RE: Seitz Roundshot and QTVR technique

[Chris Dahl <cmd@xxxxxxxxxx>]

There is an Anti-Newton Ring" powder on the market, we use it in our lab. I will try and find out where it can be purchased.

"God grant me the serenity to accept the things I cannot change
The courage to change the things I can
And the wisdom to know the difference"

Chris Dahl

Meteor Photo & Imaging
404-870-6145 (voice/Fax)
chris_dahl@xxxxxxxxxx


-----Original Message-----
From:	Robert Erickson [SMTP:bob@xxxxxxxxxxxxx]
Sent:	Thursday, November 05, 1998 3:52 PM
To:	panorama-l@xxxxxxxxxxxxxxxxx
Subject:	Re: Seitz Roundshot and QTVR technique

Peter Lorber told me about how he got rid if the Newton ring problem with
his Roundshot enlarger. He said that he rubbed corn starch on the glass.
Don't ask me how or why it worked, but it solved the problem.

What he told me was that he rubbed the dry corn starch powder on the glass
and then remove as much as he could with a dry towel. May he was just
telling me a story. But when he first used his Roundshot Enlarger the Newton
ring problem was very obvious. Now he has no problem with it at all. Give it
a try and let us know if it worked.


Robert Erickson, bob@xxxxxxxxxxxxx
http://panoramic.net
-----Original Message-----
From: Jook Leung <jook@xxxxxxxx>
To: panorama-l@xxxxxxxxxxxxxxxxx <panorama-l@xxxxxxxxxxxxxxxxx>
Date: Thursday, November 05, 1998 11:41 AM
Subject: Seitz Roundshot and QTVR technique


Hello eveyone,

I'd like to start a discussion about scanning long films from  panoramic
cameras like the Roundshot 220VR
and processing them into stitchable files for QTVR.

For scanning I've tried using a Umax PowerLook II flat bed transparency
scanner and only get MEDICORE results.
Newton rings are created when the film touches the glass and I would have
to put the film in some kind of holder. But I'm not happy with the image
quality of the scans anyway.

I'm wondering if anyone out there scans long their negatives on a Nikon
LS4500AF scanner. It suppose to
be capable of handling "panoramic strips".

I know some people get PhotoCD scans of their films that are shorter than 5
inches.
Any comments on PhotoCD and special handling? Ultimately Drum scanning?

Anyone care to describe their technique on stitching say a 400 degrees
Roundshot film for QTVR.
I need a reliable receipe here!

I've had the Roundshot 220VR for about 2 weeks now. An absolutley fine
precision piece of equipment
but it documentation/translation and usage is sparse leaves alot to be
desire.

So far I've only operated the camera with Auto Exposure and Variation Modes
On and it seems to be
quite reliable. Can more sophisticated users comment here.

I'm thinking of trying a 28mm PC-shift lens for full coverage of the film
area. Comments on favorite
lenses? Slit sizes? Anyone use the camera without the slit aperature in
place, giving about 3mm.
Would this be a good technique in low light situations?


Some of the mistakes I've made:

Using the wrong "b" value for a particular lens gives incorrectly warped
distortions. Will this also
impact on the image's sharpness? Then setting the exact "b" value is only
an approximation to half a mm on the rail!

Some of my shots were soft in focus even for a 14mm lens!  Others were
sharp and in focus.
Do users set their lens focus at infinity and put that value into the
RoundShot or can I apply closer focus setting and use hyperfocus-depth of
field/f-stop settings to keep infinity also in focus?

The term "Nodal point" is only mentioned once in the manual and is not
normally accounted for as it is
in other QTVR rigs. So that was absolutely confusing.

Yikes, horizontal bands of flare at bottom of image: Taping a curved piece
of black paper over the backside of the compendium will take care of the
flare problems of the Sigma 14mm lens.


<^J^>

---------------------------------------------------------------
JOOK LEUNG    jook@xxxxxxxxx    http://360vr.com    201.894.5881
360VR PHOTOGRAPHY - Immersive Imaging - QTVR  LivePicture  IPIX
         (^_^)OOK>>   j(^_^)k    J(^.^)K    J(^o^)K    J(^J^)K....vr