Paul C. Buff, Inc. Technical Forum

Hi Everyone,

Please bear with me as I just opened my new photography studio and I am very new to strobe lighting. I'm currenlty using 3 SB-800 Alienbee strobes with a 36" Octo-softbox and 10 x 13 hairlight softbox with grid. On the third bee, I have it bouncing off of an umbrella.

My question today is regarding correct arperture/f-stop combination for "in-studio" portraits. I am using a 10' x 12' chroma-key backdrop (as I want to be able to digitally choose the backgrounds) and was wondering if F/8 @ 1/125 is a reasonable setting (just for conversation purposes let's say that I'm shooting waste-up shots? My shots are coming out clear and my histogram is practically dead-on. Should I leave well enough alone? I'm just not sure if there's a right or wrong here. I want to be consistent with what other photographer's are doing and sound like I know what I'm talking about when I get into a conversation.

Also, totally different topic... Is there a way to eliminate two catch lights in the eye's? I have the hairlight over the subject on a boom-arm set off to the side and then the Octo-box set on the left side and the umbrella-bounce on the right side.

I appreciate any critiquing anyone can offer (good or bad) because it will make me a better photographer.

Thanks for your time! : )

To avoid confusion, I must clarify that aperture and f/stop are the same. The combo you are asking about is a shutter speed/aperture combination.


The definition of aperture is an opening. f/stop defines the relative size of the opening. This dictates how much light the sensor recieves in a given time frame.


Shutter speeds are expressed in seconds, so the 1/125 is 1/125 of one second. This is the given time frame referenced above, or how long the sensor will be receiving light.

The combination of the two (along with the ISO and light intensity) make up how bright your image will be.

For the purposes of studio photography with flash, shutter speed is not going to affect your exposure within 1/60 to 1/200, so it will not matter what shutter speed you set within those bounds. If you wish to know the why's, I will be glad to explain them.

ISO will affect exposure. However, it is typically best to shoot at the lowest available ISO, 100 or 200. This keeps noise down and image quality up.

The aperture you wish to use is subjective. All else being equal, the smaller the aperture number, the less depth you have to your focus. If you shoot a group 3-4 people deep, f/3.5 will not render all of them clearly. On the otherhand, if you are shoting only one person, and you want to draw attention to thier face, using f/3.5 will blur everything but thier face (or even thier eyes). The aperture you use is situation dependent. f/5.6 to f/11 is often regarded as the sharpest zone for most lenses, so may people shoot at those apertures. There is really not a right or wrong.

The combination you gave will work fine, and is a common setting.

Once you decide on the aperture you wish to use, you will need to meter and adjust the lights to match that aperture.





One of the two light sources will need to be moved so that it does not reflect in the eye back to the lens. This will be difficult as the surface of the eye is convex. I would not put too much stake in the catch lights.

Thanks so much... One of the mistakes I think I'm making is that even though my histogram looks dead-on, I don't believe I'm metering the strobe outputs so I don't really know if the f/8 arpeture on my camera matches the arpeture from my flash meter reading.

I'm so glad there's forums like this because there's always somone out there smarter than me and I rely on this feedback.

Thanks again - MUCH appreciated!

When you hit the button for your meter, do the lights fire?

Please bear with me as I just opened my new photography studio and I am very new to strobe lighting.

Scary question from anyone who has just opened a photography studio. Hopefully you got the help that you needed.

Stop using the histogram to meter studio lights...buy a lightmeter. That's what they're for...

A histogram is pretty useless if you ever try high or low key...