Re: [Leica] M6 HM focusing improvement

["Raimo Korhonen" <raimo.korhonen@pp2.inet.fi>]

The 2.8/135 has auxiliary wievfinder attachments which increase the
magnification. It works!

- ----------
> From: David Morton <dmorton@journalist.co.uk>
> To: leica-users@mejac.palo-alto.ca.us
> Cc: dmorton@journalist.co.uk
> Subject: Re: [Leica] M6 HM focusing improvement
> Date: 08. toukokuuta 1998 4:00
> 
> Shawn London wrote:
> 
> > Erwin Puts calculated the theoretical maximum f/stop at which accurate
> > focusing could be possible on the M6 quite a few months ago.  I do not
> > have the email saved, but I do remember that at 50mm the normal M6
> > rangefinder is accurate enough for an f/.85 lens or something of that
> > sort.  At least at 50mm, you are quite within the capabilities of the
> > regular M6 with a Noctilux.
> 
> Here it is:
> 
>
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> 
> 
> There is a mechanical/optical relationship between the accuracy of the
> rangefinder and the baselength in relation to the maximum aperture/.
> The equation will be published elsewhere, but here is the result:
> 
> Focal length	Max aperture	Max aperture
> 		M3		M2, M4, M5, M6
> 21 mm		0.12		0.15
> 28 mm		0.21		0.26
> 35 mm		0.33		0.41
> 50 mm		0.67		0.84
> 75 mm		1.5		1.88
> 90 mm		2.17		2.71
> 135 mm		4.88		6.1
> 
> This equation then tells you that the 21 mm can be reliaby focused when
> the
> maximum aperture is f/0.12 (incredible!).
> At 50mm the Noctilux approximates the theoretical maximum values when
> attached to the M6.
> The 135mm seems to be overstretched when used at its maximun aperture of
> 2,8.
> Hope this info has some value
> Erwin
> 
>
- -----------------------------------SNIP-----------------------------------
> 
> 
>             David Morton  |  "saepius ventis agitatur ingens
> dmorton@journalist.co.uk  |  pinus est celsae graviore casu
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>       (+44) 171 272 8908  |  fulgura montis." (Horace)
>