AV News 186 - November 2011
Although the 'Automatic Tab' facility is convenient, quick, and simple it's
much better to use the 'Custom Tab'. Within this tab all the features of the
'Lens Correction tool' are available and may be fully controlled with the
mouse via sliders or by inserting values in their appropriate box. The 'Custom
Tab' is ideal if you intend to use any of the features creatively by deliberate
over exaggeration, and of course
all effects introduced may be
adjusted or removed if required.
To understand the achievable
effects it's a useful exercise to
experiment
with
an
Adobe
calibration chart or grid pattern
drawing. It doesn't matter what size
you make the grid but if you create
it on a white background with black
lines you will easily observe the
various corrections and effects
possible,
including
barrel,
pincushion and vignette.
In the bottom third portion of the
'Custom Tab' both horizontal and
vertical perspective controls are
situated together with an 'Angle'
control. This latter control is useful
for rotating the image in either
direction using the mouse or
numeric values. Obviously black
grid lines on a white background
will not show any colour fringing but
you can always play around with a
suitable colour photograph or chart
to check these effects.
If you wish to create your own
lens profiles to suit your own
camera body and lens combination
then Adobe provide a most useful
downloadable tool named 'Adobe
Lens Profile Creator'. This file is available in either MAC (DMG) or Windows
(ZIP) versions and is around 80MB in size. When uncompressed this file
creates a directory containing three sub directories for calibration charts,
documentation, and sample images. It also contains one executable file that
does not need to be installed, just double click the file to run the profile
creator. Full instructions on how to use the profile charts and how to make
your own lens profile is included in the documentation. This file can be
downloaded from: http://labs.adobe.com/technologies/lensprofile_creator/
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