Fireflies

[rick55]

I was looking for information on how to capture the flashes of the fireflies in the back yard, and I ran across a site by Terry Priest, describing how he photographs the individual insects. So I tried that instead, with moderate success. This is something I want to spend more time on.

Both are with Canon 500D, 100mm f/2.8L macro lens, 580EX II flash with an Opteka diffuser, firing at 1/4 on manual.

F/11, 1/90



f/8, 1/90



C&C greatly appreciated.

Cheers,
Rick

[carregwen]

Rick

Good attempt but I think you need to crank up the shutter speed - 1/90s doesn't seem very fast for this type of shot. Is f/8 necessary?

[rick55]

Rick

Good attempt but I think you need to crank up the shutter speed - 1/90s doesn't seem very fast for this type of shot. Is f/8 necessary?

I probably need f/8, because I'm about 0.5m away with the 100mm lens, which only gives me 6mm DOF, even with the default 0.01 inch feature size, which is pretty borderline.

I think you're probably right about the shutter speed, but I think I should do it without opening the aperture: I think the wing blur could be from the ambient light. In the second shot, the background is far enough away to have a big fall-off of the flash illumination, but it appears to be lit to about 3 stops below the firefly. So I need to get more of the illumination coming from the flash to freeze the wings.

Cheers,
Rick

[Dave Humphries]

Not bad for a tricky subject Rick,

So I need to get more of the illumination coming from the flash to freeze the wings.

That sounds logical, but it will dim the firefly too

#1 looks like the FF is illuminating the end of the leaf, is that how it was, or is it just a happy coincidence?

Thanks,

[carregwen]

I probably need f/8, because I'm about 0.5m away with the 100mm lens, which only gives me 6mm DOF, even with the default 0.01 inch feature size, which is pretty borderline.

I think you're probably right about the shutter speed, but I think I should do it without opening the aperture: I think the wing blur could be from the ambient light. In the second shot, the background is far enough away to have a big fall-off of the flash illumination, but it appears to be lit to about 3 stops below the firefly. So I need to get more of the illumination coming from the flash to freeze the wings.

Cheers,
Rick

This keeps cropping up, and I still have to scratch my head over it. As I understand it, if the ambient light is low level, and the flash is sufficient to illuminate the main subject the shutter speed won't make much difference as the flash fires at a much faster speed (typically 1/1000s at least). IOW you ideally want low ambient light to prevent the blurring that you mention... someone help me out here, I'm floundering!!!

[Dave Humphries]

This keeps cropping up, and I still have to scratch my head over it. As I understand it, if the ambient light is low level, and the flash is sufficient to illuminate the main subject the shutter speed won't make much difference as the flash fires at a much fater speed (typically 1/1000s at least). IOW you ideally want low ambient light to prevent the blurring that you mention... someone help me out here, I'm floundering!!!

Reducing the ambient exposure can only be done with shutter speed increase, aperture and iso will also reduce flash exposure.

Of course the increase is limited by flash sync speed to probably 1/200 max anyway, but a stop less background vs flash is good, but it'll give a stop less firefly too (I believe)

Or increase flash output with same results

[rick55]

I think both comments are right. First, the lower ambient light can make it easier to freeze the action with the flash. It seems to me that you have three ranges of ambient light. If ambient is quite bright, you can use an aperture and ISO that you like, and a fast shutter to freeze the motion. If ambient is quite dim, you can set shutter, aperture, and ISO such that with no flash, the histogram is just a line at the far left, and the display is black. Then with a flash, you freeze the action with, as Rob says, sub-1000ths of a second bursts. In the in-between, it may be tricky. This is why DSLRs offer second-curtain shutter. If your exposure is set up so that you're getting some of the image from ambient, and some from flash, it can look strange if the motion blur seems to come forward from a car or running person. Second-curtain lets that comet trail of ambient exposure come across, then fires the brief flash at the end.

And I agree with Dave: if I open the aperture, I need to decrease flash output. That could be good, though, since it decreases flash duration. From that standpoint, the relationship between flash duration, aperture, and ISO when shooting with purely flash acts much like the relationship between shutter speed, aperture, and ISO when shooting without flash. Assuming it's dead dark, opening aperture or raising ISO causes flash duration to shorten, just like shutter speed shortens when shooting in daylight, which makes sense.

Cheers,
Rick

[rick55]

#1 looks like the FF is illuminating the end of the leaf, is that how it was, or is it just a happy coincidence?

I think if the firefly were lit, it would be much brighter. I think it's just a coincidence. I thought about cloning that out, but it provides some context/reference.

Cheers,
Rick

[Jim B.]

Rick,

Nice shots.I shoot a bit differently and I don't have any examples of insects in flight,but maybe try this.Set camera to manual 1/200" ISO 100-200, f/8-f/11 leave flash in ETTL.Use FEC to adjust your flash intensity.

[rick55]

Hi, Jim;

I thought about that, but I'm afraid that the insect is occupying enough of the frame to tell the ETTL when to stop, and it will expose for the background, not realizing the subject is that thing that's about 5% of the frame. Having said that, I have to admit that you're right: I should try it, not assume it won't work. If it does, it takes advantage of the automation built into the camera/flash system.

Cheers,
Rick

[rick55]

I tried a couple of technique changes last night and tonight.

I did try the ETTL, and it did respond to the background, as you see here:



I think this could still be useful if I can get a more horizontal shot of the fireflies, but they mostly seem to stay quite close to the ground. Also, I could set some negative FEC, but depending on how far the insect is from the background, the compensation would be wrong for the insect.

The other thing I did was raise the ISO, and cut the manual flash to 1/16 (instead of 1/8). I also raised the shutter speed a bit, to 1/125, but the increased ISO would cancel that out. There doesn't seem to be enough ambient light to have much motion blur: it would be worth raising the shutter speed, perhaps, but the wings seem frozen here.



Now all I need is to keep trying until I get a decent view of one from the front. So it's simple: all I need is some cooperation from the bugs.

Cheers,
Rick

[Jim B.]

Rick,

Last shot...WOW! Lighting is perfect IMO.Looking forward to your next series.

[rick55]

Thanks, Jim - I especially appreciate that from you.

Cheers,
Rick