Focus tracking

Started 2 months ago | Questions thread
KentG Veteran Member • Posts: 4,577
Re: Focus tracking

A lot depends on how smart and fast the processor is in the camera. This falls under both predictive-AF and the panning skills of the shooter. The more focus points you enable, the more the processor has to watch, and the slower it will respond to change. Pretty much each camera, regardless of brand, has a limit. The old PZ-1p with its 1 AF point was actually not bad at shooting with panning. Not as good as the Minolta Maxxum 9 I used for motorsports at the time which had 3 AF points and the smarts to successfully follow cars moving and changing aspect ratios close to 200MPH (It actually did 168 MPH once when I happened to have a crew member from Roush with a radar gun standing right next to me). I have found that most digital cameras have a hard times going as fast as the last few series of professional film cameras. The point is the fewer AF points you allow it to use the more time it can devote to figuring things out. So the better the panning skills the fewer AF points you can get away with having to use. BIF is generally much easier for the camera than race cars.

Art Morris, one of the best bird shooters there is, used to teach that the maximum lens you could easily use for BIF with a FF (film) camera is 400mm F5.6. Because the scale of the image in the VF determines how much real-estate you have to deal with to keep the bird on the AF points. Too little magnification and you will need to blow the image up, too much magnification and its hard to keep the bird centered on the AF point (s). For APS-C the equivalent view due to the "crop factor" is, as it happens, about 300mm. Which is one reason why Pentax never offered anything above 300mm F4 in the APS-C era. I hear people all the time saying "I need to get closer" or "I need more magnification". That's fine but if you do you need to accept a lower number of keepers. Doesn't apply if they are not moving of course. I could use my K-1 and 150-450 zoom, but at my age I can't move the combo as fast as a lighter one. So when I want to get above 50% keepers I use my Canon 60D and Sigma 100-300/4 zoom with or without a 1.4x TC on it (Canon 1.4x II). Which is why I took that only to Daytona for the Rolex 24 in 2017 when I was invited down.

To get the maximum number of keepers you have to balance all the factors. And be realistic to boot.

 KentG's gear list:KentG's gear list
Pentax K-5 IIs Pentax K-S1 Pentax K-1 Pentax smc D-FA 50mm F2.8 Macro Pentax FA 150-450mm F4.5-5.6 +3 more
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