Hi Greg
Hopefully, you can make sense of the below,,,,
Referring to your question about ISO here:
http://bioacoustics.cse.unsw.edu.au/birding-aus/2010-07/msg00379.html
I am definitely no authority on photography but can recommend always
choosing the fastest shutter speed possible for flying birds to freeze
motion (which is probably what most people would want me thinks). Getting
the fastest speeds means using high ISO 400 to 800 or even more, and
depending on the camera body and your exposure technique (which I explain
in more detail below) the noise will be still quite acceptable and most
certainly manageable with plug-in software such as noise ninja or Neat
Image (I use Neat Image and love it). Though, the more you pay for the
camera, generally, means you will get better noise handling capability due
to the quality of the sensor in the body and generally better quality
images straight out of the box. But, one's ability to be able to expose
correctly (in a digital sense) will also determine the noise evident in
the image and it's quite possible to get great results from entry level
gear too. Generally, I never shoot below ISO400 even in good light, I
don't have a noise problem because of how I create the exposures in the
camera. It takes a little practice and getting used to trust the camera's
histogram! :) First, one needs to turn on the histogram preview option via
the camera menu. It shows the digital exposure for each image taken. MOst
cameras should easily handle ISO400, even the new, entry level DSLR
cameras. Sometimes, and not often, will I shoot at an ISO up to 1600, but
then the exposure becomes even more critical than at ISO400.
I have learned and applied with reasonably acceptable results the
following: to minimize the graininess or noise, one should try and
overexpose the images to a point WITHOUT blowing the white tones in the
image (by clipping the histogram on the right side). To check this
process, one needs to understand digital exposure in a bit more depth than
looking at an image on the back of a camera and judging by one's eye
whether the exposure is good or not. The histogram is the best friend to
any budding digital photographer and is a graph showing you the exposure
that one made by the graph, which really represents tonalities from the
left of the graph to the right as black to white. In other words, the left
of the histogram is the blackest of black pixels and the right of the
histogram the whitest of white pixels with the peaks in the graph
representing the number of pixels for that tonality. The middle of the
graph is around the old 18% grey mark (if you know what that means). The
histogram is numerically representative from 0 to 255 with 0 being black
and 255 pure white. Now, the trick is to expose the frames with as many of
the pixels getting close to the right side of the graph without any
clipping of the white tones (clipping means you lose detail). This means
that when one looks on the LCD on the back of the camera, the image will
look like total, utter crap, but the correction to a more visually
pleasing (and correct) exposure can be made when one converts the image
from RAW by reducing the exposure in the RAW conversion software; whether
one uses DPP, Aperture, ACR, NX or Lightroom. Needless to say, it is
always best to work with RAW files in the camera to maximize the detail
captured and the post processing will be far more superior than those shot
as jpegs that will not have the range of tolerance when it comes to
correcting (in the post process) a poorly exposed image. Which does happen
too! Even to the best out there. LOL!
Feel free to ask more questions if something is not clear. For example, I
show you this image I made with the following gear, HAND HELD. If you do
the maths, the field of view equivalent is 1,344mm with the sensor being
APS-C thus having a 1.6x crop factor. (300mm + 1.4x + 2x = 840mm; 840 x
1.6 = 1,344mm) So having image stabilization in the lens also gave me some
more security to get an acceptable image. It is almost full frame from the
sensor as presented.
http://www.amatteroflight.com/wordpress/wp-content/uploads/2010/06/Focal-840mm-Brown-Falcon_0041.jpg
Canon EOS 30D, 300mm f/4L IS USM, 2x + 1.4x, ISO1600, f/16, 1/250th, +1EC
Of course, my camera is an old, obsolete, 8.2 megapixel heap of junk in
today's world of technology; being four and a half years old. Yet it's
more than capable of producing images that are and have been published in
calendars, cards and books as well as prints to A2.
I have written two tutorials so far that you or your friend may find of
some use. You can download and read the pdfs here:
http://www.amatteroflight.com/tutorials_files/CHECK%20FOR%20CLIPPING.pdf
http://www.amatteroflight.com/tutorials_files/Quick%20Masking%20and%20Noise%20Reduction%20made%20simple.pdf
kind regards and best of luck
--
Ákos Lumnitzer
http://www.amatteroflight.com
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