    with a distance similar your usual distance shooting a portrait
    use center focusing point to focus any $10 note at the four corners,
    once focused, switch to manual focus
    recompose your framing to place the center $10 note at the center
    take a shot

    do a series of test with different aperture, lenses. tell us about your finding.

    nothing beats hand on
    Cheam.. will find a time to try it out. Thanks!
    Nikon D90 | 18-55mm f/3.5-5.6 | 55-200mm f/4-5.6 | 35mm f/1.8G | 50mm f/1.8D

  7. #27
    Senior Member madmartian's Avatar
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    Default Re: Advise on focusing

    Quote Originally Posted by eltonteo View Post
    Cheam.. will find a time to try it out. Thanks!
    Take the shot!

  8. #28
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    Default Re: Advise on focusing

    Quote Originally Posted by eltonteo View Post
    Pardon me for saying this, I know you are senior and with due respect, you probably is good in your skills. But however what you are saying is not helping at all. It is just like telling a primary 1 student to read a textbook by himself and expect him to understand fully what the text is saying. If you have no patience to share, mentor, or to impart the skills and art, it's ok. Thank you still for the time you take to reply.
    It is not about patience. I do share, mentor and impart.

    Thing is you are not listening (or reading)

    The article has been shared, and you mentioned you read. If you really read the article, the article already clearly explained why with a thin DoF, the recomposing will shift the focus plane away from your target of focus.

    Other CSers have also mentioned the same thing in their posts.

    Yet you still kept on asking if using the center AF point and recompose is the right or wrong way AFTER they showed you the article, and AFTER the other people wrote about this. *throw hands in the air*.

    Either you are not able to comprehend English, simple diagrams, or you are just stubborn in your own ways.
    Last edited by daredevil123; 14th March 2010 at 10:33 PM.

  9. #29

    Default Re: Advise on focusing

    Quote Originally Posted by eltonteo View Post
    Cheam.. will find a time to try it out. Thanks!
    Try it out. It should take 5 - 10 minutes. Surely can spare 5-10 mins?

    Thing is, photography is all about science and physics - what people do with that science and physics is sometimes labeled as 'art', but that does not change the nature of photography itself. Sometimes, it's difficult to grasp a concept or principle the first few times. I know a lot of folks never do, and I too struggle with the physics part till this day.
    Last edited by Dream Merchant; 14th March 2010 at 10:58 PM.

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    Default Re: Advise on focusing

    Quote Originally Posted by daredevil123 View Post
    It is not about patience. I do share, mentor and impart.

    Thing is you are not listening (or reading)

    The article has been shared, and you mentioned you read. If you really read the article, the article already clearly explained why with a thin DoF, the recomposing will shift the focus plane away from your target of focus.

    Other CSers have also mentioned the same thing in their posts.

    Yet you still kept on asking if using the center AF point and recompose is the right or wrong way AFTER they showed you the article, and AFTER the other people wrote about this. *throw hands in the air*.

    Either you are not able to comprehend English, simple diagrams, or you are just stubborn in your own ways.
    Thank you for your comments. I read all that was given. I guess you must be a scholar or something who had aced all your subjects when you were in school since you have such high level of comprehension? Pardon my stupidity and ignorance if that irks you. Btw, have I offended you in anyway before? You seems to be quite hostile ya? Chill it man. This is just a forum for people to post questions. Not everyone here are born geniuses.
    Last edited by eltonteo; 14th March 2010 at 11:12 PM.
    Nikon D90 | 18-55mm f/3.5-5.6 | 55-200mm f/4-5.6 | 35mm f/1.8G | 50mm f/1.8D

  11. #31
    Member LexLim's Avatar
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    Default Re: Advise on focusing

    Ahaha at least your problem only arise when you focus and recompose. Mine happens with or without recomposing due to front focus
    Nikon D60|18-55|55-200|105 f/2.5 ai|35 f/1.8|
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  12. #32
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    Default Re: Advise on focusing

    Quote Originally Posted by eltonteo View Post
    Thank you for your comments. I read all that was given. I guess you must be a scholar or something who had aced all your subjects when you were in school since you have such high level of comprehension? Pardon my stupidity and ignorance if that irks you. Btw, have I offended you in anyway before? You seems to be quite hostile ya? Chill it man. This is just a forum for people to post questions. Not everyone here are born geniuses.
    No I am not a scholar. No I do not ace all my subjects. No I did not even study university in Singapore because they say I am not good enough. And if I can understand it, anyone can.

    Thing is people already told you to select an AF point apart from the center one. What sort of comprehension do you need to understand that? And you kept on going back to the center AF point. I am not saying you are stupid. I am not saying you are ignorant. I am just saying: People already told you to try using another AF point. You could have just tried it out in your room and confirmed it right away, instead of going on and on about that center AF point.

    I am not feeling hostile. I am at peace when I type all these posts. If you prefer I add a smiley to it, sure thing. There you go. Good bye and good luck.

  13. #33

    Default Re: Advise on focusing

    Quote Originally Posted by daredevil123 View Post
    I am not feeling hostile. I am at peace when I type all these posts. If you prefer I add a smiley to it, sure thing. There you go. Good bye and good luck.
    my friend,

    the man who asks for fish, and gets it, will never learn how to fish. soon, you will understand and give up all hope, like me, and give out fish when you are in good mood, and stay away when not so good mood.

    cheers.

  14. #34

    Default Re: Advise on focusing

    Quote Originally Posted by night86mare View Post
    my friend,

    the man who asks for fish, and gets it, will never learn how to fish. soon, you will understand and give up all hope, like me, and give out fish when you are in good mood, and stay away when not so good mood.

    cheers.
    i want a fish! otoro preferably.

    TS - you need to provide us more details. otherwise all of us are like shooting in the dark.

    if you have a focusing problem, do the ruler test.

    if it is due to shallow DOF, then it can be controlled by using a smaller aperture.

    if it is hand-eye co-ordination, cut down on your alcohol.

    if it is fish you want, ask nightmare.

  15. #35
    Member driveanegg's Avatar
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    Default Re: Advise on focusing

    Oh fish ..... yumyumyum..... night86mare... may I have fish.... ???? preferbly in sashimi style.... nice nice nice nice....

    to TS, focus - recompose is not an ideal means of shooting wide open on a 35mm, depth of field is very shallow .... still if the shooting distance is far enough the depth of field may still be sufficient to keep everything in focus...

    Re-read that article more times, its the best one that has been posted regarding this topic for a while....

    Happy shooting !!!
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  16. #36
    Senior Member wildcat's Avatar
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    Default Re: Advise on focusing

    To the TS:

    I agree with most of the rest here... except for me, I don't have a problem when I focus centre and re-compose (the Nikkor AF-S 35mm f1.8 is very sharp, even with aperture opened full, for me). However for you, it seems to. The info that I am missing, and which I think is the first thing you should do, is NOT to change the plane of focus.

    Means, you aim at A, you shoot at A, so is A sharp?

    Rather than you aim at A, you shoot at B, so A is not sharp... which could be caused by a thousand and one things, but if you do this and confirm that the problem is (or is not) caused by a change in focus plane, then we can zoom in on the problem.

    Various suggestions have been given already, but I think you have problems applying them to your situation or maybe we don't get enough info about what you are really doing. Yes, it's better to teach others to fish than to give them a fish... but I find some people, need to give them fish coz no matter how hard they try, they will have problem fishing. But if people give you fish already, you still must take the fish else how else can we help?

  17. #37

    Default Re: Advise on focusing

    Personally i say give the TS a break. maybe it is a matter of explaining a couple of times and then explaining again a few more times. It seems pretty obvious he didn't get the message, even if it seems crystal clear to the more experienced ones. I know from personal experience that sometimes it can be right there in front of your nose, and yet you cannot see it. And then EUREKA.

    Anyway - i don't think its abuse, but sometimes when you are trying to help and mentor, and yet the "student" doesn't get it, it can be frustrating...

    Two sides here - Maybe it is time to check with the TS - do you get it yet?

  18. #38
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    Default Re: Advise on focusing

    Let me try to keep this simple.

    "Focus lock" which you are doing now, tells the camera and lens to stop focusing after it is supposedly in focus.

    This means that if your object is 50cm away, the lens will be locked to be sharpest for things that are 50cm away from your lens.

    This also means that if you swing your camera around and point at something else after that (extreme example), the focus will still be only 50cm away. If you have swinged your camera in such a way that the thing you want to make sharp is not 50cm away, pressing the shutter will not give you what you want.

    In your case, let's say you had focused on the eyes. Focus locked. Eyes are 50cm away when you put them in the centre. Then you moved your camera. The eyes are not in the middle of the frame anymore. The eyes are then not 50cm away from your lens, BUT the somehow the shoulders are.

    There.

  19. #39

    Default Re: Advise on focusing

    1. When you focus lock at something, focus remains well, locked. i.e focus will be set at 50cm.

    2. You recompose, subject is now of different distance to camera, another subject is in the way at 50cm.

    3. Camera focus becomes on the second subject instead of the first, since its focus has been locked at 50cm, and the other subject you want to shoot wasn't in the 50cm range.

    There. If you still don't get it after countless explanations that other CSers have offered, well, you've a couple of other options.

    1. Use a bigger f number.

    2. Experiment, now. (This would've solved your problem right from the start but 5-10minutes was apparently too much a waste of your precious time.)

    3. Just give up using that lens(or photography) altogether.

    Hostile, yes. But if you aren't willing to slowly think through what replies refer to when they're as explicit as they can be, well.. I don't know what to say.
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  20. #40

    Default Re: Advise on focusing

    Quote Originally Posted by heshanj View Post
    i also read another article (cant remember where, sorry) which disagreed with the article linked here, and said that the focus/recompose technique works like 99% of the time, and needs drastic conditions for u to get an out of focus image. it was a pretty reputable site i read this on (i think bob atkins). so im not sure wat to believe. i generally focus/recompose, and my images are pretty well in focus, but im not sure. maybe i should start changing AF points and focusing like that more
    http://www.bobatkins.com/photography...recompose.html

    this, but that's with the assumption that you don't happily recompose too much.

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