Archived posting to the Leica Users Group, 2007/09/02
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Len- I adjusted my M8 as well. I think I improved things a bit - then let it go (so I could take pictures!) Cocktail du jour: The Hemingway. Eric On 9/2/07, Leonard Taupier <len-1@comcast.net> wrote: > > Eric, > > I agree with you to a point. I adjusted my M8 5 months ago and > haven't looked back. For me it was make the Noctilux work or get rid > of it. Then the new prices of the Noctilux almost doubled and I knew > I had to make it work. I have been very happy with my M8 and lens > system ever since and don't even think about it any more until a > thread starts up on the LUG. > > I will have that cocktail though. > > Regards, > Len > > > On Sep 2, 2007, at 9:43 AM, Eric Korenman wrote: > > > I obsessed about this for a few weeks (esp with my noctilux) > > Then I let it go.. > > Certainly your camera should be in proper alignment, but to chase > > after each > > lens' focus shift will make you insane! > > > > I am learning to compensate (again, esp with my noctilux) for wide > > open near > > focus. > > > > The issue is focus shifts that none of us noticed prior to the > > advent of > > super thin image sensor surfaces. > > > > take pictrues > > have a cocktail > > > > Eric > > > > > > On 9/2/07, Leonard Taupier <len-1@comcast.net> wrote: > >> > >> Hi Hoppy, > >> > >> It is a global focus error on the Noctilux, 75 Summilux, and the > >> 90AA. In the case of the Noctilux there is also a focus shift at f2.0 > >> and f2.8. Without the adjustment it takes an f5.6 setting for the DOF > >> to bring it in focus. That is because the DOF increases quicker > >> behind the target then in front. The other lenses don't appear to > >> have the focus shift problem when stopping down. > >> > >> Cheers, > >> Len > >> > >> > >> On Sep 2, 2007, at 2:20 AM, G Hopkinson wrote: > >> > >>> Len, understood. You are describing a focus shift as you stop down > >>> slightly, rather than a global focus error requiring individual > >>> lens adjustment. Focus presumably correct wide open, shifts as you > >>> stop down owing to residual aberration. Error not apparent as you > >>> get to smaller apertures with greater DOF. Evidently your method > >>> works for you guys and that's what is important. Worth reading the > >>> article in the August LFI on the subject, if you get a chance. > >>> Thanks for the information. > >>> Cheers > >>> Hoppy > >>> > >>> -----Original Message----- > >>> Subject: Re: [Leica] Re: do it yourself back-focus adjustment..." > >>> > >>> Hoppy, > >>> > >>> The adjustment is the infinity adjustment cam just inside the camera > >>> mount. The close focus adjustment is actually behind the Red leica > >>> dot on the front of the camera. It's not a case of just adjusting > >>> DOF > >>> to be favoring in front or in the rear of the focus point. In the > >>> case of the Noctilux and the 75mm Summilux, from wide open to a stop > >>> or two closed all the photos are just plain out of focus. Between > >>> about 5 to 10 feet from the target, the only thing in focus was > >>> behind the target. I own 19 M lenses that I can use on my M8 and 5 > >>> LTM lenses I use with adapters. After my adjustment every lens > >>> focuses perfectly on the M8 except the 135mm at infinity. So I am > >>> not > >>> matching 1 lens to 1 body. I don't think the 24 lenses needed > >>> adjustment and the M8 didn't. BTW leica does not recommend using a > >>> 135mm on the M8. > >>> > >>> Len > >>> > >>> > >>> On Sep 1, 2007, at 7:15 PM, G Hopkinson wrote: > >>> > >>>> Guys can someone be explicit there regarding what you are > >>>> correcting? Focus wide open at practical infinity or a close > >>>> position? > >>>> Focus at a particular f stop? Someone said that they are adjusting > >>>> so that there is more apparent DOF in front than usual. Since > >>>> the acceptably sharp zone will always be deeper behind, I read this > >>>> as actually moving the sharpest point forward. > >>>> There is a difference between a global back focus (lens adjustment > >>>> error) and a focus shift visible near wide open as you stop down. > >>>> > >>>> I can certainly understand that you may end up with an adjustment > >>>> that works in practice for your own circumstance (lens and use), > >>>> I'm just really interested as it seems to me that you are > >>>> introducing new errors, especially with other lenses for example. > >>>> It may > >>>> be that DOF masks the error with other lenses. Just guessing, I > >>>> imagine that Leica is checking/adjusting the individual lens focus > >>>> mechanism, which is not the same as adjusting the camera body > >>>> roller arm naturally. > >>>> > >>>> The inquiring Hoppy wants to know. > >>>> > >>>> -----Original Message----- > >>>> Subject: [Leica] Re: do it yourself back-focus adjustment..." > >>>> > >>>> Vick, > >>>> > >>>> The original idea to do this came from the Leica Forum. Look there > >>>> if you want to find a more rigorous approach to the problem. > >>>> > >>>> Bob > >>>> > >>>> On Sep 1, 2007, at 4:33 AM, Vick Ko wrote: > >>>> > >>>>> Okay, now I understand. > >>>>> > >>>>> You are adjusting the RF arm. I anticipate that it only takes a > >>>>> very very > >>>>> small amount of adjustment. If the adjustment is large, then you > >>>>> will end > >>>>> up affecting the infinity alignment of the RF image. > >>>>> > >>>>> Congratulations on discovering this method. > >>>>> > >>>>> regards > >>>>> Vick > >>>>> > >>>>> -----Original Message----- > >>>>> From: Robert Rose [mailto:robert.rose@mac.com] > >>>>> Sent: Saturday, September 01, 2007 2:33 AM > >>>>> To: Leica Users Group > >>>>> Cc: vick.ko@sympatico.ca; Leonard J Kapner > >>>>> Subject: do it yourself back-focus adjustment..." > >>>>> > >>>>> Vick, > >>>>> > >>>>> We had a thread on this around March or so. I had posted some > >>>>> samples and > >>>>> how to do it at: > >>>>> > >>>>> http://gallery.leica-users.org/v/rjrose/focus/ > >>>>> > >>>>> Bob Rose > >>>>> > >>>> > >>>> > >>>> _______________________________________________ > >>>> Leica Users Group. > >>>> See http://leica-users.org/mailman/listinfo/lug for more > >>>> information > >>>> > >>>> > >>>> > >>>> _______________________________________________ > >>>> Leica Users Group. > >>>> See http://leica-users.org/mailman/listinfo/lug for more > >>>> information > >>> > >>> > >>> _______________________________________________ > >>> Leica Users Group. > >>> See http://leica-users.org/mailman/listinfo/lug for more information > >>> > >>> > >>> > >>> _______________________________________________ > >>> Leica Users Group. > >>> See http://leica-users.org/mailman/listinfo/lug for more information > >> > >> > >> _______________________________________________ > >> Leica Users Group. > >> See http://leica-users.org/mailman/listinfo/lug for more information > >> > > > > _______________________________________________ > > Leica Users Group. > > See http://leica-users.org/mailman/listinfo/lug for more information > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information >