[pinhole-discussion] Re: Bellows factor

[Guy Glorieux]

"G.Penate" wrote:

>  just plain physics of light.
> This case is in no way different than if you were using a glass lens.
> <snip>
> 84.5 seconds (uncorrected for reciprocity, time)

Guillermo,
Can you remind me how you worked this out.
Guy