Close-up and Macro Photography
Uncle Ronnie shares the secrets behind perfect macro and close-up
How often do we spot that ladybug resting underneath a blade of grass while walking along a grass-covered path? We do not often acknowledge the existence of this teeny, but colourful world. However, a peek into this world of tiny living and non-living things is surely exciting and immensely satisfying to a photographer. This month, let us help you explore this world with a few tips.
At the outset, let us be clear about certain terms and definitions about close-up and macro photography so that we are on the same wavelength. Note that though there are several ways to achieve higher magnification, I will be stressing more on close-up filters and macro lenses.
Close-up photography
This is a general term for ‘tight shots’. You take the shot by moving closer to the subject – using one of the several methods available – while taking in very little background. The idea is to get a large frame-filling image that can show more details than a ‘normal’ shot – one that includes the subject with a generous amount of background.
Close-up photography is limited to a maximum magnification ratio of 1: 10.
Close-up lenses, also known as close-up filters or dioptre lenses are supplementary lenses that attach to the front of the lens via the filter thread (consider them as magnifying glass). This is the easiest and the cheapest solution for close-up photography. Generally, we attach close-up filters only to prime lenses and not to zoom lenses but with extra care, that too is possible.
Dioptre lenses are available in different strengths, ranging from +1 dioptre to +10.
Let’s take an example of its usage. We will attach a +1 dioptre to three lenses – 50 mm, 100 mm and 200 mm. You know that the 100 mm lens provides an image two times larger than the 50 mm; the 200 mm lens provides an image four times larger than the 50 mm. We will set the three lenses (with +1 dioptre attached) to their minimum focus distance (MFD). All three combinations (50 mm +1 dioptre; 100 mm +1 dioptre and 200 mm +1 dioptre) will now focus at 1 metre (40”) because the +1 dioptre has a focal length of 1 metre (40”). Similarly, if you were to attach a +4 dioptre lens to the same three lenses and
set those to their MFD, all the three lenses would focus at 1/4 metre (10 inches) since +4 dioptre equals 1/4 metre.
Whatever focal length you use, the lens gets the new focal length of the dioptre that you attach.
Since they will now be focussing at the same distance, the longer focal length (in our case the 200 mm) will offer the maximum magnification.
Close-up filters are inexpensive, lightweight and very easy to use.
Image quality with close-up
In life, you get what you pay for. Don’t expect pictures shot using a close-up filter to be as good as those shot using a macro lens. I am not trying to run down the close-up filters; what I am trying to say is that don’t compare your closeup filter images to macro lens images. Having said that, I have used close-up filters often and up till now, no one has yet pointed out a resolution flaw.
Tips: (1) Stay away from unknown makes. Cheap does not always mean better. (2) Use the optimum aperture of your lens (the aperture that offers the maximum sharpness) (3) Limit the usage to not more than +4 dioptre. (4) Avoid using a close-up filter on zoom lenses if possible. (5) Since the image will be magnified, consider using a tripod to avoid blurry images.
Disadvantages of Close-up Filters
1. Attaching a close-up filter restricts your focus range. If you suddenly need to focus your lens to a distant subject, you first need to remove the close-up filter. 2. On some lenses, close-up filters (like any other filter) may cause vignetting. 3. Attaching and detaching any filter time and again increases the risk of crossthreading.
Macro photography
When we talk of macro photography, we are referring to photographing small subjects/objects. You cannot, for example, create a macro photograph of a mountain or a person. For the sake of records, macro photography can be done using macro lenses, extension tubes, lens reversal rings, bellows and even tele-converters added to prime lenses.
Magnification ratio refers to size of the image on the film/imaging sensor, compared to its original size.
So, for example, if you are photographing a butterfly that is, say, 1-inch wide and the image formed on the camera’s imaging sensor is also 1-inch in width, we would say that the magnification ratio is 1:1. In other words, the captured image is the same size as the original subject.
Continuing with the same example, if the recorded image is half-an-inch (1/2 inch) wide, then the magnification ratio is 1:2. In other words, the image is half the size of the original subject. Or to put it another way, the original subject is twice the size of the recorded image.
Going still further, if the recorded image is quarter inch (1/4 inch) wide, then the magnification ratio is 1:4. In other words, the image captured on the film/ sensor is 1/4th the size of the original subject.
Note: Even though the recorded image is smaller than the original subject, in photographic parlance, it is mentioned as ‘magnification’.
If the recorded image is twice as large as the original subject, the magnification ratio is 2:1. And so on.
Macro photography ends when the magnification ratio reaches 10:1. Magnification ratios greater than 10:1 qualify as photomicrography (the photographs are taken using a microscope).
Macro or Micro?
Technically speaking, macro and micro is not the same thing, but Nikon calls their macro lenses as micro lenses.
Macro lenses are specialised lenses that allow you to focus very close to your subject. Technically speaking, a lens cannot qualify as a macro lens unless it can achieve a magnification of 1:1. But like several things in life, some leeway is tolerated and lenses that achieve a magnification of 1:2 (half life-size) are also considered as a macro lenses. Some zoom lenses have a letter ‘M’ on them denoting that they are macro lenses. Please note that they are not true macro lenses; they are close-focussing lenses. Macro lenses have magnification ratios displayed on the lens barrel.
Macro lenses, besides offering very high image quality, are convenient to use for close-up/macro work and they can be used for general photography as well. Note that macro lenses are ‘flatfield’ lenses that provide edge-to-edge sharpness even at high magnifications (you can check out SP, January 2020 for further information on Flat-field lenses).
Macro lenses are available in several focal lengths, like 50/60 mm, 90/100/105 mm, and 200 mm. So which one should you get?
The answer depends on the type of macro work that you do. Keep in mind that the longer the focal length, the longer is the ‘working distance’ (the distance between the front of the lens and the subject). So, for example, a 50/60 mm macro lens would be perfect for photographing coins, stamps, flowers etc. But if your interest lies in photographing, say, butterflies or dangerous /venomous subjects like scorpions, snakes etc. you would be better off with a longer focal length macro lens. With insects and animals, you need to stay outside their ‘fear circle’. If you approach too close, the subject may fly away (a butterfly for example) or the subject may attack you (think of venomous reptiles, scorpions etc.). Since the longer focal length lens has a greater working distance, you can be relatively safer. The longer focal length lens also allows better illumination on the subject without casting its own shadow on the subject. And lastly, a longer focal length macro lens will include less of a disturbing background.
Use a tripod for maximum sharpness
Remember, a macro lens magnifies the subject. But this means that any loss of sharpness due to hand shake during exposure will also be magnified. For best results, use of a sturdy tripod is recommended. A tripod also helps to compose better. Of course, there will be situations where you might prefer not to use a tripod – I leave that decision to you.
When using a macro lens, how do you focus?
Your reply is likely to be, “autofocus of course”. While it cannot be taken as a wrong answer, it isn’t the ideal.
First set the magnification ratio on the macro lens. Let us assume you’ve set it to 1:2 (half life-size).
Now, without touching the focus ring, go closer to the subject till it appears sharp. Avoid trying to focus the lens (you have set it for a particular magnification ratio, and if you turn the focus ring in either direction, you will change the magnification factor).
Macro focussing rail
An accessory that I love is the macro focussing rail. Used with a sturdy tripod, it allows for very accurate focusing. Once the magnification ratio is set on the macro lens, the focussing knob on the rail allows you to move the camera forward/backwards without changing the magnification ratio.
Another useful accessory: A
Very often your macro subjects will be found in shade or in very low light conditions. An electronic flash – preferably a TTL flash – will get you out of the tight spot. A flashgun will also help you to use narrow apertures for increased DOF, freeze the subject and provide you with super crisp images. Used correctly, it can also help you to darken changing backgrounds.
When you shoot 1:1 at f/2.8, why does the camera show f/5.6?
Let’s say that you are using a macro lens having a maximum aperture of f/2.8. You set the aperture to f/2.8 and attempt a 1:1 (life-size) reproduction photo. Your camera will indicate that you are shooting at f/5.6. So what’s going on?
You must remember that when your reproduction ratio is 1:10 or greater, the amount of light passing through the lens and reaching the imaging sensor, is reduced. This is generally not noticeable until you try to achieve a magnification ratio of around 1:4 or greater. At 1:1, there is a light loss of two f/stops and that is why you camera shows f/5.6 instead of f/2.8.
photography
For the sake of record (and for newcomers), let me define depth of field (DOF). DOF is the zone of acceptable sharpness in an image. I will not get into the nitty-gritty of how DOF is controlled but suffice to say that out of the total depth of field, (for non-macro photography) one-third is sharp in front of the subject and two-third is sharp behind the subject. This means that if the DOF is say 12 feet (DOF changes with every shot, unless you use the same aperture and also shoot from the same position), it is four feet in front of the subject and eight feet behind the subject.
With macro photography, things change. Whatever be the DOF, with macro photography, it is 50 percent in the front of the subject and 50 percent behind the subject. Also keep in mind that since your lens will be extremely close to your subject, DOF will be very shallow. To give you an idea, if you are shooting at 1:1 magnification ratio, at f/16, the total DOF is 2.14 mm (using any focal length), based on a circle of confusion of 0.03 mm.
Explaining what ‘circle of confusion’ is, without elaborating on the subject, could cause more confusion than it can solve. Hence, for the sake of simplicity, the explanation is avoided. But you can consider it as one of the standards used in calculating DOF.
If you are shooting at 1:1 three macro lenses (50 mm, 100 mm and 200 mm), with identical aperture, which lens will provide greater DOF if all three provide the same sensor?
The answer that most photographers would give is that the 50 mm lens, being the shortest focal length, will provide greater DOF. That would be totally incorrect.
To achieve the same image size on the camera sensor, the 50 mm lens would be the closest to the subject, while the 200 mm lens would be the farthest. The correct answer, based on a corollary, is that all the three lenses will provide the same DOF.
Diffraction of light
When light passes through very narrow apertures – like f/16, f/22, f/32 – it causes overall softness in the image. This is due to what is known as ‘diffraction’ of light.
You are unlikely to notice the softness on small prints but this softness will be visible on large prints (say, larger than 12 x 16 inches). If you are in a situation where you are forced to use a very narrow aperture and are also worried about the effects of diffraction, I suggest you go ahead and use the narrow aperture and ignore the diffraction effect.
Summing it up
Macro photography opens up a new world for those interested in this genre of photography. What is more, you need not travel to exotic (and expensive) places; macro subjects are found everywhere, even in your own backyard.