Light meter question

Do you use the dome or flat diffuser when shooting portraits. I saw in a book that you should always use a flat panel diffuser, as the dome would pick up inadvertant light that could throw the reading off.

Hi Tim,

When taking incident readings of three dimensional objects you always use the raised dome. When it comes to portraits and photographs of the human face, the dome closely approximates the dimension and curve of the features on a human face.

If you were shooting flat artwork or documents, fabrics, etc. then you would use the flat disc.

You should throw that book in the trash where it belongs.

tmonatr wrote in post #5965785
Do you use the dome or flat diffuser when shooting portraits. I saw in a book that you should always use a flat panel diffuser, as the dome would pick up inadvertant light that could throw the reading off.

Also... think about it. If you want to get an accurate exposure on a person's face, wouldn't you want to measure ALL the light that falls on the face? What is being called inadvertent light is important light because it is contributing to the overall exposure.

If you didn't want to have inadvertent light in your exposure then you would need to block that light with a flag or gobo of some sort. Then, not only does it not reach the meter but it's not being factored in to the exposure.

But you always want to measure whatever light is falling on the subject.

TMR Design wrote in post #5965829
Hi Tim,

When taking incident readings of three dimensional objects you always use the raised dome. When it comes to portraits and photographs of the human face, the dome closely approximates the dimension and curve of the features on a human face.

If you were shooting flat artwork or documents, fabrics, etc. then you would use the flat disc.

Thanks, Robert. I was thinking that was the case, but wanted to make sure.

cdifoto wrote in post #5965842
You should throw that book in the trash where it belongs.

Actually, I left it on the shelf at the bookstore.

I am getting the Polaris SPD100 ( cheap and allows exposure compensation). At B&H Photo they have a package with the flat panel diffuser for only $10 more than the meter alone and was wondering if I would really need it.