Luminous Landscape Forum

Equipment & Techniques => Cameras, Lenses and Shooting gear => Topic started by: BJL on June 19, 2013, 09:54:45 am

Title: the difficulties of live view focusing on the Leica M: do it wide open!
Post by: BJL on June 19, 2013, 09:54:45 am
I think I have an explanation for why a number of users of the new Leica M, like Mark Dubovoy (http://www.luminous-landscape.com/reviews/cameras/i_will_not_buy_that_camera_i_promise.shtml) and Tim Ashley (http://tashley1.zenfolio.com/blog/2013/6/leica-m240---executive-summary-final-thoughts-conclusion-is-it-a-keeper) find its live view focusing inferior to using the traditional range-finder mechanism. In short, I suspect that this is because the most natural and convenient way to use live view on a rangefinder has the lens stopped down to the taking aperture: SLRs and the new compact system cameras instead normally hold the aperture wide-open during composition, only stopping down at the last moment during shutter release, and this intensifies out-of-focus effects, making manual focusing far easier.

I have a similar experience manual focusing with the small apertures of the Olympus 12-50/3.5-6.4, where I am often taking at close to maximum aperture; it is far easier to focus manually with the brighter, adaptor mounted, 12-60/2.8-4 or 50-200/2.8-3.5 lenses.
Title: Re: the difficulties of live view focusing on the Leica M: do it wide open!
Post by: kers on June 19, 2013, 11:51:02 am
Nikon also uses Live view at the given aperture. ( so stopped down)
I like that because focus shift etc are taken into account and you know exactly what you get at the given aperture..
Title: Re: the difficulties of live view focusing on the Leica M: do it wide open!
Post by: BJL on June 19, 2013, 02:18:36 pm
Nikon also uses Live view at the given aperture. ( so stopped down)
I like that because focus shift etc are taken into account and you know exactly what you get at the given aperture.
Stopped down all the time when Live View is active and then opening wide when using the optical VF? That is weird! The E-M5 gives the choice, which is a far better approach for manual focusing (and for working in low light.) Given the greater accuracy in most cases of focusing with the shallowest possible DOF, from a wide open lens, it makes far more sense in most cases to AF wide open, with the option of stopping down for a DOF preview.
Title: Re: the difficulties of live view focusing on the Leica M: do it wide open!
Post by: BJL on June 20, 2013, 10:16:57 am
I realize now that this has been said before, by Sean Reid on this site.  The italics are mine:
Quote
The M lenses are also fully mechanical and, of course, have never needed to have an auto-aperture stop-down system (so they don't). To focus the M precisely in live view mode (unless the chosen lens suffers from a lot of focus shift) one needs to focus with the lens wide open (for minimal depth of field) before stopping down to the taking aperture. So that aperture changing takes some time as well. Of course, some photographers may choose to compromise some focus accuracy (setting focus while the lens is stopped down) in order to gain speed.
-- Some impressions from beta testing the Leica M 240 (http://www.luminous-landscape.com/essays/some_impressions_from_beta_testing_the_leica_m_240.shtml)

And in the hard case that a lens "suffers from a lot of focus shift", it seems agreed that live view stopped down will do a better job than the rangefinder, which cannot adjust for that.
Title: Re: the difficulties of live view focusing on the Leica M: do it wide open!
Post by: kers on June 20, 2013, 11:10:08 am
Liveview stopped down is not only good in the case is of focus shift - it is also the sharpness in corners vs central area.
Try almost any wide angle at d8-liveview and you will see that the corners peak sharpness and central-peak-sharpness is not at the same focus point.
you have to choose a compromise for overall sharpness.
Title: Re: the difficulties of live view focusing on the Leica M: do it wide open!
Post by: Wayne Fox on June 21, 2013, 02:59:24 pm
Liveview stopped down is not only good in the case is of focus shift - it is also the sharpness in corners vs central area.
Try almost any wide angle at d8-liveview and you will see that the corners peak sharpness and central-peak-sharpness is not at the same focus point.
you have to choose a compromise for overall sharpness.


However, when focusing there is a specific plane most are desiring to be in critical focus.  If the lens is stopped down, hard to do.  Focusing when wide open allows more control of where the critical plane of focus is and resulting control of depth of field.
Title: Re: the difficulties of live view focusing on the Leica M: do it wide open!
Post by: ErikKaffehr on June 22, 2013, 09:09:18 am
Hi,

Well, yes, unless you have focus shift, which almost all fast lenses seem to have. One of the main reason I have little interest in fast lenses. But I seldom shoot available darkness with no tripod...

Best regards
Erik

However, when focusing there is a specific plane most are desiring to be in critical focus.  If the lens is stopped down, hard to do.  Focusing when wide open allows more control of where the critical plane of focus is and resulting control of depth of field.