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05-23-2022, 07:37 PM - 1 Like   #1
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My experience shooting with the Mk III and 55-300 PLM using Hold AF Status

After reading a member's remarks about using 'Hold AF Status' shooting birds in flight, I decided to try using 'Hold AF Status' to shoot landing commercial, private and military aircraft. The approach speeds of these aircraft were in the 100 to 140 mph range. My settings were TAV, f/8.0, shutter speeds either 1/320sec or 1/1,000/sec, Expanded Area Large, Continuous AF High, Hold AF Status either High or Medium. Out of 424 images not a single one of them was as sharply focused as I have been accustomed to with the Mk III 55-300 PLM combo. So my opinion is that with 'Hold AF Status' on, the camera is always "behind" the target a small amount resulting in not totally out of focus images but soft focused images that lack fine details. I'm still going through the images and I will post a couple along with a couple from my previous outing for comparison.

Has any one else had a satisfying experience using 'Hold AF Status' while shooting aircraft?

05-23-2022, 10:47 PM - 2 Likes   #2
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QuoteOriginally posted by Larrymc Quote
So my opinion is that with 'Hold AF Status' on, the camera is always "behind" the target a small amount resulting in not totally out of focus images but soft focused images that lack fine details.
If this is the same as in the K1, I can tell that AF hold is suitable when subject motion is transverse (X, Y), across the frame. And AF hold should be set to zero (OFF) when the subject is moving towards or away from the camera (Z axis). And if you set the camera to FPS priority, AF hold get in the way to acquire the first frame in focus. So, if AF should be "sticky", AFC should be set to first frame in focus priority with some amount of AF hold depending is the subject motion is fully or partially transverse.
05-24-2022, 03:48 AM - 1 Like   #3
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AF Hold is far more appropriate for objects moving in and out of view. I do generally keep mine on Low, and it does pretty well, except in the cases that Biz mentions: The subject moving quickly towards or away from me.

It makes perfect sense since the Hold setting is meant to keep focus at a set subject distance until it moves out of the focus zone enough to force a change. Perfect for a flying bird momentarily disappearing behind a bush, not so much for a jet flying towards me.

Last edited by gatorguy; 05-24-2022 at 01:07 PM.
05-24-2022, 04:17 AM   #4
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As guys said above - system needs to know that something changed and it uses AF points coverage change for this. With plane moving toward you it changes when it grows bigger or moves due to your movement or wind etc. Unless it happens there will be no change in AF and in your case there will be always slight backfocus.


From my experience when photographing planes during landing it is best to use AF-S, not AF-C. And with center point AF or SEL-21 and focusing tied to shutter button depending on how the runway looks from your position. You press, lens acquires focus, shutter is released. It works very well even with screwdriver lenses. Unless you need FPS rate for whatever reason, then what Biz said will work.

05-24-2022, 05:18 AM   #5
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I wonder if an outing was for consistent incoming flight if one could adjust the fine focus to be front focused to compensate.

It would be a pain to set up each time and I would be sure to forget to switch it back.
It would make an interesting user mode to change fine focus.
05-24-2022, 11:58 AM - 1 Like   #6
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QuoteOriginally posted by Larrymc Quote
After reading a member's remarks about using 'Hold AF Status' shooting birds in flight, I decided to try using 'Hold AF Status' to shoot landing commercial, private and military aircraft. The approach speeds of these aircraft were in the 100 to 140 mph range. My settings were TAV, f/8.0, shutter speeds either 1/320sec or 1/1,000/sec, Expanded Area Large, Continuous AF High, Hold AF Status either High or Medium. Out of 424 images not a single one of them was as sharply focused as I have been accustomed to with the Mk III 55-300 PLM combo. So my opinion is that with 'Hold AF Status' on, the camera is always "behind" the target a small amount resulting in not totally out of focus images but soft focused images that lack fine details. I'm still going through the images and I will post a couple along with a couple from my previous outing for comparison.

Has any one else had a satisfying experience using 'Hold AF Status' while shooting aircraft?
Exactly. I use my 150-450mm lens with my K-3III almost exclusively for airplane photography and I have exactly the same experience. "Hold AF Status on" does not work at all. Images are mostly soft at all common F-stops (around F8). No problems with AF-C when it is set to off.
05-24-2022, 07:02 PM   #7
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QuoteOriginally posted by jersey Quote
As guys said above - system needs to know that something changed and it uses AF points coverage change for this. With plane moving toward you it changes when it grows bigger or moves due to your movement or wind etc. Unless it happens there will be no change in AF and in your case there will be always slight backfocus.
You kind of lost me with that dissertation. What I was doing was testing the Hold AF Status technique that another member had posted for birds in flight. I wasn't advocating using the technique just reporting my findings track and shooting relatively high performance aircraft doing approaches.


QuoteOriginally posted by jersey Quote
From my experience when photographing planes during landing it is best to use AF-S, not AF-C. And with center point AF or SEL-21 and focusing tied to shutter button depending on how the runway looks from your position. You press, lens acquires focus, shutter is released. It works very well even with screwdriver lenses. Unless you need FPS rate for whatever reason, then what Biz said will work.
If you are shooting with a Mk III you are under utilizing the capabilities of the system but, whatever technique works for you, I prefer tracking an inbound aircraft in AF-C and shooting short bursts then "bumping the focus" and shooting more short bursts. I usually start my tracking with the aircraft somewhere outside of 600 meters and track it all the way to touchdown. The Mk III is very capable of doing this even with screwdrive lens

05-24-2022, 07:13 PM   #8
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QuoteOriginally posted by biz-engineer Quote
If this is the same as in the K1, I can tell that AF hold is suitable when subject motion is transverse (X, Y), across the frame. And AF hold should be set to zero (OFF) when the subject is moving towards or away from the camera (Z axis). And if you set the camera to FPS priority, AF hold get in the way to acquire the first frame in focus. So, if AF should be "sticky", AFC should be set to first frame in focus priority with some amount of AF hold depending is the subject motion is fully or partially transverse.
I find that Hold AF Status when photographing aircraft in the X, Y axis the focus is always behind the aircraft Therefore always a little soft focused even though in theory the focal distance changes very little when photographing an aircraft in straight an level flight. I never use Frames per second as my first frame action in AF-C.
05-24-2022, 07:47 PM   #9
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Series of shots using AF-C and not using Hold AF status.

Here are a few shots with crops of a USAF T-1 Jayhawk shooting an approach. There were 46 shots in the continuous sequence. The initial capture was from well over 500 meters away with the aircraft approaching at an angle. Shutter Speed 1/1000 sec, Aperture value f/7.1, ISO 200, Hold AF Status off, Drive Mode Medium, Autofocus EX S Continuous.
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