Ups, just noted I still owe you the continuation of my report on the nature photography workshop with Konrad Wothe I took in April. Read the first part here.
So, after the first against the sun shots we arrived at Tiger’s headquarter, and it quickly turned out to be very difficult to say the least to get Tiger cooperating and be a willing model, and control the lighting with the sun coming in from the side already quite strongly. From the session with the tigers, there was not a single photo that did not contain either an unsightly fence not successfully blurred into the background, some other parts of the enclosure, or simply completely unmanageable contrast range. I spare you the results.
We started looking for alternatives to make some interesting photos.
[svgallery name="Hellabrunn2"]
Now, we found one cute little guy in his tree, and then it was when I came to dread the new camera…
Problem was, he was quite high up in that tree fork, maybe 4 meters, and the distance to the tree from the closest point where you can put your camera without actually entering the enclosure was also certainly 6 meters from the tree’s trunk. Taking my Pythagoras this would put me at a distance of about 7 meters from him to cross with my flash, because without any flash he was by far too dark. The image below was taken at camera automatic “neutral” position: No exposure correction, no flash exposure correction (using my SB800 flash, not the tiny internal one). So I started out at the neutral setting with ISO 400, camera on my monopod, aperture of 5.6 (wide open with my Sigma 100-300 f/4 with 1.4x TC) resulting in an exposure time of 1/500s. Image comes out ok, but I thought I could do better…
My goal was to emphasize the animal in the picture, and if at all possible get rid of the obnoxious bright sky background and try to turn it back to blue, because this is what my eyes told me it was. Below the series of pictures I took, with the following exposure changes:
- Test shot with exposure compensation dialed down -1 EV, no flash. The sky is more blue, and the animal is dark. Nice sun-lit fur. Data: f/5.6, 1/1000s, ISO 400. Now I just needed to flash that bear!
- Add flash, with flash exposure even dialed up to +1 EV. Data: f/5.6, ISO 400, 1/1250s. Doesn’t really pop – flash blinking, doesn’t have the reach! Ouch.
- Ergh. More flash reach? Well, I’m beyond the flash sync speed of 1/250s of the D300, so the flash is indicating with it’s FP marker it is operating in high speed sync mode. This is bad, because it reduces flash output, e.g. the guide number for max flash goes down from 112 to 28 at ISO 400.
Solution: Get the exposure time down below the natural sync speed. Only idea: Close the aperture down to f/9, resulting in 1/500s. That was not enough! Resulting image: Not much difference, as the closed down aperture eats away the increased flash output! I would have needed to close the aperture down to f/14 to get 1/250s! - Next idea – damn, he moves, looks up, catchlight in the eyes! frantic shooting – to increase the ISO to 800, to allow for the more sensitive sensor to pick up the flash light. Result: f/5.6, 1/2500s. Back into FP mode, and the result is not better at all…
- He is yawning! Don’t worry about flash output, keep taking pictures! He might decide to do a loooong nap soon!
- Next try: Lower ISO to 100 and close the aperture to get to the real flash sync speed of 1/250. Result: Bear is sleeping by now, but the camera reads at f/6.3 and 1/250s. And I actually like the result (but not the pose)!
[svgallery name="Hellabrunn3"]
Lesson learned: Better know you math before you do flash shooting. In FP mode, the SB 800 will no longer help you compute the flash reach, you need to go back to the old guide number formular:
distance in meters = guide number depending on ISO : aperture
So if I calculate this for the 6 pictures above, and find out the maximum flash reach at the settings I made (all with the zoom reflector of the SB 800 at it’s full position of 105mm):
- No flash
- Using the guide number of 40 at ISO 400 as the SB 800 manual indicates, I would have had a flash reach of 40 : 5.6 = 7 meters. Barely enough, and I was on 1/1250 and not on 1/300. The SB 800 manual does not state the effect of higher shutter speeds than 1/300s, it is assumed it gets even less…
- 14 meters on full flash output, so closing down the aperture had it’s effect. But with high speed sync I was down to 4.5 meters, not near enough. This was the wrong direction, because I did still required the FP mode at 1/500s.
- 20 meters on full flash output, guide number goes up to 56 for high speed sync – giving me theoretically 10 meters reach at 1/300s. Could be good enough? The picture doesn’t look like it, the dark shadows do not show any fill flash.
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- No high speed sync, so I get the full guide number of 56 for ISO 100 giving me 8,9 meters reach at f/6.3. Now I got the bear!
My old and loved D70 in contrast to the D300 I used got a fully electronic shutter – it was capable to sync to flash speeds of up to 1/2000s (I tried!) without the need for FP mode and the resulting loss of power. So with the D70, I would easily have had 20 meters and more flash reach with my first pictures, and neither missed the yawn nor had to start calculating guide numbers at all!
Ah, sentimental thoughts – my D70′s shutter (the additional mechanic one, not the electronic shutter) had died after about 60000 actuations. I couldn’t make me spend the money to repair that 4.5 year old digital camera but rather decided to go straight to a new D300, a step I did not regret, until maybe that day in Hellabrunn
More tk…
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Tags: Flash photography, Photo
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