Fancy doing some insect macro out in the wild and I’ve been trying out various lens solutions and lighting. Last time I did any of this I just brought the flies into the studio and this works well. See here. This time I wanted portable rig for capturing the flies in their natural environment. Here’s the first rig. A Sigma 105mm Macro with some passive extension tubes on it to give more magnification, but with the loss of auto-aperture control. Normally, with modern automatic cameras, the aperture diaphragm is wide open when you are looking through the finder, and only stops down to the aperture you dialled in when you take the shot. This means there is plenty of light to see and focus the subject by. Without auto-aperture control, you either have to open up and stop down the aperture using the aperture ring manually (and in doing this you’re mess up your focus) or you need to look into the darkness and attempt to focus the subject with the aperture stopped down. As you can imagine, the success rate isn’t high :-/
For the light I jammed on a small soft box, which has enough surface visible to the subject to cast some light on it. Most of the light is lost though, and it’s a bit harsh. I’ve switched out the soft box for the Rogue Flash bender XL with the soft box attachment. This gives a good wrap around light and the best bit is that of course, you can bend it, so if you want more light on the right or left you can bend the appropriate side down, or bend the far edge down for some more backlight etc. The subjects will be around 40mm from the front of the lens (or back of the lens in this pic as it’s reversed :P) so from that position it’s a really nice soft light.
I’m just using the flash on TTL, with the camera in manual exposure, 1/250th of a second at around f/8 to f/16. I’ve left auto ISO on for these as well. As you’ll see below, this means more or less ambient in the scene depending on the magnification, with an almost black background for the higher magnification shots, as the ratio of distance to camera (and the light) between subject and background increases (and so the light falloff is more pronounced).
So, having got the light sorted, what about lenses? I have a 105mm Sigma macro lens, and this renders 1:1, however this isn’t enough to get really detailed shots of spider eyes and such like. So I bought a set of Meike extension tubes with electrical pass-through connectors so the lens can still talk to the body. Extension tubes are a great solution to boost magnification as they contain no optics – no glass to worry about or degrade the image. With these on we can take pictures as normal – looking through the viewfinder, with the aperture wide open to give us a view of the subject, moving the camera back and forth slightly and taking the shot when the subject appears to be in focus. With this we get this shot of a brand new brass wood screw. This is around 4mm in diameter at the edges.
Next, I swapped this out for a 20mm f/2.8 AIS lens mounted backwards on a reversing ring. You can pick these up from various suppliers via eBay for around £3 to £4 each. You need to buy one to fit the filter ring diameter on the lens you want to reverse. Wider angle (shorter focal length) lenses provide more magnification when reversed. Remember you will need one with a manual aperture ring so you can open it up a little from the minimum (or stop it down from wide open on Canon lenses). Nikon G lenses are no use for this really – as they have no aperture ring and the aperture will be fully closed when not connected to the camera in the normal way. This gave me this shot of the same wood screw. Already you can see it’s much bigger in the frame, and details on the apparently shiny surface are becoming visible. The background has gone almost pure black, and I’ve pushed it all the way there in Lightroom. This was shot hand-held up against a window so I had a chance of seeing the screw through the stopped down lens. I wasn’t worried about camera shake as I knew almost all of the light would come from the flash. From the sound of the flash pop, I reckon it was on no more than 1/8th and so the flash duration was around 1/5000th of a second.
For the final shot, I attached all of the tubes to the reversed 20mm lens. Still no connection pass-through remember – as the connections on the lens that normally hook up to the camera via the lens mount are now facing away from the camera. However, with all 3 tubes attached, we get some real magnification. I have no idea how much exactly, but compare this final shot to the others in terms of how much of the frame the width of the screw takes up. You can now see an entire landscape on the surface. A surface that just looks shiny and yellow to the naked eye (well, a normal naked eye anyway, I have macro eyes with a focal range of about 10cm to 14cm, so I can see some of this texture anyway). Just look at the colours on it, and the apparent crude nature of the casting. So, if you want real high magnification macro shots, forget macro lenses, get some tubes (£10 for a manual set, £30 for some with connections on, although they won’t have anything to connect to on a reversed lens, if this is your intended use, get the cheaper ones that are literally just metal tubes) and a reversing ring for a wide angle lens.
So can you have your cake and eat it? I.e. can you have a reversed lens and auto-aperture control? Yes, you can. You need to use 2 lenses. The “primary” lens, you attach to the camera in the normal way. It is the aperture in this lens that we’ll use to control depth of field. Then using a reverse coupling ring you attach a secondary lens in reverse to the front of the primary. On this lens, you leave the aperture wide open (so only the secondary needs an aperture control ring). Use a telephoto (prime or zoom) as the primary and wide or normal prime as the secondary. As soon as my coupling rings arrive, I’ll post up the results from that.