Words and images by John Gravett of Lakeland Photographic Holidays.
Macro lenses are great for getting close to subjects, but their limit is usually 1:2 or 1:1, what can you do – at reasonable cost, to get greater reproduction ratios – simple, fit your lens on in reverse!
- SLR camera
- lens – standard or wide angle
- Reversing ring
So what exactly is a reversing ring, and what does it do. The function is simple – a reversing ring screws into the filter thread of your lens, and has a built-in bayonet mount, allowing the assembly to be mounted in reverse on your camera body.
What benefit does that give?
In normal use, the subject is further away from the front of the lens, than the rear of the lens is from the sensor. This is the way lenses are designed to work, and give their best, corner to corner, sharp results. If you make a lens focus so close that the front of the lens is nearer to the subject than the rear is to the sensor, then you begin to suffer from vignetting, chromatic aberration and general unsharpness in the corners. The simple action of reversing a lens when you're really close to the subject then puts the (reversed) rear element closer to the subject than the front element is to the sensor, maintaining a quality result.
Reversing rings are generally available, and really inexpensive, I checked Ebay and found some Nikon-fit at under £10 in a variety of filter sizes.
Macro lenses usually come in fixed focal lengths, as computing zoom lenses to work well in macro situations is almost impossible, so reversing a fixed focal length lens is likely to give you better results than reversing a zoom lens. Although I did try it with a 35 – 70mm zoom and was surprised at the results.
Reversing standard or wide-angle lenses are more successful than telephotos, so reversing your 90/100/105mm macro lens will not give great results – the working distance simply remains too far.
105mm macro at life size.
I tried firstly a 55mm macro (any 50mm lens will do really well), which gave a slight increase on magnification over the lens mounted normally, but maintained excellent corner-to-corner sharpness.
Above: 55mm lens reversed at life size.
Above: 55mm macro at half life size.
A 28mm lens reversed offered about 2.5:1 magnification ratio, which is a greater magnification than all regular macro lenses. The 35 – 70mm zoom worked amazingly well reversed, and it was easier to control the degree of magnification by altering the focal length of the lens.
Above: 28mm lens reversed.
Above: 35-70mm zoom reversed at 35mm.
There are a number of problems in using a lens reversed, though. Firstly, unless you have a lens with a separate aperture ring, controlling the aperture is impossible, although there are other adaptors which allow aperture control on reversed lenses. More importantly though, assuming you have aperture control, as there are no electronic connections between the aperture and the lens, you will be viewing at your taking aperture, which, with such close distances and with extremely narrow depth of field – will need to be around f/22! Giving you a very dim viewfinder image. Live-view can be used pretty well to give a brighter image than squinting through your viewfinder.
Secondly, using a reversed wide-angle at 2:1 magnification does mean close working distances, and we're talking of 2 or 3 centimetres, (about an inch) from the lens to the subject, so be careful not to damage your lens by bumping it into the subject. Furthermore, with such close working distances, not much natural light will get around the lens to the subject, so supplementary lighting – either flash or LED lights, might be useful, the latter would of course, give you a brighter image to compose and focus on. With the difficulty of using reversed lenses, photographing static subjects at first might be the best move!
Reversing rings may not be the easiest way into real macro photography, but they are certainly the cheapest, and give really outstanding results.
Words and images by John Gravett of Lakeland Photographic Holidays
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