Why No SONAR AF On DSLRs and Mirrorless?

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So after playing around with my Polaroid SLR 690 with SONAR autofocus, I asked the question "why hasn't SONAR AF been incorporated into today's DSLRs and mirrorless?"

There would definitely be absolutely no AF hunting in low light at all! (y)
 
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Sound waves will bounce against glass but IR waves will pass through it. I guess the ultimate AF system would have SONAR, IR and LIDAR built in and all 3 would be comparing notes with each other using a fast processor.

Sean
 
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And less accurate when trying to shoot between near objects.
Imagine it being like this......
Will SONAR be the priority AF system? - Nope!

But when the light gets really low, a flick of a switch or setting, now you're in SONAR mode specifically for low light situations. When the light is back on, turn off SONAR mode and return to your regular/primary AF system. :)
 
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And less accurate when trying to shoot between near objects.

Related to this is how accurate can you aim the sonar AF system?
What is the angular coverage?

I think default AF logic will be closest subject.
So it will focus on the dinner table in front of your guests, rather than your guests.

Also how far will the sonar work?
Will it AF the length of a football field?
And at the distance of a football field, what is the angular coverage, and how accurate is the sonar ?
IOW does the sonar have an angular coverage like a 28mm lens? Then what happens when I am using a 300mm lens?
 
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I think PDAF wouldn't hunt at all either, if let run at the same level of accuracy than those sonar systems for film Polaroids.
 

Growltiger

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A narrow beam of low powered microwaves might work. But the battery would go flat quickly.

A better solution that I have sometimes used is a head torch. Turn it on, and as you turn your head the central area can always get focus. Then turn off to take the photo.
 
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Related to this is how accurate can you aim the sonar AF system?
What is the angular coverage?

I think default AF logic will be closest subject.
So it will focus on the dinner table in front of your guests, rather than your guests.

Also how far will the sonar work?
Will it AF the length of a football field?
And at the distance of a football field, what is the angular coverage, and how accurate is the sonar ?
IOW does the sonar have an angular coverage like a 28mm lens? Then what happens when I am using a 300mm lens?
Tough to say since SONAR AF hasn't been worked on since I'd say 1996 when the SLR 690 (Polaroid) was introduced. I'd say after 25 years, better results than what was achieved on the SLR 690 is a distinct possibility.
 
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Tough to say since SONAR AF hasn't been worked on since I'd say 1996 when the SLR 690 (Polaroid) was introduced. I'd say after 25 years, better results than what was achieved on the SLR 690 is a distinct possibility.
It may well be that the limitations of sonar autofocus accuracy matched the limitations of the lens and instant paper resolution.
Instant photography is lo-fi, even current instant cameras have serious resolution limitations IMHO.
 
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Also, just a thought, sounds waves are MUCH slower than light in the air.
In real life, after 30 meters sound and light are no longer synchronised.
Not sure laws of physics could be broken.
Sonar works well in water because in water light does not travel far, unlike in vacuum and air.
 
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Instant photography is lo-fi, even current instant cameras have serious resolution limitations IMHO.
Might explain in part why many Polaroid shooters today are using the refurbished SONAR AF bodies.....And if they're the folding cameras, then they also benefit from having a glass lens whereas all the others have plastic lenses.
 
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