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

["animal" <s.jessurun95@chello.nl>]

> 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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