Re: Is EBL a construct? Was: Re: [Leica] M6 TTL .58 accurate witha Noctilux?

[Dennis Painter <dpainter@bigfoot.com>]

Dante,

I think Erwin has also made some comments, but:

1) Yes, IMO, if we compare apples to apples. By apples to apples I mean
if you don't have a line to allow the vernier capability of the M finder
to be used. The eye can discern alignment of a line far better than two
superimposed images, but not all objects we focus on have lines we can
use. (given the same eyesight of course!)

2) EBL is does not take into account limits or averages of the human
eye's resolving power.  I prefer Erwin to speak for himself but I think
when he computed the EBL of the .58 and the Noctilux he used pretty poor
'eyesight' to come up with his conclusion.

Given 2 different bodies with the same EBL and differing magnifications
I think the one you find easiest to focus is the winner. If you have to
fuss a lot to focus one you will miss photos. I don't mean to sound
flipant or obvious here but I think ease of focus is more important than
other factors, all other focus releated things equal. (that the finders
are actually focusing where you think!)

I hope this is helpful,

Dennis



Dante A Stella wrote:
> 
> I will rephrase these questions into a format that is more pointed.  And yes, I will see
> if I can locate a copy of Osterloh's book, although I am not sure it will answer any of
> these questions.  Mr. Small may be able to shed some light on this, especially the
> development of the III vs the M3 and Zeiss's theories...
> 
> Question 1.  At more than 100% mag - is a III really as accurate as an M3 or M6 0.85
> solely by virtue of the EBL?
> 
> Question 2.   At less than 100% mag - are the minimum EBLs needed, as computed today,
> computed using (a) the limit of human resolving power or (b) the average human resolving
> power?
> 
> This is relevant to me because we are often faced with two bodies presenting the same EBL
> - one long actual base (and low mag) and one moderate with higher magnification).  If the
> determinant is the best human sight, it would seem more sensical to go for the lower
> actual BL, higher mag, equal EBL model.
> 
> Cheers
> Dante
> 
> Dennis Painter wrote:
>