K-1 II AF-C Real World Report
For those not on both DPR and PentaxForums
On DPR when I mentioned I got my K-1 upgraded to a K-1 II I also said I had an airshow coming up and would report back on the new AF-C.
I went through all the photos, 1249 that were relevant to AF-C performance, I tried hard to identify the issues with those that weren't perfect, I split the bad ones into these categories. 1) Motion blur due to slow shutter speeds. 2) Out of focus (miss-focus by the camera, however some are as a result of atmospheric distortion, sun glare, heat haze, smoke haze, or the camera focusing on the smoke trail) so it may not be as bad as reported if you give a pass to the camera for some of those issues. 3) Heat ripples, not an AF-C problem unless they cause the AF to miss, these were just blurry due to heat ripples. 4) Clipping, well certainly not an AF issue but a user error issue.
Initially I felt there was little to no improvement while chimping during the airshow, however most of that turned out to be motion blur slow shutter speed panning issues. Its very hard to balance shutter speed and prop blur especially when the planes aren't flying in a straight line, banking, pitching, yawing, doing crazy aerobatics all ruin slow shutter speed photos. I wanted there to be a noticeable improvement not just for Pentax's benefit or good news to the forum but also for my benefit as the upgrade wasn't cheap. I set out to concentrate on getting the best results I could but I got easily caught up in the moment and made the usual lack of concentration mistakes and I doubt my intention resulted in any skewing of the results. I used shutter speeds from 1/200th to 1/8000th sec, AF-C, AF Hold off and low, Expanded area 9 and 25, focus priority (not that it works), A wide range of ISOs and Apertures, the Sigma 100-300mm F4.0 and Sigma 500mm F4.5 both with and without the Sigma 1.4x TC. I also hadn't been to an airshow in over a year, I missed last year as other things came up.
In the past I figured I'd average 40-60% keepers at an airshow, this didn't isolate just the miss-focus issues but all issues that related in a deletion.
410 of the 1249 photos were deemed delete worthy in the previously mentioned categories (32.8%) so already a bit better than previous years. 16.7% were a result of the camera missing focus, 10.8% were a result of motion blur, 3.4% a result of heat ripples and just 1.8% a result of user error frame clipping.
At just 16.7% miss-focus I have to say I'm pretty happy with the K-1 II, thats about 1 in 6 photos where the camera missed. assuming the ratios are similar for each show over a broad average one could suggest that the camera performed at least 12% better then the estimated best from the original K-1, and possibly 34% or more better.
Its no Canon or Nikon that might miss 1 in 10 or 1 in 20 but its good enough at 1 in 6 being a miss.
Here are a few points I figured I'd share from this exercise, some mentioned above
- Most OOF photos come at the beginning of a burst
- As always if focus isn't ideally acquired on the first shot of a burst it can ruin the rest of them
- Sometimes the camera figures it out and re-acquires lock
- Sometimes the camera looses focus despite having it in the first place
- Sometimes its hard to figure whether the item was out of focus or just had too much atmosphere in the way. The further the subject the greater its chance of appearing out of focus, that too could be as a result of too much atmosphere, It wouldn't be a worthy photo anyways
- The camera did well with an F18 jet coming in fast straight towards me with the sigma 500mm F4.5 until the last shot
- typical things like loss of contrast (shooting very close to the sun) would help the camera lose focus
- I did keep some slightly out of focus photos
- I did keep some slightly motion blurred photos
- Smoke haze contributed to some out of focus results
- On a few occasion the trailing smoke is what the camera preferred to lock onto
- Sometimes Out of focus shots were a result of heat haze or atmospheric distortion, even though listed as out of focus its hard to fault the camera on those
- Of course if the plane went outside the focus point area the camera would drop focus
The photos of this event will come in time, they've yet to be edited.
Final thoughts, airshows aren't the be-all and end-all of AF tracking, far from it. I did find out there was an improvement but to what degree will be user and subject dependent. I suppose YMMV. However my results seem to be in line in some degree with all the other reviews saying AF-C is mildly but noticeably improved. These AF improvements will not compensate for sloppy photography so don't think you won't have to keep working at it to get the best out of it. Its up to you to determine if this improvement is worth the money or not. I'm happy as I'll take any improvement I can get without having to switch systems or spend a fortune. I'm going to try to get out and shoot some terns in flight, some footie and there is another airshow coming up too, I doubt I'll give as detailed a report from them but I probably will comment on any noticeable difference over my experience with the K-1.
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