High Key Imaging

[Bill Giles]

Originally Posted by bobbyz

Benji,

You say " My background lights read F 10 at the subject. I take ALL meter readings at the subject, so for my background light reading I place the dome of the meter right beside the cheek of the subject aimed at the background and I take my reading."

I tried that where my main was at f8, and bg as measured at my subject with the dome (recessed) pointing towards the bg was at f10. But that settings gave me horrible flare on my subject. Subject was 6 feet away from the bg and bg light was behing the subject, hald way between subject and white seemless bg. I had to crand my bg light way down to get good exposure on the subject and still keep white on the bg.

I don't understand why it has to be f10 at the subject pointing towards the bg and don't care of what's actually falling on the bg? Suppose I increase the bg to subject distance. Now I will have to increase output of my bg light to get f10 on the subject. That will throw more light on the bg than what's needed to make it white but now totally over blwon, isn't it? Just trying to learn.

When you are measuring the light falling on the background, the background is your subject. If you are measuring the incident light reflected from the background and falling on your primary subject, then you aren't really measuring anything, because that part of your subject isn't in the picture. It's different if you're measuring rim light or hair light.

When you measure the incident light falling on your background, that doesnt change when you move your subject or your camera, within reason. If you take an incident reading on the stage at a concert, that reading will be the correct exposure whether you are in the front row or the back row, providing the light doesn't change.

Bill

[Benji]

Bobby,

There is a law called the law of reflection. This law states that the angle of incidence is equal to the angle of reflectance. What this means to the photographer is that if you place a light off at a 45 degree angle on one side of a background (and level) it will strike the background and reflect back at a 90 degree angle (45+45=90. This will be on the opposite side of course. With two lights (one on each side) you will have twice the amount of light each bouncing off and being reflected at the same angle back. If that happens to be directly bounced into the lens you will get flare.

In my set up the lights fire straight up into my box and is then bounced straight down. I simply cannot get lens flare. BUT if my lights were at 45 degrees to the background there is a good possibility that my lens could get flare. So, I would place the lights so they are not level with the background, but are up high and then angled down. That way any bounced light will be reflected down and out rather than straight out and possibly into your lens.

Benji

[bobbyz]

Bill,

I thought the subject is always the subject that you trying to take the picture of. Background is background. If you are taking a picture of the background, then I would call it the subject. If you read the tutorial, it says, measure your bg light at the cheek of your subject facing towards the bg and it should be 2/3 stops higher than what's falling on the subject. It says, don't worry how much light is falling on the bg.

Shouldn't we be measuring incident light on the bg and keep it say 1 stop higher than what's falling on the subject in this case? Like in the case mentioned, if f10/f11 on the bg and subject is f8, it should give you nice white bg. Now if you move the subject say 5 feet towards the camera and if you still keep f8 on the subject, the bg should still be white as light falling on it hasn't changed.

If instead, I measure f10/f11 at subject location, facing the bg, as I change the subject distance by 5 feet, I will have to really crank the bg light power due to inverse sqaure law. That's what I didn't understand in Benji's explanation.

[Benji]

Bobby,

If you move the subject five feet closer to you and maintain the same exposure on both the background and the subject the background will be underexposed by about one stop due to the inverse square law.

Benji

[bobbyz]

Benji,

When I said, "keep the same exposure on my subject" I meant that I adjusted my main light (as I moved the subject 5 feet closer) to make sure my subject was still gtting f8 at the new position.

[Benji]

Originally Posted by bobbyz

Benji,

When I said, "keep the same exposure on my subject" I meant that I adjusted my main light (as I moved the subject 5 feet closer) to make sure my subject was still gtting f8 at the new position.

Bobby,

If the correct meter reading was F 8 on the subject at the first position (and the aperture of the camera was also at F 8 ) and then you move the subject five feet closer to the background, and maintain the same F 8 exposure on the subject (and of course on the camera also) the background will now be overexposed by an additional one stop (or so) again this is due to the inverse square law.

Overexposing a background this much however could cause ghosting problems around the edges of the subject because the background is receiving considerably more light than what is actually needed to make it white. You really only need 2/3rds of a stop more light than what is on the subject to make the background white. This is one time when too much of a good thing is really too much of a good thing.

Benji

[joshranwest]

Thank you so much!

[UBSeng]

Another great tutorial. Love the example images of what is and what isn't. A picture is indeed worth a thousand words

Now you need to write a tutorial of "how to convince your spouse to let you cut a hole into the family room ceiling"

Thank you, Benji!!!

[Benji]

Originally Posted by UBSeng

Another great tutorial. Love the example images of what is and what isn't. A picture is indeed worth a thousand words

Now you need to write a tutorial of "how to convince your spouse to let you cut a hole into the family room ceiling"

Thank you, Benji!!!

I can't illustrate it with images, sorry.

Benji

[UBSeng]

[quote=Benji;294469]

I can't illustrate it with images. Sorry.

OK

[tmerz]

This is another excellent tutorial. So many photographer friends I know think they've got high key simply by blowing out the background to whiter than white, no matter what the subject is wearing.

Thanks for posting.

[qiv]

I like the tutorial too, it is about what I understand under high-key photography nowadays.

For a tutorial I miss the historical background. Back in the black and white days in Hollywood they used to place the key light high for the good guys, while they lite the wretches from below. This is where the terms come from, though the interpretation in photography nowadays is something else

Another non-tech question. When do you use high-key (besides brides )? What are your associations with high-key?

[Benji]

qiv,

A well done high key image is beautiful to look at and since it is fairly difficult to do, a well done and beautiful high key image will set you apart from the guy down the street who can't do it at all or doesn't do it well when he attempts to do it. Furthermore, the more variety you can show clients the more images they will buy!

Ben

[KellyL]

Thanks again, Benji!

[qiv]

What about those who take pictures for fun or arts sake?

[Benji]

Originally Posted by qiv

What about those who take pictures for fun or arts sake?

The people who take images for arts sake are usually called "starving artists." (For some reason my wife and I prefer that I be known as "well fed artist!")

I don't know what people who take images for fun are called. In addition to this being my profession, it is also fun! Maybe photographers?

Ben