Olympus-OM
[Top] [All Lists]

[OM] Re: Free OM-to-E-System adapter?!

Subject: [OM] Re: Free OM-to-E-System adapter?!
From: Winsor Crosby <wincros@xxxxxxxxxxx>
Date: Sat, 17 Jan 2004 18:25:48 -0800

On Jan 17, 2004, at 4:55 PM, Tim Hughes wrote:

>   An interesting aside somebody made at a
> talk I attended, was that although lensed chips increase sensitivity, 
> the on chip lenses do
> not work well for very fast lenses, causing increased light dropoff, 
> so the super fast
> lenses have an effective slower maximum aperture than you might expect 
> from marked
> F-stop.

That is really interesting. I wonder if it is related to the diffusion 
layer that is frequently used to limit moire. Maybe the diffusion also 
flattens out the brightness a bit. I know that they are dealing with 
reflection, too. There are instances when a lens at small aperture in 
very bright conditions will have a light circle in the image that is 
the result of light reflected from the sensor plane bouncing off the 
back surface of the lens onto the sensor.

I also wonder whether the exposure circuitry takes the fast lens fall 
off into account. Is it an even fall off or does it also get worse 
toward the edge?

>
>  The CMOS Foveon sensor should theoretically be much better in regards 
> to
> using non-digital lenses as the wells  are much shallower and the 
> sensor area is at least 3
> imes larger per pixel, dramatically reducing the bottom of the well 
> effects.

I have wondered about part of that. While the top sensor may be very 
shallow and unlike a well, wouldn't the bottom one be in a well? Or is 
the whole thing very shallow? I could see that at the edges of the 
sensor the top pixel might be almost completely exposed while the 
bottom one might get very little energy because of the angle. That 
might make it difficult to get the color balance right at the edges.



Winsor
Long Beach, California
USA



The olympus mailinglist olympus@xxxxxxxxxx
To unsubscribe: mailto:olympus-request@xxxxxxxxxx?subject=unsubscribe

To contact the list admins: mailto:olympusadmins@xxxxxxxxxx?subject="Olympus 
List Problem"

<Prev in Thread] Current Thread [Next in Thread>
Sponsored by Tako
Impressum | Datenschutz