Often, we spend a fortune on lenses that can shoot at extremely wide apertures. They are generally used for the purpose of isolating a subject from its background. Kind of handy when the background is really boring or when you want to create a sense of dimension in your photos.
But really do you always shoot at f/1.8 of for that matter f/1.4? No, and one of such moments is when you are photographing something very small from up close and want to have nearly the whole of the subject to be tag sharp.
At such close focusing distances, the head of a small fly may be in sharp focus while the thorax may be blurred out. The wide aperture of our lens becomes a hindrance for us in such situations.
In macro photography, ideally, we need a combination of a really wide aperture and sharp frame. That however becomes optically impossible to achieve unless we use additional tools. This is where focus stacking comes into the picture.
Focus stacking – the technique
Focus stacking is a technique that allows the photographer to blend more than one images to create one perfectly sharp image. This is usually achieved through a two-step process.
First step is to take several photos of the same frame, each time focusing on a different plane of focus and thereby ensuring that a particular part of the subject (and the frame) is in sharp focus and the rest is out of focus.
The second step involves blending all the images thus taken and creating a single image that is sharp across the frame. For this you will need a photo editing software like photoshop.
The process is comparable to bracketing in which three or more images of a frame are taken using different exposure settings and then combining to create one perfectly exposed photo.
Focus stacking demands that you shoot in an environment where the light does not change between the shots. It is also a requirement that the subject does not move either. Easier said than done! Focus stacking is used as often in indoor conditions as in outdoor, and out there nature can be really unpredictable. The slightest wind or a cloud shifting in the sky can ruin all your hard work in an instant.
Then again when you are trying photograph small creepy crawlies, they seldom stay in one place for extended periods of time allowing you the luxury to compose, shoot, change the focusing point and then shoot again. You get the point.
The solution – what you need
Your first tool, apart from the gear, would be patience and oodles of it. Believe me at times you will feel that it is the only thing that you need!
Camera & lens
Any interchangeable lens camera will do as long as you can attach a macro lens that can be manually focused. When purchasing ensure that it has a magnification ratio of at least 1:1. For macro photography the minimum standard is 1:1. That means a lens can focus close enough to make the image of a subject appear ‘life-size’ on the sensor.
There are plenty of lenses available in the market which comes with the tag 1:2 (which means half of life-size), but I personally prefer something that is at least 1:1. For really small subjects and for that really close-up shot you can look for magnification ratios of 2:1 or even higher.
Image stabilization will not be a necessity as you would be shooting on a tripod all the time. Even if you have image stabilization you would need to turn it off because when the camera is mounted on a tripod with the image stabilization turned on, it would go bonkers trying to correct a non-existent shake.
Extension tubes are a cheap and effective method for really close focusing. They are cheaper than dedicated macro lenses which can be prohibitively expensive. They are widely used by amateurs trying their hand at macro photography for the first time. Extension tubes have no optical elements (no glass surfaces, no focusing rings etc.) in them. Their only function is to sit between the lens and the camera body and take the lens away from the focal plane or the sensor, where the image is being formed. This allows the lens to focus more closely and increase the magnification.
Downside to using extension tubes
There are certain downsides to using extension tubes and here I shall be discussing about them in brief. Extension tubes obviously have one big problem and that is they will reduce the quantity of light reaching the sensor. This means when using extension tubes you will have to either use a larger aperture (smaller f-number) and or increase the ISO. Increasing ISO in low light conditions will again throw up the challenge of having to counter digital noise.
Most cheaper varieties of extension tubes do not have any electronic connection with the camera and that means you lose the ability to focus manually and or meter the scene.
The best results with extension tubes can be obtained when you add the tubes (extension tubes can be stacked allowing for greater magnification) to a smaller lens such as a 50mm. When you add the tubes to a telephoto lens the result is less dramatic.
Types of extension tubes
There are two different types of extension tubes available in the market. One which comes with an electronic connection between itself and the camera and the other which does not. The second one is obviously cheaper than the first but then you lose auto-focusing and metering. To be honest, auto-focusing is not much of a requirement as you would be using manual focusing for the larger part.
A sturdy tripod
A sturdy tripod is a must. You cannot have camera shake in your images. Apart from a tripod a remote cable release is also a requirement, if you need to further eliminate camera shake.
This is a tool that can save your life out in the outdoors when the light changes frequently. Preferably buy an umbrella that is white and can soften the light of the sun making it uniform in the process. At the same time the umbrella can also save you and your gear from rain during inclement weather.