Translucent mirror focus accuracy question

Discuss Sony A-mount Alpha Digital SLRs and SLT models.
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Posts: 4
Joined: Mon Jan 13, 2020 10:39 pm

Translucent mirror focus accuracy question

Post by tommy »

I'm thinking of switching over to a Sony SLT camera (translucent mirror technology)

I've been doing some research on how they work, & as I understand it so far the translucent mirror allows 70% of the light through to the sensor, & 30% of the light reflected up to the phase detection auto focus sensor.

My question is, does that mean the dedicated auto focus sensor is only receiving 30% of the light for its focusing, compared to a DSLR who's moving mirror would reflect 100% of the light to its auto focus system. If that's correct would it mean that the focusing accuracy of the SLT's would be compromised due to the reduction in light its focusing sensor receives? Or have I got some of that wrong?

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Joined: Sat Aug 22, 2020 5:54 am

Translucent mirror focus accuracy question

Post by Davidadubs »

I saw the announcement of the A99 and it has sensor on-chip PDAF. Since the SLT design was so that a bit of light could be redirected by the mirror to PDAF sensors does this mean the A99 doesnt have a mirror since it isnt needed anymore?

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