Archived posting to the Leica Users Group, 2007/09/02
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]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