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AF troubles: X-T2 & XF100-400

Discussion in 'X-T2, X-T1, X-T20, X-T10' started by pipetman, Apr 18, 2017 at 10:11 PM.

  1. pipetman

    pipetman Premium Member

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    Yesterday, I went to the Boston Marathon to get some close-up shots of the runners with my X-T2 and the XF100-400 + 1.4 extender. I had the camera/lens on a tripod with a fluid head for smooth panning. I set the camera to CL and used AF-C mode with zone focusing in preset 1 (seemed most applicable here). OIS on the lens was left ON. After a bit of back and forth, I settled on fully manual exposure control with the apperture wide open (between 7.2 - 8 with the focal length kept between ~400 - 560mm most of the time), exposure time of 1/1000 and varying the ISO depending on light (usually around 1000 give or take a stop).

    With these settings, I would lock focus on to a runner at about 50ft away, pan and take shots in shorts bursts (3 images at a time, sometimes more) with the runner about 20 - 30ft away. But while the focus squares indicated a good lock on runners, the vast majority of my shots turned out not very sharp.There are only a handful that are ok in that regard. Here two examples of good and not so good focus at 100%:

    DSCF6171_crop.JPG
    DSCF6206_crop.JPG

    Given the above mentioned settings, I was expecting much better results and now I wonder where the culprit lies? Do I need better technique/settings? Am I asking too much of the system? Some advice would be greatly appreciated.

    P.S.: While most of the images are not tack sharp, the full images still look halfway ok on a monitor, especially when converted to a gritty B&W look. I might post a few later this week.
     
  2. Woodlink

    Woodlink Premium Member

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    turn off the OIS

    increase shutter speed to 1/2000
     
    Fujiphotog likes this.
  3. Richard_R

    Richard_R Eclectic eccentric

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    Agree about OIS. It should not have been on at those shutter speeds regardless of whether the camera was tripod mounted or not. All it does in situations like this is slow focus acquisition down.
     
  4. Fujiphotog

    Fujiphotog Amateur photographer.

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    Woodlink's suggestions are good ones, and may make the focussing a lot better. But you may also be expecting too much if you think that any AF system can focus sharply on the eye of a runner at that with a long tele lens and tele extender. The camera may be focussing a bit ahead of or behind the eye. The green focussing squares are probably not small enough to focus on the eye at that distance .
     
  5. ojporqpojrewpo

    ojporqpojrewpo Premium Member

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    I would agree about the shutter speed. I get best results with this lens at about 1/2000.
     
  6. pipetman

    pipetman Premium Member

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    Thanks for the advice. I inquired here about the OIS issue a short while ago and the consensus at the time seemed to be that it doesn't make too much of a difference and if using a ball or fluid head, it might be left on. Seems like, that might be the main culprit, though. Also, I'm surprised that shutter speeds of 1/2000 might be required - something I'll definitely try next time.
    With regards to the eyes being specifically in focus, that was not the goal here, I just picked them out as an area of interest. The shots that were in focus actually had the entire face is in focus (what I was aiming for) and where it was slightly out of focus, it was so pretty evenly across the entire face.
     
  7. jecottrell

    jecottrell Member

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    It's impossible to determine the problem with the information provided. The only way to start is with better data. Several RAF files from the problem images will help. That will allow inspection to see if it's motion blur or missed focus(front/back).
     
  8. ojporqpojrewpo

    ojporqpojrewpo Premium Member

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    You may not need 1/2000 but I find it easier to work my way back from something that works. At the last airshow I went to really high ISO and fast shutter speeds and for really sharp pictures. Then I worked my way down to shutter speeds that worked. With jets i can see a difference between 1/1500 and 1/2000. Now I have a baseline to experiment.
     
  9. pipetman

    pipetman Premium Member

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    Good point. Had to dig around a bit for the review of focus points, There seems to be an obscure LR plugin, but I don't use LR. Then I simply checked some focus points in the camera review mode and they were all firmly placed somewhere in the face and the focus point area exhibited focus blur (like the rest of the face). So OIS or exposure time seem to be the most likely culprits.
     
  10. Aphotographer

    Aphotographer Active Member

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    These were moving subjects, correct? They may have moved out of focus faster than the AF could compensate.
     
  11. bobbyzfx

    bobbyzfx Premium Member

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    1. Loose the TC. I would never use a TC unless it is 300/400mm f2.8 for action. Even then they slow down AF and this on canon 1 series. Not sure why folks so bent on using them on slow f5.6 glass when shooting action.
    2. Agree with other about IS but why tripod, pan. Shoot HH and less problems.
    3. Use CH mode
    4. And make sure PDAF points only.
     
  12. MikeHuff

    MikeHuff Member

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    I saw similar results when I rented this lens a while back to use on my X-Pro2. I was super frustrated with the results after viewing them on my computer. I had seen countless great results from the lens/body combo, but in the end I chalked it up as a bad lens and lost no more than the rental fee.

    Fast forward a bit, and on another forum I started seeing a lot of reports of this kind of result. Completely contrary to what we knew was possible. In the end a contributor determined that the IS mode made all the difference in the world. I presume the modes to be the same, but on the XP2 there is a menu setting for mode 1 or mode 2. One os for "continuous" IS, the other for "shooting only" IS . The default is continuous. Changing to mode 2, shooting only, produced the results everyone knew were possible.

    Fairly recently I decided to purchase this lens and try again. I figured if the tests I had seen were accurate I would get the results I was expecting. So far so good. I changed the mode to "shooting only" and have had good results. I've not seen an image with the ugly out of focus/strangeness that I had seen with the rental. I've not done enough testing to make the determination 100% but it is leaning that way.

    Oddly, I don't see any of this with the 50-140. That lens has produced great images from the first click I made with it. In the end however, with the sports and long lens work I like to do, I may end up keeping the Canon big guns instead. I really want this system to replace the Canons, but so far I simply cannot get the same results when it comes to moving objects and long glass. Time will tell for me .
     
  13. Macmodus

    Macmodus Premium Member

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    My experienc in any case, by following setting.

    ISO AUTO SETTING /MIN. SHUTTER SPEED >> not use the the AUTO setting!
    That does not work with the XF100-400, at least not good enough!
     
  14. Shootingstar100660

    Shootingstar100660 Member

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    Yep, increase the shutter speed. In the old film days, I was always taught that 250-1000th is the way to freeze a moving subject with a "standard" lens. If you magnify the image several times with a tele, you will need to "magnify" the shutter speed accordingly. At these focal lengths, a stationary subject will require a 1000th, for moving subjects, you will need probably 4000th minimum.
     
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  15. 5280Pics

    5280Pics Well-Known Member

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    How much of a crop are you adding, to the images to posted? I'd like to see the full size images.
     
  16. DanGleabols

    DanGleabols Well-Known Member

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    I don't think it's been mentioned; but did you have face detection on?
     

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