Fast AF Rangefinder, possible?

two remarks (besides af and rf are different mechanisms):
1. it's not always the motor that is slow. in many af versions the detection and hunting for the right autofocus position is what takes time, not the speed of the focusing motor.
2. im not sure the slr lens examples you bring up to show how big af makes a lens, is valid, since the same focal length/aperture slr lenses from pre-autofocus era were not smaller at all.

i suggest you look at the konica hexar af's active infrared af mechanism. it is fast and working well even in the dark. but it is not cheap to build in a camera (and it has its limitations esp.for longer lenses where focusing on 25m and 50m makes a difference)
 
There is nothing wrong with the contax g's AF, super fast and up there with the best, however the system did always have to focus from infinity to whatever. So SLR's have the speed advantage if the AF distance only has to change 1 meter or so. I'm sure the same system can be designed to work around this. It can also focus in the dark. Just add a visual confirmation to the viewfinder as well and everything will be spiffy.

The AF 'problems' of the G series are actually user error, not computer error. It's a rangefinder, and like all rangefinders its focusing is very pinpoint and so is it's AF bracket. Most focusing errors come from misplacing the bracket or dirty (fingerprints) AF windows.

Phil, the Hexar's IR is good but it doesn't really count because it's a fixed lens. Also, the IR doesn't work through windows or fog. But the Hexar is pretty damn sure and quick.
 
buzzardkid said:
The solution for that was invented long before the M3 and it is called zone-focusing. That's why all the RF lenses have aperture scales on them.

Use a 35mm lens, set the aperture to f8.0 and the lens distance to 3 mtrs and you will have everything covered from approx 1.5 mtrs to 20 mtrs. Loading the light-correct film and setting the correct shutter speed does the rest.

Simple as pie.
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Problem is that in some situations you don't have enough light but a fast lens. Now the inability to focus fast and correct leads to smaller aperture, higher iso (or faster film) with all the disadvantages.
Took my M8 to a school event and tried to take photos of my dancing daughter. Had to use bloody iso 1250 to have an aperture of 5.6 because accurate focussing was not possible due to the movement. :bang:
In this situation a focus confirmation wouldn't help at all, but a fast AF.
The solution for me is not AF in an rangefinder style camera but to use a DSLR for such situations.
 
here's an idea i would love to see made:
A separate, active infrared focusing unit to be sold as accessory that you mount into the accessory shoe (of, let's say the x100 or any modern camera) that measures focus and transfers info between itself and the camera for focusing.
Would be doable! i think :D
 
tom.w.bn said:
Took my M8 to a school event and tried to take photos of my dancing daughter. Had to use bloody iso 1250 to have an aperture of 5.6 because accurate focussing was not possible due to the movement. :bang:
In this situation a focus confirmation wouldn't help at all, but a fast AF.
The solution for me is not AF in an rangefinder style camera but to use a DSLR for such situations.
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i am surprised by that. It is digital. Why dont' you use the (only one real) advantage of digital? Make 2000 shots wide open FOR FREE and i am sure 20 of them will be in great focus!
And let your daughter select the sharp ones, :D coz i could never convince myself to go through 2000 shots for this purpose :D
 
I would rather have an RF hybrid finder with a Digital RF spot overlaid on the optical finder. Build a 10x magnification zoom on the electronic RF patch to "zoom in" for critical manual focus.

My main reason for using a Leica is lens selection going back 80 years. You would have to build an AF camera that moves the lens with relation to the sensor/film, such as Contax did with their SLR.
 
Livesteamer said:
I use an M6 .85 and a 50mm Summilux to do a lot of little kid pictures under available light. My depth of field is normally very, very thin.

Until AF knows where I want to focus the mechanism is pointless. Just my opinion. Joe
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Of course it knows where you want to focus. You want to focus at the centre of your frame, because that's all you can do with your rangefinder.
 
Pherdinand said:
i am surprised by that. It is digital. Why dont' you use the (only one real) advantage of digital? Make 2000 shots wide open FOR FREE and i am sure 20 of them will be in great focus!
And let your daughter select the sharp ones, :D coz i could never convince myself to go through 2000 shots for this purpose :D
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I'm pretty sure you don't expect an answer, right?
 
The term "rangefinder" refers to a specific method of determining focus by means of parallax error between two horizontally displaced beams. In order for an AF system to retain the characteristic of rangefinder it would have to use such a method as the means for determining subject distance.

Otherwise, you are left with the concept of faux-rangefinder-ish cameras, like the Olympus EP and Lumix GF series cameras, which superficially may have similar styling as a true rangefinder but don't actually function to provide the actual rangefinder focusing.

Which leads to the thought that we need a better term for cameras with non-TTL optical viewfinders and interchangeable lenses, other than "rangefinder," especially when they don't actually sport rangefinder focusing.

As for the idea that contrast-detect AF is slow, that used to be true at one time, but I can say through personal experience that the Lumix 14-45 lens (the original u-4/3 kit zoom) is one of the fastest focusing of any autofocus lens.

~Joe
 
Spyro said:
Of course it knows where you want to focus. You want to focus at the centre of your frame, because that's all you can do with your rangefinder.
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Only if you cannot turn your neck more than one degree.
 
Pherdinand said:
here's an idea i would love to see made:
A separate, active infrared focusing unit to be sold as accessory that you mount into the accessory shoe (of, let's say the x100 or any modern camera) that measures focus and transfers info between itself and the camera for focusing.
Would be doable! i think :D
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That's the Nikon F3AF...

Everything old is new again.

Phil Forrest
 
The Contax G series is the only real autofocus rangefinder with interchangeable lenses I've seen (or course, it doesn't have the patch, but it still works the same way). I've had autofocus issues with my G2, but I've only owned it for about a week and I would blame all of it on user error at this point! Very capable camera with excellent lenses, fits in my hand (and in my budget) better than Leica M.
 
BobYIL said:
There is an ongoing discussion about autofocus almost in all forums related to Leica or rangefinders. Autofocus, undoubtedly is a great plus; to focus a 50mm high speed lens on a moving subject with the speed and accuracy of a professional DSLR.. to keep the subject in focus while moving and being sure of a tack-sharp picture each time you pressed the shutter button.. What a great street camera would it be! Who did not dream of such a possibility?

But could there be a Leica or any rangefinder with interchangeable lens mount to have a fast autofocus? In a near future, sure, there must be, for it could be the next step of development for rangefinder.. But how? What are the possibilities and what could be the limitations? Why it could not be done until today? Here are my thoughts:


In-body motors:
Linear extension micromotor mounted in camera body to drive lens, like in some conventional, relatively older design AF lenses or the Contax G: Low AF speed; this design is to phase out, not used anymore in the recently issued designs. Although this design can be squeezed in relatively smaller lens diameter (only a worm-gear drive), I do not believe that any new RF design based on a low speed AF activated by a step-motor installed in the body could be attractive for the majority of users in our day.
(cont'd...)
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(Highlight)

Ummmm..... Let's say, there are those who doubt it.


And @ jsrockit

Ok, so let's put aside "rangefinder" and call them AF VF Cameras.

Or 'point and shoots'.

Cheers,

R.
 
I never thought I'd see another thread arguing whether a Contax G is a rangefinder or not. Ahhh... if you wait long enough you'll see everything come around again, kind of like fashion.

Roger...P&S, that's funny :)

Kent

PS- The only lenses that get a little quirky, at times, with the G2 focusing are the 90mm and the 35-70mm. Even those cause very little problem if you're used to the system and what the auto-focus is looking for.
 
jsrockit said:
See, but is like saying that a camera turns into a point and shoot simply due to auto focus.
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Well, I had a Rollei AFM 35, and basically, yes, it was a point-and-shoot with manual override. Much like a fixed-lens Contax G-series, really, except that I found the autofocus more reliable. I'll see if my daughter still uses it, and if not, I'll ask for it back. Quite a nice little camera but NOT an RF. Much like a G or an X100, in fact.

Cheers,

R.
 
Mr. bobYIL, between this and the digilloyd post, I swear you like to start fistfights on this site....:)

I'll go with Pablito on this one. A "rangefinder " as I understand it, is a camera which uses a manual focus triangulation system ( I think that's what you'd call it). As far s I am concerned any autofocus camera is NOT really a rangefinder, though it might look like one. Otherwise, I guess the Olympus EP-2 counts as Pa "rangefinder".
 
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