The future of Pentax PDAF

Mark Ransom said:

You don't need prediction. If you can get full readout of the sensor at the display rate, you can save that readout in a buffer. Then when you press the shutter button, instead of exposing the sensor again you just use what is saved. You don't eliminate the lag, but you make it irrelevant.

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You need the prediction to eliminate the exposure time.

Roland Karlsson said:

Mark Ransom said:

You don't need prediction. If you can get full readout of the sensor at the display rate, you can save that readout in a buffer. Then when you press the shutter button, instead of exposing the sensor again you just use what is saved. You don't eliminate the lag, but you make it irrelevant.

Click to expand...

You need the prediction to eliminate the exposure time.

Click to expand...

There is a finite lag time within the brain as the image is processed into something one can experience as well. At best it is a close approximation of reality running slightly in the past. ;-)

Roland Karlsson said:

--
/Roland
Kalpanika X3F tools:
https://github.com/kalpanika/x3f

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Petroglyph said:

Petroglyph said:

You need the prediction to eliminate the exposure time.

Click to expand...

There is a finite lag time within the brain as the image is processed into something one can experience as well. At best it is a close approximation of reality running slightly in the past. ;-)

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Yes, but that lag we are used to. So - our brain can compensate. Otherwise we would e.g. have problems catching a ball in low light, where this lag is greater.

The extra lag we get by the exposure, in the camera, is a totally other thing. And it may be considerable in low light.

Roland Karlsson said:

Petroglyph said:

Roland Karlsson said:

You need the prediction to eliminate the exposure time.

Click to expand...

There is a finite lag time within the brain as the image is processed into something one can experience as well. At best it is a close approximation of reality running slightly in the past. ;-)

Click to expand...

Yes, but that lag we are used to. So - our brain can compensate. Otherwise we would e.g. have problems catching a ball in low light, where this lag is greater.

The extra lag we get by the exposure, in the camera, is a totally other thing. And it may be considerable in low light.

--
/Roland
Kalpanika X3F tools:
https://github.com/kalpanika/x3f

Click to expand...

I get exactly what you are saying regarding the brain's inability to calculate any lag at a certain point. This has come up regarding pTTL discussions where proof that the lag between the pre-flash and main flash didn't sway some folks. Even the best performing bodies (pretty much everything since the K-5 series) have enough lag that blinks or at least changes in facial expression are apparent due to lag (which is still considerably longer than the Nikon implementation, for instance).

Even when shown proof of measured lag time, responses were almost unanimous that the lag was not discernible and therefore had no impact - especially not enough to trigger involuntary reactions "instantaneously." The argument had to end when the theme moved to "I trust what I sense, not what is measured." Can't argue that logic.

--
JNR
www.jamesrobins.com