Archived posting to the Leica Users Group, 2000/02/28

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Subject: RE: [Leica] Re: The Summicron
From: "Stewart, Alistair" <AStewart@gigaweb.com>
Date: Mon, 28 Feb 2000 21:45:29 -0500

David,

which summicron focuses to 1/3 meter?

All of my models of various generations got to 1m or .7m, and no closer.

best of light,

Alistair

- -----Original Message-----
From: drodgers@nextlink.com [mailto:drodgers@nextlink.com]
Sent: Monday, February 28, 2000 7:34 PM
To: leica-users@mejac.palo-alto.ca.us
Subject: [Leica] Re: The Summicron



Austin

You wrote:

>>Since the 'lux opens up more than the 'cron, the 'lux is capable of far
less depth of field than the 'cron.<<

Technically, because the 'cron has a closer mimimum focusing distance, it
is capable of creating a photograph with less depth of field than the 'lux.
For instance, a 'cron will at it's minimum focusing distance (approx 1/3
meter) and maximum aperture (f2) have less depth of field than a 'lux at
it's minimum focusing distance (approx 1 meter) and maximum aperture
(f1.4).

So in theory the 'cron is capable of less depth of field than the 'lux. DOF
is a function of focusing distance, not just aperture setting. The closer
the plane of focus, the less depth of field.

However, I'd agree that if both 'cron and 'lux were wide open and focused
at, say, 10 feet, the 'lux could provide less depth of field with f1.4.

David