Autofocus with high open lenses

[salvatore_reitano]

Dear Leica friends

 

I have a general question concerning Autofocus.

Appart that it is much faster than to focus manualy is it also

accurate as to focus with an M6 or a manual SLR?

What interest me most is the range from 24 up to 50mm lenses with

high open lenses like Noctilux, Summilux and Sumicron.

Or asked in a other way does it make sens to use for exemple a Canon

EOS 1V, EOS 3 / Nikon F5, F100 with high open lenses?

Are this kind of cameras realy good tools for to play with DOF that

results form 35mm lenses with aperutre 1.4 etc... .

 

Thanks for shearing your opinions ans experiences.

[geddert]

I found/find a Canon EOS 1V and EOS to be much more accurate than an M6, in all but the lowest of low lights for 50mm lenses (i have experience with a 50/1.4 USM - and a Summicron 50 on the leica), but for wide angles, i have found that focussing the 24/2.8 elmarit to be more accurate than when using a 17-35/2.8L canon lens... if you goal is to "play with" shallow depth of field and you haven't used it much in the past i would recommend a SLR over a rangefinder because you will know what you are getting... once you have experience shooting these focal lenghts you will instinctivly "know" the effects of depth of field and a rangefinder can have advantages - like being able to see the whole scene in focus.

[el_fang]

I suppose it comes with practice. If you insist on using an EOS 1V, EOS 3, Nikon F5, or F100 manually then it's definitely a bit harder to manually focus a wider lens vs M6. But then turn on autofocus and my F100 with SB-28DX IR assist will focus my 28/1.4D much faster and more accurately than the next guy twiddling his M6 and 28/2 wondering if those two images are really lined up or not. Of course in TOTAL darkness, I win hands down. Technology, when applied correctly, is not always a bad thing...

[el_fang]

I should have added "assuming you're working in low light" to my above answer. But then even in good light, with large aperture lenses you're talking fairly narrow depth of field, so I'd rather be able to use the entire viewfinder to focus and compose simultaneously than go through the focus-recompose dance I'd have to do with the rangefinder.

[fotografz]

Interesting question, and no easy answer if everyone is honest

about it. I use the fastest glass I can, usually wide open on all

my cameras, so the issue of focus accuracy is a key one. The

quickest of the lot was my now sold EOS 1v and 24/1.4 & 35/1.4.

Yet, the combination of shooting wide open at slow shutter

speeds often countered the speed of this set -up. Where I found

that my % of apparent "in-focus" shots was just as high

with the M cameras for many situations ( and more candid ).

Most of my SLR work lately has been done with a Nikon and

28/1.4 & 85/1.4, as I still believe AF is a must for certain

situations, but not as often as one would think. I've recently taken

to using a Contax N whos' AF is inferior to an EOS1v and

pro-Nikon, yet has a unique feeling dual focus system that I've

come to really appreciate. The best combo for me is a AF SLR

and a M with the fastest lenses as it's hard to do it all with one

system alone.

[kelly_flanigan1]

With the F1 Noctilux the DOF is very small at F1; and close distances of less than 15 feet....When photographing 3 people at say 8 feet away @F1 ; one must think what person; and what part of that person that the focused point will be.....Here is a shot at F1 @ 1/25 second with asa 800 film:<BR><BR><img src=" http://www.ezshots.com/members/tripods/images/tripods-175.jpg"><img src="http://www.ezshots.com/members/tripods/images/tripods-176.jpg">

[jay_.]

IME focus *accuracy* as an absolute, between Nikon F5/F100 (I used to own them), EOS 1V (currently own) and Leica M (always owned) with wide-aperture lenses is pretty much equal with lenses such as 20-21/2.8, 35/1.4 (Canon & Leica only, Nikon doesn't make one), 50/1.4 and 50/1 (Canon and Leica only, Nikon doesn't make one)and 85/1.4(Nikon)/85/1.2(Canon) vs Leica 75/1.4. However with the 50 and 75, it is much more difficult to achieve that accurate focus with the Leica. In all cases, the AF-SLR's are much faster to focus-and-shoot and moreso if the subjet is moving. However, in dim light where I can still see easily to focus an M, the Nikon and Canon must rely upon an infrared beam from an attached flash to supplement the AF, and there is no way I've found to simply use the IR beam without also using the flash ;>( So this contest doesn't have a definitive winner.

[kelly_flanigan1]

Jay; can one see the "autofocus aim point feature" on an autofocus SLR in dim light? Do some models illuminate the feature (on the screen); so that one could properly choose the aim/focus point in real dim light?

[kelly_flanigan1]

Marc; <BR>Your phrase <b>" My % of apparent "in-focus" shots "</b> is GOOD.<BR><BR>In low light ; my percentage always drops..whether using a manual focused SLR; or rangefinder camera.<BR><BR>With moving targets/people and super dim light; the success ratio is even worse...<BR><BR>With my limited usage of autofocus cameras in dim light; something in the field of view will always be in focus; but not always the feature/person I wanted!!!!!!!!!!!!!

[carl smith]

Kelly, are you talking about having focusing points light up? The EOS 1v, EOS 3 and Nikon F100 all do this, they glow red.

 

As far as not using flash but still using the AF assist, I know that with some Canons you can turn the flash off with certain speedlites and just use the focus assist. I'm not sure about the Nikon however.

[jay_.]

Kelly: On multi-AF-sensor Nikons like the F5 and F100 when the flash is switched on and the IR beam operates, only the center AF sensor is active. With my Canon system, which I only use for wildlife with the flash set to a constant -1/7 stop ratio, all the sensors in my 1V seem to operate...but I doubt if I have ever used it in light low enough to trigger the IR beam.

[kelly_flanigan1]

Thanks Carl & Jay for the answers;<BR><BR>I was wondering how the Modern top end Canon EOS or Nikon Auto Focus systems handle with Super fast Auto Focus lenses; in dim light ..Can one see/define what the focus point is in dim light? ( Like on the guys faces above ) I have used older autofocus cameras in decent lighting a couple of times; but never in dim lighting...Auto focusing is cool stuff;