Canon 580EX with Flash Extender

I am a beginner in Australia going for a trip to photograph birds.

I have new Cannon 30D, 70-200 f/2.8 IS lens with 1.4 extender, 580EX

and Flash Extender (Better Beamer).

How should I use flash with that extender?

Normanl flash or High Sync flash?

Manual zoom on 580EX or authomatic, if manual what value?

What shutter speed? (probably high for flying birds).

What power should I have on the flash for fill flash.

At what distance flash would be effective at max power?

Thank you for your help.

Andre4 Roszkowski M.D.

<I>. How should I use flash with that extender? Normanl flash or High Sync flash? Manual

zoom on 580EX or authomatic, if manual what value? What shutter speed? (probably high

for flying birds). What power should I have on the flash for fill flash. At what distance flash

would be effective at max power? </i><P>

 

I don't have a 580 but do use a 550 with better beamer very frequently in bird

photography. Most all of the time I use it for fill-in, using ETTL exposure in normal mode

(not high-speed synch). Sometimes it's used as the main light source, and again I use

ETTL exposure. Maybe once or twice I've used manual exposure. To answer your specific

questions:<P>

 

1. Use manual zoom at 35 or 50 mm. That best matches the optics of the Fresnel

lens.<P>

 

2. You will get the most flash power if you use normal flash mode at or below the

maximum synch speed of your camera (probably 1/250 or 1/200. My understanding of

the high synch flash is that instantaneous power output -- and hence range -- drops

dramatically as shutter speed goes up. Thus there is a trade-off: if you use a high

shutter speed to stop action (say, of a flying bird), you get low flash power output. It

depends on how much light you want the flash to provide: if all you want is a little fill-in

on a flying bird, it might work. But if you're attempting to get strong flash illumination on

the underside of a flying bird during the day, it's probably not going to work except at

close range. In dim light, however, it's a different story: you can use the flash to provide

the main light source and even in normal mode the flash duration (and hence the effective

exposure time) is 1/500 or less -- sometimes a lot less.<P>

 

3. Fill flash settings are highly variable, depending on ambient light, subject tonality, and

what effect you are trying to achieve. Usually I use a flash exposure of -1/3 or -2/3

stops, sometimes less.<P>

 

4. Since the better beamer adds 2-3 stops of intensity by narrowing the flash beam,

that's very roughly equal to twice the range you'd get without it. And that will depend on

ISO and lens aperture, and to some extent the subject and background color.

check out www.birdsasart.com

Mark, thank you for your answer.

I would probably have no problems with resting birds, but only with moving birds, where I belive I need to have 1/1000 sec shutter speed to freeze them and at the same time to give them some underbelly fill-flash.

I shall try to do high-sync flash on high ISO may be I shall get some results.

Travis, thank you for the web side but I already have "Better Beamer".

Andre

<I> I shall try to do high-sync flash on high ISO may be I shall get some results.</i><P>

 

The problem with increasing ISO -- at least in daylight, when the flash is for fill-in -- is

that for a given shutter speed you need a smaller aperture to achieve good exposure for

ambient light. But using a smaller aperture decreases the range of the flash, cancelling

the effect of increasing ISO. If you increase the shutter speed to keep aperture constant,

that decreases the power output of the flash. Think of it as a balance between the

intensity of the flash and the intensity of ambient daylight. In order to have a perceptible

effect on the subject, the light intensity from the flash has to be reasonable similar to the

intensity of ambient light. Alas, ambient light intensity is more or less independent of

distance to the subject, but flash intensity falls off as the inverse square of that distance

(twice the distance = 1/4 the intensity, etc.).<P>

 

All I can suggest is: try it and see what you get. For a good test, make some exposures

with and without flash. Good luck and have fun! FWIW, I only use flash on <A

HREF="http://biology.ucr.edu/personal/MACphotos/flyingindex.html">flying birds</a>

when ambient light is pretty dim, so that the flash is the main light source.

Mark, I have seen your magnificent pictures, sadly I will probably never reach your standards. What shutter speed do you use to for flying birds with and without flash? What settings do you use if the flash is your main source of light? Andre

I'm glad you liked the pictures, and don't be so modest. Keep practicing and you can get

images you can be proud of (I don't show the high percentage of my attempts that don't

look so good!).<P>

 

<I>What shutter speed do you use to for flying birds with and without flash? </i><P>

 

Generally, 1/1250 to 1/2000, but except for a few dragonflies and a hummingbird or two

at very close range (4 m or less), I haven't used flash for flight shots in strong

daylight.<P>

 

<I>What settings do you use if the flash is your main source of light?</i><P>

 

It's pretty variable. A few times I've tried photographing large birds (cranes, geese)

passing overhead near or shortly after sunset. For those I used the normal flash synch

speed (1/250) in normal ETTL mode, or a slower speed if it was pretty dim ambient light.

None of those images are all that great, but other folks, notably Art Morris, use the

technique to very good effect. <P>

 

For non-flying subjects, I'll either shoot at 1/250 in normal flash mode if that gives a

reasonable background, or a slower speed if necessary to avoid an excessively dark

background. For night shots (owls), I use 1/250 and accept a black background. Usually

I set the flash exposure compensation at 0 or -1/3. Sometimes, as with strong backlight

like in the royal tern below, some overexposure (+2/3 or +1) may be useful -- I don't

think I gave this one quite enough:<P>

 

<center>

<img src = "http://biology.ucr.edu/personal/MACphotos/birds2/royalsunset1.jpg">

</center>

Mark, I feel I abuse your kindness with all those questions, but what camera and flash mode you use during those flash shots, Av or Tv on camera, manual on flash?

<I> what camera and flash mode you use during those flash shots, Av or Tv on camera,

manual on flash?</i><P>

 

I'm almost always in Tv mode (shutter priority) unless it is extremely dark (i.e., night) when I

use manual. Flash is always in ETTL mode, usually with some exposure compensation, most

typically -1/3. Use of Tv instead of Av is mainly force of habit: for me it's more instinctive

to control aperture by adjusting shutter speed than to do the reverse (in Av mode).

Mark, thank you for all your help. I am going for a trip in 10 days time and try all your suggestions. Andre