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E-M1 C-AF Lock Settings & 43 Lenses

Discussion in 'Olympus Cameras' started by tradesmith45, Jun 2, 2015.

  1. tradesmith45

    tradesmith45 Mu-43 All-Pro

    Dec 13, 2012
    Oregon
    While back posted something over at share birds reporting the struggle the E-M1 has getting & staying locked on BIF. I now have some test results to report for C-AF Lock settings & want to find out what others have found about using these.

    Share Your 43 Lens C-AF Experience So we Can All Get Better Results
    Here's some of my old post:

    I'm starting w/ perhaps the easiest C-AF issue - focus accuracy & consistency. My experience w/ the E-M1+ZD300+EC14 combo is AF accuracy during sequential shooting is erratic on both fixed & moving subjects. Do you ZD300 (or 43 lens) owners have the same experience or do I need to send mine in to Oly for service?

    Here's examples chosen because they do not have other interfering factors like a distracting background & the subject is always square in the middle of the PDAF sensor area.

    Settings C-AF, All AF targets on, Release Priority Off, C-AF Lock Off, EVF Frame Rate High, Sequential Rate 9 FPS, IS Off, SS 1/1600", Apertures F6.3 - F7.1
    I often get the 1st frame in a sequence is sharp followed by 1-3 frames that are off just a bit or the first 1-3 frames are off before getting it nailed. Dialing the aperture down to F8 does not prevent this problem for me.
    2 frames in sequence - easy to track mostly flying perpendicular to my line of sight, 1.5 Mp crops, F7.1:
    _5090075 - 2015-05-09 at 08-50-09 by tradesmith45, on Flickr

    16873780433_d55b70e753_o. _5090076 - 2015-05-09 at 08-50-09 by tradesmith45, on Flickr

    The 2 sec. later release the shutter again & nail it w/ the 1st frame:
    _5090079 - 2015-05-09 at 08-50-12by tradesmith45, on Flickr
     
  2. tradesmith45

    tradesmith45 Mu-43 All-Pro

    Dec 13, 2012
    Oregon
    Suspecting that C-AF Lock would have an impact of this kind of problem, I did some testing w/ the static resolution chart & I've logged some keeper stats for real subjects.

    On the resolution chart, shot three 3 sec. bursts in H drive w/ all 4 C-AF lock settings using the E-M1+ZD300+EC14, firmware 3, EVF frame rate High, Release Priority Off. I then looked at all the 65 images per setting for being in focus. Shooting distance was 67' outdoors & thermal turbulence was visible in the resulting images. I knew from past testing that sequential shooting in C-AF mode w/ a fixed market can lead to focus errors. Thermal turbulence among other things can cause PDAF errors. Wanted to see how C-AF Lock affects this.

    I divided the images into 3 groups - in focus, not in focus & really out of focus. Here's an example of the last category:
    18357979042_76d60973c7_o. C-AF Lock=High by tradesmith45, on Flickr

    The results I got from this Q&D test are

    C-AF Lock Setting----% Sharp------%Really Out
    Off------------------------37%------------3%
    Low-----------------------75%------------2%
    Normal--------------------20%----------15%
    High-----------------------43%----------22%


    There's certainly random error here & when using MF w/ mag view, it was hard to get more than 50% sharp results from a few tries given the turbulence. But there seems to be a pattern that suggests using C-AF Lock Low may be helpful. I've suspected that AF system on the E-M1 is much faster than the AF drive in the ZD300 & that the lens can't keep up with the camera resulting in increased focus errors. Perhaps the lowest damping setting of C-AF Lock produces a better match between the 2.

    To see if this is helpful, I've tried it in the field a few times using the same camera/lens & all AF points active. So far, clearly for slower moving subjects C-AF Lock Low has increased my keeper rate. Swimming ducks & hovering Osprey have been my subjects. But there is a caveat: I do not have a reliable way of testing if this setting reduces AF success for fast BIF w/ a bird coming directly at the camera. Please share your experience.

    Here are some keeper rate stats from several outings all while shooting HH:
    W/C-AF Lock Off - 550 Captures
    % w/ Bird Poorly Framed------% Well framed & Sharp
    --------------27% ----------------------63%

    C-AF Lock Low - 152 Captures Hovering Osprey
    ---------------25%-----------------------71%
    70 captures - Swimming Ducks
    -----------------4%-----------------------70%

    But this doesn't reveal something. W/ Lock Off, it is really common that the 2nd to 4th image in a sequence is out of focus. The out of focus captures occur later in a long sequence w/ Lock=Low.

    Hope this is helpful -:)
     
  3. Speedliner

    Speedliner Mu-43 All-Pro

    Mar 2, 2015
    Southern NJ, USA
    Rob
    I can't add any practical knowledge to this discussion though I'm very interested. I just don't have the knowledge or experience to draw from.

    One change I did make shooting a lax game last weekend was to shoot c-af in L mode rather than H as I did last time. I thought that H is very fast and after thinking about it, H seemed much faster than the 50-200 with or without the ec-14 could ever maintain and I though that could cause some wayward hunts for focus. I didn't record numbers, but I am certain that L had a higher hit rate. In fact there were very few complete misses. There were many not-quite-perfect-but-close-enough shots, but none were complete misses.

    I need to calibrate this lens and the TCs, but you may be onto something in that the older 4/3 lenses are interfered with by H speeds and hit rates will be lower than L. L is what - 6 frames per second? That seems faster than these lenses can focus on a rapidly moving object. But what do I know...
     
  4. tradesmith45

    tradesmith45 Mu-43 All-Pro

    Dec 13, 2012
    Oregon

    Thanks Speedliner. I have used both L & H modes & haven't noticed a keeper rate difference but haven't tested for that. So its just an impression. H mode was not available for C-AF w/ 43 until firmware 3 so have lots of time w/ L mode from the past.

    The actual sequential shooting rates w/ 43 lenses is significantly lower that what you select on the camera too. But that's another thing I haven't tested since v3 was installed - its is faster. I think I only saw 3-4 FPS out of the ZD 300 w. firmware 2x & L mode set to 6.

    For shooting BIF & other fast subjects, H mode is really helpful so my goal is to try to get it to work better. As you can see my keeper rate is above 50% & even by DSLR standards, that's pretty good. But all this testing is w/ subject against the sky or water. My results are not so good when shooting against a busy background & that's where something like a D4, D810 or 7DII would really make a big difference.
     
  5. tradesmith45

    tradesmith45 Mu-43 All-Pro

    Dec 13, 2012
    Oregon
    There is another value to using C-AF Lock at the slower settings.

    As everyone who has tried knows, getting & keeping a fast subject well framed is challenging w/ long FL & shooting HH. When the subject lies outside the area covered by PDAF points, the lens tries to find something to focus on. If shooting against the sky, this can lead to the lens doing a full range hunt completely blurring the subject & making it impossible to reframe it. So you loose track.

    Setting C-AF Lock to Normal or High delays the start of a full range hunt. This can make it easier to get the subject back into the frame.

    It may also help keep focus on a moving subject you've successfully acquired as it moves in front of a busy background.

    I don't have enough experience to know if these benefits are worth the loss of AF speed these setting give.
     
  6. tradesmith45

    tradesmith45 Mu-43 All-Pro

    Dec 13, 2012
    Oregon

    By the way check my post about AF calibration if you haven't. https://www.mu-43.com/threads/77008/#post-778021

    Unless you're seeing obvious AF misses w/ fixed subjects, I recommend you simply use the Default lens data & avoid calibration - it a big time eater.
     
  7. Speedliner

    Speedliner Mu-43 All-Pro

    Mar 2, 2015
    Southern NJ, USA
    Rob
    I saw that trade smith. I own FocusTune SW and plan to give it a try. Others have had luck with it. My 50-200 native and with ec-14 are ok. But with the ec-20 focus and sharpness are awful. Hoping I can tune that combo to be more useful. Could be a problem with this ec-20, but though it wouldn't hurt to try and tune it. If it helps , then tune native and ec-14 too. Tedious stuff though, but I'm determined to have 400mm though. :)
     
  8. tradesmith45

    tradesmith45 Mu-43 All-Pro

    Dec 13, 2012
    Oregon

    Yup, 400mm is my fav for most wildlife. Have owned several legacy 400s.

    Not sure the otherwise fine zoom is up to going 2x though. Have seen a comparison of a not so sharp copy +EC14 to a really sharp copy of the M.Z 75-300mm. The later was clearly better. So it will depend on your copy.

    I've been surprised how do the ZD300+EC20 combo is - really impressive. Its the best lens+2x TC I've ever seen by a wide margin.
     
  9. Speedliner

    Speedliner Mu-43 All-Pro

    Mar 2, 2015
    Southern NJ, USA
    Rob
    600mm. I can only dream....
     
  10. tradesmith45

    tradesmith45 Mu-43 All-Pro

    Dec 13, 2012
    Oregon
    Speedliner, I went to the FocusTune site. (Impressive videos there.) Which version do you have? Have you used it? Does it capture the focus adjustment camera setting data from Olympus JPGs? Couldn't find a list of supported cameras anywhere? I'd gladly pay $55 to no longer have to run up to the target & change a sticky w/ the adjustment on it for my test shots -:) I'm think FocusTune+Olympus Capture could be a very efficient combo.

    Also found a couple long DPR threads about earlier versions of FocusTune w/ the usual +- comments. I do think a couple comments are sound. It is important to test at typical shooting distances (50xFL is the usual suggestion). A lens may well have wear or manufacturing variation in parts of the AF drive system or have focus breathing that could affect results.

    But w/ long FLs, 50x makes for long shooting distances (about 65' @ 400mm) & probably being outdoors. In addition to the usual challenges of keeping a long lens from shaking, you face wind & thermal turbulence. A bunch of my testing has (due to other life demands) been done over a gravel driveway. Even with cool cloudy conditions, heat waves are obvious in my captures. I also have another location next to a building that in the morning shades the optical path but allows me to place a target at the end in full sun. Its much better & I suspect would substantially improve the accuracy of FocusTune.

     
  11. tradesmith45

    tradesmith45 Mu-43 All-Pro

    Dec 13, 2012
    Oregon
    Oops, just found the search function on their site & located this. I think I'm going to take the plunge.

    Hi ned,

    yes, EM-1 is supported in the V3.0 version being released this week. (I shoot E-M1 as one of my primary cameras :>)

    Of course the AF Adjustment is only enabled when using 43 lenses as opposed to m43. But you can measure relative sharpness of test shots done in the same session with same lens.
    Michael