Photographing Fireflies in a Jar

Wanna be a kid again? Here’s how you can relive your childhood and take pictures at the same time! I’ve been getting a lot of interest in the firefly photos I shot this summer. Everybody wants to know how I shot and processed them. Truth is, I used several different techniques depending on the particular shot I was after and it will take a lot more than one blog post to cover them all. For now, let’s explore how to be a kid again!

First, you gotta collect the little buggers. Do it at dusk, while there’s still some light in the sky. It’ll make it a lot easier to see them after they flash so you can catch them in your hand or with a net. A net is much easier and has less chance of harming the fireflies.

Fireflies in jar with meteor and Milky Way

Fireflies flash in jar on porch, while a meteor streaks across the Milky Way in the background. Stack of 55 exposures, 54 for the fireflies and 1 for sky.

Collect a dozen of so and put em in a jar. But not just any jar. Those with raised writing, like Mason jars, will distract from the flashes. Mayonnaise jars work best, but you should use Duke’s. You can use Hellman’s in a pinch, but for goodness sake, please don’t try it with that nasty Miracle Whip! Stick some wet leaves or moss in the bottom of the jar and DO NOT punch holes in the lid. There’s plenty of air in there for lightning bugs and if you have holes in the lid they may be harmed by getting too dry. Make sure the jar is clean.

Now, set up the jar in a pleasing composition, like on a porch or in a window sill. To get the same type of perspective as in my shot, you’ll have to get up close with a wide-angle lens. Focus on the jar, not worrying about the background. Set the aperture to f/4, ISO to 1600, and the shutter speed to 30 seconds as a beginning point. You may have to fudge based on the ambient light. The idea though, is to use a high ISO and wide aperture to capture as much of the flashing as possible. The fireflies can go minutes without flashing or go crazy over a few seconds. To make sure you get plenty of flashes, set the shutter on continuous, lock down the cable release, and come back in an hour or two.

Now, remove the jar and very carefully let the fireflies go unharmed. Then, without changing anything else, focus on the sky and shoot an aperture/shutter speed/ISO combination that will record the stars well. You have to do this WITHOUT the jar in place, because otherwise when you shift focus to the sky it will change the relative size of the jar and you won’t get a smooth blend, not to mention that you’d be trying to blend with a shot of the jar out of focus. Shoot one exposure for the sky and you’re done with the fieldwork.

Now, back at the computer, choose however many jar shots you want to use, based on how well the fireflies flashed. I used 54 exposures for the photo here. Load them as a stack in Photoshop and use the Lighten blend mode, which will allow all the flashes to show through. Now flatten the file and blend it with the shot for the sky. That’s it!

Admittedly, this is a very simplified explanation. It’s going to take a lot of work to get everything blended properly and cleaned up. You’ll probably want to get a little more creative with the capture as well, possibly by adding a little fill light into parts of the scene depending on your composition. The main thing is to previsualize the scene long before you shoot it and think about every step required to make it happen.

My favorite quote comes from Louis Pasteur, who said “Luck favors the prepared mind.” If you do everything you can to prepare for a shot, sometimes you’ll get lucky and it will all fall into place. And sometimes, you get REALLY lucky. I finished shooting two hours worth of the fireflies in the jar and refocused on the sky. Just a few seconds after tripping the shutter I saw one of the biggest meteors I had ever seen streak across the sky. My first thought was, “Hey, that was really cool.” Then I realized that it had streaked within the lens’ field of view and I thought…”Thanks Louis!”

BTW, if you’re interested in learning more about how to photograph at night, my friend Donna Eaton and I are teaching a monthly online photo course called Digital After Dark for the Perfect Picture School of Photography. I cover all sorts of cool nighttime stuff in the course. 

Update on 6/3/2013: I no longer use mayonnaise jars. I’ve found that the standard Ball Mason jars work better, even when the lettering is seen. They add a sense of nostalgia that Duke’s mayonnaise jars just can’t compete with.

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