Of all the different photographic genres (i.e. portrait, landscape, sport etc) macro photography is often perceived to be the most difficult to master. It can also be one of the most rewarding genres once you have the basics to get started, with subjects found everywhere around us.
Although the methodology can initially be difficult to grasp, once mastered this particular genre can often be the most fascinating in terms of the results achieved. In order to fully understand the concept and to produce desirable result the following factors and appropriate terminology have to be fully understood. This post is one of our series of tips and inspiration posts aimed at providing photographers with just that, so that they get out to shoot and fuel their passion!
This term is often described as close-up photography usually of very small subjects. Classically a macro photograph is one in which the size of the subject captured by the camera is greater than life size (1:1).
Unfortunately both camera and lens manufacturers often refer to their products as having a “macro’ facility. For example, your existing kit lens which may typically be a 18mm-55mm (this focal length lens is designed for APS-C size crop sensor cameras) may be listed as having a macro facility, this however is not necessarily the case or true.
As mentioned the term “macro” refers to images captured at a reproduction rate of life size (1:1) or higher. The macro facility on your kit lens will reproduce an image as a quarter life size (1:4) at best. Therefore in order to capture true life size or large images a dedicated macro lens or accessory has to be used.
Dedicated macro lenses allow for a greater reproduction / size (1:1 or more), in addition they allow for the ability to focus closer to the subject. Macro lenses are available in different focal lengths ranging from 35mm to 200mm, the main difference between the shorter and longer focal lengths is the ability to increase the subject to lens distance. With a shorter focal length i.e. 35mm the photographer will generally be very close to the subject, this in itself can cause problems with lighting and exposure as being so close will tend to cause a shadow. If the subject matter being photographed is an insect being so close can also disturb or disrupt your subject. Using a longer focal length such as a 100mm can prevent this problem as the user is able to maintain the same reproduction size from a longer distance Note: When using a dedicated macro lens, the depth of focus can often be measured in millimeters as opposed to inches, feet or meters.
Unlike portrait photography in which it is often desirable to have a shallow depth of focus, macro photography requires that the depth of focus be considerably greater.
When using a macro lens several factors need to be understood, without which the subject may lack the correct depth of focus and will not appear properly focused, these factors are as follows
Working distance and size of the subject
If the subject is relatively small and your working distance (distance from the camera to the subject you are photographing) is reasonably long then it is not necessary to stop the lens down to a small aperture i.e. F22 or F29. In this case an
aperture of F11 or F16 would suffice.
If however your subject is relatively small and your working distance is very close then it is necessary to ensure an aperture of at least F22 or higher is used.
Focal plane of the subject
If your subject is relatively flat in terms of perspective and lacking considerable depth (for example a butterfly shot from straight on) it is not necessary to use a small aperture, again F11 would normally suffice..
If however your subject has considerable depth, for example a butterfly with its wings open and shot from an angle as opposed to straight on it would therefore be necessary to choose a smaller aperture. This would then ensure a deeper depth of focus, in this case an aperture of F22 or more would be required to ensure sufficient focus is achieved from front to back.
Lens focal length and magnification factor
Generally the longer the focal length, the greater the magnification factor and thus the smaller the aperture required. The aperture required to ensure deep focus on a 100mm or 180mm macro lens would be greater than that required for a 50mm or 60mm macro. (Most 50mm macro lenses have a macro reproduction value of 1:2 - half life size whilst all 100mm and 180mm macro lenses have a reproduction of 1:1 - life size or more).
When shooting at small apertures such as F16, F22 or higher it is often necessary to increase ISO / film speeds. This is necessary to prevent camera shake which often occurs as a direct result of slower shutter speeds set by the camera. It is often necessary to choose ISO ratings of 800 or more.
For the reasons as mentioned above it is advisable to consider using a tripod, this will help prevent camera shake and excessive movement when working with small apertures.
Note: Some of the latest macro lenses now incorporate image stabilization, their subsequent use allow for shutter speeds as much as four stops lower to be used. With the case of the Canon EF 100mm F2.8 L IS USM macro lens which has a two stop image stabilization system a shutter speed of 1/60th of a second can be used as opposed to the recommended 1/250th . The way this is calculated is as follows
Minimum shutter speed required to prevent camera shake = Focal length of the lens x Crop factor of the senor (1.6 x - Canon APS-C sized sensor)
1/100th = 100mm x 1.6 = 1/160th, nearest full stop in terms of shutter speed = 1/250th .
Shutter speeds in full stops are as follows: 1/250th, 1/125th, 1/60th.
View our huge range of tripods here.
In some situations it may not be desirable to select a faster ISO / film speed. This could be to prevent excessive noise which often occurs when using faster speeds or the need for an additional light source in order to prevent under exposure. In this case the use of a flash would be required, using a flashgun will help prevent under exposure, add depth to the image and also ensure a faster shutter speed can be achieved as this will allow for selection of the cameras designated syncphy speed to be used.
Note: Sync speeds tend to differ from one manufacturer to another and often from one camera model to another within a range.
Note: If using a Canon DSLR, Aperture Priority and a flashgun it is necessary to set the appropriate Custom Function mode to ensure the flash sync speeds are set between 1/60th -1/250th as seen below, the normal default selection is Auto which in low light when using small apertures may result in very slow shutter speeds being selected which in turn can result in camera shake.
If you are considering the use of flash it is advisable to look at using a specialist unit designed for macro, this is otherwise known as a ring flash.
The main advantage of such a unit is the delivery of the light source, if the camera’s built in flash is used this will result in a flat two dimension subject and one which exhibits considerable shadow. A ring flash ensures light is delivered evenly as the light tube is 360 degrees in terms of output, this also ensures a three dimensional shadow less result.
Macro Ring flashguns or lites as they are often referred to are available in both the proprietary camera manufacture brands i.e Canon, Nikon etc or alternatives such
as Sigma Macro Photography. Check out our flashguns here from all major manufacturers.
Note: The result of having used a ring flash is often a dark underexposed background, this is not always acceptable.
When shooting close up subjects it is not always beneficial to use the Auto Focus Facility of the camera or lens as often the subject lacks sufficient contrast and can thus lead to the focus hunting to and fro and preventing the shot being taken. Thankfully all dedicated macro lenses are supplied with a sufficiently large manual focus ring in which to manually focus.
Note: If you lens is equipped with a focus limiter it is advisable to switch this if using auto focus, this will prevent the lens traveling from minimum to maximum focusing distances when hunting occurs.
When focusing on small objects always ensure you focus on the leading edge / closest part of the object and select an aperture to ensure sufficient depth of focus from front to back.
Most if not all macro lenses tend to be fixed in terms of focal length and are have a fast or wide maximum aperture i.e. F2.8 or F3.5. Although the maximum lens aperture is considered generous these apertures cannot realistically be employed as their use will only ensure the smallest depth of focus, for macro use more often than not the reverse is required.
In order to determine the appropriate aperture necessary for correct depth of focus it is advisable to experiment with various aperture settings. Viewing the images on a computer screen can the help determine the appropriate aperture to use. As a general rule as you close down the aperture (F3.5, F5.6, F11 etc) the depth of focus will subsequently increase.
By Park Cameras on 05/05/2018
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