One Speedring to Rule Them All: One Set of Modifiers for Speedlights and Strobes

[OK, if you're a longtime reader of this blog you know I've used that headline before.  It was just too tempting... :) ]

Are you new to studio strobes or are thinking of getting strobes in the future?  One of the issues with moving up to studio strobes is the modifiers.  You may already have modifiers for speedlights.  Do you really need to buy a whole new set of modifiers for a studio strobe?  Not if you plan ahead.  Details after the jump.

BTW, this post is part of a series called Toys for Big Kids, where we discuss modifiers for setup shots, when considerations of time, convenience, and/or cost take a backseat to emphasis on control and getting the best result possible.

Do small modifiers offer any benefit? (Basic to Intermediate)

We know that the quality of light (softness vs. hardness) is based on the apparent size of the light source compared to the subject.  Soft light, with blurred shadows or no shadows at all, results from a large light source.  Hard light, with a well defined shadow, results from a small light source.

It is frequently said that in order to get soft light, the light source has to have a larger apparent size than the subject.  It's hard to disagree that soft light would result in such circumstances.

What happens though if the light source is larger than a point source but is smaller than the subject?  Will there be any softening of light?  Initially, it may seem that with a small modifier, the shadow will be smaller but just as hard as the light from a point source:

However, the above analysis is actually incomplete because light from opposite edges of the modifier will also illuminate the subject.  As a result, even if the modifier is smaller than the subject, the shadow edges will appear softer:

Let's take some test shots to check if this is true.  For this test, my subject was a 47-inch TV with a width of about 41 inches, a height of around 23 inches, and a surface area of around 943 square inches.  For my light source, I tested a bare flash as well as a 19.5-inch reflective umbrella with a surface area of around 299 square inches.  The light source was therefore smaller than the subject in every respect - height, width, and surface area.  In addition, the umbrella surface was positioned about 2 feet from the TV, which further decreased its apparent size.  The flash was triggered by the popup flash (covered with an SG-3IR panel to avoid affecting the results).  Here is the setup shot:

Test shot 1: bare flash at 105mm zoom.  As expected, the shadow looks hard.  The bit of blurriness at the edge is because the TV's bezel has a glass edge (which presumably caused a bit of refraction).

Test shot 2: bare flash with the built-in diffuser.  As expected, the shadow looks just as hard as with the zoomed flash because diffusion by itself doesn't soften light.

Test shot 3: flash with the 19.5" reflective umbrella.  The shadow edges have become a little blurred, evidence that the light has become softer.

Thus, we've confirmed that a light source that is larger than a point source can create soft light even if it is smaller than the subject.  Of course, the smaller a modifier is, the less of any softening effect it will have


I'm not saying every small modifier out there is useful.  There are a number of modifiers out there that are simply too small to have any material softening effect for portraits.  Moreover, there are modifiers that are designed primarily for diffusion - but the problem is that diffusion by itself (without a material increase in the size of the light source) has no softening effect whatsoever.  There are also some modifiers that do cause a slight increase in the size of the light source but are no better (in my opinion) than using a bare flash.  Finally, please consider that although light quality is important, other aspects of light such as its direction and the highlight-shadow contrast may have a bigger impact on your photos.

Looking for a small modifier?  You may be interested in a double bounce card, or better yet, these small umbrellas for a handheld umbrella.

Handheld umbrella - an excellent light modifier

I've tested what I think is a very useful light modifier - a handheld umbrella.  I'm not claiming to be the first to come up with the concept. Renowned photographer Bob Krist mentioned it in his blog in April 2009. Here's my preferred implementation of the handheld umbrella concept, which I'll call H2U for short (pardon the crappy pictures of the device):

I used the following components:
umbrella - Westcott double-fold 43" convertible umbrella  (got mine here)
umbrella swivel (got mine here)
Nikon AS-19 speedlight stand (the one that came with the SB-800)
and the flash (SB-800).

The umbrella swivel I have has two studs - one male and one female. I switched them from their normal positions to use the male stud on the tilting portion of the swivel. I connected the stud to the bottom of the AS-19, which has a tripod socket. Next I tilted the swivel to as close as 90 degrees as possible (note: the AS-19 is positioned sideways, with the Nikon logo facing away from the swivel handle). Finally I connected the SB-800 (with the head positioned to bounce vertically) to one of the cold shoes for an SB-R200. When all is done, the SB-800 is positioned very close to the axis of the umbrella, and I can use the non-tilting part of the swivel as a sort of handle. If I need to use the umbrella with a lightstand in a jiffy, I can do that via the female stud on the non-tilting portion (although the umbrella won't be tiltable).

The advantage of using an AS-19 is that it has a receptacle for the SB-800's locking pin, so I feel it's more secure. Without an AS-19, it's possible to use instead the cold shoe that came with the swivel (hopefully your swivel was supplied with one). The problem is that my cold shoe won't hold the SB-800 in place. If I had to do it this way, I would position the SB-800 with the back against the umbrella's handle to sort of prevent the flash from sliding off.

Advantages:
Larger light source (hence can produce softer light) than most portable modifiers (I'm talking about the various forms of plastic modifiers that can be attached to a flash.
Once the components are assembled, deploying the system is pretty fast - you just open the umbrella.
If a collapsible umbrella is used, it's reasonably portable when folded.
Cost - If you already have an umbrella, you probably also have a swivel and could assemble it without buying anything new.

Disadvantages:

• Sometimes gets attention from onlookers.
• Even when collapsed, it's bigger than a typical modifier.
• Hard to use from camera right.

So how well does this modifier work? I tested it in one of the most demanding lighting situations - outdoors, midday sun in summer, no clouds. Here are the shots I got:

Example 1


Example 2


In both shots, I asked my wife to stand in a shade (to avoid having to overpower the very bright ambient). I held the H2U camera right as key light. I triggered the flash with CLS. I shot in RAW to give me as much leeway as possible. The shots aren't great but I think they prove the usefulness of the H2U. I think the end result is close enough to what I had in mind in terms of lighting (although I had to do quite a bit of postprocessing to try to save the background - and I am unskilled at postprocessing).

Ideally, if I had a flash with sufficient power (and/or a camera with a really high sync speed), I could have brought down the ambient exposure by 1 or 2 stops, then used sufficient flash power to light the subjects. Like this shot by Neil van Niekerk. I tried this but the shot came out underexposed. To be fair, I had the flash with the wide angle diffuser to cover the entire umbrella, and I was trying to use the reflective underside of the umbrella without putting the black cover (though I'm not sure how much the black cover would have helped). Maybe next time I'll try a more efficient non-convertible reflective umbrella and I'll zoom the flash head. It would also have been nice to put the subject at the edge of the shade to use the sun as rim light, but here I opted to prioritize the composition. And my wife was getting impatient. :)

You may have noticed the light is coming from the camera right. I held the H2U with my right hand while I took the shot holding the camera with my left hand, pressing the shutter with my ring finger. It's not so easy to do that and depending on your camera/lens combination, that might not be feasible. An alternative is to use a remote (holding the remote and H2U with your right hand, and holding the camera with your left).

I also tried the H2U indoors to simulate situations where bouncing is for some reason not possible such as really dark or really far/high walls and ceilings. I'll discuss how those shots turned out here.

Update 4/17/10: I recently tested a handheld convertible umbrella against a handheld softbrella for efficiency.  These are the results.
Update 4/25/10: here is a list of small umbrellas that are convenient for use as a handheld umbrella.

Update 5/4/10: I reviewed what may be the ideal handheld umbrella here.