Barry said:
In considering the move to digital, I ran across an editorial that made
a pretty convincing argument that the current crop of digitals were
still essentially modified film cameras. for instance, the editorial
pointed out that there' no reason a digital camera needs a shutter, and
made the argument that there was no reason a quality LCD couldn't give a
better image than the mirrors we're used to in our SLRs.
So - is anyone working on a digital camera that's digital from the
ground up?
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Well, the E-1 is digital from the ground up. I'm afraid the editor who
wrote the article you're referring to simply doesn't understand the
technology.
Having said that I must point out immediately that there are plenty of
digital cameras which do not require a mechanical shutter. So, how come
the E-1 and all the other DSLR's on the market do have a mechanical
shutter. It has nothing to do with being derived from film cameras.
The cause is sensor technology which the editor may not understand.
There are actually two main types of sensors used in cameras. One is
called "inter-line transfer" and the other is "full-frame". Caution:
"full frame" in this context has nothing to do with the size of the
sensor or equating it to a 35mm film frame. The sensors used in DSLR's
are full-frame and absolutely require a mechanical shutter. Inter-line
transfer sensors do not require a mechanical shutter.
Along side each photo receptor site on an inter-line transfer sensor
there is a storage cell. The storage cell is used to capture the input
from the photo receptor and this value can be electronically read while
the photo receptor gathers the charge for the next frame. The values
read out from the storage cells can be used to write the image file or
be displayed in an EVF to make a real-time image (and histogram).
Cool stuff and I really, really like my Minolta A1 which can operate
like this. So how come all the top end DSLR's don't use this cool
technology? It's because the storage cell next to the photo receptor
occupies a large amount of real estate on the sensor chip. This cuts
down the area allowed for the size of the photo receptor. In a
nutshell, inter-line sensor photo receptors are a lot smaller than
full-frame sensor photo sites on the same size chip. And we all know by
now that small size means big noise. Not good for expensive DSLR's.
As to the EVF, the technology isn't here yet to make a really high
resolution EVF that could begin to equal the mirror. And, even if you
had it, you'd need an inter-line transfer type sensor to drive it.
Will it get better in the future? Sure. But you probably don't want to
wait that long to buy a camera.
Chuck Norcutt
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