Here's some stuff on exit pupil. <http://en.wikipedia.org/wiki/Exit_pupil>
AFAIK a digital lens can be digital in the sense that it's telecentric
(as Olympus envisioned) or in the sense that the rear element is
shaped/coated to avoid reflections from the sensor back onto the rear
element. Telecentric lenses were favored by Olympus to avoid light rays
approaching the edge of the sensor at steep angles. Pixels are located
inside a shallow well and light rays approaching at steep angles would
be cut off by the edge of the well. However, I think this has all been
obviated by cleverly designed micro-lenses over each pixel position.
Chuck Norcutt
William Sommerwerck wrote:
>> More pixels on the 4/3 sensor? At 12 Mp it's already almost
>> twice the pixel density of the Sony Alpha 900 or Nikon DX3,
>> both of which are very close to 25 Mp. You're going to have
>> to go to a full-frame camera.
>
> When I bought an E-500, I never thought I'd own a 5D, then a 5D2. (At least,
> not as soon as it happened.)
>
> The head of Olympus has said the company has no intention of going beyond
> 12Mp, as this is all that's needed for even fairly big enlargements. He's
> right. I've taken "low-resolution" pictures on the E-500 that, when enlarged
> to 12x16, have to be viewed with your nose poked against them to see that
> they aren't "perfectly" sharp. It's amazing what you can get from a 1.4MB
> file.
>
> The real advantage of a large sensor is that it allows high resolution and
> low noise at the same time. (I've taken full-resolution shots on the 5D2 at
> ISO 6400 with no visible noise. I still don't believe it.) Barring a
> technology breakthrough that permits a major reduction in noise, Olympus
> isn't going to push the 4/3 sensor much past 12Mp. It just isn't needed for
> most photography.
>
> What we really need is good user documentation. I'm working on it for the
> 5D2, to be posted on my blog or site. I intend to rip Canon a new one.
>
>
>> I didn't and wouldn't say I am 100% happy with the situation.
>> Sure, I wish we had an OM-size DSLR with a 35mm-size
>> sensor, but let's be realistic, it's not going to happen anytime
>> soon.
>
> It's not going to happen at all, ever. (At least, not within the next
> decade.) The OM body is too small to support the volume of electronics,
> battery, and LCD needed.
>
> As for bulky lenses... I still don't understand the difference between a
> regular lens and a "digital" lens, which is supposed to provide more-even
> edge illumination. I assume this is done by moving the exit pupil farther
> forward, which makes the lens bigger, but I don't know. (I can't find a good
> explanation of the optical "meaning" of "exit pupil", or much about how its
> position affects the lens's performance -- other than that, the farther it
> is from the film plane, the greater the reduction in cos^4 effects.)
>
> I still have my champagne OM-4T (still for sale). A comparison with the 5D2
> or even the E-500 is pathetic. The OM cameras were truly "Leica SLRs", and
> are among the most-elegant cameras ever designed. It will be a long time, if
> ever, before we see a full-frame DSLR that matches them.
>
> Or the lenses. By the way, I believe one of the reasons the f/2 wide angles
> were so compact was that Olympus lied about their speed -- some were at
> least a half-stop slower. I intended to test this with slide film, but kept
> putting it off.
>
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