Autofocus speed: Nikon 300mm f4 PF vs AF-S 300mm f2.8

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faunagraphy
faunagraphy Regular Member • Posts: 429
Autofocus speed: Nikon 300mm f4 PF vs AF-S 300mm f2.8

Hi,

I am looking for a solution for a very specific scenario - this is to use with my D500.

Lately, I've been shooting violet-green swallows at very close range - under 30 feet. I've even managed some decent BIFs with my Olympus 8mm fisheye lens, to give you some idea.

These swallows are used to me and I like the idea of shooting them when they're extremely close - anywhere from 5 feet to under 30 feet. For everything else, my Olympus E-M1 Mark ii and Olympus 300mm f4 is more than capable and gives me excellent IQ.

At these close ranges, the extremely high relative velocity of swallows makes them virtually impossible to track in the EVF (because of panning distortion). I use the focus limiter feature on the E-M1 and a red dot sight to keep up with the birds, but the results this way are hit or miss and if the subject is misfocussed (as is often the case), I get a whole sequence of shots that are out of focus. At such high speeds and close ranges, none of my current lenses can move lens elements quickly enough to retain focus.

My keeper rate for such scenarios is around 5%, but the ones I get are very sharp. For example:

Enter my D500. Theoretically, the Group AF featureshould offer a clear advantage, since it should always focus on the nearest object - e.g. focusing on the swallow if she's skimming the ground or passing by a tree. Sadly my keeper rate has been even lower than that with my Olympus, despite the fact that Olympus AF is nothing special.

So I'm blaming the lens. I used to own a 200-500, but I replaced it with a Sigma 100-400 for these reasons:

  • Carrying it made it exhausting to carry anything else.
  • Its AF is SLOOOOOW
  • I thought that the Sigma would focus faster because it is lighter and I could program focus limiting with the Sigma dock

However, I'm finding that I used to get many more keepers with my 200-500. The 200-500 won't help me in this "close and high speeds" scenario, however.

Looking at videos of focusing speeds on YouTube, I'm convinced that it's because of focusing "hesitation" (due to a small aperture) on part of the Sigma and perhaps some trouble "speaking" with the body.

Given my specific scenario, 300mm on DX would be sufficient for my needs. I need responsive AF and I've heard tons of praise for the Nikon 300mm f2.8 on this forum.

A Nikon 300 PF would allow me to carry all my other gear in the field, which I prefer, but if its AF speed is significantly slower than the f2.8, I would rather buy that instead. Used prices will be similar. I own a Canon FD 300mm f2.8 so I'm familiar with its real-life implications.

So here are my questions:

  • Is the AF of the 300mm f2.8 fast and responsive enough to help me with this demanding shooting scenario? I'm guessing yes, and I'm sure it would better than my Olympus setup with the D500.
  • Is there a difference in the AF speed / responsiveness for different AF-S versions of the f2.8? I do not need VR and would prefer the second version (non-VR) to save weight.
  • If the 3m-infinity focus limiter is enabled, is the 300mm PF close enough to the 300mm f2.8 in AF speed?
  • Is there any other lens that ($2000 used or cheaper) that could help me?

Your advice would be greatly appreciated! Thank you!

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Formerly known as 'anupamkatkar'.

 faunagraphy's gear list:faunagraphy's gear list
Olympus OM-D E-M5 Olympus PEN E-PL6 Nikon D500 Olympus E-M1 II Olympus Zuiko Digital ED 50-200mm 1:2.8-3.5 SWD +23 more
Nikon D500 Olympus E-M1
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