[Tig] plane of focus (still cam)?

Rob Lingelbach rob at colorist.org
Wed Mar 12 14:05:01 GMT 2008

Hi woz

On Mar 10, 2008, at 10:34 PM, woz wrote:

> Rob
> How well defined was the edge of the 'stain'?

quite defined.  It had all the properties of a stain if you looked at  
it on a drinking glass, for example.

> Have some greasy food (joking!) put a print on the lens and shoot a  
> plain background at f5.6, f11 then f22 and if you have it f32 (never  
> mind the diffraction effects we'll assume they are  
> insignificant);.also have you considered the possibility that the  
> print on the lens could cause flare with certain light directionality?

it wasn't so nice a photo as you describe; it was fairly flat in  
focus, like 5.6 or so, and used flash.  But... now that I've cleaned  
the objective lens, and took the same shot again, it's gone.   I  
didn't realize that depth-of-field on CCD cameras could show such  
anomalies.   Now I know my next entreprenurial entreprise:  Digital  
Lens Cleaner.  You use it with your fingers and a Digital Lens Wipe,  
which conforms to Digital Standards, and the fluid can be broken down  
into digital form, ...... (the analogy fails at this point).

> Vaporous! Now there's a word I would not have thought to use, I hope  
> you don't mean miasmic!

miasmic is what I found prevalent in the machine room when entering  
after someone else had just left.  Or, when one enters a supermarket  
aisle in an unprepossessing manner, then shortly later realizing an  
emanating presence had been there before you.

Rob Lingelbach
rob at colorist.org  http://www.colorist.org/robhome.html

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