The process I used was as follows. Set the camera to manual with shutter speed on the maximum sync speed. Set an aperture of around f8 and set ISO to 100 or 200. Take a test shot and chimp the histogram. Adjust the aperture to achieve the background effect you want, make it really dark if you want, there is no correct exposure. Position the subject with the sun over his shoulder at 45 degrees. Set up your flash directly opposite the sun. Maybe half power. Try it out. Adjust flash power or flash distance to suit.Thursday, 20 September 2007
Crosslight in Full Sun
This aim of this exercise is to use flash balanced with ambient light to create an interesting image in a situation when the light is essentially awful for 'available light' photography. 
The process I used was as follows. Set the camera to manual with shutter speed on the maximum sync speed. Set an aperture of around f8 and set ISO to 100 or 200. Take a test shot and chimp the histogram. Adjust the aperture to achieve the background effect you want, make it really dark if you want, there is no correct exposure. Position the subject with the sun over his shoulder at 45 degrees. Set up your flash directly opposite the sun. Maybe half power. Try it out. Adjust flash power or flash distance to suit.
The process I used was as follows. Set the camera to manual with shutter speed on the maximum sync speed. Set an aperture of around f8 and set ISO to 100 or 200. Take a test shot and chimp the histogram. Adjust the aperture to achieve the background effect you want, make it really dark if you want, there is no correct exposure. Position the subject with the sun over his shoulder at 45 degrees. Set up your flash directly opposite the sun. Maybe half power. Try it out. Adjust flash power or flash distance to suit.
Friday, 14 September 2007
Twilight Balance
The idea of this exercise from Strobist is to practice controlling the ambient versus flash component of an image. Twilight or dawn are the best times to do this as you do not require huge flash power to achieve a result in the face of strong sunlight. The potential backgrounds available can also be more interesting with sunset or sunrise colours. There are plenty of people out there who still advise the use of a meter to achieve the sought after balance between flash and ambient. I currently like the cheaper iterative approach made available by digital cameras and their LCD screens.
So, this is the process I use. Set the camera to manual mode, shutter speed at the maximum sync speed, 1/200th in my case. Estimate an aperture, maybe f5.6, I'm normally starting with ISO200 too. Take a shot of the proposed background, chimp the result and it's histogram. Adjust the aperture if required and chimp again. Persuade my ever willing six year old that it won't take that long really darling (chocolate works well here!). Set my SB800 to remote, dial in manual flash at say 1/8th power in my camera menu. Take a shot. Chimp it. Adjust flash power if necessary. OK, the background will be getting darker so either enjoy this change or slow the shutter to compensate. This will not affect flash exposure. If it is necessary to open the aperture by a stop then the flash power will need to be reduced by a stop too. So far I have only been trying to do this in the garden. The next step is to jump in the car and go up the hill a bit for a better backdrop, we're lucky to be in sight of the New Zealand alps. That may incur a higher chocolate cost for the model.
Thursday, 13 September 2007
Heading the Ball (Auto FP)
The other day I decided to experiment with Nikon's Auto FP high speed flash sync. This system allows you to exceed the camera's normal flash sync speed. This can be very useful in the case of fast action requiring flash. 
This shot is no masterpiece but it includes action and the nightmare lighting conditions of mottled afternoon sun. I wanted to see if I could stop the action and provide some fill flash. This was taken at 1/500th sec, f5.6, ISO200. The camera was in manual and the flash was on the camera and set for TTL. This means you can set the ambient exposure with a test shot with no flash then turn on the flash and let the TTL system have a go at exposing the subject correctly. Over at http://www.strobist.com/ they would be frowning on this as they advocate manual flash wherever possible. Actually I have experimented with manual flash with Auto FP and it works but you have to be a little bit careful as you move from below to above the normal maximum sync speed of your camera. Why?
First, we should look at why Auto FP is needed? Without a system like Auto FP, trying to take a shot above your camera's sync speed could result in a partially dark frame. In other words a nice photo of part of the back of your shutter. This is because at high shutter speeds there is effectively a slit moving across the film or sensor. Flash at full power is only on for about 1/1000th second, this means that you get a burst of light at some point during the time it takes the slit (shutter) to move across the frame. The maximum sync speed of your camera is therefore the fastest shutter speed at which the entire film frame or sensor is exposed at the same time. The flash must occur at this time. Enter Auto FP!!
Auto FP is a system whereby the camera instructs the flash to remain on for the time it takes for the shutter slit moves across the frame. It appears to work rather well. There is of course a downside, isn't there always! The range, or effective power of the flash is reduced by about two stops.
This is why I have found it slightly tricky when moving over the maximum sync shutter speed with the flash in manual. All of a sudden I have to bump the flash power by a couple of stops for the correct subject exposure.
Having said all of the above, the system seems to be very useful even if it is never a replacement for a faster maximum flash sync speed. I intend to experiment more with this in the near future.
This shot is no masterpiece but it includes action and the nightmare lighting conditions of mottled afternoon sun. I wanted to see if I could stop the action and provide some fill flash. This was taken at 1/500th sec, f5.6, ISO200. The camera was in manual and the flash was on the camera and set for TTL. This means you can set the ambient exposure with a test shot with no flash then turn on the flash and let the TTL system have a go at exposing the subject correctly. Over at http://www.strobist.com/ they would be frowning on this as they advocate manual flash wherever possible. Actually I have experimented with manual flash with Auto FP and it works but you have to be a little bit careful as you move from below to above the normal maximum sync speed of your camera. Why?
First, we should look at why Auto FP is needed? Without a system like Auto FP, trying to take a shot above your camera's sync speed could result in a partially dark frame. In other words a nice photo of part of the back of your shutter. This is because at high shutter speeds there is effectively a slit moving across the film or sensor. Flash at full power is only on for about 1/1000th second, this means that you get a burst of light at some point during the time it takes the slit (shutter) to move across the frame. The maximum sync speed of your camera is therefore the fastest shutter speed at which the entire film frame or sensor is exposed at the same time. The flash must occur at this time. Enter Auto FP!!
Auto FP is a system whereby the camera instructs the flash to remain on for the time it takes for the shutter slit moves across the frame. It appears to work rather well. There is of course a downside, isn't there always! The range, or effective power of the flash is reduced by about two stops.
This is why I have found it slightly tricky when moving over the maximum sync shutter speed with the flash in manual. All of a sudden I have to bump the flash power by a couple of stops for the correct subject exposure.
Having said all of the above, the system seems to be very useful even if it is never a replacement for a faster maximum flash sync speed. I intend to experiment more with this in the near future.
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