on 2005/01/10 4:16 PM, Chuck Norcutt at chucknorcutt@xxxxxxxxxxx wrote:
> You may recall my recent post where I measured these light falloff
> values for a T-32 at coverage angles for a 24mm lens.
>
> ...
> Fall-off from the center as 0 point: T-32 @ 28mm
>
> Top center -1/3 stop
> Left center -1 stop
> Top left corner -1 stop
What were you using for a target and how far away was it?
- If it's too shiny instead of matte, light will bounce away
from the lens instead of scattering in all directions
- If it's too close even a matte surface will have falloff
as it won't be perfectly "lambertian".
Apologies if you've already taken this into account. Assuming you have,
that's interesting. Perhaps they assumed a certain amount of vignetting was
acceptable, given usual compositions - people in central areas of frame,
distractions like half the dog at the edges. :-)
Andrew
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