Bat Question

After reading a few posts from googlin the subject, thought I would check here for advice as well. Im wanting to photograph local bats at dusk as they fly out of their cave. From what I have heard, I should be able to get within 20 feet of the cave entrance. Im also thinking I an get under them as they fly out, using what little light in the sky as contrast if needed. My question relates to the lens, Im thinking of using the nifty fifty, as its my largest ap at 1.8. The focal length does seem as vital as the availability of the light.

I will be using the 430ex flash along with the tripod. Any recommendations or suggestions for photographing the bats?

thanks

 

Good point Mike on the DOF, this may end up round 1 of many. If I can get a good shot of their silhouette, I'll be lucky.

 

cant wait to see the resaults! Sounds really cool. Sorry i dont have any more input...

 

take an umberella, Im sure its nasty under flying bats.

 

Flash duration gets shorter as the power output is decreased. As flash power is decreased you need to open the aperture to capture enough light to make a good exposure.

The shorter flash duration is more effective at stopping motion

 

A friend of mine used to shoot masses of swifts as they headed to their roosts in the evening....he had some really wonderful shots done back in the 1990's on slower-speed slide film, probably 100 to 200 ISO film. He exposed for the sky tones and used Vivitar 285 flash as the flash to illuminate the birds closest to the camera....the flash could not light or stop the motion of the more-distant swifts, which flitter around a lot like bats do.

My guess is to set the flash to a manual power control level, so that the FLASH exposure (ie. the output level of the flash) remains constant; firing a flash out into open sky in an automatic mode might easily cause severe,irreparable over-exposure of close subjects. Full power flash output at ISO 400 at somewhere around f/5.6 to f/8 at around 1/30 second ought to give you both a sky exposure and a flash-illuminated bunch of bats at the 20-25 foot distance....with average equipment and based on a mythical average late spring-time evening sky!

If you get down into a really slow ambient shutter speed, like 1/8 second, the bats in the background will be blurry; so, if the sky is too dark, you'd need to raise the shutter speed to a faster speed, AND boost the ISO value as well.

This kind of a situation could call for a very tricky balancing act. Manual, user-adjusted focusing is a good idea for obvious reasons; the 50/1.8 will struggle mightily on something like flying bats against the sky at dusk,so you'll need to sert the focus by hand, in manual focus mode. Balancing or optimizing the trio of ISO/f/stop/shutter speed is the key; if the bats come out pretty late and the sky is dark, you'll need higher ISO settings to allow faster shutter speeds. If the bats are kind of far away, you'd also want a higher ISO speed to get enough effective "reach" for the flash's output. If you are some distance away, say 40-60 feet, you would have enough depth of field at that focusing distance to open the lens aperture up to something like f/4, which will give a pretty good amount of light entering the camera, and will also allow you to use a moderately fast shutter speed, like let's say 1/125 second at ISO 800-1250, so that you could get 1) a fast shutter speed 2) good range on the flash and 3) and f/stop that will be large enough to pick up the ambient lighting from the sky in the regions beyond where the flash reaches.

You could try a Programmed Auto type of exposure, to see what the camera give you in terms of exposure--it might, or it might not be what you are looking for on this very unusual subject matter. If the automation cannot handle it, then the above advice ought to get you in to the ballpark. Good luck and have fun with it!

 

Thanks Derrel, much appreciated.

 

maybe some rear curtain on a ~1sec exposure?

keep in mind (and maybe it got mentioned and i missed it)...if you use your 50 at 1.8, it's likely that your strobe will blow out a lot of it (if you stay within sync speed), not to mention the shallow dof that was said already.

im curious to see results.:thumbup:

 

need some updagrades before the rear curtain is an option. Ive invested in galss, but still working with the Canon Xs

 

Get a remote trigger. Put your camera mounted on tripod with flash and the focus set, exposure set with a somewhat decent DOF. Then sit back a good distance and wait with your hand on the button. ORRRRRR if you REALLY want to do it, get an Infrared sensor. I am not sure how much they run, but thats how people get those close ups of like owls attacking prey or bats flying down to drink from water.