Reply to thread

Message

<blockquote data-quote="WayneF" data-source="post: 176738" data-attributes="member: 12496">About the little diffuser...&nbsp;&nbsp; Arguably anything is better than nothing, but still tiny, and wishful thinking.&nbsp;&nbsp; IMO, you really will instead enjoy bounce flash indoors, when possible.&nbsp;&nbsp; The little diffuser could be great up very close (when it might appear big), like for macro work.&nbsp; Nothing wrong with it then.&nbsp; <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile&nbsp; &nbsp; :)" loading="lazy" data-shortname=":)" />&nbsp; For this reason:Our trig can compute the angular size of a light, as seen from the subject, by 2 arc tan(radius of size / distance).A bare 2 inch flash head at five feet:&nbsp;&nbsp; 2 arc tan(1/60 inches) = 2 degrees size.The diffuser appears four inches, so double that, nearly 4 degrees size.A 40 inch umbrella,&nbsp; 2 arc tan(20/60) = 37 degrees.See?&nbsp; &nbsp; The light (big and close) has some light coming from subjects left, and some light from their right, etc,&nbsp; so that every light path fills the shadows from all the other light paths.&nbsp; That size is what makes light soft... big and close.&nbsp; Close makes it bigger.Our Sun is 0.5 degree size (harsh shadows, not soft).&nbsp;&nbsp; 2 or 4 degrees is not all that much different. 37 degrees though, that is quite different. And 60 degrees is even better.The rule of thumb for guaranteed soft enough for practical purposes is a light diameter more or less equal to its distance from subject.Bounce flash makes a pretty large lighted area on the ceiling.</blockquote>

[QUOTE="WayneF, post: 176738, member: 12496"] About the little diffuser... Arguably anything is better than nothing, but still tiny, and wishful thinking. IMO, you really will instead enjoy bounce flash indoors, when possible. The little diffuser could be great up very close (when it might appear big), like for macro work. Nothing wrong with it then. :) For this reason: Our trig can compute the angular size of a light, as seen from the subject, by 2 arc tan(radius of size / distance). A bare 2 inch flash head at five feet: 2 arc tan(1/60 inches) = 2 degrees size. The diffuser appears four inches, so double that, nearly 4 degrees size. A 40 inch umbrella, 2 arc tan(20/60) = 37 degrees. See? The light (big and close) has some light coming from subjects left, and some light from their right, etc, so that every light path fills the shadows from all the other light paths. That size is what makes light soft... big and close. Close makes it bigger. Our Sun is 0.5 degree size (harsh shadows, not soft). 2 or 4 degrees is not all that much different. 37 degrees though, that is quite different. And 60 degrees is even better. The rule of thumb for guaranteed soft enough for practical purposes is a light diameter more or less equal to its distance from subject. Bounce flash makes a pretty large lighted area on the ceiling. [/QUOTE]

Verification