RE: [Leica] how much is a 6.8 opening?

["Don Dory" <dorysrus@mindspring.com>]

Simon,
First, congratulations on getting out of your F5 while prices were still
reasonable.

Now I understand the images that you have posted.  Coming from
telephoto's you are accustomed to nothing in the background being in
focus and standing 10 meters away.  Coming from the raptor world and
entering the land of the prey beast is a hard transition.

My best suggestion when using the wider focal lengths is to see
everything in the same light as you just lost your only engine at 3000
meters: you are looking for a sorta level clear spot while watching your
descent rate, horizon, air speed, deciding on when to balance flaps vs.
airspeed vs. distance to your goal, talking on the radio, and reassuring
your passenger(s) that it will turn out OK.

Using a lens with significant DOF you identify the main subject, level
the horizon, and check the background so that when events support your
image you trip the shutter or move around so the background does add to
the image.

I think the above is why I take to the M system.  Looking through the
window, I can decide what is in the image because I can see everything.
It also explains why so many have difficulties with a rangefinder:
without a very good knowledge of what a lens will do at a set aperture
the image will never turn out as you saw it.


Don
dorysrus@mindspring.com

- -----Original Message-----
From: owner-leica-users@mejac.palo-alto.ca.us
[mailto:owner-leica-users@mejac.palo-alto.ca.us] On Behalf Of animal
Sent: Sunday, January 25, 2004 11:44 AM
To: leica-users@mejac.palo-alto.ca.us
Subject: Re: [Leica] how much is a 6.8 opening?


> Simon,
> From a mathematical standpoint it is a half a stop.  However, B.D. is
> correct that from a transmission standpoint it is much closer to a
5.6.
>
> So, if using a handheld meter, consider it a 5.6 lens if you usually
use
> a handheld meter and have calibrated all your other steps accordingly.
> On the other hand, if you are merely trying to find out just how slow
> this lens is, then do consider it a 6.8.  In daylight conditions, the
> ergonomics of the Telyt package are very good for holding the lens
> still.  This doesn't do much good if you are getting 1/30th for an ice
> skating event however.
>
> On another practical note, the faster telephoto's used up close have
> real issues with what is out of focus; composition is critical wide
open
> which is why those who do use fast long glass successfully are truly
> talented individuals.
>
> In the Leica realm, I highly recommend the 400 Telyt as a first long
> lens as it is very light, amazingly sharp in any 8-12mm dimension on
the
> film plane, and relatively inexpensive so not much is lost if
> telephoto's are not your cup of tea.  One other reason to have a Telyt
> in your arsenal is that making one flare is next to impossible; as a
> cemented doublet the only flare is reflections off the flat black tube
> and any bright spots in the mirror box.
>
> Don
> dorysrus@mindspring.com


Hi Don and B.D.
Thanks for your reply.
Luckily i,m a long lens person and have lots of problems getting used to
the
smaller focal lengths on the M.
As a matter of fact i traded a Nikon F5 and 300 2.8 to get the noctilux
and
m6.
I just wondered since my minolta meter never shows 6.8 ever how much it
is.
Here are some shots i took with the 400 and 560 6,8

http://www.leica-gallery.net/apekop/image-42319.html
http://www.leica-gallery.net/apekop/image-49959.html

By coincidence i found a list of half stops today in an article on
screwmount timings
      1.4 1.7 1.6 1.7
      2 2.4 2.2 2.4
      2.8 3.4 3.2 3.4
      4 4.8 4.5 4.8
      5.6 6.8 6.3 6.8
      8 9.6 9 9.6
      11 13.6 12.5 13.6
      19 19.2 18 19.2
      22 27.2 25 27.2

Simon
Amsterdam



















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