Family of Angles

[Dylan-06]

I'm really hoping someone can help me !!

Most of my images have been taken using natural light, but I want to learn more about studio lights, flash and light in general.
I'm reading 'Light, the science and magic', and I've got to 'the family of angles', !! I've read this section and re read a number of times, but it's just not going in !!!

Please can someone try expaining it to me...



Thanks in advance for any help

[scootermcq]

Sure the angle of incidence = angle of reflection

Think of a pool table. It the ball strikes the rail dead on, it will bounce straight back the same same way. If you bounce a ball off the rail on an angle, it will leave the rail at the same angle and travel down the table.

If the ball is your light source and you are shooting a reflective surface, if you place the camera where the ball is going to bounce, then you will have glare or reflection. If you place the camera anywhere else on the table, then you will not get glare.

This is important with shooting items behind glass, or people with glasses etc.

[Doug Sundseth]

As Scott noted, AoI = AoR. The family of angles bit comes into it when you have a large light source (which means that you'll get reflections off of a flat surface over a variety of angles), a large reflective surface (same thing), or a curving reflective surface (which is the spawn of the devil).

In each of these cases, you'll get a direct specular refection (that is, you'll see the reflection of the light source) on some part of your subject when your camera is anywhere in the cone (a simplification that assumes a flat reflective surface) of reflection from the light source.

[Dylan-06]

Originally Posted by scootermcq

Sure the angle of incidence = angle of reflection

Think of a pool table. It the ball strikes the rail dead on, it will bounce straight back the same same way. If you bounce a ball off the rail on an angle, it will leave the rail at the same angle and travel down the table.

If the ball is your light source and you are shooting a reflective surface, if you place the camera where the ball is going to bounce, then you will have glare or reflection. If you place the camera anywhere else on the table, then you will not get glare.

This is important with shooting items behind glass, or people with glasses etc.

Thanks Scott, this is a great explanation, I think i'm starting to understand now

[Dylan-06]

Originally Posted by Doug Sundseth

As Scott noted, AoI = AoR. The family of angles bit comes into it when you have a large light source (which means that you'll get reflections off of a flat surface over a variety of angles), a large reflective surface (same thing), or a curving reflective surface (which is the spawn of the devil).

In each of these cases, you'll get a direct specular refection (that is, you'll see the reflection of the light source) on some part of your subject when your camera is anywhere in the cone (a simplification that assumes a flat reflective surface) of reflection from the light source.

Thanks Doug, another great explanation ( I'll beware of the curving reflective surface, for now) lol

[ccting]

using a reflection disk with stand, perhaps?