Thursday, August 05, 2010

Q&A: Feathering a Soft Box

After the Monday's OA post on Betty Allison, reader Łukasz Kruk asked about feathering the small LumiQuest soft box that was used as a key light:


I understand how this works with directional light (e.g., a bare speedlight) - but doesn't the softbox's flat white panel send the light in all the directions more-or-less equally, thus rendering feathering more or less impossible? Can you feather a shoot-through umbrella -- and how?


(a) No, (b) sort of -- and (c) lemme explain…
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First off, the light in question here is a speedlight in a LumiQuest Soft Box III, but feathering will work with any soft box.

Light coming of of a soft box panel does not have a defined beam like a small light source inside a reflector would, but it still has some shape. Think of in terms of how much of the soft box panel you can see from different positions around the light.

If you are directly in front of it, you will see the full face of the soft box, and the intensity of the light you receive will be a function of how far away you are. But as you move around toward the side of the soft box, you will see less apparent surface area because of your angle of view.

You can use this "edge" of the light to control how light falls across your subject, as in this close-up portrait (more here) that I did with the same light source.

In that example, instead of pointing the light right at his face it was rotated around away from him (towards me) and also pointed further up than you would expect. This placed his face in the area where the intensity of the light is falling off, which is what gives you that nice gradient towards the camera-left ear and down his torso.

(If you need to get even more of an edge to a small soft box, that's an easy mod, too.)

The light is less than a foot from his face, and hand-held. That way, it is easy to look at the image popping up on the back of the camera and adjust the angle as you shoot. Kind of the ultimate voice-activated light stand, 'cause it's you at both ends.


Umbrellas (speaking of shoot-through versions here) are a different animal, because they present themselves as almost hemispherical -- sending the light out in almost a 180-degree pattern.

You can't really feather a shoot-through umbrella per se, but you can control the spill by partially gobo'ing it.

The photo at left is a good example -- more details and a diagram here.


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12 Comments:

Blogger Ray said...

I'm very much amateur and like a lot of others practise their craft in their spare rooms which may be quite small.

The thing that I've learned is that with small rooms, feathering across the subject as in DH's article may end up with unintended fill bouncing off the wall that the softbox is pointed at (unless you have negative fill cards etc)

For this reason, when indoors/tight spaces, I will generally feather past the subject so the face of the softox is at the background behind the subject. Doing this avoids the potential for unintentional fill.

Ray

August 05, 2010 5:49 PM  
Blogger Scott said...

I've always thought of a feathered soft box as a strip light, no?

August 06, 2010 12:25 AM  
Blogger David said...

Hey, Ray-

Not quite sure why you would choose to feather past the person towards the BG, as that would keep all of the light on the light-side of the subject. Kinda defeats the purpose for what I am usually trying to do.

But if you are having trouble with light bouncing around on the other side of the subject, I would suggest bringing it in really close and letting the inverse square law be your friend for the day!

-D

August 06, 2010 2:32 PM  
Blogger David said...

@Scott-

It does have less horizontal wrap, to be sure - which makes it similar to a strip light in tat way. But it also has an edge to the beam that a strip light does not have.
-D

August 06, 2010 2:33 PM  
Blogger Happy Photography Blog said...

Nice picture. Thank you for sharing LumiQuest SoftBox experience. I made my picture with similar LumiQuest setup.

http://photologs.net/portfolio/pludmales-fotosesija/

Maybe you can comment?

August 06, 2010 3:29 PM  
Blogger Łukasz Kruk said...

woah, now that was unexpected. thanks for detailed answer.

being lazy that i am i wrote that comment first, and went to experiment LATER - with a shoot-through, on a sunny noon. conclusion was similiar to your answer here, that the amount of light received depends on area of light softener's surface "seen" by the subject. it still seems to me that that every point on the brolly sends light in all directions though - if not equally much of it, then at least reasonably close, so the main thing one should watch out for here is the area.

i was also surprised by how big a difference is made by facing (roatating) the umbrella away just by literally few degrees when working close in - or by moving it by a few centimeters (anglophones might want to divide that by 2.5 for inches...)

oh, and thanks for not linking my website in the post as it probably wouldn't have withstanded the typical strobist traffic effect. oh no, wait, it's hosted by google (HINT) ;)

August 06, 2010 5:27 PM  
Blogger Tom Nutter said...

Can you feather a shoot-through umbrella...yes, of course, I did it today. While I agree that because it is more directional, feathering a softbox is easier, you can employ the same concept with a shoot-through umbrella.

I only had a 45-inch shoot through umbrella available in my kit today when I photographed a doctor in white for a headshot. At first, I shot with the umbrella aimed directly at the doctor from fairly high.....the white jacket was way over-exposed compared to his face. I didn't have a gobo, so I simply turned the umbrella to a much more extreme angle, so it was basically aiming at the ceiling in the cramped office, and the jacket went to a much more manageable value. The light was extremely close to the subject... about two feet, so I basically turned a big circle of light into more of an elipse of light that fell off much more quickly.

August 06, 2010 10:47 PM  
Blogger Bo said...

A language question from a non-native-english-speaking reader:
what do you mean with "feathering" a umbrella or softbox?

August 07, 2010 4:41 AM  
Blogger RayPlay said...

Bo
a bit like using the'hardness' of a brush in photoshop

August 07, 2010 3:07 PM  
Blogger Donovan said...

Bo,

When the edge of a light's reach is well defined, forming a line between lit and unlit, that is a hard edge. When the light drops of gradually, we called that a feathered edge, so the light source is considered to be feathered.

August 07, 2010 3:50 PM  
Blogger Ray said...

hi Dave,
Perhaps I'm misuing the term.

In this image here:
http://www.flickr.com/photos/whatdoineed2do/4869899738/

I am 'feathering' past the subject - the softbox starts off at 45 and then gets rotated away from the subject and camera so there's still a little bit of modelling.

Am I using the wrong terminlogy?

August 07, 2010 6:43 PM  
Blogger Surly said...

Sort of Off Post
Syl Arena addressed the Canon optical sync issue
http://preview.tinyurl.com/36ccgub

Enjoy your vacation!

August 10, 2010 10:47 AM  

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