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 p.2 #2 · Things that can go wrong | |
On a 580ex High Speed and Second Curtain are set with successive presses of the same button which has three modes:
• Off (normal single burst sync as sensor is fully exposed)
• High speed FP sync
• Second curtain (single burst while shutter is fully exposed, just before end of the exposure).
Thus it is physically impossible to enable high-speed sync and second curtain sync on the flash at the same time. Secondly, second curtain, like normal sync, because it is a single burst mode and is subject to the same sync speed limit as normal flash.
Second curtain is typically used in situations where where the shutter can be dragged for 1-2 sec., giving a subject moving linearly across the frame time to create the blur trail behind the subject against a sharp background before the shutter freezes the foreground action. The problem with second curtain is the opposite of x-sync: getting long enough shutter times in the range of (1-2 sec. needed) to create the blur. Getting the shutter that slow requires a darken room indoors, or the use of ND filters on the lens.
An alternative to second curtain to achieve a similar illusion of motion in a still photo is panning the camera, which can be done without flash. It is a technique used for photographing fast moving objects like race cars. The difference vs second curtain is that the background is blurred, which is an effective way to isolate the foreground from the background clutter.
If shooting a waiter carrying a tray of food across a crowded room where the context of the background is important then second curtain would be the most effective technique. On the other hand if you wanted to convey the waiter as a cool and calm amidst the chaos of the crowded space you might instead choose to pan the camera, with or without second curtain flash, so the waiter is isolated on a blurred background. Start with the goal for the message of the shot, the then apply the technique most effective at creating the underlying perceptual reaction which will convey it.
Zenon:
With regard to your latest set of tests they all look artificial for two reasons: 1) the foreground is brighter than what would be seen by eye in similar lighting, and 2) the direction of the flash fill is flatter (coming form a lower angle) than the natural lighting.
To get results which appear more natural start with an ambient only shot which is exposed for the background. It will make the foreground darker than perceived by eye because the camera sensor can't handle the contrast, but you will be able to see the pattern the natural fill light from the OVERHEAD skylight. What you then need to do is just add enough flash to bring the shaded side up to the level you perceived by eye (i.e. the baseline for normal) while at the same time retaining the direction of the natural fill from the sky. You need to raise the flash on the camera so its angle is more similar to the downward direction of the sky fill to avoid the flash creating a flat looking foreground.
I did the edit below in Photoshop from your last photo (right) to show how would need to be illuminated with the raised frontal flash to make in more natural; like the ambient only shot fill direction, only brighter to overcome the physical limit of the sensor:
The biggest difference in the edit is the darkening of the gap between the posts which by virtue of the flat near axis lighting sends the clues that the lighting is artificially low, not naturally downward.
Its a matter of developing the ability to see past the physical limits of the camera to pre-visualize the final desired result using the natural fill lighting from the sky as the foundation and augmenting it, not overpowering it, with the flash to the point were what the camera records (and what you can do in Photoshop) matches what was perceived by eye. That's straight out of the Ansel Adams playbook, but with a new twist: using flash, not negative development, to match scene to final image.
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