Recognition Sensitivity on a6700

Jigal said:

The manual is a bit more accurate.

It's a sensitivity setting. Let's assume that the camera is trying to recognize a face.

With a higher sensitivity setting it will sooner say "Yes, this is a face" and mark it as a point to focus on. With a lower setting it has to be more sure that it's really a face.

You can also see it this way: if something looks like a face it will give it a score to indicate how sure it is that it's actually a face. With a higher sensitivity it's for example enough that it's 40% sure. With a lower sensitivity it has to be 80% sure that it's a face.

With a lower sensitivity there will be less false positives (something is considered a face but it isn't a face) but also more false negatives (something is a face but not recognized as such). With a higher sensitivity there will be more false positives and less false negatives.

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DutchMM said:

Digging again into the manual, I came to the conclusion that I could force AF only in the presence of a Subject Recognition Target ("target"). This matters because of the thousands (literally) of shutter actuations I have accumulated in the past 4 summers where no target was in the frame.

If you are interested, the way to do this is:

• Have "Priority set in AF-C" to Autofocus - this prevents shutter from actuating unless the camera has focus on a target
• Assign "Subject Recognition AF" (those exact words! don't confuse with Subject Recognition in AF!) to a custom button.
• Set the subject recognition target you want, with the parameters that suit. I suggest you start with the defaults.

Having done all this, and made it work on a portrait we have hanging in the house, I set out to capture the darn swallows. But no amount of fiddling with the sensitivity and stickiness parameters makes the camera recognise my swallows before they are gone again; this appears to be the case even when the lens is at 70mm and the birds are flying quite high. It's easier to capture them against a blue sky with subject recognition OFF than against any background with recognition turned ON.

For other, slower, birds this recipe works reasonably well.

Cheers

Mike

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DutchMM said:

What's your shooting distance at the volley ball, José?

I was sitting about 8.5 paces (say: 9 metres) from the portrait. It's a print of an 18th century engraving (a portrait of my 6 great-grandmother). I got eye focus on the portrait immediately, with the lens at 70mm.

This is wikipedia's copy of the engraving.

Like you, I traded in my a6600 so I can't prove this, but I would say the eye-AF is at least as good, possibly better, than it was on the a6700, so I think you will be fine.

Cheers

Mike

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