[Leica] 28mm Summicron vignetting

[mark at rabinergroup.com (Mark Rabiner)]

On 1/16/07 4:04 AM, "Marty Deveney" <freakscene@weirdness.com> typed:

> It's not polarisation.  It's not mechanical vignetting - it's optical
> vignetting.  Here:
> 
> http://www.leica-camera.us/photography/m_system/lenses/461.html
> 
> You can access the datasheet.  At f5.6 the 28 Summicron retains about 42%
> of the illumination at the centre for saggittal structures - and that's
> according to Leica.  It will be proportionally worse for wavelengths with
> lower transmission as these are averaged figures for white light.  The
> other factor that I've noticed is that scanned film can show higher
> contrast in tonal ranges that do not have high contrast in normally (or
> even abnormally) developed and chemically printed photos.  This sometimes
> exaggerates the appearance of vignetting - luckily Photoshop can fix it
> perfectly.
> 
> The Leica 28/2 is a fantastic design with incredible performance - but as
> always there are some compromises, the biggest still being cost.  In
> providing maximum contrast and resolution to the edges of a very flat
> field, one priority the Leica designers chose was to make every element
> do as much as possible - recent Zeiss designs have greater numbers of
> elements, each of which contribute less to the final performance.  Some
> are also slower, easiing the design restrictions.  The resulting lenses
> have slightly more distortion in some respects, but resolve more detail
> albeit with slightly lower contrast.  It's a difference in design
> philosophy that makes a difference that only people who look really
> closely will notice.  95% of photographers never eve think about it.

F8 is not even on the chart which is my point.
http://www.leica-camera.us/assets/file/download.php?filename=file_118.pdf

I think in darkroom prints this is not an issue.
But with scanning when you're moving those level bars so there's not air
spaces on the sides there you end up with Agfa Brovira #6 in straight Dektol
selenium toned with no safelight. With a point source enlarger. Covered by a
thin candy shell.
I think its a retrofocus lens with ASPH elements costing thousands and a
cutting edge modern design from Leica. Vignetting is not going to be an
issue.
Shame about that UV filter though.
I don't buy there is no effect.
I'll buy "often not an appreciable effect".
But not blanket "no effect".
And such subtleties are why glass like this cost all that money in the first
place. And to screw it up for nothing?....
To add an unnecessary wildcard variable?

Mark Rabiner
New York, NY
40?47'59.79"N   
73?57'32.37"W

http://rabinergroup.com/