Reverse Lens Macro and Another ABC Project
Reverse lens macro shot of part of a glass drinks coaster
This post describes the reverse lens macro setup that I’m using to take photographs for a current project.
The ABC Color Project
The last ABC project (more below) was so enjoyable that I have instigated one myself over on Google+. this time around it is all about color, a subject chosen for several reasons:
I wanted to test a macro set up (more about this shortly)
Most of my recent output has been black and white and I really needed to start thinking in terms of color again.
I wanted to do something much more abstract than the last series and color as primary consideration lends itself well to this. The task that I set myself was to do something that made the viewer think of the color before anything else such as composition, material, texture etc.
Anyway, a couple of dozen or so of us are working with this theme on Google+ and as with the previous ABC games project, I’m posting my photos here as well as there. At the time of writing the project is at day seven and the letter G though that will probably not be the case by the time you read this. The image at the top of this post represents the letter E and the color emerald green. Here is the rest of the set.
There are many close up images on this website but they were all shot using available light and using what is basically a magnifying glass screwed onto the end of a normal lens. This cheap and cheerful arrangement is one that I’d recommend for creative close ups but not where accuracy is of prime importance.
This time out I wanted something different, technically cleaner and more accurate work. I also wanted a higher magnification – to move into the realm of true macro as opposed to close up. The working definition of macro is any image that does not have to be shrunk to fit on the cameras sensor. In the case of the camera I use, a crop sensor Nikon DSLR that means that if the image is of a scene approximately one inch on its longest side or less it is true macro.
Anyway here is the setup that I’ve used for all of these images.
A Nikon D3100 camera
A 18 mm – 55 mm kit lens (non VR) that originally came with a Nikon D40X – this lens is OK but not nearly as good as the current version of the same lens. It is, however, more than good enough for this task. This lens is attached to the camera backwards using a reversing ring which costs less than $10 from Amazon. There are branded ones available but they are about four times the price.
A Nikon SB600 flash but any flash should do the trick as non of the high end dedicated functionality is being used.
A Synch Chord – cheap one is fine as it only has to trigger the flash (or some kind of remote triggering).
Mount Lens onto the camare using the reversing ring and attach flash using the synch chord.
Put all settings for camera and flash to manual.
Set shutter speed to around 1/60
Set the flash for 1/4 output if it is a Nikon SB600. If flash is a different model this will probably vary. Possibly 1/8 for an SB800 or 1/2 for a cheaper generic flash but these are guesses at best.
Now, one slightly but not very tricky bit – if you are using a lens without an aperture ring then there is a lever, now on the front of the lens, which will have to be wedged open with a folded piece of cardstock (move the lever and you will work out what is required very easily). This is to open the aperture as wide as possible – its normal resting position is a minimum aperture. This is true of Nikkor lenses, mileage may vary with others. I think I heard that Canon lenses default to the widest aperture – if this is the case do nothing.
At this point it is worth mentioning that many photographers will recommend a 50 mm prime for reverse macro. I tried an f/1.8 50 mm and while the results were OK I preferred the kit zoom described above. The 18 mm – 55 mm zoom allows for the photographed ‘scene’ to be anywhere from 1/4 inch to 1 1/2 inches wide which is a pretty good range for macro. The 50 mm prime works to around 1 1/4 inches which is just outside true macro territory. An important thing not mentioned until now is that the smaller the focal length the higher the magnification. The 18 mm end of the zoom under discussion gives the 1/4 inch image while the 55 mm gives the 1 1/2 inch. I’ll give one final set of numbers that may or may not be useful then I’ll return to English – promise! Roughly speaking a 50 mm lens coupled with a full 35 mm sensor will give a ratio of approximately 1:1. A 1:1 ration means that the sensor records its own size in the real world. Of course we are using a crop sensor so the 50 mm becomes, in effect an approximately 80 mm lens. This is why the crop sensor/50 mm combination yields a close up as opposed to true macro result. By my reckoning a focal length of around 33 mm will give a 1:1 result when coupled with Nikon’s crop sensor.
My reverse lens macro setup for back lit subjects
The subject of the image at the top of this post is a stained glass coaster – the round thing is a transparent rubber ‘foot’ to stop it sliding or marking a tabletop. This is where the positioning of the flash is important; As it is a transparent subject back-lighting is required and having the raised platform (OK, box) and the flash off camera means that this can be achieved. with an opaque subject on camera flash, bounced off the ceiling would probably work OK. To be honest it is easier for me to just leave the set up in place and use it for everything regardless.
The zoom changes the focal point – in other words as the magnification changes so does the focal distance (this isn’t the case with normal zoom photography) . I find it easiest to start off at the lowest magnification and work in towards the largest – it is really easy and instinctive but does rule out the use of a tripod (unless you have some sort of racking device attached).
As the zoom changes so does the aperture (at least on cheaper lenses). If the shot is correctly exposed at the lowest magnification it will be a couple of stops underexposed at the highest. I use the ISO setting to compensate. This again becomes really instinctive very quickly.
Below is a quick snapshot taken with this setup that shows how the light actually looks with a more traditional type macro shot.
Please use the comments to ask any questions or to tell me where you think I am going wrong 🙂 I am always interested to here about setups that others are using. The ABC Color project is producing some excellent photographs – Click here to see them.
By Steve Johnson