Sunlight And Strobes

You know I don't do winter right? All I could muster was standing by the open door to take a picture of the arctic conditions this morning. I've mentioned more than a few times I snap images of lighting conditions I like - even if I have no subject to speak of. I'm obsessed with them. I thought I would share two that I shot quickly today. Think of this as a preview to Simulating Sunlight Part II.

Last time I illustrated this exact scene I pointed out a few factors to consider when using strobes to simulate these beautiful conditions. I won't bother repeating myself, instead I just wanted to point out a few things that are different here from the same scene a while back. I also spent the additional effort to shoot it again a half hour after the shot at the top.

First off – the image at the top. Biggest difference from last time? Color. Both shot using in camera daylight white balance. More subtle difference? The ratio between whites in shadow and whites in the sun is even closer than last time. Just a tad not wildly so but enough to make the image feel completely different. Tiny 1/3 stop ratio differences are a big deal. I usually use hyperbole to make a point. I don't even know how to exaggerate enough to make it clear in mere words how that ratio between highlight and shadow is so important and minor variations have a giant impact visually.

Here's the second shot about twenty minutes later. Let's take a look at this analytically for a moment. I have to congratulate myself on being able to reproduce hand held framing from memory of irrelevant subject matter – that's amazing isn't it? More to the point it's a very different image but still attractive. The difference is again color - both shot at daylight white balance and again what on paper looks like an insignificant difference in highlight shadow ratio. Visually it has a very different effect.

While the differences are interesting let's talk about the similarities. Does it feel like the morning or late in the day? Ask yourself why that might be… Which one feels more morning like to you? Why? A lot of that kind of stuff you have to figure out for yourself and your own personal perceptions. I will give you a bit of a hint. A heck of a lot of that has to do with color and that highlight/shadow ratio. The ratios here are all within a third to half stop. The color while wildly different does have a few similar characteristics. The biggest one that I drone on and on and on about is that all of them have cooler shadows than highlights to varying degrees. None of them have cooler highlights than shadows. Not even close - that feels very night time. So do large shadow/highlight ratios. The other thing to note is the overall color balance in the shadows are what is tending toward neutral not the highlights.

At these low ratios where the whites in shadow are all above midtone grey and skin will generally be slightly above or at midtone levels this is a titanic factor on your perception of an image. If this color relationship is inverted so that the shadows are warmer than the highlights it will just look really really wrong and there is no quick white balance fix. No matter what overall white balance you choose the relationship will still be wrong and humans are really good at detecting that relationship even if they are not so good at absolute color measurement. If the relationship of shadow/highlight ratios and color balance is attractive (like most natural cases) almost any overall white balance and contrast will look great. I am speaking within reason of course not crazy shifts.

Too bad speedlights are always always always cooler than real sunlight by at least 1000 points. What makes that worse is that indoors the vast majority of interior fill and bounce back is going to be far warmer than a bare speedlight. Gels are the answer to fixing as well as fine tuning this color relationship when trying to reproduce this using strobes. The other tiny little tidbit for those of you starting to play with things beyond what I demonstrated in Part I is that speedlights are not color consistent. They are all over the map depending on output level.

Even if you cut all ambient out and are only using neutral light shapers and identical speedlights to light the entire scene the color variance and gels are a fairly big part of fine tuning. Especially for location work. A long time ago location work was my bread and butter. Making it look transparent and creating mood with light on demand was a big part of that equation. One of the things I valued was color consistent lights. Before you spend a bunch of money on dinky TTL speedlights you might want to think about what you really want to accomplish and some of the things that will make it a lot easier down the road.

I'll leave it as an exercise for you to figure out what other subtle differences there are between the two images. It's healthy – every photographer should make it a habit to sit down and analyze light often. Especially when they find it attractive. Sometimes it's actually easier to evaluate light when the subject is bland and not influencing your emotions. If you can make StupidCrap™ look good just thing what you can do with a meaningful subject. Recipes are great but are only a coarse and wide brush. The tiny bits are make or break.

RB

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