On 7/27/2011 6:08 PM, Brian Swale wrote:
> It looks as though for landscape photography anyway, it would be an
> advantage to remove any anti-aliasing filter from the camera.
>
> See here
>
> http://www.maxmax.com/nikon_d200hr.htm.
This is not as simple as you might imagine. Look at the vertical moiré
patterns. Assume you have shot something without
an AA filter, and such patterns afflict it. How are you going to fix it? A
whole lot of hand work will improve it, but .
. .
Then how about the circular one? How will the details of your feathery foliage
look with no AA filter? Obviously,
different makers make different compromises. I'm guessing Oly shots of those
tests would show no visible moiré.
Anywhere, including foliage, where fine lines run parallel, even for a short
distance, moiré can rear its head.
But wait, there's more! Instead of looking only at the things he points to,
look at the whole images.
Look closely at the letters below the first moiré test pattern. I can see it ,
but you may need a glass or to enlarge
it. The AA letters are softer edged, but the others have little busy artifacts
around them that are hardly visible in
the AA version. It would appear that the AA filter is also covering up pixel
level failings of the sensor and/or
demosaicing algorithms.
So a weaker or non-existent AA filter is going to be a mixed blessing, no?
Also, deconvolution algorithms are
specifically designed to deal with the kind of OOF that AA filters cause - not
by intent, perhaps, but by nature. So
take a look at this. <cid:part1.04030301.06010407@gmail.com>
Deconvolution, in this case in the form of Focus Magic, has at least leveled
the playing field, if not given the AA
image a slight edge in sharpness/detail definition. But look at the thin black
on white lines of letters and scale. FM
has also enhanced the artifacts around them to about the level of the non AA
image.
If this were a really important image to me, I could do some masking and use
other tools to get the best of both worlds,
but it admittedly takes time. But I sure prefer dealing with the AA softening
to trying to correct moiré problems.
So think before you leap; is there a fire outside the frying pan? I know you
want images direct from the camera that are
as close to finished as possible. In this case, I think you are better off with
the AA filter than without. Yes, there
are cameras with weaker and/or different AA filters and/or sensor systems that
may hit a better compromise, but that's
another story.
I'd stick with the camera you have, and learn to correct the problem is those
cases where it is necessary. If that
doesn't do what you need, then it's time to consider a different camera or
camera system. There are real reasons why
some of us decades long OM shooters went with other digital systems.
I'm afraid that my advice may run you into a different problem. Deconvolution
is computation intensive. Assuming you are
still running computer equipment of modest power, memory, etc., you may find it
tediously slow. No free lunch. :-(
Moose
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