|Yongnuo YN1410 LED video light with plain diffuser|
The LED panels have very simple controls: an on/off switch and a pair of buttons to increase or decrease the light output over 16 steps. They are quite well daylight balanced, but tends to be a little towards the blue side at max output (5800-6000K). I find that, with the camera set to auto white balance, I get very acceptable colour reproduction.The max light output of each panel is rated at 960 lumens. What is probably a more useful way to describe it is that, for the MP-E 65 macro at 1:1 reproduction ratio and f8, the exposure is around 1/60-1/80 second at ISO100.
|Specimen lit with 3 x Yongnuo YN1410 panels|
|Hilara matrona (Empididae, Diptera) male. LED lighting.|
In the past I have used three flash guns: the two heads of my Canon MT-24 EX and the Yongnuo YN565EX as the third. These require some diffusion, so in the picture below, the MT-24 heads are fitted with plastic diffusers which roughly double the effective area whilst the 565 is fitted with a large, home made soft box. The flash exposure is manual and with the 565 set up as a slave controlled by the MT-24. For this particular shot, the MT-24 heads were both set to 1/16 power and the 565 to 1/64 power. This is best judged by taking test shots and assessing the image and histogram on the camera's rear LCD panel. (The articulated LCD screen of the Canon 60D really scores here. It makes it easy to view the screen without having to go through contortions to get down and directly behind the camera! Being young and bendy would probably be equally effective ...) For this sort of shot in the 1.5-2:1 range, the flash power require is generally low. This has the advantage that the flashes recharge very quickly. At higher reproduction ratios, say 4-5:1 for shots parts of the animal, more flash power may be required. For things like tarsi details at 5:1 you may even need full power. In these cases the StackShot's programming will need adjusting to allow a longer pause between shots to allow the flashes time to recharge.
|Three flash heads with diffusers. The YN565 has a large, home made diffuser head fitted.|
|Stronger specular highlights. Note those on the hind femur.|
|Plastazote softbox built around the specimen|
Note that the MT-24 head is mounted on a small ball & socket head. I find these extremely useful for mounting lights and flashes. They can be bought quite cheaply off eBay.
|Small ball & socket head, metal flash "cold-shoe" mount and standard 1/4 inch photo screw, all bought off eBay, are very useful for mounting lights.|
- With flash, you need another light, such as desktop halogen lamp or an anglepoise lamp, to provide the light to to view the specimen for focussing and setting the start and end points. You then need to move that out of the way and move the flash heads into the correct position before you shoot.
- You generally need several test shots to get the right flash exposure and to adjust the diffusion and flash head positions to manage specular highlights.
- The exposure of successive flash shots can sometimes be a bit variable (probably an indication that the flashes did not have sufficient time to fully recharge between shots). This can impact on the quality of the finished image.
In the next post I will talk about software for processing the stacks.