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Thread: HELP needed to check the lens focus & pic sharpness

  1. #1

    Default HELP needed to check the lens focus & pic sharpness

    I am bit worry if my lens (bought 2nd hand) is in perfect shape for focusing.
    Calling for any pro photogr. to check my camera+lens to see if everything is fine.
    Bought my Canon 40D few months ago as a new and later 24-70mm f/2.8L (2nd hand)
    Just want to make sure equipments are doing they best and confirm the problem is behind the button.

    Even try with many diff settings I find I cannot get very sharp pics what I was expecting.

    I know there are some tests available in internet, but I am bit lack of time and do not own tripod. So if anyone can help on this it will be appreciated with some kopi money too :-)

    I want to check this before sending the camera+lens for calibration.

    Anyone wanna earn some easy money?
    Call&sms me 98233122/Tom

  2. #2
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    Default Re: HELP needed to check the lens focus & pic sharpness

    I'm not pro, so I don't qualify.

  3. #3
    Moderator ziploc's Avatar
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    Default Re: HELP needed to check the lens focus & pic sharpness

    My suggestion is just perform some simple ruler tests:

    1. Place a ruler on top of a piece of news paper on a table in a well lit area.
    2. Make sure that the shutter speed is sufficiently fast (1/focal length or greater).
    3. Hold your camera near the ruler. Make sure minimum focusing distance or greater is attained. You can rest your elbows on the table to provide better support.
    4. Start testing by focusing at a selected mark on the ruler and take a shot.
    5. Refocus by focusing your lens to some objects far away, and repeat the test from steps 4-5 until satisfied.

    You will be able to find out whether there are any focusing problems (front/back focus, etc) with your camera + lens combination by looking at the test shots.

    And last but not least,
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    I'll send you the bill for providing the above test procedures.
    Last edited by ziploc; 3rd October 2008 at 12:19 PM.

  4. #4
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    Default Re: HELP needed to check the lens focus & pic sharpness

    Actually, why not just upload a handful of your images for us to see.

  5. #5

    Default Re: HELP needed to check the lens focus & pic sharpness

    I could do that, thanks guys. What dpi resolution I should use to resize the image so that sharpness doesn't get too effected?
    Resize should be max 800 width I assume. Can I posted here so you guys can have a look?

  6. #6
    Senior Member Override2Zion's Avatar
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    Default Re: HELP needed to check the lens focus & pic sharpness

    Quote Originally Posted by Teekoo View Post
    I could do that, thanks guys. What dpi resolution I should use to resize the image so that sharpness doesn't get too effected?
    Resize should be max 800 width I assume. Can I posted here so you guys can have a look?
    Perhaps you shouldn't resize? You could just crop and post the small area with the interesting details. Shooting a ruler is a good idea, shoot roughly at the 45 degrees angle.
    Last edited by Override2Zion; 3rd October 2008 at 01:21 PM.
    Nikon D200/D700/D800 User :)
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    Default Re: HELP needed to check the lens focus & pic sharpness

    Quote Originally Posted by Teekoo View Post
    I could do that, thanks guys. What dpi resolution I should use to resize the image so that sharpness doesn't get too effected?
    Resize should be max 800 width I assume. Can I posted here so you guys can have a look?
    Quote Originally Posted by Override2Zion View Post
    Perhaps you shouldn't resize? You could just crop and post the small area with the interesting details. Shooting a ruler is a good idea, shoot roughly at the 45 degrees angle.
    Actually, just any picture will do. Seeing a lens in everyday use should be good enough to tell whether there is any optical flaw, or whether problem lies behind viewfinder, but do post a 100% crop of perhaps the center portion.

  8. #8

    Default Re: HELP needed to check the lens focus & pic sharpness

    I have downloaded some shots in Flickr, please have a look. In the small size they looks pretty sharp, but if you downloaded and zoom it, you might see the difference... These are strait from the camera without any C&C... Please note some pics have too much light, just tried to get more sharp doing that (Exp +1 2/3) ... It was claudy day, I have added setting in the comment section under the pics.
    Feel free to comment, appreciated.

    http://www.flickr.com/photos/31073040@N04/

  9. #9
    Moderator ziploc's Avatar
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    Default Re: HELP needed to check the lens focus & pic sharpness

    Eh, nothing wrong with your photos in terms of sharpness.

  10. #10
    Senior Member Kit's Avatar
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    Default Re: HELP needed to check the lens focus & pic sharpness

    All your shots looked fine except for the 1st one withe the brick structure and that was shot with 1/15th shutter speed, others were shot with much faster speed. Its probably your hands shaking.

  11. #11
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    Default Re: HELP needed to check the lens focus & pic sharpness

    Quote Originally Posted by Teekoo View Post
    I have downloaded some shots in Flickr, please have a look. In the small size they looks pretty sharp, but if you downloaded and zoom it, you might see the difference... These are strait from the camera without any C&C... Please note some pics have too much light, just tried to get more sharp doing that (Exp +1 2/3) ... It was claudy day, I have added setting in the comment section under the pics.
    Feel free to comment, appreciated.

    http://www.flickr.com/photos/31073040@N04/
    Seems that nothing's wrong... But to make sure, download this focusing test chart, and make sure you have no back or front focusing problem.

    Was the JPG straight from the camera? It is better to check the sharpness on the RAW files since jpg was actually compressed and lost the original characteristic of the image.

    Btw, adding exposure will not increase the sharpness.
    Achetez ce que vous souhaitez, pas ce que vous voulez...

  12. #12

    Default Re: HELP needed to check the lens focus & pic sharpness

    Thanks All for the comments! I will try to test according to the instruction. I just need to get a tripod 1st. I do have RAW files available if someone wanna take a closer look of the images. Just PM me your email, I will send it to you.
    I find if I zoom out 200% from the RAW i can see some blur there but it might be already in the limit. Maybe it is just the lens what soften some of the images too, as some of the shooters prefers that as well. After seen those nice shots in the forum etc. I came across this feeling, but of course most of the shots are C&C what you see what are published. Waiting for good sunny day to shoot more and also test some other lenses...

    Brick shot I took in purpose with slow shutter to get more deep focus on the pic with high aperture.
    Next lenses will be either 50mm 1.2L or 85mm 1.2L and 70-200mm 2.8L... just need some cash 1st... :-)
    Later 5D or higher....

  13. #13
    Senior Member Kit's Avatar
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    Default Re: HELP needed to check the lens focus & pic sharpness

    Quote Originally Posted by Teekoo View Post
    I find if I zoom out 200% from the RAW i can see some blur there but it might be already in the limit.
    and the mystery solved. You zoomed in at 200%, what were you expecting???

  14. #14

    Default Re: HELP needed to check the lens focus & pic sharpness

    zoom 200%, to be honest, don't know what I was expecting :-)
    Like said I just came across this after seen so many beautiful shots and thought I wanna get a good camera to get the same!
    But after shooting some with a semi-pro camera and pro lens, i thought it might be just me, or lens problem :-)
    Looks like a editing is a key thing for digital photos, not always necessary but let say in decent conditions.

    Understood that fixed focal lenses gives a bit better color saturation, is that right?
    Maybe future considering more fixed lenses too...

  15. #15
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    Default Re: HELP needed to check the lens focus & pic sharpness

    When you view the "wonderful images" taken by a pro, I don't think you view them at 200% do you?

  16. #16

    Default Re: HELP needed to check the lens focus & pic sharpness

    Quote Originally Posted by calebk View Post
    When you view the "wonderful images" taken by a pro, I don't think you view them at 200% do you?
    You are rite, No :-)

    Is there any posts in this forum, where are only pics from strait from the camera without C&C or any editing. Just courious to see the real ones...

  17. #17
    Moderator Octarine's Avatar
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    Default Re: HELP needed to check the lens focus & pic sharpness

    Quote Originally Posted by Teekoo View Post
    zoom 200%, to be honest, don't know what I was expecting :-)
    Not even a 1DmIII will give you a sharp picture when you zoom at 200% - that's simply beyond the resolution.
    Quote Originally Posted by Teekoo View Post
    Looks like a editing is a key thing for digital photos, not always necessary but let say in decent conditions.
    Post-processing is still essential as it was for the old film days. No post-processing - no pictures. The difference now is just the media and the fact that cameras do already post-processing internally by converting RAW to JPG. If you like the results it's fine, but most people want to do additional things.
    Quote Originally Posted by Teekoo View Post
    Understood that fixed focal lenses gives a bit better color saturation, is that right? Maybe future considering more fixed lenses too...
    Saturation can be changed in post-processing, why do you want to spend lots of money for things that can be done with a few mouse clicks? Of course, the lens should not degrade the information in the first place. Prime lens have their advantages and characteristics. But I don't think you need to spend too much time and money on that topic - yet.

  18. #18
    Senior Member Kit's Avatar
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    Default Re: HELP needed to check the lens focus & pic sharpness

    Quote Originally Posted by Teekoo View Post
    zoom 200%, to be honest, don't know what I was expecting :-)
    Like said I just came across this after seen so many beautiful shots and thought I wanna get a good camera to get the same!
    But after shooting some with a semi-pro camera and pro lens, i thought it might be just me, or lens problem :-)
    Looks like a editing is a key thing for digital photos, not always necessary but let say in decent conditions.

    Understood that fixed focal lenses gives a bit better color saturation, is that right?
    Maybe future considering more fixed lenses too...
    Post editing is always a necessacity in a photographer's workflow. Some may think otherwise but that's another issue altogether.

    There are a lot of factors governing colours. Sure, some lenses will give you better colour rendition but that's not the only thing to consider when you buy lenses. Learning how to read the light and how your subjects behave under different lighting conditions is just as important. If you are presented with a condition which simply doesn't cast quality light on your subjects, then no lens can help.

  19. #19
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    Default Re: HELP needed to check the lens focus & pic sharpness

    Quote Originally Posted by Teekoo View Post
    You are rite, No :-)

    Is there any posts in this forum, where are only pics from strait from the camera without C&C or any editing. Just courious to see the real ones...
    If you think pictures straight from camera are any more real than post-processed ones, you are sadly mistaken. The camera does processing too, right from the time the light hits the sensor to the time it is saved onto your memory card.

  20. #20

    Default Re: HELP needed to check the lens focus & pic sharpness

    Saturation can be changed in post-processing, why do you want to spend lots of money for things that can be done with a few mouse clicks? Of course, the lens should not degrade the information in the first place. Prime lens have their advantages and characteristics. But I don't think you need to spend too much time and money on that topic - yet.[/QUOTE]

    Thanks for the comments and advice, I think you are very right, but some of the things cannot be explained rationally :-) E.g. buy a exp. car in singapore with the 500Hp, it is kinda of thing, nice to have, even not really needed :-) or if your wife want to get LV or Gucci bags, no point right, but it is necessary to have louder exhaust pipe in your car or motorcycle what cost the same, but that is needed hehe :-)

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