For entertainment sake, (grin), I repeated my dynamic range tests with a
Canon 40D. I did some quick and dirty analysis last night and determined
that further tweaking of the files is necessary to overcome some oddities.
These oddities are standard-fare stuff that differentiates one camera
brand/model from another. The Olympus digital cameras have some seriously
strange characteristics, but it turns out that this particular Canon does
too.
Just a few quick observations, though:
1. Images are extremely clean with very very nice tonal gradient.
2. SERIOUS image softening at higher ISO settings and in the shadows.
3. Reds--what reds?
4. Color shifting, similar to the E-3 in the shadows.
5. Very nice highlight transition--there is actually a "shoulder!"
6. Color saturation decreases at higher ISOs and in the shadows.
Now, a note regarding these observations--this is NOT a condemnation about
the camera, just a comparative to what I'm used to seeing. I'll be working
with the raw files in several different converters to make sure that what
I'm seeing is "normal", but I did have the camera set to RAW+JPEG and have
the in-camera JPEGs to use as a baseline. Observation #1 and #5 are big
praises of the camera. Where the Olympus cameras tend to blow the highlights
out, the 40D is giving the better part of another stop of gradient--however,
this extra gradient does tend to false-color as all digital cameras will do
when aggressively recovering lost highlights.
I really appreciated the cleanliness of the ISO 1600 images--but at a cost.
With this baseline tests, I think I can do a few things to improve the
Olympus files to give the same impression of cleanliness at about the same
level of detail and color retention. The 40D's sensor reminds me of Kodak
T400CN--the higher the exposure value, the sharper the image. The lower the
exposure value, the more mushy the details. This variable sharpness and
contrast is dependent on exposure AND iso setting. Inotherwords, a midtone
detail at ISO 100 is nicely detailed. But if you underexpose by four stops,
it has about the same sharpness and contrast (when recovered) as the ISO
1600 image. It is worlds apart from the highlight sharpness. As compared to
the E-3, the E-3 maintains near maximum detail at high ISO as at low ISO.
It is very obvious to me that the Canon is doing in-camera noise-reduction
prior to the RAW file being written. At normal viewing, it isn't visible at
all, but when you pull up the shadows during conversion you can see a
non-linear application of something going on.
I can see why "Expose to the Right" is so important with this particular
Canon. For maximum color, contrast and sharpness, you need to lean into the
sensor a lot. At least it is forgiving enough at the highlight transition to
save your bacon. I cannot do that with Olympus cameras.
A side note about reds. The reds in my tests seemed to mutate towards brown.
This was true in both the raw conversions as well as the in-camera JPEGs.
Not totally brown, but not as red as Olympus red is. The blues are similar
in that they also are not as intense as I'm used to. Without comparative
images, you'd be none-the-wiser, but when A-B testing, it's pretty blatent.
Back to point #1. The midtone gradients are very nice in the 40D up to ISO
400. It looks to me that the camera is sacrificing and remapping bits from
the lower values to provide good tonal separation in the upper-mids and
highs. Once you get below mid-tone, though, watch out.
The Olympus cameras have what looks like injected noise (dithering) at all
brightness levels. The 40D has absolutely no evidence of that.
Anyway, the 40D is a very good camera--I'm convinced that a Canon will be in
my future for some types of photography--maybe not all, but some. It gives
good "deliverables" with little effort. But at the same time, I'm also
impressed with how well even the lowly E-1 holds up under load.
Further testing will occur with the 50D, 5D, 5Dmk2, 7D, 1Dmk4...
AG
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