Olympus-OM
[Top] [All Lists]

[OM] Re: Flash coverage angles - Oly found to be optimistic

Subject: [OM] Re: Flash coverage angles - Oly found to be optimistic
From: Earl Dunbar <edunbar@xxxxxxxxxxxxxxxx>
Date: Mon, 10 Jan 2005 18:31:40 -0800
Since there is no universally accpeted standard for the term "coverage" 
or "covers", in this context, it really depends on the specific photo's 
requirements.

Earl

Andrew Gullen wrote:

>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
>  
>



==============================================
List usage info:     http://www.zuikoholic.com
List nannies:        olympusadmin@xxxxxxxxxx
==============================================

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