using the AF500FTZ in manual mode
Posted 18/02/2004 - 15:52
Link
Flash intensity from a flashgun drops off with distance in the following way
- doubling subject distance reduces flash intensity 4x.
This is the basis of how guide numbers work and the relationship is based on the divergence of light from a point source through 3d space. The solid angle of the beam itself is irrelevant, the relationship still holds.
In relation to your problem therefore, you have stated that at full power your subject has correct exposure at 4m with the camera settings you have chosen. Therefore at 8m your subject will have 1/4 of this exposure. As a rough calculation, for a -1 stop (1/2 exposure) you would need to move the subject back to approx 6m (It is not exactly 6m as the relationship is not linear but this can be calculated more accurately with guide number calculations). Of course now your flashgun will tell you that your subject is out of range (pay it no attention).
In the case where you have set your flash to 1/2 power you say your subject has correct exposure at 2.4m (notice how it is not 4m due to the flash fall off relationship I have given you) and 1/4 of this exposure at 4.8m, therefore for -1 stop exposure you would need to move the subject back to approx 3.6m.
Andy
- doubling subject distance reduces flash intensity 4x.
This is the basis of how guide numbers work and the relationship is based on the divergence of light from a point source through 3d space. The solid angle of the beam itself is irrelevant, the relationship still holds.
In relation to your problem therefore, you have stated that at full power your subject has correct exposure at 4m with the camera settings you have chosen. Therefore at 8m your subject will have 1/4 of this exposure. As a rough calculation, for a -1 stop (1/2 exposure) you would need to move the subject back to approx 6m (It is not exactly 6m as the relationship is not linear but this can be calculated more accurately with guide number calculations). Of course now your flashgun will tell you that your subject is out of range (pay it no attention).
In the case where you have set your flash to 1/2 power you say your subject has correct exposure at 2.4m (notice how it is not 4m due to the flash fall off relationship I have given you) and 1/4 of this exposure at 4.8m, therefore for -1 stop exposure you would need to move the subject back to approx 3.6m.
Andy
Posted 18/10/2005 - 02:17
Link
What anonymity levels of HTTP proxy servers exist?
1. Transparent - these proxies are not anonymous. They don't hide IP-address of a client and let a web server know that you are surfing through a proxy server. The task of such proxies, as a rule, is information caching and/or support of Internet access for several computers via single connection. Such proxies are not applicable for security and privacy while surfing on net. You can use them only for network speed improvement.
2. Anonymous - these proxies don't show your real IP but change the request fields so it is very easy to detect that you are using proxy.
3. High Anonymous - these proxy servers do not pass an IP-address of a client and don't send any variables indicating that you are using proxy server to host and look like real browser.
http://www.socksproxylist.com
1. Transparent - these proxies are not anonymous. They don't hide IP-address of a client and let a web server know that you are surfing through a proxy server. The task of such proxies, as a rule, is information caching and/or support of Internet access for several computers via single connection. Such proxies are not applicable for security and privacy while surfing on net. You can use them only for network speed improvement.
2. Anonymous - these proxies don't show your real IP but change the request fields so it is very easy to detect that you are using proxy.
3. High Anonymous - these proxy servers do not pass an IP-address of a client and don't send any variables indicating that you are using proxy server to host and look like real browser.
http://www.socksproxylist.com
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2277 posts
24 years
i wantthe flash to burst 1/2 of its power so it is 2 ambient light and 1 flash light
from the flash manual it says to push the button of compensation for example to 1/2..
when the flash is still in full power 1/1 the lcd display tell for example 4 meter which mean the distance from where i should take my picture.. but when i push the button to make it 1/2 the lcd mark 2.4 m... so the question at which distance i should take the pic to have the flash 1/2 of its power...in the flash manuall too it says for example
GN for 1/1 50 at 28mm and 40 for 1/2 and 20 for 1/4.. so which GN i must use to have the fill in result i want.. thank