Future focusing methods

[2WK]

The other night I was thinking about focusing. More specifically, low light focusing. Has there ever been at attempt at a auto-focus rangefinder that actually has an (IR) Beam to measure distance?

I'm not an expert on lasers, but I have seen military shows, with special forces using an invisible beam to aim, that is only visible with night vision goggles or scope.

So an invisible beam used in a camera to measures focus distance.
It sounds cool in theory..Instant focus under any lighting.
Would that even be possible?

 

[kxl]

What you see with your eyes are "imprinted" on your retina. The (distant?) future will probably scan that retinal imprint and somehow determine area of focus. Pretty cool, although it's probably more sci-fi than reality at this time.

 

[f16sunshine]

Hexar AF does just that and brilliantly I should ad.

 

[2WK]

Hexar AF does just that and brilliantly I should ad.

What? Cool..I didn't know that. Does it work well in low light?

 

[f16sunshine]

It works better than my eyes do 😛
Seriously I can focus in less light using the Hexar than any other camera I've tried.
Do the math backwards on this one.

iso 1600 1/8 of a sec. f2. It was light by orange string lights from halloween.

 

[thegman]

What might be cool is some kind of light beam to judge distance, invisible to the human eye like IR. However, if the camera's viewfinder could seem the beam, then the camera user could see a sort of 'red laser' to see what is being used for the point of focus, whilst the laser would be invisible to everyone else.

Failing that, I think the range finder system is superb, but if there was some way of it never going out calibration, that would be perfect.

 

[Harry Caul]

Doesn't the Contax G2 also focus using IR?

 

[Landshark]

The earliest P&S cameras licensed Minolta's IR technology.
Think L35AF, Sure Shot, etc.

 

[JoeV]

Many camcorders from the 1980s era used parallax autofocus using an IR beam. The sender and receiver unit were behind a dark red plastic window under the lens. The receiver was coupled to the lens' focus ring, so that as the focus motor drove the lens, the baseline between IR sender and reciever was altered.

IIRC (it's been many years since I worked on them), the IR sender went through a lens that modified the beam to have severe astigmatism, while the receiver was a quadrant of four IR sensors. Proper focus was achieved (or sensed) only when the received beam hit all four sensors simultaneously, otherwise either diagonal pair would receive most of the return beam. Which diagonal pair of sensors received the beam determined which way to drive the lens to correct focus. Thus, the return IR beam was only in proper focus when it was circular, otherwise it would be elliptical. This is similar to how a CD/DVD laser pickup servo tracks focus on the disc.

Later AF systems (pioneered by Sony) went to using active filter circuits to look at the high frequency (i.e. fine detail) part of the video signal, and altered focus to peak the fine detail. Not sure if this was the forerunner of phase detect or contrast detect AF, might have used both to prevent hunting.

~Joe

 

[2WK]

Ok, so my idea wasn't groundbreaking hahaha.
I still think it could be improved upon with modern tech.
The IR assist could be turned off/on when required.

Fuji, if you are listening, it's not to late to add it to the X-Pro 2!

 

[2WK]

It works better than my eyes do 😛
Seriously I can focus in less light using the Hexar than any other camera I've tried.
Do the math backwards on this one.

iso 1600 1/8 of a sec. f2. It was light by orange string lights from halloween.

That is impressive!

 

[Roger Hicks]

An acquaintance of mine, shooting in the White House many years ago when this was a new technology, told of a nasty moment when his camera projected a spot of red light onto the president. Guns were out of holsters before people realized what it was...

Cheers,

R.

 

[Takkun]

If you look at most film point and shoots, you'll see two windows or lenses near the finder for this purpose.

I am curious though why this technology hasn't evolved in the digital era. Parallax error I assume?

 

[johannielscom]

What? Cool..I didn't know that. Does it work well in low light?

It works in NO light. Since it emits its own infrared light beam and picks that up with a second IR sensor.

See it here:

Shot taken with a Leica M8 without IR filter, so you can see the IR unit on the Hexar​

And the AF on the Hexar is a 290-step autofocus engine.

A goodworking Hexar never misses, unless you shoot through windows, which throw the IR beam off.


Find my portal page on the Hexar AF here: http://johanniels.com/index.php/camera-gear-articles/42-konica-hexar-af-the-ultimate-compact-camera. Has all the thing Hexar you ever wished for.🙂

 

[2WK]

Awesome Hexar page. I used to think the Hexar RF was the one to get...now not so sure about that!

 

[Frank Petronio]

The problem with the Hexar AF wasn't that it wouldn't focus, it was knowing/confirming/remembering what YOU wanted it focused on.

98% of the time it didn't matter but every once in a while I would loose track of where it was originally focused on or something would move or my finder would let up... and I'd miss. Although no more often than with other techniques to be honest.

I think Linhof and Horseman had some sort of IR RF for their short lived electronic RF 4x5s.

 

[Godfrey]

In addition to the IR focusing systems that have been talked about, Polaroid used sonar AF systems on various models from the late '70s onwards. Despite some easily recognized limitations (can't focus through a window being the most obvious), it is incredibly fast and very accurate, of course requires no light at all.

G

 

[judsonzhao]

plz bring eye focus back

 

[2WK]

In addition to the IR focusing systems that have been talked about, Polaroid used sonar AF systems on various models from the late '70s onwards. Despite some easily recognized limitations (can't focus through a window being the most obvious), it is incredibly fast and very accurate, of course requires no light at all.

G

That is interesting. Googling this!

 

[johannielscom]

When the Fuji X100 was introduced, I saw possibilities to have a 'digital Rangefinder' with that in future models. Would have been pretty easy to create I'd say too!

My initial idea: The X100 viewfinder is a hybrid, it can be optical (OVF) or digital (EVF). So, what if it were posible to project a centre image from the sensors Live View in the OVF, with sharp edges? That way you could line that image up with the OVF image and have a rangefinder-like focusing mechanism.

To my understanding Fuji later on did just that, only they let you line up two halves of the image, one through OVF and one through EVF. Much easier of course... IIRC correctly I aw it announced somewhere, but cannot recall what model has this option!?