Archived posting to the Leica Users Group, 2001/09/08

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Subject: Re: [Leica] 360 degrees of Midway fun at
From: Johnny Deadman <john@pinkheadedbug.com>
Date: Sat, 08 Sep 2001 19:17:24 -0400

on 9/8/01 6:53 PM, Ted Grant at tedgrant@home.com wrote:

>>>>> the Canadian National Exhibition.
>> 
>> http://www.pinkheadedbug.com/360/623-pan-3-crop-flat.jpg <<<

> What I'm surprised at is, the quality and consistency of the exposures as
> you matched them to look as though the finished photograph was taken with a
> Panon or some type of panoramic moving camera.
> 
> How long does it take to assemble the exposures to the final product?

the first thing is to shoot the images at the exact same exposure and do it
quickly before the light changes. You can get away with exactly ONE ugly
discontinuity, but it has to be where the pan breaks. You can cover up an
error this way but at the expense of choosing the center point of the final
image.

you pretty much have to use color neg because the exposure variation between
a shot into the sun and a shot with the sun at your back is extreme, and you
can't stop down/up to compensate

the second thing is to scan them identically with a fixed exposure etc.
Vuescan is the easy way to do this, otherwise you scan 'em raw and do
exactly the same manipulations to each image

then the hard work begins!

about 30 mins to set up the control points between the images so the
software knows how to match them up

about 30 mins to optimize yaw, pitch, roll etc to compensate for camera
movement between exposures. This is where you find out how well you shot it.

about 90 mins processing time for the software to churn away and remap them
to a cylindrical presentation (I do this on a second computer)

about 10 mins for an action in Photoshop to build the remapped images into a
massive layered file and apply the first (very bad) automated stitches using
layer masks.

about another 60 mins to do the proper stitches manually, color correct, and
produce the final image

but it's fun so it doesn't seem like hard work

(the hardest thing is choosing the spot to take the pan from... if you don't
get THAT right everything else is a waste of time. It's really hard....
trying to find some magic place... there is a greek word for it I think...
'omphalos'... the place of power)

sometimes the lens vignetting causes dark bands... to correct these you take
the final image into LAB color mode and dodge the lightness channel
- -- 
John Brownlow

http://www.pinkheadedbug.com

Replies: Reply from "Ted Grant" <tedgrant@home.com> (Re: [Leica] 360 degrees of Midway fun at)