Introduction: Reversed-Lens & Cellphone Macro Photography….Amazing Macro Pictures on the Cheap!
Hi everyone and welcome to this instructable! I’ve always enjoyed taking pictures of random things for fun, and only recently decided to get a proper camera to expand the scope of my pictures. Not wanting to spend too much on what could potentially become a very expensive hobby, I only got the general purpose kit lens that is supplied with the camera, but from time to time encountered the expected limitations of the “basic” lens for some types of photography. While learning more about different techniques for taking pictures, especially of intricate, small, or detailed objects, I came across the techniques described in this instructable for taking macro pictures, which can give decent results while avoiding spending more on a dedicated (and expensive :) ) macro lens, at least for the time being.
Hope you enjoy!
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Step 1: Macro Photography & Camera Lenses – How They Work
The camera “lens” that attaches to the front of a Single – Lens Reflex (SLR) camera is actually a group of several lenses designed to gather light from an object and focus it onto a sensor inside off the camera (which can be film, a CCD, or other light-detecting surface). Using multiple lenses helps to overcome the limitations of a single lens, one of which is its tendency to focus different colours of light at different points (to test this out, try looking at a dim – moderate light source through a cheap magnifying glass – you may notice a slight “rainbow” effect, especially near the edges). The lens on a camera can also modify the magnification of the image – essentially how big the image seen is perceived by the detector. “Zoom” lenses magnify objects by focusing light rays from only a small region of ‘space’ in the field of view onto the detector, causing the object to be perceived as comparatively larger, from the perspective of the sensor inside the camera.
In addition, many lenses can also adjust how much light from the target passes through to the sensor; this is referred to as the aperture of the lens, and is often controlled by a small lever at the base of the lens. As you can see in the pictures, moving this lever changes the amount of light that falls on the camera sensor when taking an image, which (in combination with the shutter speed and sensitivity of the sensor, or ISO) affects the overall brightness, or exposure of the resulting image. The aperture also controls how much of the object is in sharp focus in the resulting image, which is referred to as the depth of field of the image – using a wider aperture (i.e., wider opening) gives a shallower depth of field (i.e., smaller range of the image in focus) and vice versa.
Macro lenses are designed to capture light from a very small region of ‘space’ (a flower, the head of a pencil, some salt grains, etc) to give a magnified image, while capturing enough light to give a properly exposed image, and controlling the depth of field so that the most interesting parts of the image are in focus (sounds like a lot, huh!). To find out exactly how we do this with a regular kit lens, check out the next page :).
Step 2: Reversed Lens Macro – Bare Bones
The simplest method of doing reversed lens macro really only requires two items:
- Your camera (we’re using a DSLR for this example, although a film SLR or mirrorless camera may work as well)
- Your kit lens
I’m using the 18 – 55mm kit lens here. Although not necessarily the most ideal way to take macro pictures, this works to get really decent pictures (with a few caveats – more on those later).
- Ensure that both lens surfaces are clean. We are going to hold the front surface of the lens against the opening on the camera body, with the rear of the lens pointing towards the subject. If the lens isn’t clean, dust can get inside the camera, and potentially on the sensor (and we really don’t want this to happen).
- If using a zoomable lens, set it to its longest focal length. Because we are inverting the orientation of the lens, longer focal lengths give smaller magnifications (and vice versa), which are easier to start with. Note that you can reduce the focal length later to obtain higher magnifications.
- Identify the aperture lever on the lens, and hold it so that the lens is fully open – this ensures you have enough light from the subject to take a fully exposed picture.
- Set your camera to “manual”. Because the lens will not be attached to the camera, the camera cannot obtain any information from it, and will usually flash an error message saying “lens not attached” or something similar. This also means you have to input your ISO and shutter speed manually – which is the tricky (but fun) part. A good starting point if the lighting is very good (daylight or bright external lights) is to choose ISO 100/200 and a shutter speed of 1/100s or 1/200s and then take one or two sample images to check the exposure, which can then be adjusted by changing the shutter speed or ISO as required.
- Carefully holding the lens with one hand against the camera body in the other hand, move into position to take the picture. In order to get a clear image, focus by moving the camera backwards or forwards until the subject looks clear through the viewfinder or LCD. Take a sample picture and check the result - If the depth of field is too small, you can release some pressure on the aperture lever (allowing it to close slightly), which will increase the range of in-focus points in the image. However, this will reduce the exposure of the image, so you may need to increase the ISO or decrease the shutter speed accordingly.
Once you're satisfied with the exposure, snap away! Remember to hold the lens very carefully, and avoid using this method if the environment is dusty, dirty, or very damp or humid,as you may get stuff inside the camera body that really has no purpose being there. The example pictures on this page show the results of this method (no post - processing was done, except for adding the watermark).
Step 3: Reversed Lens Macro – Using a Reversing Adapter
A better solution than holding the lens against your camera (although that works in a pinch) is to obtain a reversing adapter for your camera. They typically have threads that allow them to screw on to the front of your lens, and mount directly onto the camera body, as shown. Using a reversing adapter makes it harder for dust to enter your camera, avoids the chance of dropping the lens, and makes it easier to get a good shot of your subject; when buying, make sure to get the proper size to match your lens.
When using a reversing adapter:
- Carefully screw the adapter to the front of the lens, where you would normally attach a filter. Try to avoid over-tightening, as this may make it harder to remove or damage the threads on the lens.
- Carefully mount the adapter onto the camera body, just like a regular lens – some have a small dot (see pictures) to indicate how to orient the adapter relative to the camera.
Once you’ve finished taking pictures, do the reverse - remove the lens and adapter first, then unscrew the adapter from the lens.
Again, you will need to hold the aperture lever open, along with manually inputting the settings required - but this method is better for your camera, pictures, and probably your sanity as well :). Another good thing about using an adapter is that the additional stability helps with pictures of very small objects, like the two salt crystals in the pictures (shown beside the Lego figure for size reference). You can also mount the camera on a tripod as well, and use a small piece of folded paper or plasticine/molding putty to carefully hold the aperture lever open, allowing for even more stable pictures. An even better solution would be to obtain another adapter for the exposed end of the lens, which would allow you to set and maintain the exact aperture instead of holding it open to some arbitrary value. Reversing adapters sometimes come combined with aperture adapters in inexpensive packages, and are definitely worth considering.
Step 4: Alternative: Using a Macro Lens Add – On
One way to avoid the difficulties that reversing your camera lens brings is to obtain a screw-on macro lens that fits your kit (or any other) lens. The advantage of this method is that having your lens connected directly to the camera means that the camera “knows” how to set exposure, aperture, etc. However, many of these are simple lenses, and due to the limitations of single lenses mentioned earlier, these are typically prone to suffering from chromatic aberration – the tendency for different colours of light to be separated by the lens (see the image of the coin).
This effect is different from lens to lens, but seems to be more pronounced at higher zooms. In spite of this, you can still obtain some decent pictures using this method (again, be careful when screwing on the add-on lens to avoid damaging the threads). These add-on lenses are also readily available online, so you can shop around and read reviews before buying. However, one point of caution is that being convex in nature, they bulge at the middle, so take when first attaching to your lens, as if the add-on lens is too thick, it can end up scraping the surface of the kit lens while being attached.
Step 5: No DSLR? No Problem!
If you don’t have a DSLR or expensive camera, don’t worry – you can still take great macro pictures with a little DIY and some elbow grease (don’t get any of it on your cellphone though :) ). In fact, some photographers actually recommend developing your compositional skills by photographing extensively with “lesser” photographic equipment such as a smartphone before (and sometimes even after) purchasing a more serious camera (http://erickimphotography.com/blog/2017/03/26/10-reasons-why-your-smartphone-is-the-best-camera/ , http://www.makeuseof.com/tag/6-reasons-smartphone...
One simple way to get “macro-esque” pictures, especially with a higher resolution cell-cam, is to take a clear shot of the target up close (using the built-in digital zoom if necessary) and crop the image afterwards. Although not necessarily a “true” macro picture, this works to an extent, especially if you don’t have any of the additional materials required. However, we can improve on this by using the ability of a convex (converging) lens to focus light rays, forming a magnified image of an object. Convex lenses can be found in a number of locations or products, including:
- Magnifying glasses
- (Some) Laser pointers
- Reading aids
- Cheap telescope/microscope eyepieces
Once we have a suitable convex lens, we can construct a simple holder to position it at the right distance from the cellphone camera, assemble it, and begin taking pictures! For the example provided, the following materials were useful (feel free to improvise as you see fit):
Note: hot glue and scissors are dangerous - please get someone to supervise you if necessary!
- Convex lens
- Thin cardboard scrap
- Hot glue
1. Identify the focal length of the lens. Ideally, this is the distance we want between the lens and the cellphone camera (or more technically, the image sensor). Place the lens above an identifiable pattern, and move it back and forth until the sharpest image is formed, with the ruler beside the lens. Once a sharp image is formed, record the distance between it and the surface – this is the focal length of the lens.
2. Cut a rectangular piece of cardboard long enough to encircle the lens when wrapped around it, and between 1.5x to 2x as thick as the measured focal point of the lens (for example, if the focal length was 1cm, the thickness of the cardboard strip should be 1.5 – 2cm. Carefully place hot glue around the circumference of the lens, and wrap the cardboard strip around the lens, trimming any excess if necessary (optionally, leave about an inch of excess at each end of the strip, and form the two ends into a handle as shown).
3. Cut two smaller strips of cardboard just long enough to fit around the circumference of the lens, and glue them carefully on the inside of the lens holder as shown. These will keep the lens firmly in place. If the thickness of the holder is just right, then placing it against your cellphone camera and holding it near to your subject will allow you to take very magnified images as well.
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