In recent weeks I’ve been trying to tie the posts on this blog to techniques, or equipment I have recently used in my 365 Challenge. This week is no different. However it is also the first in a series of short posts discussing a specific range of focal lengths of lenses. In these posts I’ll talk about the lenses themselves, challenges with working with them, and touch briefly only techniques for using them effectively. The series likely with not be posted in consecutive weeks, but I’ll be sure to hit the three major groups: wide-angle, normal, and telephoto. This week is all of about wide-angle lenses.
In a previous post on zoom and primes lenses a touched briefly on focal lengths and how they are determined. I’m not going to repeat that all again here, but please check it out in the other post if you want more info. What I will do is define the major ranges of focal lengths, starting with normal lenses. Normal, as accepted by photographers and lens manufacturers refers to lenses with focal lengths around that of 50mm on a 35mm frame. Normal lenses ultimately range from about 35mm up to around 75mm. The notable feature is that lenses in this range produce images approximate to human vision. In actuality the range is not defined by human vision but actually by the relationship to the diagonal measurement of the film or digital frame. On a 35mm frame, the diagonal measure around 43-44mm, but for ease of definition is was agreed to make the standard length 50 mm on this frame size. It should be also noted the remaining ranges are all based on a 35 mm frame size. For cameras with a smaller or larger frame size, crop factors should be used to compare the ranges (check out this post for the reason why). Here are the ranges for the 6 focal length ranges as commonly accepted by photographers, although these may vary slightly.
Lens Range | Focal Length (35 mm frame) | Focal Length (1.5x Crop Sensor) |
Ultra-Wide Angle | < 20 mm | < 14mm |
Wide Angle | 20mm - 35mm | 14mm – 24mm |
Normal | 35mm – 70mm | 24mm - 47mm |
Short Telephoto | 70mm – 105mm | 47mm - 70mm |
Telephoto | 105mm – 300mm | 70mm – 200mm |
Super Telephoto | > 300mm | > 200mm |
As stated early on, this post will focus on the wide and ultra-wide angle ranges. Lenses in these ranges allow you to capture an image with an angle of view that is wider than normal human vision. As such there are both technical and artistic advantages to using a wide angle lens. Wide angle lenses can have an effect on images by distorting the perception of depth. A shot taken of two objects that are not in the same plane from the camera using a normal lens with roughly reproduce the perception of depth between the objects as witnessed by looking at them. However when using a wide angle lens, the perception of depth is distorted so the objects look further away from each other than they are in real life. This distortion can be used both practically and artistically. By getting up close to a subject with a wide angle lens, you can make the subject stand out from the background. The near subject will look very near and much larger than subjects in the background. Conversely, subjects further away from the lens will look very far away and smaller. When shooting with a wide angle lens, it increases the focus on the near subject. This effect can also be used to deceive the viewer intentionally be changing the proportions of the subjects. While used artistically can have the effect described above. However, it can also be used intentionally by altering the perceived spatial relationships of the viewer. This technique is often used by real estate agents when taking photographs of the interior views of a structure (house, building, etc). This effect can make the rooms look larger than they are in real life. While this may be seen as deceiving (and trust me the realtors know they are doing this), it also allows the photograph to capture more of the space with a single photo and can give a better idea of the space than one shot with a normal lens.
On the same note, the use of a wide angle lens can also allow the photographer to capture more of a scene than would otherwise be possible. For example, when shooting a large group of people, a photographer may opt to use a wide angle lens to capture everyone without having to position themselves very far away from the group (or maybe there is not space to be that far away). This can be a real advantage. Landscape photographers also tend to use wide angle lenses to be able accentuate the vastness of a scene. For example a shot of the Grand Canyon would have more impact when taken with a wide angle lens rather than a normal lens as it intentionally makes the scene look even bigger than it already is resulting in a greater impact.
Using a wide angle lens has some considerations that need to be accounted for by the photographer. First off, as pointed out above, a wide angle lens distorts the perception of distance in a photograph. It also distorts the perception of the depth of field, or the area in front of and behind the subject that is considered to be in acceptable focus. As a result, the use of a wide aperture has a less dramatic effect with a wide angle lens as it does with a normal or telephoto lens. This is not just a negative, but a positive effect as well. It potentially allows the photographer to take a photo using a wider aperture, allowing in more light, with less of an effect on the depth of field. This can be very useful. Additionally, a wide angle lens captures more light than lenses of longer focal lengths as it is collecting the light from a much larger angle. As such, cameras with wide angle lenses can usually be hand held a slower shutter speeds than those of greater length. Also, wide angle lenses, due to the nature of the short focal length, tend to be physically shorter as well (not always true, but often). The shorter length lessens the effect of handshake from the photographer. The “Sunny 16 Rule” is a standard that all photographers should know. It states that at f/16 on sunny day, the slowest shutter speed that can be handheld is 1 over the focal length of the lens. For a normal 50mm lens, this would be 1/50th of a second (why the most commonly used shutter speed acknowledged for handholding is 1/60th of a second). That means for telephoto lens of 200mm focal length, the slowest shutter speed for hand holding would be 1/200th of a second. On the side relating to wide angle lenses, a 20mm lens could potentially be handheld at 1/20th of a second. This rule is no exact as it also depends on the steadiness of the hands of the photographer, but it is a good approximation.
An additional consideration is a negative of wide angle lenses (although can be used artistically). Wide angle lens tends to distort the view of straight lines in an image. Although considered rectilinear, meaning that the lens should make straight lines look straight, distortion can still be apparent when using wide angle lenses. Manufacturers go to great pains to correct this distortion in the design of the lens. However, in ultra-wide angle lenses, the distortion can still be present. This type of distortion is known as barrel distortion as it causes straight lines to bow out towards the sides of the frame like the shape of a barrel. This effect is often minimal in the center of the image, but can become predominant at the edges of the frame. Thankfully, many of the popular post-processing software can easily correct this type of distortion, but if you happen to still work with film, this is a big consideration when shooting.
Lastly, most filters can be used on a wide angle lens, but there are a few exceptions. The first exception is with the use of polarized filters. Due to the polarization of light by the filter and the angle of view, polarized filters can cause problems when shooting (the polarization can causes darkness and patterns around the edge of the frame). The second exception is with the use of ultra-wide angle lenses. In the ultra-wide range, the metal ring used on circular filters, or the filter holders for square filters, can often be seen in the view of the lens. To get rid of this you would need to crop the photo which reduces the effective benefit of using an ultra-wide angle lens. Thankfully filter manufacturers make low profile circular filters and low profile holders for square filters, however if you lens is really wide it may not matter. I happen to use Tiffen’s wide angle filters and have no major issues when using my 10-24mm zoom lens at 10mm (15mm on a 35mm frame). Any wider though and I would not be able to use a filter on my lens. The last exception is also with ultra-wide lenses. Due to the design of lenses at the very short focal lengths to allow for a very wide angle of view (approaching 180 degrees), often the front element of the lens can actually be convex in shape. One example of this is the 8-16mm lens from Tokina. This causes issues when trying to attach a flat filter on the front of the lens. Be sure to read up on your lens before buying filters (or even the lens if you want one that you can use filters with).
That’s it for this week. I am trying to keep these ones shorter as some of my past posts have been very long. Using wide angle lenses can be great both artistically and for practical purposes. Thankfully many of the lenses that come with entry level and mid-level DSLRs usually encompass part of the wide-angle range (Nikon’s usually start at 18mm). This can allow you to test out using the range before investing in a dedicated wide angle prime or zoom lens. Like any of your lenses, you should practice using them and you will get the hang of it. As always, get out and shoot.
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