We all have styles of photography that we prefer, and what I like to shoot are macro images of flowers and bugs, like bee's and dragonfly's on Lily's. The problem that I always seem to have is that when I have time to go and shoot its exactly the time that everyone tells you that you should not be shooting. One of the places that I like to shoot flowers is Tower Hill in Boylston Ma. but they don't open until 10:00am. Another problem is that I am not a morning person and don't see sunrise as much as I did when I was younger because I don't stay up that late as often. So I find that most of my macro work happens from 10:00am until about 2:00 pm. This is when the sun has harsh shadows and strong contrast. A while back I was at Tower Hill with a friend shooting flowers and even when using the foldable diffusers and fill flash I was just not getting the results that I wanted, everything looked a little flat. So I started reading everything I could about lighting. Another macro issue I was having was to small a "Depth of Field" at the magnification that I wanted.
During this time I was also reading a blog on lighting by a photojournalist (Strobist) and it related flickr group. I was looking to learn more about lighting in general but I also have been looking at how to better light people and groups of people outdoors. One of the things that I picked up from the blog is that there are times when shooting outdoors that you need to over power the sun to get the shadows the way you want. I also reread all my books on macro photography. And at NECCC this year I followed the lighting and macro trend by attending a portrait lighting session, and all of the macro sessions.
When I started thinking about all I had learned in the previous few months I realized that the one way to eliminate the harsh effects the sun on my macro photography was to use what I had learned from the photojournalist reading and make the sun a secondary light source that was at least 2 f-stops less than my primary light. What I needed to do was create a bright primary light source that is large (relative) with very defused light at an angle to the subject which would bring out the texture of the flowers. Many things that I had read talk about how small a light source a strobe is and how it can look harsh when used as a fill flash. To make the strobe look like a large source I needed to get it very close to the subject and to diffuse it. In John Shaw's" Closeups in Nature" book he describes how to make what he calls a butterfly bracket. Having a bracket something like this would allow me to get a hot shoe flash with a wide angle diffuser very close to the subject creating the very large light source that I was looking for.
I built a bracket to hold a flash close to the hood at the end of the lens similar to what John Shaw describes in the book. It was made using aluminum stock that came with a garage door opener, bent and drilled a little. One of the differences is that I used a small ball mount so I can change the position of the flash easily. On the bracket I mount my old Vivitar 283 with the VP-1 module which allows me to manually set the power level, and a 24mm wide angle diffuser.
So how did it work? When using a 90mm macro lens getting close to 1:1 ratio, a power setting in the 1/16th to 1/8th power level was more than enough to over power the sun, and allowed me to use aperture setting in the f29 to f40 range, but I need to be careful not to get to much light from the strobe. If it is set to high, harsh shadows form which is no better than just using the sun. It takes some experimenting for find the best power/aperture settings. Using the histogram I would adjust the aperture to get the proper overall light level. Because the strobe was the brightest light source and has an extremely short duration in effect I was controlling the light from the strobe by setting the aperture. I can control the sun's contribution, which is a continuous, by adjusting the shutter speed. Another way to say this is I am controlling my lighting ratio by adjusting the aperture and shutter speed.
Here are some pictures showing the camera mounted on the flash bracket. Very often the subject to flash distance is less then the subject to lens distance. Hiving the light off to the side some helps bring out the texture of the subject.
This is the view from the front of the camera. The diffuser is right next to the end of the lens.
This is the view from behind the camera.
Shows the details of the small ball head where the strobe is mounted.
Below are some of the pictures taken with this configuration. Note that none of these images have not had any changes made to them other then a very minor amount of sharpening. I have included the exposure details as well as the time the images were taken, ranging from about 8:30am until 3:30pm.
This is one the first picture that I took using the butterfly bracket. The texture of the flower shows up much better then earlier attempts and techniques.
Time: 8:21am
Aperture: f32
shutter 1/250
What you can see here is how soft the shadows are for a light source that over powered the sun. It also has good depth of field for this level of magnification.
Time: 5:11pm
Aperture: f36
shutter 1/250
There are times when its better to be lucky than good. I set everything up to take this picture and the bee flew in just as I pressed the shutter. I didn't know the bee was there until I had the image loaded into the computer. Notice that by having the strobe as the primary light source which has a very short duration it froze the wings on the bee. It also froze the pollen that was blowing around and has a good depth of field. Again you can see the soft shadows.
Time: 11:29am
Aperture: f36
shutter 1/250
This shot was almost planned. I was taking a picture of the bee on this flower and just as I was pressing the shutter it started to fly away. Again the wings are frozen with a good depth of field.
Time: 3:32pm
Aperture: f29
shutter 1/250
Some other thing I found from trial and error. The auto white balance on the camera is easily fooled. For the best results I set the camera WB to flash which matches the primary light source. Another thing I found was that the diffuser on the old Vivitar 283 does a far better job diffusing the light than the diffuser that comes with an SB800 because its surface area is almost twice as large. When that close to the subject it looks like a much larger light source.
The other thing that I found was that I get much more consistent results by using the strobes with manual output settings rather than using i-ttl. When using i-ttl more than half of the pictures were over exposed. After a little use I developed a feel for what the aperture should be for how far I was from the subject, and how light in color the subject is.
