A Simple Experiment of Natural Light vs. Flash

Blinding myself with science!

(The point of this write-up is not to take sides on the flash vs. natural light discussion or to pick on people who have a strong, nearly unflappable preference. It’s to point out that for the most part light is light (especially when you’re comparing flashes to sunlight.) If anything, the discussion should be about how you modify the light regardless of its source.)

I’ve seen people advertise themselves as “natural light specialists” and then go one to explain why that makes them a superior choice for your portrait work needs. It’s good marketing, I guess (just ask your non-photographer friends which kind of light is better), but the science behind it didn’t feel right. It got me thinking about what it would take to replicate that “natural light look” entirely with flash.  After some brainstorming and a few sketches I came up with an idea that made sense on paper, but to make sure I wasn’t missing something I decided to actually build it so we could test it out. Fortunately for me, my friends at Bold Sheep Photography have studio space with amazing window light and they were kind enough to let me borrow it for a day to test out my idea.

The Build

Before I began building, I spent some time trying to quantify exactly what I was trying to replicate in order to have some way to measure success or failure. I used a light meter to take readings throughout the room as well as at different spots on the windows to find out if the light was coming through evenly or if it was more intense in one spot. I also took some “before” photos to try to replicate later.

Once I had an idea of what I needed to replicate, I used a tarp to cover the window to block out the incoming light and got started. A simple wooden frame made out of 2x4s was built and attached to the existing window frame. Thin sheets of reflective material was used to line the inside. I built mounts for the speedlights and positioned them so they would land across the areas that roughly matched the existing window panes.

Four speedlights set to project lights to where the window panes would be.

The outside of the box was covered with white nylon to diffuse the light to and to better match the apparent evenness of the light that was previously coming through the window.

One half of the box complete. You can see the tarp over the window, the wooden frame, and the flashes firing through the nylon diffuser.

Very underexposed view to see the light patterns being created inside the box.

Finally I tried to put the room back like it was for the comparison shot. The camera angle isn’t exactly the same and some of the objects have moved because I needed the room to build, but here it is…

Top: Natural; Bottom: Flash;

Not bad. The main difference you can see is the way the light falls off in the upper corner of the wall nearest to the window. This is because the window being inset into the wall by 4 inches gives it a small snoot/barn door effect which could be emulated by adding small furring strips around the lightbox frame.

I had gone into this not knowing how much tweaking and repositioning and rebuilding I’d have to do. I was so pleasantly surprised at how well the first attempt worked I decided the time spent trying to get an exact match on the corners could be better spent elsewhere, so I called it done and went out for a milkshake.

Now what?

So what does all this prove? Well, not much really… but it does show that it’s possible to create one specific natural light look with flash.  At the very least what I hope it achieves is being a good demonstration of the idea that light is light and what matters is how we modify and use it.

The next step is having an one of my high-end photographer friends use it for a shoot and give me some feedback on how they think it compares. To me that’ll be the real test and I hope to have an update on for you on that next week!

And here is that update… Natural vs. Flash Follow-up: The Test Shoot

 

Finally, some considerations…

  • It’s not always practical to create the lighting situation you want. In my test, the setup was fairly simple – one large window in the wall of an enclosed area. More complex scenarios may require many large panels and complicated setups.
  • Natural light will not always be when and where you need it. If your ability to do portraiture work is based on a few specific hours in the day and requires certain weather conditions, then you’re setting up a huge obstacle for yourself.
  • Flash lighting can get expensive. While the light box materials only cost me roughly $30 to build, you’re seeing about $2,000 worth of strobe equipment in there to light it. And while quality flash equipment is getting more and more affordable these days, it’s still hard to beat the cost of standing someone in the shade and hitting them with light reflected from a car window sun shade.
  • Flash gives you more options to achieve your creative intent. In the before/after photos above the exposures were the same, but in order to make that happen my settings were quite different. In order to shoot at f/8 and ISO 200 I had to use a shutter speed of 1/15 in window light. With flash, I was able to shoot the same f-stop and ISO at 1/200 with only 1/4 power flash. To translate that for those that don’t speak EXIF yet, that means that I have the option of shooting both shallow or deep depth of field without worrying about my subjects being blurry or covered in noise.
  • Often, the right answer is a combination of the two. Look around at some of those photos where people are standing in front of a colorful sunset sky. If they look amazing, odds are the photographer was skilled at using fill flash in concert with the available light.

What would you add to that list?

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Buy This

I frequently get asked about which lenses, equipment, books, etc. to buy so I’ve decided to start a list to direct people to instead of digging up the links each time I answer. (I’ll be adding more as questions are answered.)

Tripods
One of the easiest ways to waste money in photography is to buy a cheap tripod. Unless you’re spending $150 or more, you might as well be lighting that money on fire for all the good your flimsy tripod will do you. If you’re not ready to invest in a tripod, hold onto your money until you are. When you’re ready, these are the ones to look at:

Lenses

Accessories/Cleaning

  • LensPEN Lens Cleaning System $8 – Handy lens cleaner. Brush gets rid of dust and special pad removes smudges.
  • Sensor Swab Plus Type 3 w/ Eclipse (4pk) $18 – This is what I use to clean my camera’s sensor (it’s not as scary as people have told you it is.) Easy to use and premoistened with exactly the right amount of cleaner. There are different sizes for different camera sensors, so check the reference to be sure you’re getting the right size for your camera (if you have a crop sensor you probably want this one.) Some of the reviews make it sound like a bad product, but my experience has been completely opposite. Easy to use, great results, and about a tenth of the cost of paying someone else to clean it for you.

Color Management

 

Books

Software
Lightroom is the software for you to manage, edit, print, and share your photos.

 

Full disclosure: if you buy something through one of these links I’ll get between a 4-10% kickback. I won’t be upset if you don’t buy through these links, but I’ll be very appreciative if you do.

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Want to critique my photos? Well, buddy… SIT and SPIN.

So I was working on a presentation for a local photo club on how to give proper and useful critiques and I wanted to come up with a mnemonic to give people for remembering the parts that go into a good critique. I wrote them down and stared at them for a bit trying to see what kind of acronym would come out, and then there it sat… A mnemonic that people would remember even if they didn’t remember what the letters stood for… SIT/SPIN.

So, let’s break it down…

  • S – See: Take a moment to really look at the photo and absorb it. Look at the big picture, look at small sections for hidden detail, notice where your eye enters, where it goes, where it rests, where it exits. Try to see everything there is to see about the image.
  • I – Interpret: What does the photo make you think of? Emotions? Mood? What do you think the photographer was trying to accomplish with their shot? This step can seem silly to some people, but it’s actually one of the most useful parts. As someone with no emotional attachment to the shot, you can provide untainted feedback that lets the photographer know if they accomplished what they set out to do with the photograph. Also, this is the only step that the photographer can’t learn on their own.
  • T – Technicals: Go through the aspects of the photo that deal with skill using the equipment. Is it in sharp focus, is it exposed properly, how is the noise, etc.
  • S – Subjectives: Go through the artistic parts of the photo. How is the composition? The depth of field? Framing?
  • P – Praise: Talk about the things you like about the photo and why you like them. Again, this part of the critique some people find silly or unnecessary, but it’s a very important part of the learning process. You’re not giving praise to brace them for the impact of what they can improve upon. You’re maintaining their positive attitude to promote learning.
  • I – Improvements: Talk about the parts of the photo that could be improved and be sure to include how to improve it and why you think it would be an improvement. If there are many things that can be improved, focus on one or two that will have the most impact rather than overwhelming them. Remember that your critique is intended to improve the photographer’s future work, not the photo you’re critiquing.
  • N – Nutshell: Wrap up by going back through the highlights to condense any previous rambling you may have done into the concise couple of sentences you’d like the photographer to take away from your critique.

So there you have it. The next time you’re asked to give a critique… SIT & SPIN.

Slides from the presentation to the RCC:

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Calculating Stops

"She'll make point five past light speed."

Understanding stops (and how to calculate them) is a very important skill that is becoming all but lost in the age of built in exposure meters. Not that there’s anything wrong with letting the camera do the mundane work, but what happens when you’re going for a shot that’s outside the ability of the camera to calculate? For instance, with night photography or when using a neutral density filter to get that nice cotton candy water effect your camera may not have enough light to figure out what’s best and suddenly the weight is on your shoulders. The good news is that it’s pretty simple if you know how to multiply and divide by 2.

A Brief Aside on Correct Exposure
Correct exposure is subjective, but when speaking in normal terms, a well exposed image has the shadows just above black and the highlights just short of being blown out. (This post is about figuring out equivalent exposures so I’m going to assume you already know how to identify a good exposure.) When taking a picture we have three things we can adjust: the amount of light we let onto the sensor (Aperture), the length of time that light is allowed in (Shutter Speed), and how sensitive our sensor is to the light hitting it (ISO.) When you combine those three things you get the Exposure.

The Stop
When talking to other photographers you’ll hear things like “expose it a stop higher” or “when shooting HDR, shoot a normal exposure and shots a few stops higher and lower.” What does that mean? It means make the exposure lighter or darker, but beyond that, it means by a specific amount. A stop is a relative measurement of half or double an amount of light and it’s useful for quantifying how much of an adjustment we’re talking about. (BTW, you’ll sometimes see stops referred to as an Exposure Value or EV.)

The Equation
Here’s what you need to know. Doubling any one of the three exposure controls increases the exposure by one stop while halving them decreases the exposure by one stop.

  • Shutter speed is easy. If you’re shooting 1/100, then 1/200 is a stop darker and 1/50 is a stop lighter.
  • ISO is easy too. If you’re shooting at ISO400 you can stop down to ISO200 for a darker image or up to ISO800 for a brighter image.
  • That leaves us with aperture.  Aperture is referring to the size of hole in the lens that the light passes through. If you double the size of that hole, you let in double the light. Halve the size and you halve the light. Easy! Aperture is a simple concept, but can be confusing because of how it’s measured. Let’s stick with simplicity for the purpose of this post and not dive into why those numbers are measured the way they are (I’ll cover that in-depth elsewhere, but the short version is that it’s a fraction.) Just know that the bigger number means a smaller opening and a smaller number means a bigger opening (so f/2.8 lets in a lot more light than f/11.) Some of the common numbers you’ll see are: f/2.8, f/4, f/5.6, f/8, f/11, f/16. (Each jump in that list represents a stop, so f/2.8 to f/4 is one stop. f/5.6 to f/11 is 2 stops. And if you have trouble with memorizing that list, just remember 2 and 2.8 and you can figure out the rest from there by doubling – 2, 4, 8, 16 and 2.8, 5.6, 11)

Scenarios
So, you’re shooting at night and you take a shot at 30 seconds, F/11, and 200ISO. Your image looks okay, but your friend shooting nearby says it’d look great if it were 2 stops brighter. So what can you do?

– Change the shutterspeed by 2 stops. Doubling it once gets you 1 minute. Again gets you 2 minutes.

– You could increase the ISO by 2 stops. From 200 to 400 to 800.

– You could open your aperture by 2 stops. From f/11 to f/8 to f/5.6.

All of those examples will work to brighten the exposure, but you could also make smaller adjustments to multiple settings to get two stops. For example, increase the shutter speed to 1 minute and increase the ISO to 400.

Go Practice!
The math is easy, it just takes a little bit of practice and you’ll be calculating stops in your head in no time. One of the best resources I’ve found for online practice is the DSL Simulator at CameraSim.com. Give it a try!

Churning Backbone Rock

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Exposure Roanoke Model Shoot – March 2011

Robert Bryant, one of our photo club members, is into video and he put this together during our most recent outing. Check it out for a good idea of what the Exposure Roanoke photo club is all about.

Exposure Roanoke Model Shoot – March 2011 from HappyCatFilms on Vimeo.

And be sure to check out Rob’s website too: http://www.happycatfilms.com

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