[derekkite]

Last year I attempted to capture bats in flight with some success, enough to make me want to try again. This evening was the third time out and everything worked.

Three bodies, two K3 and one K5 mounted on a rail. The K5 with 50mm, the K3's with a 70 and 90mm. The 50mm was f16 iso 100, the 70 was f11 iso200, the 90 f8 iso 400. 5 flash units, Yongnuo 560 II and III units. A raspberry pi board with a piface interface, using the digital outputs to trigger the bodies and flash units. The board is powered by a cell phone charging battery unit, in a plastic box with audio jacks connecting the devices. A button input triggers an interrupt which triggers the three bodies, delays a bit, then triggers the 5 flash units. A burst of 10 shots, then a rest. The flash units were 1/16 power.

If someone wants the python code and details of the setup, I can send it to you.

The flash units worked extremely well. If I did 5 or 6 consecutive 10 shot bursts all five would sit for a few seconds cooling down, then away they would go again. The bodies seemed to work fine as well, although I suspect the slight softness may be vibrations set up by all three triggering at the same time. I have a 3/4 x 1 1/2 aluminum bar with arca swiss angles cut for mounting the bodies, on a decent tripod, but there may be a weakness. Next time I think I'll set them to live view as the vibration is considerably less.

[jbinpg]

Nice work, Derek. We have a pair of Big Brown Bats in the yard I have been wanting to take photos of. They return the first week of July every year. Too bad light levels are too low for CIF to trigger. I think I would still prefer all camera mirrors to be locked up before the shutter fired. You could probably do that by hand with an IR remote before the script kicked in. If you did that, you may not need to use the much power-hungrier live view. I am also fearful that full spectrum flash may affect the night vision of these nocturnal creatures. Contrary to what people believe, they are far from blind. Yes, they echolocate their prey, but they only use it for hunting, not to get around. Not sure if there are filters that fit flash units to only pass the IR band. These wavelengths may reveal a different part of the bat story and could be easier on their eyes.

Jack

[nowo1978]

Wow! Impressive setup, thanks for sharing! Did you try using the mirror-up feature to reduce camera shake?

[sergysergy]

What a set up!

[Nass]

Superb. I'd be tempted to try this except the bats round our house are 10m up

[Caver]

Bats again

Serious setup and very nice result! Keep up the good work!
You didn't mention, or my English is poor, but how are the cameras triggered? How you know when to shoot? And where to focus?

Shooting bats is complex and challenging, it takes lots of time and effort to came up with a decent photo, so all my respect!

---------- Post added 29-07-15 at 16:21 ----------

Nice work, Derek. We have a pair of Big Brown Bats in the yard I have been wanting to take photos of. They return the first week of July every year. Too bad light levels are too low for CIF to trigger. I think I would still prefer all camera mirrors to be locked up before the shutter fired. You could probably do that by hand with an IR remote before the script kicked in. If you did that, you may not need to use the much power-hungrier live view. I am also fearful that full spectrum flash may affect the night vision of these nocturnal creatures. Contrary to what people believe, they are far from blind. Yes, they echolocate their prey, but they only use it for hunting, not to get around. Not sure if there are filters that fit flash units to only pass the IR band. These wavelengths may reveal a different part of the bat story and could be easier on their eyes.

Jack

I am not a specialist regarding bats (even if I am a caver from long time ago and also shoot bats since a few years) but I can tell for 100% sure that bats (at least the microbats) are using echolocation for ordinary flight, as they can fly in caves and mines where the visibility is zero - as there is no light at all. They can fly in - pitch black - narrow subterranean places without a problem. I saw bats for many times in caves at great depths and distances from the entrances.

Regarding to the flash: yes, it is pretty sure it disturbs them, as they are not completely blind, but they do not rely on a common vision for orientation.

[JimC1101]

BIF.....Bats in flight this time..What a difference.


Impressive work.!!

[derekkite]

Serious setup and very nice result! Keep up the good work!
You didn't mention, or my English is poor, but how are the cameras triggered? How you know when to shoot? And where to focus?

Shooting bats is complex and challenging, it takes lots of time and effort to came up with a decent photo, so all my respect!

---------- Post added 29-07-15 at 16:21 ----------



I am not a specialist regarding bats (even if I am a caver from long time ago and also shoot bats since a few years) but I can tell for 100% sure that bats (at least the microbats) are using echolocation for ordinary flight, as they can fly in caves and mines where the visibility is zero - as there is no light at all. They can fly in - pitch black - narrow subterranean places without a problem. I saw bats for many times in caves at great depths and distances from the entrances.

Regarding to the flash: yes, it is pretty sure it disturbs them, as they are not completely blind, but they do not rely on a common vision for orientation.

Thanks. I'm aiming for the level of sharpness that you manage to get. I have a ways to go, and some ideas.

The bats go back and forth on the water just off shore. Last night I set the contraption about halfway out the rock point pointing towards the left in the photo, about 30 degrees out. The bats were more diffuse last night, we have had some cool weather and rain. It seems they are thicker when it is hot.

So I don't have a precise point where I can focus and trigger. I tried two different IR sensors; one didn't sense at all, the other was a 6 degree angle of view which missed too much action. So I trigger manually. This all happens a few minutes at dusk, there is light from the sky reflected off the water and I can see them approaching.

As for a trigger, I'm using a Raspberry Pi with piface interface board. Three of the eight outputs are for the three bodies, the other five for the flash units.

Here is the routine that triggers.

def quickflash(self,cycles):
# a series of exposures and flashes, count to self.flashcycles, then recycle delay.
self.alloff()
for c in range(0,cycles):
# start exposure. camera multiple frame shooting low. assuming 1/10 second exposure
self.p.output_port.value = self.camerabits
time.sleep(0.12)
self.p.output_port.value = self.flashbits
print(time.time())
self.p.output_port.value = 0x00
time.sleep(0.35)
time.sleep(self.recycledelay)
self.input1 = 0

I see action, press the button and this does 10 exposures. I was pleased how it was working, it captured lots of bats.

Google Plus Bats Album

The bodies are focused at 3500mm 5300mm and 6500mm, using a 50mm @f16, 70mm @f11 and 90mm @f8lens.

I didn't get anything with the 50mm, the best were with the 70mm, lots with the 90mm but they were just out of reach. The 90 has the narrowest depth of field.

The softness is coming from two sources I believe. They may be slightly out of focus. The best shots were near the edge of the frame so they didn't show up in all the bodies depending on field of view, so they may have been just outside the depth of field. The only solution is persistence.

The second is slight vibration. The bodies are 1/10 of a second, all three trigger at the same time. The only way to get a quick recycle is live view. I had intended to set that up last night but forgot. I also haven't tested the timing with live view.

[jbinpg]

Yes, bats will echolocate in total darkness to get around. But if there is light available, they will use their visiion.

6 Bat Myths Busted: Are They Really Blind?

And some recent news re. studies on White-Nose Syndrome:

Bats treated for white nose syndrome released in wild: New optimism -- ScienceDaily

I am glad we have bats in the yard. They eat an incredible amount of flying insects.

Jack

---------- Post added 07-29-15 at 09:35 AM ----------

Derek, I am not clear on one thing. Are you triggering 10 flash pops within 1/10s or is each flash pop 1/10s apart? Continuous shooting mode should work if the flashes are 1/10s apart.

[Nass]

The second is slight vibration. The bodies are 1/10 of a second, all three trigger at the same time. The only way to get a quick recycle is live view. I had intended to set that up last night but forgot. I also haven't tested the timing with live view.

Don't know if this is really a factor. Flash duration at 1/16 is on the order of 1/8065 for YN560 - should eliminate vibration I'd have thought?

[Caver]

Yes, bats will echolocate in total darkness to get around. But if there is light available, they will use their visiion.
6 Bat Myths Busted: Are They Really Blind?
And some recent news re. studies on White-Nose Syndrome:
Bats treated for white nose syndrome released in wild: New optimism -- ScienceDaily
I am glad we have bats in the yard. They eat an incredible amount of flying insects.
Jack[COLOR="Silver"]
---------- Post added 07-29-15 at 09:35 AM ----------

Thanks for the articles, especially the one about the white-nose syndrome! (forwarded to local bat conservation guys)

[derekkite]

Don't know if this is really a factor. Flash duration at 1/16 is on the order of 1/8065 for YN560 - should eliminate vibration I'd have thought?

Not sure. Everything is magnified by the cropping necessary.

More than likely it is focus. The depth of field calculations essentially come down to what level of softness is acceptable. The sharp focus is near the center of a band where it gradually gets softer the closer and further away. So instead of 3.8 meters with the three lenses I may in reality have about a meter or maybe slightly more where each lens is very sharply in focus for 1/3 of a meter or so.

Using a web DOF calculator, 70mm lens, f11 focus distance 500cm gives an in focus range from 407cm to 607cm. My calculations with a more exacting circle of confusion number gives 442 to 574cm, or 132 cm. I will try to narrow that down by half and see what happens.

When I setup the focus using live view, a tape measure and three little boxes set at those distances, the focus peaking wide open covered that span, and when I stopped down to check it was more than generous.

Incidentally, last night was a wash. One of the Yongnuo 560II flashes worked intermittently and the batteries were very hot when I took them out, so into the garbage bin it goes. Good thing they are cheapish. I finally got some hotshoe to 3.5mm jack adapter gizmos so I'll try the so far bulletproof Metz as a replacement. Last year a friend came out to try and destroyed his Nikon flash in one session.

I also got rid of the hardware input that seems to be flakey. Either the series of plug connectors and mechanical switch attempting to close a low voltage circuit or the board hardware interrupt mechanism, or the software was unreliable. A cell phone charging battery powers the raspberry which is set up as a wifi server, so I ssh in to control things. Last night I was triggering with key presses on the phone, and it was bulletproof; quick and reliable.

Now to get a bat in just the right place doing something interesting and have the flash trigger at the right moment. Last night 204 shots on three bodies, which I thought was quite reasonable trigger control. I missed a couple opportunities when the batteries got too hot and the refresh was very slow, maybe up to 10 seconds.

[Nass]

Good luck - hope the Metz doesn't cook