In A Pinch (using built-in flash for fill light)…

Maybe this has happened to you too… a photographic opportunity presents itself and the lighting is low and the timing is crucial.

For me this is usually when my pup is doing something cute, like sleeping with her ear dangling off her bed.  Or she’s cuddled up in a self-made den under a side table with her toys all around her.

When these photographic opportunities presented themselves, I had to move fast before she was aware that I was taking her picture.  I take her picture often enough that she instinctively knows the sounds of me setting up the camera.  All too often I miss the shot because she hears me and moves.

On those occasions when I did get the shot, usually the light was too low and my exposure was too dark.  Until recently I had to rely on post processing to correct for underexposure.  Sometimes the photo turns out nice other times it’s just too noisy for me to be able to do anything with it.

Case in point, take these photos… I was using a 180mm lens, so 1/200s was as slow as I can hold and still get a decent sharpness, the aperture was at the maximum for the lens, and the iso was at the maximum for the camera… and still it was too dark…

f/3.5  1/200s  iso6400

f/3.5 1/200s iso6400

In post, I was able to tweak the exposure to +1.5 stops while still keeping the noise down.  It’s a cute photo of her face, but the ear over the side of the bed is still lost in the shadows.

corrected in post: +1.50 exposure

corrected in post: +1.50 exposure

I was able to set the camera on something sturdy, but I had to move forward and I lost the ear portion of the photo entirely.  Also it seems I over compensated a bit and had to change the exposure to -1 in post.  It’s a really cute photo… but it doesn’t tell the same story.

f/3.5  1/15s  iso6400 corrected in post: exposure -1

f/3.5 1/15s iso6400
corrected in post: -1 exposure

In this next set… again I set the camera to the maximum settings for my camera and 180mm lens (f/3.5  1/250s  iso6400) and it was too dark…

f/3.5  1/250s  iso6400

f/3.5 1/250s iso6400

In post, I tweaked the exposure to +1 and was able to get a nice photo, but the details in the shadows are lost…

corrected in post: +1 exposure

corrected in post: +1 exposure

Of course this has been bothering me for awhile.  I just happened to be reading a book called The Traveling Photographer by Sandra Petrowitz and she happened to mention using the built-in flash for fill light.  She also mentioned that she uses exposure compensation on the built-in flash.

It was like a light bulb went off in my head!  For some reason, I had always thought that the built-in flash was like the other auto settings on the camera, something I couldn’t control.  Also I believed that this auto flash would assume that the flash was to be the main source of light, which in most circles is considered to equal a bad photo.  You know you’ve heard it… flash = bad.

But once I realized that I had some control on how bright the flash would be I realized that was silly.  I mean the flash is a tool, and if you know how to use it you can make it work for you instead of against you.

Now that the seed had been planted, I decided to give it a try.  I got out my camera manual (which I always carry with my camera, just in case) and found out how to do built-in flash exposure compensation.  My camera (Canon Rebel T2i) has the ability to do ±2 stops exposure compensation.

The first experiment went something like this… slightly lit room from a window, aperture opened all the way on my 40mm lens, shutter set to 1/80s for hand held shot, iso 400.  A pretty good exposure, let’s give it some fill light with the built-in flash…

f/2.8  1/80s  iso400

f/2.8 1/80s iso400

I set the built-in flash exposure compensation to -2, and am pretty pleased with the results.  The hard shadows were softened, the contrast between light and dark has been reduced, and there is more detail in the shadows.

built-in flash: exposure compensation -2

built-in flash: exposure compensation -2

Ok, now let’s really put this to the test… with my camera set to f/2.8 1/60s iso6400 and a 40mm lens, I got the following results.  I set the built-in flash to -2 exposure compensation and then played with the iso to change the ambient light.  In the first photo (top left) there is no flash, and the light parts are blown out and the shadow areas could use a boost.  In the second photo (top right), I added flash (-2 ex comp) and kept the rest of settings the same.  The shadows look better but the light parts are even more blown out.  In the third photo (bottom right), I kept the flash the same but reduced the iso to 3200.  The light parts are now less blown out and the shadow areas look nice.  In the forth photo (bottom left), I reduced the iso to 1600.  In my opinion, this one is just a tad too dark now, but the blown out sections are much better.

teacup-polytych-text-wm_hp-LR500

For this particular setup, I like the third photo (bottom left).  You will notice that the flash does add a bit of spectral highlights on reflective objects, but I don’t think it distracts too much here.  Plus in the reflection of me in the cup is greatly reduced with the flash and the lessening of the iso, which is a plus.  Overall, I would consider this a good exposure, with some nice detail in the shadows.

For my next experiment, I decided to play around with the flash exposure compensation.  This experiment is the heart of my research.  Here I have a sleeping pup, low light, and presumably a limited amount of time to get the shot.  I set my camera to the maximums with my 180mm lens (f/3.5 1/250s iso6400) and it was just way too dark.

As far as I’m concerned I had three options… 1. fix it in post, 2. get out my tripod, or 3. try out the built-in flash.

f/3.5  1/250s  iso6400

f/3.5 1/250s iso6400

We’ve seen what happens when I try to fix it in post… this time it didn’t work out well at all, it was just way too noisy… and the colors are all weird.

sleeping pup - corrected

The tripod would have been the best choice technically speaking, I could set the shutter much slower and get all kinds of light in my photo.  Assuming the pup didn’t move, of course.  The problem with the tripod is that I would have to set it up, and hope that she didn’t wake up.  Timing was critical, so I had to go with option 3, built-in flash.

Oddly she slept right through it, which was a relief.  I was able to make three more photos with gradually increased flash output.  Exposure compensation -2 is the dimmest I can make my flash, whereas, 0 is the default amount of flash.

pup-polytych-text-wm_hp-LR500

Again, I like the third photo (bottom left) best.

So to recap… when you are wanting a bit of fill light, the built-in flash can be your friend.  Especially when you don’t have all your gear with you, timing is critical, and you are in low light, or you just need a bit more detail in the shadows.

teacup - fav

sleeping pup - fav

Next time, I’ll talk about my experiments with built-in flash outdoors.  Stay tuned.

Until next time…
~nic

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