Family of Angles.

[xpatUSA]

I think the phrase conveys the totality of the meaning reasonably well. To quote from Light: Science and Magic beginning at the bottom of page 41: "Each surface is made up of an infinite number of points. A viewer looking at a surface sees each of these points at a slightly different angle. Taken together, these different angles make up the family of angles that produces direct reflection." (The italic font that provides emphasis is in the book.)

Thanks Mike. I hadn't read the book but that explanation does indeed make sense of the phrase.

Big family, though.

[Manfred M]

Personally I hate the expression of "family of angles", when what they are really trying to say is: "Postion your light off to the side so that the camera does not pick up its reflection".

This is really no different than a photographer taking a picture that has a mirror in it and positioning him / herself in such a way that they don't show up in the shot.

[Manfred M]

Okay. Fair enough Manfred. I certainly don't want to confuse the issue. I see enough of that as it is!

So my apologies to you and Haseeb.

Haseeb, Manfred is right in saying that it is not the type of light you are using (diffuse or not).

It is the type of surface you are lighting and how it reflects light that makes the determination.

No problem Terry. I can be as confusing and obtuse as the next techie.

[Mike Buckley]

Personally I hate the expression of "family of angles", when what they are really trying to say is: "Postion your light off to the side so that the camera does not pick up its reflection".

I disagree, Manfred. To use your context, they are trying to say: "Depending on how you want the image to look, position your light off to the side so the camera doesn't pick up its reflection or position it in line so the camera does pick up its reflection." As an example, traditional photographs of shiny metal subjects would be made using the latter method.

I'm not suggesting that there isn't a better phrase than Family of Angles. I'm only saying that it's reasonably appropriate because, by definition, it's as reasonably complete as any three-word phrase can be.

[Manfred M]

I disagree, Manfred. To use your context, they are trying to say: "Depending on how you want the image to look, position your light off to the side so the camera doesn't pick up its reflection or position it in line so the camera does pick up its reflection." As an example, traditional photographs of shiny metal subjects would be made using the latter method.

I'm not suggesting that there isn't a better phrase than Family of Angles. I'm only saying that it's reasonably appropriate because, by definition, it's as reasonably complete as any three-word phrase can be.

I hear you Mike; but to paraphrase a quote that has been attributed to Einstein; "Things should be made as simple as possible, but not any simpler."

I'm afraid that this phrase fails that test. I understand what the authors are trying to do, but unfortunately clarity has been lost by trying to simplify a principle that won't simplify to three words.

[Mike Buckley]

Manfred,

I wonder if you are aware that one of my favorite authors about making monochrome photos, Vincent Versace, also uses that Einstein quotation prominently in at least one of his books.

I understand what the authors are trying to do, but unfortunately clarity has been lost by trying to simplify a principle that won't simplify to three words.

Of course clarity is lost if one relies only upon the phrase. Fortunately, the authors explain the purpose of the phrase in great detail. The phrase, "family of angles," is used as nothing other than a reference to the detailed explanation.

People refer to a particular phrase regularly here at CiC that is used prominently in at least one CiC tutorial: "exposure triangle." That phrase means nothing on its own; very much like the phrase, family of angles, it requires clarification in order for one to be able to achieve practical application.

Personally, I see no problem with phrases such as "exposure triangle" and "family of angles" until someone improves upon them. Their meaning isn't to be fully understood by reading only the words of the respective phrases; just the opposite, their meaning is to be fully understood only after comprehending a full explanation. If we eliminate the use of all phrases that require comprehension of their full explanation, reasonably practical communication would come to a halt.

[Manfred M]

Again Mike; I hear you and it's great that you and I have the same book and understand what it is written there.

The issue I have with these phrases; "circle of confusion" is another one, is that they end up in common use and unfortunately tend to confuse more than they clarify.

The problem is that there is no such thing as a "family of angles". Not only is is mathematical nonsense, it actually not particularly descriptive of what is happening. We really have an angle that is the reflective limit. Anything inside that angle will be seen in the image and anything outside of it won't show up in the image. The diagrams in the book are two-dimensional, yet what we see happens in 3-D space; so we actually have to watch were we position the light in both the horizontal and vertical planes.

[Mike Buckley]

[these phrases] end up in common use and unfortunately tend to confuse more than they clarify.

Agreed. Another good example of that: "expose to the right"

[xpatUSA]

The issue I have with these phrases; "circle of confusion" is another one, is that they end up in common use and unfortunately tend to confuse more than they clarify.

The problem is that there is no such thing as a "family of angles". Not only is is mathematical nonsense, it actually not particularly descriptive of what is happening. We really have an angle that is the reflective limit. Anything inside that angle will be seen in the image and anything outside of it won't show up in the image. The diagrams in the book are two-dimensional, yet what we see happens in 3-D space; so we actually have to watch were we position the light in both the horizontal and vertical planes.

I suppose those old-fashioned ball-room spheres with the small mirrors might qualify. Or models wearing similar dresses: "Excuse me, Miss, I just need to check your family of angles . ." - should go down well

Speaking of spheres, a geeky thought occurs. How would one avoid the so-called 'family of angles' when shooting a ball bearing on a table-top, lol?

[HaseebM]

I suppose those old-fashioned ball-room spheres with the small mirrors might qualify. Or models wearing similar dresses: "Excuse me, Miss, I just need to check your family of angles . ." - should go down well

Speaking of spheres, a geeky thought occurs. How would one avoid the so-called 'family of angles' when shooting a ball bearing on a table-top, lol?

Come to think of it..

[Manfred M]

Speaking of spheres, a geeky thought occurs. How would one avoid the so-called 'family of angles' when shooting a ball bearing on a table-top, lol?

Through obfuscation?

[Mike Buckley]

How would one avoid the so-called 'family of angles' when shooting a ball bearing on a table-top, lol?

Seriously, you would do that using flags. I can also imagine lighting the ball bearing only at the extreme limit of the family of angles, such as when lighting clear glass to display white edges against a black background.

[Loose Canon]

Not to mention dealing with any mirror reflections in the ball bearing such as you, the camera, and anything else that's in the Happy Family!

[Manfred M]

Not to mention dealing with any mirror reflections in the ball bearing such as you, the camera, and anything else that's in the Happy Family!

That is why I suggested "obfuscation".

The highly polished steel ball bearing is effectively a mirror that reflects 180 degrees around two axes; in otherwords anything infront of it. The lights, camera and photographer will appear as reflections, whether we like it or not.

What we can do, is hide these items in plain sight, so to speak. The convex shape of the ball bearings means that things will look smaller in size, so by positioning the photgrapher and camera far away, with a long lens, only the sharpest eyes will pick up any details in those reflections. Same thought goes for lighting the subject. We can position a softbox so that it adds to the three-dimensional look of the ball bearings or choose a huge diffuse light source that seems omnipresent.

[Mike Buckley]

I'm not mechanically minded (I'm exactly the opposite), so I wasn't aware that ball bearings are made of bright, shiny metal. Regardless, if you really want to know at least one method of photographing a subject with similar photographic properties, refer to page 148 of Light: Science & Magic.

Manfred's suggestion to use a long lens is a good one. However, unlike how many people including myself would initially think, that's not to make the reflection of the camera smaller. It's not significantly smaller using a long focal length than being closer and using a short focal length. The difference is that using a long focal length allows the camera to be farther away from the subject and less likely to have extraneous light falling on the camera.

[Mike Buckley]

the Happy Family!

That Happy Family has made me very unhappy at times.

[xpatUSA]

What we can do, is hide these items in plain sight, so to speak. The convex shape of the ball bearings means that things will look smaller in size, so by positioning the photgrapher and camera far away, with a long lens, only the sharpest eyes will pick up any details in those reflections. Same thought goes for lighting the subject. We can position a softbox so that it adds to the three-dimensional look of the ball bearings or choose a huge diffuse light source that seems omnipresent.

That is indeed my experience in watch photography, Manfred. I use two lamps and two 8x10" diffuser panels which are actually 'huge' relative to the size of the watch body. And the longer macro lens is indeed 'better' than the shorter (70mm vs 50mm).