Tested A99ii AF performance, it was really poor, any ideas?

Started 10 months ago | Questions thread
MediaArchivist Veteran Member • Posts: 4,112
Opposite of my experience

I have had my a99ii for only a few days at this point, and have used it almost entirely for concerts. All of the musicians move at least a little, and some quite a bit and all over the stage. In general, the lighting has been quite poor for all the indoor shows. I did have an outdoor event in a stadium where it was still daylight, but it was early evening and overcast.

I used a few different modes of AF, including DMF (which is AF-S for comparison purposes). I used face detection and object tracking as well. The only lens I have used that is 100% hybrid AF compatible is the Zeiss 24/2, the rest were:

  • Sigma 50/1.4 EX
  • Sigma 35/1.4 Art
  • Minolta 85/1.4G
  • Minolta 35/1.4G
  • Minolta beercan

The Zeiss is best of the bunch for keeper ratio. Regardless of the AF settings, the lighting, or the motion of the musician; I got over a 90% keeper rate. On the other hand, the Minolta 85/1.4 was unable to AF fast enough to keep up with the action (most of the time). I used DMF and either the object tracing or face detection (not sure which) put a square around the musician's face— and turned it green when it was in focus. This allowed me to do sort of a trap focus, I get the focus "pretty close" and then when the square around the head turns green I take the shot. This worked quite well!

All of the rest of the lenses were able to keep up, the Sigma 50 and Minolta 35 in particular got me a high percentage of keepers. I had to do some MFA on my a99 for both Sigmas, I did not do any on the a99ii and I still got great results. The Sigma 35 Art hunts a bit in very low light, I am going to see if the focus limiter will help.

I used my beercan at the outdoor event, and while the camera felt a little odd with the focus motor whipping back and forth it nonetheless worked quite well. This was the best lit event of all my tests so far, but still quite happy that my 30 year old lens still has some game!

I have a lot more events coming up, and almost all are in horrible lighting conditions. I'm going to try the Sigma 70mm macro and 15mm fisheye, both are screw drive lenses. I am also going to try the 135 STF, it is a manual focus lens but I am anxious to see if the face/object tracking indicators work.

Obviously I have not been testing/using in the same environs you have been, but flailing punk rockers on a dark stage are a good enough test for me. I'll be hanging onto my a99ii

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 MediaArchivist's gear list:MediaArchivist's gear list
Sony a99 II Sony 135mm F2.8 (T4.5) STF Sony 24mm F2 SSM Carl Zeiss Distagon T* Sigma 35mm F1.4 DG HSM Art Sony Carl Zeiss Planar T* 50mm F1.4 ZA SSM +20 more
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