NOTE: Apologies for the delay in publishing this fifth and last entry… thanks for your patience!!
This last entry in the “Lenses” series is comprised of two sections, one dealing with “specialised” lenses and another with some tricks that one can employ when using lenses.
Let’s start with specialisation: what are we to understand by this? Specialised lenses include those lenses that are primarily earmarked for use in one specific scenario. Amongst the most popular we find Macro Lenses, Tilt/Shift Lenses and Fish-eye lenses.
Macro Lenses: I have touched upon this variant of lenses in my preceding post, but I’ll explain in more detail here. Macro lenses are primarily oriented towards the capture of “close-up” photography. However, it needs to be clarified that generally, a lens is considered a macro lens if it has the ability to reproduce the subject at a 1:1 ratio (or higher) on the image sensor. Therefore, a 2cm butterfly would create an image on the sensor that is 2cm in size if taken with a 1:1 macro lens. This enables the photographer to create photos that show substantial amount of detail in the final image when compared with traditional lenses. Consider, for example, the image of the fly below. As you will surely notice, the lens used (a Tamron 90mm f/2.8 Macro Lens) enabled me to capture an image that is full of detail, including very small hairs on the fly’s thorax, for instance. This lens in particular has a minimum focusing distance (MFD) of 30cm and a reproduction ratio of 1:1. This means that the camera will be able to focus even on subjects just 3ocm away from the focal plane (where the sensor resides).
The ratio can even be exceeded with more specialised macro lenses, such as the Canon MP-E 65mm which can reproduce an image that is up to 5x the actual size, or at a 5:1 ratio! On the other hand, there are lenses that purport to be “macro” lenses, which however only reproduce images at a smaller ratio, such as 1:2, 1:3 or 1:4. Be careful not to be misinformed when pursuing a macro lens. Having said that, given the availability of high-resolution sensors in cameras these days, you can easily crop into an 18MP image taken at 1:2 and produce similar results to the above image. There would probably still be enough detail left in the image to simulate an image taken at 1:1, but you would lose out in terms of maximum print size if you get to print the image at a later stage.
Tilt/Shift: Tilt/Shift lenses are also called “perspective correction” lenses, and their primary, albeit not exclusive, usage is in scenarios where the photographer wants to avoid having the effects of perspective interfering with the final photo. A common usage is in architecture photography, whereby normal lenses often result in photos that show “converging verticals”, or buildings that seem to be bending backwards or falling over. Check this image below I took in Maastricht without a tilt/shift lens.
You will immediately notice how the church steeple seems to be bending backwards. This is what happens when we point the camera upwards to include all the tower – since the sensor is no longer parallel to the vertical lines in the steeple (or whatever subject you’re shooting), the result is an image where the verticals seem to converge and bend irregularly. This is where shifting comes into play. When using T/S lenses, one thing you can do is to “shift” the lens, which implies that the lens is moved independently of the camera sensor in such a way to alter the way that the light is directed through it. This alteration ends up projecting an image with correct perspective, and hence no converging verticals. The tilting function has to do with the “plane of focus” in front of the camera. The “plane of focus” runs parallel to the direction the lens is pointed, so that if a lens is pointing straight forward, there will be a “vertical” space in front of the lens that would be in sharpest focus. However, if the angle is tilted upwards, downwards or to one side, the plane of focus would similarly tilt at the same rate to retain this relationship. T/S Lenses allow you to carry out such tilting exclusively to the lens, without having to move the entire camera. This creates surreal effects in an image by projecting images whereby the change in depth of field is not in the usual manner (that is, front to back), but could be along a diagonal in the image, or horizontally across the image, for instance. Whilst both the effects of shift and tilt can be somewhat reproduced in post-processing, the effect would not be “cost-free”, making T/S lenses more desirable for such specialised shots.
Fish-Eye Lenses: This will be a shorter explanation – fish-eye lenses are extreme wide-angle lenses with very short focal lengths. They produce images that are heavily distorted. Such lenses enable wide panoramic shots from a single image given their wide angle of view, mitigating the need for stitching multiple images together. Of course, the resultant, heavily distorted images are an acquired taste, but these can generally be “cured” in post-processing too, turning the image into a more “normal” photo without the heavily distorted perspective.
Some tricks now:
1. Zoom Blur: If your camera supports lenses with a rotating barrel (generally SLRs and ILCs), you can create “zoom blur” in an image by zooming in or out whilst taking an image. Ideally, the shutter speed needs to be sufficiently “slow” to capture this zoom blur, otherwise no effect will show up.
2. Free-lensing: Also when using SLRs, you can take a picture with the lens detached from the body. By shifting/tilting the lens a bit, you can re-create the effect of a tilt-shift camera, albeit without having any control on the electronic elements of the lens. Moreover, image quality might suffer and excessive light would inevitably enter into the camera. However, free-lensing can be adopted as a personal style and there are photographers out there who have mastered the art.
3. Inverted lens “macro”: Another trick is to turn your non-macro lens into a macro lens simply by putting your lens’ front element close to the sensor, with the mount becoming your “front element”. Again as with free-lensing, you’d be losing control over electronics but you’d be surprised just how effective a macro lens you can get simply by using this simple trick.
WORD OF CAUTION: Using tricks (2) and (3) can result in accidental drops of the lens or body, or both if you’re lucky… be careful! 😉