Ever wondered how various light modifiers shape the light and how much light they use? Knowing the quality of light a modifier produces and how much light it consumes can be a huge help in figuring out how to light any given scene.
Hopefully this post will give you an illustrated version of what various speedlight modifiers do, MUCH more after the jump...
I've been meaning to do this post for a long time, in as much for myself as well as for others. I have to say this little test came in quite handy and I hope you will get something out of it too!
The first thing I did to get as accurate of a test is possible was to set a base, ambient exposure which rendered my scene completely black. In other words, the only light I wanted in the scene was what my flash was adding. This exposure was f/5.6 at 1/250 sec ISO 200. This is also the same exposure I used for every single photo in this post. The only adjustment made was the power setting on the flash itself.
In this first photo, you can see that f/5.6 at 1/250 sec ISO 200 renders a completely back scene with no ambient light contributing to the exposure. This particular photo is available as a fine art print for a very reasonable price ...and it makes a really nice gallery wrap! :)
It should also be noted that all of these photos are straight out of the camera. There was no post work done except to rotate, add the text and size for the web. All of the following photos could probably be improved by adjusting exposure around 1/3 of a stop or doing a little touching up in post but I wanted these to be as clean and accurate as possible.
In this photo (with flash added), my lovely model is being lit with a bare speedlight at 1/16 power. This is what to my eyes gave me the most accurate exposure using the settings mentioned above. Again, the only thing that was changed from this photo and the above fine art print is the flash was added and I dialed in the power to what I thought was a proper exposure.
Also for future reference, I made sure that the light modifier (or bare light as it were) was exactly 3 feet away from my subject in every shot. So for example, the bare face of my speedlight is 3 feet away from my subject's face. When I use a shoot thru umbrella in one of the shots below, the front of the umbrella is 3 feet away from my subject's face.
The reason I did this was so that distance doesn't play a contributing roll in how the light effects my subject.
In this next photo I again used a bare speedlight, but I zoomed the flash head from 24mm to 105mm. Note that I had to reduce power when zooming the flash head! Just by zooming, it gives you a more concentrated beam of light, so to get a "balanced" exposure, I had to dial the flash power down.
Stofen Omnibounce. This is basically a slip on diffuser that spreads the light wider than the flash's fresnel head is capable of. When I used the bare speedlight at regular zoom, I had to set the flash on 1/16 power, but when I used the Stofen, I had to set my flash power to 1/8 power. Why is this important to know? Because it tells me that the Stofen eats up about 1 stop of light. So now that I know this, the next time I decide to use it, I will be more familiar with this modifier and can get a well exposed image, quicker ...at least that is the theory anyways. ;)
Honl Traveler8 Softbox. This little softbox has an 8" round face and folds down nicely in any camera bag. Its a very handy modifier to have for portraits where you can get the light in close, or it works great as a hairlight! This modifier also seems to use about one stop of light.
Lumiquest SBIII for this portrait and at 1/10 power, it appears to use just a tad less than one stop of light. I honestly love this modifier and use it quite frequently.
Westcott 43" Double Fold Shoot Thru Umbrella. It makes one of the best soft lights of any of my modifiers and this is another one I use a lot. I was surprised to see that it uses almost 2 full stops of light, but my flash was still only at 1/4 power, which means I can crank out shot after shot without worrying about recycle time. I absolutely love this modifier and actually own several of these.
Lastolite Ezybox Hotshoe. This is a really nice modifier and creates a soft light that is more directional than a shoot thru umbrella. Its perfect for headshots and 3/4 poses and folds down neatly. IMO its a little costly, but the quality is excellent and it does just what I need it to do. It uses a little less than 2 full stops of light, but produces such a nice quality of light, its well worth it.
Honl 1/8 Grid, actually restricts and shapes the light to a narrow beam. Its a hard light with defined edges. Grids work well at providing accent light, side light, background light or hair lights. It literally produces a small, circular spot of light as opposed to a larger "wash" of light. I love all of the Honl products, especially these grids, they are built rock solid!
1/4 Honl Grid. It produces a slightly larger spot of light which should be evident by the fall off of light on the wall behind the model. Something else to note about these grids is that notice the power settings? They are no different than using a bare speedlight. These grids use almost no light which means they are much more efficient than the other modifiers tested so far. Also, grids can be used as key lights with the right subjects. My model has exceptionally smooth skin (being so youthful and all) so a hard light for her is no problem, but you probably wouldn't want to use this modifier when taking a portrait of ol' Aunt Betsie. :)
Honl 8" Snoot for this shot and what surprised me was that it actually increased the power of the light a small bit. I was using a bare speedlight at 1/16 power to get a good exposure, but when I threw on the Honl snoot, I had to dial my power on my speedlight down to 1/20. The reason is, the inside of the Honl snoot is actually quite reflective, so when light shoots through it, it bounces around and intensifies when it exits. In a nutshell, this modifier is really, really efficient and gives a similar light pattern to the 1/8 Grid. I really like the snoots because they are soft material and can fold up to be stored in any light bag. I always have this one with me. Another cool bonus about this snoot, is that it can be used opened up (i.e. not closed all the way) which can then be used like a reflector or a flag/gobo.
Orbis Ring Flash adapter. I don't have as much experience with this modifier as a key light so I thought I would give it a whirl. It produces a really soft light but what surprise me was how much light it consumes. I had to have my flash at 1/2 power to light my subject appropriately which means its eating up about 3 stops of light! That may sound tragic, but honestly, it doesn't bother me in the least, because the quality of light it produces more than makes up for the lack of efficiency. Also, I rarely ever use this as a key light in this manner. More times than not, I use it as a fill light which it can handle more than adequately.
In summary, be sure to notice in each photograph the highlight area, the shadow area and just as importantly, the highlight-to-shadow transfer area. That last one really tips you off the quality of light (hard or soft) that a modifier can produce. Also take note to the power settings with each modifier. This may help you when you have to decide on power availability vs. quality of light required for a given subject.
I have a few more modifiers I wanted to test but they sorta got buried in the mess of stuff I had all over my living room doing these portraits. :) Hopefully I will get around to writing reviews about those coming up soon.
I'd also like to thank my very talented model for sitting patiently and squeaking out a little half-smile every so often while I fumbled around behind the camera like a bumbling clown. Now that I think of it, I think she was actually bribed with a honey bun or something.
Hope you found this helpful and if anyone has any questions, please don't hesitate to sound off in the comments! If I know the answer, I'll be more than glad to cough it up.