Fwd: Center Sharpness f:0.95/f:1.0

[Leikon35@aol.com]

Am awfully sorry Henning for the post being attributed to you.
I can't imagine how that happened but note was posted last
night and this is its 2nd time around.

Yesterday was a very weird day for mejac mail; there have 
been several incidents like this reported.

Marvin Moss
- ---------------------
Forwarded message:
From:	henningw@archiphoto.com (Henning J. Wulff)
Sender:	owner-leica-users@mejac.palo-alto.ca.us
Reply-to:	leica-users@mejac.palo-alto.ca.us
To:	leica-users@mejac.palo-alto.ca.us
Date: 97-09-24 12:56:22 EDT

>   I have just been chatting with an ex aerial photographer
>who has informed me that normally there is a 40-50%
>overlap beteen frames and that only the Center 25% of
>the image is used to in making a mosiac for a map.
>   This means that a lens for aerial work must be very
>sharp in the center & the rest is expendable since it isn't
>used.  This might or might not account for the alleged
>use of the un-holy Canon lens by our un-holy agency.
>   How about it Irwin & Mark and any ex aerial photogs
>on the LUG;  Do you get flare from the infra red band?
>
>Marvin

Just jumping in here. If you are using standard photographic lenses, flare
is a huge issue in IR, as the coatings are not functional in any region
except the visible. The lens could conceivably be recoated for a specific
portion of the IR spectrum, making it a lot less useful for visible light
photography. Also, the interior of the lens barrel may cause a lot more
flare in the IR than in the visible region, as the paints may not be as
absorptive.

With Kodak HIE, all the above doesn't usually degrade the image as much as
expected, since the lack of anti-halation backing on the film causes more
image degradation than the flare.

I used a Canon 0.95 once in the 60's, and in my recollection it wasn't
sharp in the center, either.


   *           Henning J. Wulff
  /|\     Wulff Photography & Design
 /###\      henningw@archiphoto.com
 |[ ]|     http://www.archiphoto.com