I was photographing a whole bunch of portraits a couple of weeks ago
and I noticed that there was a slight colorcast difference in the
images after I changed CF cards. This got me wondering so I used my
studio gear in the basement and one of my daughters posed for me.
Three CF storage cards were used:
1. Lexar 1GB 40x WA
2. Sandisk 1GB standard card (blue/red label)
3. Hitachi 4GB Microdrive.
The theory is that digital data is digital data and shouldn't be
effected by the storage media itself as long as all the bits get
stored. However, as any true audiofile knows, not all CDs or CD
players are created equal. For example, using a green felt-tip
marker on the edges of a CD will usually improve the audio quality a
touch. Before now, I have never seen CF cards compared for image
fidelity--only speed.
Here is the test setup: Olympus E-1, 14-54, manual exposure, manual
WB. Lighting is two studio strobes in umbrellas and a filtered 285HV
behind the subject. Background is black seemless paper. All images
were processed IDENTICALLY in Olympus Studio version 1.50. There are
absolutely no differences in image or camera setup between the test
images. The files were not processed in any editor in any way shape
or form--these are straight out of Olympus Studio.
I approached this test in a scientific manner and my theory was that
all images should be identical given that digital data should
maintain 100% integrity regardless of the media.
Unfortunately, the higher compression JPEGs don't do the RAW files
justice. However, you should still be able to figure them out.
The results are startling.
The Lexar had excellent color, saturation and contrast, but the
sharpness just wasn't there. The high write speed of the Lexar
evidently reduced the sharpness some. Not unlike using a high-speed
film in our OMs. I'm not sure what is causing this, but possibly the
E-1's operating system isn't able to handle the data throughput the
card is able to support. The speed advantage of the 40X card is not
to be ignored. The slight reduction in sharpness/detail is a fine
tradeoff for most of the photography I do. But for landscape work,
I'll have to avoid using this card.
Here is the link to the Lexar image. Click on the image to see the
full-size original JPEG:
http://image66media.com/Gallery/CF/TAG060
The SanDisk was totally disappointing. This card was bought the other
day from Radio Shack for $14. The contrast was muted and the
sharpness was slightly off. Maybe the loss of sharpness/detail is
related to a mistiming against the E-1's operating system, but I
cannot explain the loss of contrast and color other than the fact
this card is of a lower quality. To use a film analogy, this is like
the difference between Kodak film and KMART branded Agfa film. The
difference isn't great, but it's there. The midtones are about the
same as the Lexar, but highlight and shadow contrast is shifted.
Here is the link to the SanDisk image. Click on the image to see the
full-size original JPEG:
http://image66media.com/Gallery/CF/TAG064
The final image is using the Hitachi 4GB Microdrive. I was absolutely
shocked at what I saw. The colors were more vibrant, shadows deeper
and the level of detail is increased. This was, by far, the best
image of the three. I could output this image to the lab for final
printing without any post-processing or adjustment. I've been stewing
on this and if I were to venture a guess, it's that Olympus had
fine-tuned the read/write portion of the operation system and file
processor to be timed perfectly to the Microdrive. I also wonder if
the the data is stored with less variability on the magnetic surface.
Memory chips are known for bleed-over between adjacent memory blocks
and the Microdrive would be immune to that particular problem.
Here is the link to the Microdrive image. Click on the image to see
the full-size original JPEG:
http://image66media.com/Gallery/CF/TAG059
I've suggested a few theories here, but in reality, I'm just
guessing. I took several pictures with each card and the images were
consistant per card type. Granted, when we shoot RAW we're able to
fine-tune and match images from one card to another, but I'd never
have guessed that this variance even existed.
For the highest quality stuff, I'll be using the Microdrive from now
on. The cheep SanDisk is very disappointing and I'm not sure what to
do with them other than MP3 storage. The high-speed Lexar appears to
be a good tradeoff and I'll probably get another new one. But I'll
need to come up with a standardized test to see how it does as
compared to the other cards.
No, I haven't had a chance yet to test these cards in other cameras.
AG-Schnozz
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