Advice on focus issue

Discussion in 'Photographic Technique' started by Blurwi, Jun 13, 2017.

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  1. Blurwi

    Blurwi New Member Site Supporter

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    Canon T6
    EF-S 18.55mm f3.5-5.6 IS II
    EF-S 55-250mm f4-5.6 IS STM
    Minolta Auto 320 External Flash
    Cactus V5 Wireless Trigger
    Hi all, I have a problem with my T6 and 55+250mm f4-5.6 IS STM lens. I acquire (or think I have) focus lock and even though the photos show the focus square is on the face of the Turkey Vulture the photo is blurred. IS is on and I am in AI servo with center weighted focus. The first photo Capture.jpg was taken at TV/1,000,AV/9,ISO 125 and 250mm. The second photo Capture2.jpg was taken at TV/1,250,AV/5.6,ISO160 250mm. I would appreciate any help.
     

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  2. Robert Shears

    Robert Shears Member Site Supporter

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    Various OEM and 3rd party lenses in Pentax, Minolta and Canon.
    I do not have an answer for you but a question, were you panning the shot of the Turkey Vulture?
    Maybe panning with this lens is a problem. I had a 70-300mm lens where the IS could be set to pan when shooting, never used it but presumably there is a difference to not panning.
    At the speeds you are using you could try upping them a bit (by using a higher ISO) and shoot with the IS off and see what you get.
    Sorry it is not much help but I'm sure someone here will be more help.
     
  3. pcake

    pcake Member Site Supporter

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    55-250 STM
    18-55 STM
    Yongnuo 50mm 1.8
    do you have links to the full sized, unedited pics?

    i use that same lens for my birds in flight, and it seems to work well for me. btw, i always pan with IS on with every camera and lens i've used with no issues.
     
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  4. johnsey

    johnsey Moderator Staff Member Site Supporter

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    5dMk2, 20D, 70-200 2.8 L IS, 100mm Macro, 50m 1.4, 85mm 1.8, 17-40mm 4.0 L, Rokinon 14mm 2.8; Pixma Pro-100
    Did you receive a focus confirmation beep? You also have cropped in quite a bit so the bird must have been quite small on the original image (the pixels and fringing are starting to show). Based on a rough estimate of what the original image size probably was, you may be just experiencing issues with the lens tracking focus on a small object. The lens may also be back focusing on the camera. (it is not uncommon for a lens to come slightly back or front focused. You can look up online how to test this.

    I think the first thing to do is do some more testing to make sure its tracking larger moving objects properly.
    For achieving focus the one thing to add to what Robert suggested is to make sure to track with the bird and get the focus beep and fire off a series while holding down the shutter and tracking birds flight. That will help with obtaining some of the images in focus when you are tracking a moving object. You may also want to consider a longer lens or adding a tele-converter if you want to get closer to birds.
     
  5. pcake

    pcake Member Site Supporter

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    Canon SL1
    55-250 STM
    18-55 STM
    Yongnuo 50mm 1.8
    my first guess was the bird was maybe very small in the frame and had been upsized too much, causing the loss of sharpness.
     
  6. Blurwi

    Blurwi New Member Site Supporter

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    Location:
    Niagara Falls Ontario Canada
    Equipment:
    Canon T6
    EF-S 18.55mm f3.5-5.6 IS II
    EF-S 55-250mm f4-5.6 IS STM
    Minolta Auto 320 External Flash
    Cactus V5 Wireless Trigger
    Thank you for all your replies. The two photos posted where cropped but not severely. I have my ISO on auto and I use manual mode with AF on. What is puzzling is that I get the beep and the green light and in Canon's digital photo professional it showed the focus point right on the head but yet there slightly out of focus,
     
  7. Alice Bell

    Alice Bell New Member

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    I'm not sure I can help you with this struggle, but when I have some focus or else issues, I always consult FixThePhoto website, it's really useful one, totally recommend you)
     
  8. dmr

    dmr Member Site Supporter

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    I googled FixThePhoto and all I get are commercial sites offering paid photo retouching and such.
     
  9. pcake

    pcake Member Site Supporter

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    55-250 STM
    18-55 STM
    Yongnuo 50mm 1.8
    to the OP, you never did post any full sized versions of the pics. any chance you can do so?
     
  10. JimmyDranox

    JimmyDranox Member Site Supporter

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    I don't know a straight answer, but I can make some quess work.

    First, the image stabilization need a little time to act. About a half of a second, or so. And with many lenses, first is a very short movement in the image, and then the image became stabilized.
    There is also an question if IS is working or not. I have another STM lens, the 18-135, and there is no indicator in the camera to show if iS is working. Only if I am attentive, I can see the effects in the view finder.
    Another hypothesis is a descentrelized element inside the lens. You can try to test it on a tripod. With/out IS, and with/out AF, to see if you can get a sharp image or not..
     
  11. pcake

    pcake Member Site Supporter

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    Yongnuo 50mm 1.8
    i dunno - at 1/1250th of a second, not sure if IS is needed. i'm still wondering how deeply this image was cropped.

    could also be that the bird moved out of focus after focus confirmation and for some reason the camera wasn't able to track it.
     
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  12. Weetbix

    Weetbix New Member Site Supporter

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    there is nothing wrong with the auto focus of your camera, maybe your expectations of what your camera and lens combo should do is a little on the unrealistic side

    if i were to go by the size of those crops at a guess i would say that the birds only filled 1/30th of the frame on the original image

    my advice is if it doesn't full at least 1/8 of your viewfinder your not close enough or have the wrong equipment (no camouflage or teleconverter)
     

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