Re[4]: ATM 8" f3.8 -- Worthy project?

[Dwight Elvey <elvey@hal.com>]

Hugues_Laroche@ses-astra.com wrote:
> 
> 
> Hi Dwight,
> 
> >as was mentioned, you can use a slit but you need a way to
> >adjust them parallel. This makes a moving source a good
> 
> What about having the wire being both the source and the wire?
> By lighting it transversaly by a laser (well I agree it looks
> uncomfortable to have a laser beam cross-passing at a few mm of your
> eye) or a fiber optic like they do for the mini-maglite?
> 
> Hugues
> 
> 

Hi Hugues
 Using it this way wouldn't work. There wouldn't be enough
contrast between the light that was blocked by the wire
and all of the light that went around it. The reason
why the slit-less tester works at all is that the lit side
of the source is flipped to the knife body side by the
mirror under test. There would be nothing to block the
light from both sides of the wire. There would be a shadow
but it would be hidden by the overall lighting.
Dwight