Archived posting to the Leica Users Group, 2003/07/26

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Subject: Re: [Leica] Fast lens Focus Problems? (was Summilux/Noctilux)
From: Kevin H <kevin@2image.com>
Date: Sat, 26 Jul 2003 18:10:19 -0400
References: <DA9101E0-BF14-11D7-887F-003065BAFBD0@jphotog.com>

What I meant to say  was at the same distance the 90 is - a bit -  less 
forgiving.
75f1.4 =  1.4cm, 90f2 = 1.35cm.    But half a mm is almost (literally) 
splitting hairs.

Lots of numbers -- but it explains why my shots with the 75 at 1.4 have 
never worked if the subject was around 50 ft, specifally shoting in 
cathedrals.  Infinity (calculated) is 305 ft and beyond.  I'm going to 
start bracketing (focus) in that situation.

For max DOF  -- love the heliar.  Wide open (okay f4.5) at its 
hyperfocal distance (5.5ft) near focus starts at about 32".

Kev.


Eric Welch wrote:

>
> On Thursday, July 24, 2003, at 09:49  PM, Kevin H wrote:
>
>> At .75 m you get a whopping 7.5mm in focus. That’s 29.5 inches with 
>> just over 1/4 inch dof.
>>
>> The 90 f2 wide is a tiny bit less forgiving, but doesn’t focus as 
>> close. At one meter you’ve got 13.5 mm (1/2" )
>
>
> I think you meant to say a tiny big MORE forgiving.
>
> Eric
> Carlsbad, CA
>
> "Going to war without France is like going
> deer hunting without an accordion. All you
> do is leave behind a lot of noisy baggage."
> --- John and Alma Dunlap
>
> -- 
> To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html
>
> .
>


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In reply to: Message from Eric Welch <eric@jphotog.com> (Re: [Leica] Fast lens Focus Problems? (was Summilux/Noctilux))