reverse vision

Technique Reverse lens macro

You don’t need a macro lens to enter the world of larger-than-life photography. Attaching your lens in reverse on the camera body is all it takes to enter a world where tiny creatures barely visible to the naked eye fill the frame.

Reverse vision

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In normal photography the subject is larger than the image on the sensor. In macro photography it’s the other way around – the subject is reproduced at life-size or greater on the camera’s sensor (or film). One way to try out true macro photography is to buy Canon’s MP-E 65 lens. It’s the only Canon lens that offers magnifications from life-size to 5x life size in a single focusing action, but like all specialised lenses it comes at a price (rrp £1249.99). However, there is an alternative that is much easier on the pocket – reverse lens macro. You may not even have to buy another lens to try it out. The idea, as the name suggests, is to turn your lens around and use it in reverse. It may sound strange at first, but in this position the lens acts like a high quality magnifying glass. The image quality with this technique can be very good, matching the performance of a specialist macro lens.

Above Large Red Damselfly (pyrrhosoma nymphula). This image was created by reversing an old manual Pentax 28mm lens on an EOS 5D camera. The lens has a manual aperture ring which the photographer used to set the aperture to f8. The reversed lens acts as a high quality magnifying glass, allowing larger than life-size reproduction. The depth-of-field at such close focusing distances is very small, so the photographer took five images and blended them using focus stacking software (see EOS magazine October-December 2010, page 51).EOS 5D, reversed Pentax 28mm f2.8 lens, 1/200 second at f8, ISO 160.

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Above A reversing ring has a lens mount on one end. This attaches to the camera lens mount. At the other end is a thread which screws into the filter mount of the reversed lens. Reversing rings are available with different sizes of thread to suit a variety of filter mounts.

Single lens reverse macro

One way to approach reverse lens macro photography is to attach the lens directly to the camera using an adapter ring built specifically for this purpose. A good place to start is by using a 50mm lens or an EF-S 18-55mm kit lens. The combination of a 50mm lens and an EOS camera with an APS-C sensor gives you near life-size reproduction, matching the magnification achieved by Canon’s EF 100mm and EF-S 60mm macro lenses. A wide-angle lens will get you even closer – when lenses are reversed shorter focal lengths give you greater magnification than longer ones. The only drawback is that there is no Canon-approved method of stopping down the aperture if you are reversing an EF or EF-S lens directly on the camera. This means that you have to take photos at the maximum aperture of the lens where the depth-of-field is very narrow. Don’t let this put you off trying this technique, though, as you can still get some beautiful photos this way. To fulfil the potential of this technique you really need to find an approved method of stopping down the reversed lens. One solution is to use an old Canon FD lens (these have an aperture ring on the lens). We have instructions showing how this can be stopped down when not attached to a camera – download it in the EOS Extra! section of our website. Go to the home page at: www.eos-magazine.com and enter the password: extraeos You can also use lenses from other manufacturers – many lenses from old film cameras have lenses with a ring which alters the aperture. We’ve even heard of enlarging lenses being used this way.

Right The Novoflex EOS Retro is an adapter designed to retain electronic aperture control over reversed EF and EF-S lenses. It comes with a 58mm filter thread (use a stepping ring if the filter size of your lens is smaller) and works by linking the contacts at the rear of the lens (now facing forward) with the contacts in the camera lens mount using a short coiled cable.

Left When using a lens reversing ring we recommend screwing it into the filter thread of the lens first, then attaching the ring to the camera.

Above A coupling ring has threads on both ends so that two lenses can be joined together at their filter mounts. One lens is attached to the camera body, leaving the other lens in reverse on the first. Coupling rings can be combined with stepping rings to fit lenses of different diameters together.

Two reversing rings

How it works

These diagrams show how reverse lens macro photography works. With a lens mounted on a camera in the normal position (right top), the image of a large object is reduced in size so that it can be recorded on the sensor or film. When the lens is mounted in reverse (right below), the opposite happens. Small objects are recorded at life-size or enlarged – a 50mm lens reverse mounted on a body with an APS-C size sensor achieves near life-size

reproduction. The image quality is good. In normal photography, the distance between the front of the lens and subject is greater than the distance between the rear of the lens and the image. With the lens reversed and the subject much closer, the rear of the lens (now facing forward) is still dealing with shorter distances than the front of the lens (now facing backwards). The lens design is optimised for these conditions. Reversing the lens maintains these conditions with the subject closer to the lens than the image.

ExposureA reversed lens, unless you use the Novaflex EOS Retro (below), has no electrical connection with the camera. However, the camera can cope with this quite easily. Instead of an aperture setting, you’ll see the figures ‘00’ in the camera’s viewfinder (or the LCD screen). This indicates that the camera is unable to communicate with the lens. In this situation the camera calculates exposure according to how much light is coming through the lens. If you are using a reversed lens with a manual aperture ring, you can set the aperture to any setting you like. The viewfinder goes darker, making it more difficult to see, but the camera still works out the exposure. The easiest exposure mode to use is aperture-priority (Av). All you have to do is set the ISO and the camera calculates the shutter speed required. Program (P) mode also works well. In both of these modes you can use exposure compensation to override the camera’s settings if necessary. Avoid the basic zone macro mode. The camera takes control away from you by changing the ISO setting and activating the built-in flash if it thinks light levels are too low.

Above A Canon EF 50mm f1.4 lens reverse mounted onto an EOS 40D. With this set up, the lens aperture will normally be at its maximum setting – in this case f1.4. This gives a very limited depth-of-field and a somewhat ‘soft’ appearance to images. It is possible to set the lens to a smaller aperture (see page 56), but this comes with warnings and it is your call as to whether you wish to try the technique. If not, the EOS Retro accessory (below) is an option.

The EOS Retro is available from Speed Graphic (www.speedgraphic.co.uk). It costs £259.

54 | Reproduced from EOS magazine July-September 2011 Reproduced from EOS magazine July-September 2011 | 55


Above These two photos were taken with an EF-S 18-55mm IS lens reversed on an EOS 450D. I use very little equipment, other than a tripod and a cable release. Once in a while I may use a small LED flashlight, but I prefer natural light from a nearby window. The focal length I use depends on the subject and the magnification I’m looking for. I am most often going for high magnification, so I usually start at 18mm (the magnification is

Above These images were shot using my favourite combination of an EOS 5D Mark II and an old Canon 50mm f1.8 SC FD lens I bought on eBay. The lens has a manual aperture ring, which gives me much more control over depth-of-field. Occasionally, I will add an EF 25 II Extension tube for greater magnification. This particular combination was a real discovery for me, and has really given me more control when shooting using a reversed lens.

When I first learned about the reverse lens method of macro photography, I thought it sounded like an amazing idea, but had very little belief that it could produce a truly worthwhile macro image. How wrong I was. Reverse lens is a remarkably inexpensive way to shoot macro, very simply, with little equipment and with extraordinary and unusual results. It takes practice and patience, as do all macro photography techniques, but it yields dreamy, almost surreal results, once mastered. Early on, before I had done any research on the subject, I simply took my 50mm lens off the camera, turned it, just as the name suggests in reverse, and held it by hand against the lens opening on the camera body, using my hand to keep out as much of the light as possible. It wasn’t easy to accomplish this, as I was holding the lens with one hand, trying my best to keep out as much light as possible and shooting with the other hand. But, I was seriously hooked and hungry for more information that might help me learn how to perfect this technique and make it work for me. I did not have the funds to purchase a dedicated macro lens at the time and felt this technique held real promise. I was thrilled to discover that you can actually purchase a reverse lens mount. This inexpensive little ring allows you to mount your lens backwards onto the body of your camera. You can then begin shooting macro immediately and simply, without any other piece of equipment.

Case study Roni Delmonico

How to improve your macro images

1 Make sure you have a good light sourceA bright window, a small hand-held flashlight or an overhead light is just fine. I have never used the on-camera flash when shooting with the lens in reverse, nor an external one, as I have not found the need to.

2 Shoot in Live View mode (if available)Reverse lens produces a razor thin depth-of-field and it will be nearly impossible to focus without zooming in on Live View to the area in which you want the most clarity. Do not expect an overall sharp image. Reverse lens at maximum aperture will give you a creamy soft effect, with some areas of sharpness.

3 Use a tripodIn my experience reverse lens is very unsuccessful when hand-held. A time delay or cable release is also helpful as the smallest movements can cause shake.

4 Experiment with subject matterI’ve used everything from jewellery and seashells, to flowers and bugs, to toy cars and old LP records spritzed with water.

highest at the widest end when a zoom lens is reversed). I always shoot in Live View mode to make focusing easier and I zoom the LCD screen all the way in to the area where I want the sharpest focus. I almost always shoot indoors, unless there is little to no wind outside. To focus, I simply move the subject while watching it in Live View until the plane of focus is where I want it. I also shoot at the lowest ISO possible.

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Setting the aperture of EF and EF-S lenses

To stop down off-camera EF and EF-S lenses put the lens on a camera body the correct way around and set the aperture in Av mode. Press the depth-of-field preview button. The iris inside the lens closes down. Remove the lens from the camera with the depth-of-field preview button held down – the iris remains closed. You can reverse mount the lens and use it at this aperture. It goes back to normal when you remount the lens the right way round. The problem with this technique is that the camera has to be switched on when you remove the lens – and electrical charges on the sensor can attract dust. Canon recommends that you don’t use this method. It’s your call. The technique gives more creative control over your reversed lens images at no immediate cost, but you might need to spend more on sensor cleaning.

Focusing is tricky at high magnifications. The slightest subject or camera movement will move the point-of-focus. One way to deal with this is to mount the camera securely on a tripod, set the focusing ring to infinity, then move the subject, rather than the tripod, backwards or forwards until it is in focus. Another option is to buy a focusing rail – this device lets you move your camera backwards or forwards along a metal rail, giving you precision control over focusing. Focusing rails are available from SRB Griturn (www.srb-griturn.com).

Full frame camerasIf you have two lenses coupled together and the primary lens is too short, your images will suffer from vignetting. Vignetting is more likely with a full-frame camera than on a camera with a smaller sensor. You can reduce vignetting by stopping down or by using an extension tube between the primary lens and the camera body. The extension tube pushes the primary lens away from the camera, thereby extending the size of its image circle.

Protection

The biggest drawback of the reversed lens technique is that you are exposing the rear element of the reversed lens. Unlike the front element of the lens it isn’t recessed and there is a chance that you can damage it. If you have one, it’s a good idea to attach an extension tube to the mount of the reversed lens. This will protect the rear element from accidental knocks and also act as a lens hood, reducing flare. If you don’t have an extension tube, you can always wrap some stiff card around the lens to act as a lens hood and help protect the rear element.

Focusing

Live ViewIf your camera has Live View, use it to focus accurately. With Live View you can zoom in to see the image at up to 10x magnification giving much greater control than that offered by the viewfinder image.

Above left Live View normalAbove right Live View 10x



Case study Nadav Bagim

My technique is more or less the same for each photo. I use an EOS 450D with a set of extension tubes, an EF 100mm f2.8 macro lens and a reversed EF 50mm f1.8 lens. The extension tubes have no electrical contacts and I bought them for just $6. The 50mm lens is second-hand and I paid $80 for it. I shoot inside a home-made lightbox with one flash in order to flood the box with light. The extreme magnification with the flash and colourful flowers or backgrounds gives a very vivid result. I set the shutter speed to around 1/200 second. I set the aperture on the 100mm Macro lens to f14 with the lens connected to the camera, then press the depth-of-field preview button while removing the lens from the camera to retain the aperture setting. The choice of f14 is a balance between greater depth-of-field and keeping the subject sharp, as the diffraction with this combination is quite strong. The focus of the 50mm lens is set to infinity.

Twin lens reverse macro

Supplementary lensesOne way of trying out close-up photography is to buy supplementary lenses for your camera that you attach to the front of another lens like a filter. These are also called close-up lenses or close-up filters. Canon make two models, the 500D and 250D close-up lenses, and there are many more available from third-party manufacturers. Canon close-up lenses have a double element construction to correct for optical aberrations and so the image quality is very high. Most third party close-up lenses have a single element construction and the image quality may not be as good. The magnifying power of close-up lenses is measured in dioptres. Canon’s 250D close-up lens has a strength of +4 dioptres, and the 500D close-up lens has a strength of +2 dioptres. You can buy third party close-up lenses with strengths of up to +10 dioptres, although most of them are constructed from a single element and the aberrations may not be so well corrected. By contrast, a reversed 50mm lens has a strength of +20 dioptres, and a reversed 24mm lens has a strength of +41.6 dioptres. The image quality from a reversed lens is much better than anything you will get from most third-party single element close-up lenses. This level of magnification lets you try out true macro photography, where the subject is reproduced at life-size or larger.

Magnification calculations

Magnification is relatively easy to calculate when you couple two lenses together. The calculation applies when the primary lens is focused at infinity:

magnification = focal length of primary lens / focal length of reversed lens

So if you reverse a 50mm lens on an 85mm lens, the magnification is 1.7 times (85/50 = 1.7). Even this simple set up gives you much greater magnification than is possible with any Canon lens other than the MP-E65mm f2.8 1-5x. The magnification calculation is true when you use a camera with a full-frame sensor. If you use a camera with a crop

sensor, it appears to magnify the image even further because you are cropping the image. In reality, the magnification level is unchanged – it is only the field-of-view which changes. Another way of measuring magnification is to take a photo with your reversed lens set up of the millimetre scale of a ruler:

magnification = sensor width / ruler width captured

So if your sensor is 22mm wide and the scale shows you have captured 11mm, the magnification of your lens set up is 2 (22/11). This method takes into account the size of your camera’s sensor as well as the magnifying power of the reversed lens.

Above A coupling ring for connecting two lenses with a filter thread size of 58mm.

Above An image taken with a reversed 50mm lens on an EOS 40D body. The sensor of this camera body is just under 23mm wide, making this image very close to a 1:1 reproduction (1x magnification).

I focus by resting the camera on a beanbag and moving it backward and forward and I set the magnification with the focus ring on the 100mm lens. I use a fluorescent lamp to add light so I can see what I am shooting, as not much light comes through the viewfinder with the lens stopped down to f14. The lamp doesn’t have any effect on the exposure as it is too weak, I get all the light I need from the flash. I use fluorescent light for viewing because it is colder – the heat from a tungsten lamp could harm the insects. I prefer photographing aphids since they are pretty still and don’t move that much or that fast, plus, since they are about 1 to 2mm in length they can fit into the extremely shallow depth-of-field (and they are extremely cute!) The average magnification with this combination is around 3.5:1 (but you can go higher by adding more extension tubes), and it is considerably cheaper than Canon’s MP-E 65mm Macro lens.

Above Here the 50mm lens is reverse mounted on an EF 85mm f1.8 lens using a coupling ring. This set-up is more versatile than reverse mounting a single lens as it lets you control depth-of-field by adjusting the aperture setting on the 85mm lens.

The main limitation with reverse mounting a single lens is the lack of control over the aperture setting. If you don’t have a lens with an aperture control (that includes the entire range of Canon EF and EF-S lenses) another approach is to attach the reversed lens to another lens that is mounted conventionally on the camera. In this set up the reversed lens is called a secondary or supplementary lens, and the other lens is referred to as the primary lens. With this set up the reversed lens acts like a high powered, high quality supplementary lens. You have complete control over the primary lens, so you can set any aperture you want, and stop down as far as you need to increase the depth-of-field. You can also use shutter-priority (Tv) and manual (M) exposure modes on the camera without any issues. The primary lens should be at least a short telephoto lens, such as an 85mm lens, in order to avoid vignetting. The longer the focal length of the primary lens, the greater the magnification, and you can obtain up to three times life-size magnification if you combine a telephoto lens with a reversed wide-angle lens. The MP-E65mm is the only Canon lens that can match this. Just like reverse mounting a single lens, the best lenses to start with are an 18-55mm zoom lens or prime lens with a focal length of 50mm or shorter. To join the lenses together you need a coupling ring. Pick one that matches the filter thread sizes on your lenses. Canon makes a lot of lenses with filter thread sizes of 52mm and 58mm and it is easy to buy coupling rings to connect them.

Extension tubesIf you need to get even closer to the subject, you can add an Extension tube between the primary lens and the camera body. This also works if your are using a single lens reverse mounted to the camera.

EF 50mm lens reversed

EF 100mm lens

Extension tubes

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