RE: [Leica] Shooting Leica wide open

["Kotsinadelis, Peter (Peter)" <peterk@lucent.com>]

OK Eric,

Than I misunderstood.  You're right about the 280 F4 Apo Telyt, since it
only improves marginally when stopped down to F8.  Either way its got to be
one heck of a design.

Peter K

- -----Original Message-----
From: Eric Welch [mailto:ewelch@ponyexpress.net]
Sent: Wednesday, October 06, 1999 10:46 AM
To: leica-users@mejac.palo-alto.ca.us;
'leica-users@mejac.palo-alto.ca.us'
Subject: RE: [Leica] Shooting Leica wide open


At 08:50 AM 10/6/99 -0700, Kotsinadelis, Peter (Peter) wrote:
>With all due respect, no lens performs better wide open than stopped down.

Well, Peter, with all due respect, I didn't say that.

There are lenses that are at optimum performance wide open. The 280 f/4 Apo 
Telyt is one. It doesn't get worse on stopping down until you get to small 
apertures where all lenses degrade because of light passing on the edge of 
the aperture scatters light.

On the other hand, those lenses don't improve with stopping down either. 
That's what optimum at the widest aperture means. Most Leica lenses do 
improve on stopping down - more like 1 or 2 stops, as opposed to 3 and 4 
stops with some other brands. And differences may not be as big for most 
Leica lenses.

Nikon and Canon have a few lenses like that too. It's not unique to Leica. 
It's not common, but those lenses do exist. There are some large format APO 
lenses too used for pre-press that are supposed to be optimum used wide 
open (like f/9) so it's not all that uncommon with any format. Given a 
certain minimum focusing distance is respected. And isn't the Hasselblad UV 
lens also optimum wide open? (Who would have much use for a lens with 
Quartz elements anyway?).

Eric Welch
St. Joseph, MO

http://www.ponyexpress.net/~ewelch

There are two kinds of photographers: those who compose pictures and those 
who take them. The former work in studios. For the latter, the studio is 
the world.... For them, the ordinary doesn't exist: every thing in life is 
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