In my competition entry for the month, one comment asked for an explanation of how one does multi-flash photography, so I will use hummingbirds as an example and explain it. All of my information will be based on Canon, but the same information is applicable to Nikon as well using their respective flashes (Sb-800x I believe is their top end flash at the moment)
There are a couple of essentials to cover prior to the explanation:
1) One needs multiple flashes in one of two setups
a) All flashes are wireless and can be used as master/slave setups without a wireless transmitter (i.e. 4 Canon 550ex or 580ex flashes..all of them can communicate wirelessly without a transmitter
2) One wireless enabled flash (Such as a Canon 550ex or 580ex) and several other less expensive flashes all connected to a Canon wireless transmitter.
To do multi-flash setups for hummingbirds, the following steps are undertaken
1) Set up flashes at different angles around the bird at close range (18-24 inches away or so) using lightstands (I use Bogen Stacker lightstands) and something like stroboframe shoe mount ballheads to attach the flashes too. This gives you flexibility over where to place the flashes, and flexibility over how you point them etc. I found this to be a wonderful way to setup flashes. Ideally (and all of my shots aren't ideal, as mine are with 4 flashes) one would have two flashes pointing up at the bird towards the breast/gorget (I set up one flash towards the gorget from the left, and one towards the gorget from the right, set at 45 degree angles towards the bird), one would have 2 flashes pointed down onto the bird to illuminate the wings and the tail, and another flash or two pointed at the background to illuminate the background, plus the flash on camera. One can also do it with all flashes set around the bird, and using a wireless transmitter to trigger the flashes.
2) Set the flash on camera to master, and all flashes around the bird to be "slave".
3) Set the master flash to be on manual mode, and set the power to 1/16th or 1/32nd. Set all of the other flash on ETTL mode. This will force all of the other flashes to use the same speed setting as the master flash. You can also set individual flashes to different powers (ie higher powers for the background to provide more illumination etc). If the master flash is on-camera, you will need a better beamer to make sure the flash can get light to the other flashes to trigger them. At 1/16th power the flash only throws light maybe 2-2.5 feet, but a better beamer should get the light far enough to trigger the flashes. I was maybe 8 feet away or so and I was able to trigger all 4 other flashes relatively easily.
4) Sit yourself down with your main camera on a tripod, pre-focus manually (and leave your camera in manual focus mode) on the feeder, and adjust your lens so the feeder is slightly out of the image, and wait for the hummer to show up and shoot away. Remember, the flashes are illuminating the bird and stopping the action, so you have to wait for the flashes to recharge (a second or two) to shoot again. You want to be in one-shot mode for this, not high speed burst mode. Also make sure you are on manual setting for your camera, set your f/stop to around f/16 (and you can play with this...I did any from f/13 to f/25 with ISO's from 100 to 400 depending on light, speed of the bird, action I wanted to depict etc, but you need at least f/13 or so, so that you can get the entire bird sharp. DOF is very shallow at such short distances, so you need a pretty significant f/stop here). Set your shutter speed to the highest synch speed your camera allows (1/250th for a Canon 20D), and adjust your ISO and F/stop accordingly. It is "OK" to underexpose, and actually preferable to underexpose by several stops of light, as you want your light coming from the flashes, not from ambient light. Otherwise you will get a ghosting effect which will give you one image from the shutter speed of the camera based on the ambient light (ie 1/250th sec) and the second image based on the flash duration. This effect can be interesting, but if you don't want it, it can also be frustrating.
Some technicals as to why this works:
1) The flashes are stopping the action, not the shutter speed. At 1/16th power, the flash has a duration of about 1/6000th of a second, and at 1/32nd power the flash has a duration of about 1/10000th of a second.
2) The flashes at such a low power throw light a very short distance. That is why you set the flashes up close to the subject. Hummingbirds are so small, and so fast, and so ignorant of their surroundings usually, that a few flashes around them doesn't have any effect (at least in Ecuador...they ignored me and my flashes...unless I was changing the feeder..then they waited around near me to finish so they could get more food).
3) The more flashes you use, the more flash output you have, and thus the more creative you can be with how you light the bird, the background, etc. It also allows you to increase the f/stop because the extra flashes will compensate for lost power due to high f/stop. A couple points to remember:
a) Flash output increases as ISO increases. Every ISO increase doubles flash output. From ISO100 to 200 to 400, etc. I generally stayed at ISO200 for most of my shots, but if the situation dictated (esp with only 4 flashes) I went to ISO400 to increase flash output
b) Flash output decreases as your f/stop gets bigger. At f/16 it already is pretty small..and it decreases as you continue to increase your f/stop to f/18, 20, 22, 25, etc. Keep this in mind when deciding how many flashes and what ISO to use.
Any other questions just ask and i'll respond in this thread...
Cheers,
There are a couple of essentials to cover prior to the explanation:
1) One needs multiple flashes in one of two setups
a) All flashes are wireless and can be used as master/slave setups without a wireless transmitter (i.e. 4 Canon 550ex or 580ex flashes..all of them can communicate wirelessly without a transmitter
2) One wireless enabled flash (Such as a Canon 550ex or 580ex) and several other less expensive flashes all connected to a Canon wireless transmitter.
To do multi-flash setups for hummingbirds, the following steps are undertaken
1) Set up flashes at different angles around the bird at close range (18-24 inches away or so) using lightstands (I use Bogen Stacker lightstands) and something like stroboframe shoe mount ballheads to attach the flashes too. This gives you flexibility over where to place the flashes, and flexibility over how you point them etc. I found this to be a wonderful way to setup flashes. Ideally (and all of my shots aren't ideal, as mine are with 4 flashes) one would have two flashes pointing up at the bird towards the breast/gorget (I set up one flash towards the gorget from the left, and one towards the gorget from the right, set at 45 degree angles towards the bird), one would have 2 flashes pointed down onto the bird to illuminate the wings and the tail, and another flash or two pointed at the background to illuminate the background, plus the flash on camera. One can also do it with all flashes set around the bird, and using a wireless transmitter to trigger the flashes.
2) Set the flash on camera to master, and all flashes around the bird to be "slave".
3) Set the master flash to be on manual mode, and set the power to 1/16th or 1/32nd. Set all of the other flash on ETTL mode. This will force all of the other flashes to use the same speed setting as the master flash. You can also set individual flashes to different powers (ie higher powers for the background to provide more illumination etc). If the master flash is on-camera, you will need a better beamer to make sure the flash can get light to the other flashes to trigger them. At 1/16th power the flash only throws light maybe 2-2.5 feet, but a better beamer should get the light far enough to trigger the flashes. I was maybe 8 feet away or so and I was able to trigger all 4 other flashes relatively easily.
4) Sit yourself down with your main camera on a tripod, pre-focus manually (and leave your camera in manual focus mode) on the feeder, and adjust your lens so the feeder is slightly out of the image, and wait for the hummer to show up and shoot away. Remember, the flashes are illuminating the bird and stopping the action, so you have to wait for the flashes to recharge (a second or two) to shoot again. You want to be in one-shot mode for this, not high speed burst mode. Also make sure you are on manual setting for your camera, set your f/stop to around f/16 (and you can play with this...I did any from f/13 to f/25 with ISO's from 100 to 400 depending on light, speed of the bird, action I wanted to depict etc, but you need at least f/13 or so, so that you can get the entire bird sharp. DOF is very shallow at such short distances, so you need a pretty significant f/stop here). Set your shutter speed to the highest synch speed your camera allows (1/250th for a Canon 20D), and adjust your ISO and F/stop accordingly. It is "OK" to underexpose, and actually preferable to underexpose by several stops of light, as you want your light coming from the flashes, not from ambient light. Otherwise you will get a ghosting effect which will give you one image from the shutter speed of the camera based on the ambient light (ie 1/250th sec) and the second image based on the flash duration. This effect can be interesting, but if you don't want it, it can also be frustrating.
Some technicals as to why this works:
1) The flashes are stopping the action, not the shutter speed. At 1/16th power, the flash has a duration of about 1/6000th of a second, and at 1/32nd power the flash has a duration of about 1/10000th of a second.
2) The flashes at such a low power throw light a very short distance. That is why you set the flashes up close to the subject. Hummingbirds are so small, and so fast, and so ignorant of their surroundings usually, that a few flashes around them doesn't have any effect (at least in Ecuador...they ignored me and my flashes...unless I was changing the feeder..then they waited around near me to finish so they could get more food).
3) The more flashes you use, the more flash output you have, and thus the more creative you can be with how you light the bird, the background, etc. It also allows you to increase the f/stop because the extra flashes will compensate for lost power due to high f/stop. A couple points to remember:
a) Flash output increases as ISO increases. Every ISO increase doubles flash output. From ISO100 to 200 to 400, etc. I generally stayed at ISO200 for most of my shots, but if the situation dictated (esp with only 4 flashes) I went to ISO400 to increase flash output
b) Flash output decreases as your f/stop gets bigger. At f/16 it already is pretty small..and it decreases as you continue to increase your f/stop to f/18, 20, 22, 25, etc. Keep this in mind when deciding how many flashes and what ISO to use.
Any other questions just ask and i'll respond in this thread...
Cheers,
