Written by Rob Nyffenegger
Episode 4 – Lens Types
Although lens selection for mobile devices is a fairly limited affair, it is still useful to understand what type of lenses there are available and their uses. And if you decide to go with a larger camera option over a mobile in the future, then you already have an idea of what lenses suit your needs.
There are essentially six types of lenses.
- Fisheye (ultra wide)
- Standard or Prime lenses
- Telephoto / Super Telephoto
The ultra-wide lenses are those that are in the 8-24mm focal length. Used to take panoramic shots, city scapes, abstract images and generally getting a lot of visual information into one frame. Due to the curved look of fisheye images or the extreme wide angle effect, not really used for portrait work.
Wide angle lenses range in the 24-35mm range. Similar to the ultra-wide, these lenses are good for interior or area / landscape photography without the extreme distortion that ultra wide lenses generally have. Wide angle lenses also give a “close to subject” perspective and can also be also be used for humour by using the distortion to good effect.
Wide angle images showing the distortion effect typical of those lenses
Wide angle mistakes
- Everything in the image is equal distance from the lens
- Having no clear subject in the image
- Using a wide angle lens just to be able to fit more “stuff” in the image – have a purpose
- Taking unflattering photos of people (very distorted features)
Standard or Prime
These have fixed focal lengths making them lighter than the zoom or telephoto lenses, usually capable of taking sharper images and have no moving elements within the body. Typical prime lenses are:
35mm, 50mm, 85mm and 135mm. They serve as great street photography, wedding or wildlife lenses and don’t have unnatural zoom appearance or wide angle distortion.
As a point of information, a 50mm lens is likened to what the human eye sees in terms of scale / zoom factor when viewing the world.
These lenses describe flexible focal length lenses and they cover ranges over the previous categories. For example, 24-70mm, 10-18mm, 70-200mm. While these present a flexible shooting solution for a photographer, there are several drawbacks. These lenses are generally heavier due to extra lenses within the body and typically “slower” than the prime lenses. Zooms have moving elements within the body that can be a weakness after long periods of use that causes the lens issues due to mechanical wear or in some cases electrical connection problems due to repeated operation of the zoom.
The terms “slower” or “faster” in relation to lens comparison, refers to the widest f-stop of a lens. For example, a lens with a wide open aperture of f2.8 is faster than one that can only go to f5.6.
Zoom lenses normally have a min and max aperture setting that varies with the zoom setting selected. A 24-70mm lens with a number on the lens body that looks like f3.5-5.6 means at 24mm, the largest aperture is f3.5, while if using the maximum 70mm zoom, the largest aperture is f5.6 – so as you can see this is limiting how wide open the aperture can be.
Professional lenses can have a maximum aperture that applies over the entire zoom range. An example is the Canon 24-70mm f2.8. This indicates a lens that has a wide open aperture of 2.8 no matter what focal length the photographer uses on that zoom lens. However, these lenses can cost between two and four times as much as the same focal length lens of a lower quality. The difference between a $986.00 24-70mm f4.0 lens compared to a $2375.00 24-70mm f2.8 lens.
Telephoto images – a portrait shot at 190mm and rally car at 170mm
These speciality lenses allow the photographer to take extreme close up images of their subject and are usually of a fixed focal length. As a speciality lens, they have limited use in other areas, since they are by nature, for taking extreme close up images – capturing detail that other lenses cannot. A particular macro as an example, is a MP- E 65mm 1-5 X f2.8 lens and can fill the frame taking a picture of a grain of rice!
Due to the close working nature of the lens to subject (typically), the depth of field is extremely narrow and for best results shooting macro photos, a tripod is required. Even setting the lens at f22 to give a large depth of field, in macro scenarios this still only gives a very narrow band of “in focus” subject matter.
Another potential area of concern with macro photography is getting enough light onto the subject, and / or not casting a shadow on your subject. This will depend on the macro focal length being used, but can be minimized or avoided using the longer macros like the 100mm or 180mm.
Telephoto / Super Telephoto
135mm – 300 fall into the telephoto category, while 300mm and up fall into the Super Telephoto – with one of the largest lenses being the yard-long, 16.5kg Canon 1200mm f5.6 that is no longer in production. There may be larger lenses out available, however, the practicality of them is just not there and the per unit cost is prohibitive.
These lenses are workhorses for sports and nature photographers where you cannot get close enough to the subject with the shorter focal lengths. Telephoto lenses also offer optical cropping, allow image capture in otherwise dangerous environments, don’t disturb your subject – an important detail when photographing wildlife and on the lower end of the scale (135 – 200mm), can lend themselves well to portrait photography.
For most uses telephoto applications, a focal length of between 200 and 600 is “practical,” but it does come down to individual capability and being able to support the weight after the 400mm range.
*Using teleconverters decreases the speed of the lens, in this case by two stops since two 1.4s are being used
- Use a tripod – mount using the TRIPOD collar, NOT the Camera
- Use a shutter release cable / and or mirror lock up mode to avoid introducing shake
- Turn off image stabilization / vibration reduction when using a tripod
- Brings near and far subjects together (compression)
- Tightly frame your subject
- Don’t use the smallest aperture to avoid soft images
- Remember – tele-converters reduce your widest f stop by 1 or 2 stops and slow your lenses focus speed. Also amplify the previous point
- Try and set a shutter speed of at least 1 / focal length used, to avoid camera shake in the photograph. E.g: if shooting at 200mm, a recommended minimum shutter speed is 1/200
Super Telephoto image – avoid disturbing your subject. Canon 400mm lens
Remember Foto PhreakZ – get out there, get Phreaky and get to know your lenses. Get to understand how they can best be used to capture images and know what the strengths and weaknesses of the types are. Bigger isn’t always better – pick the right tool for the right job. A prime can lighten your kit bag and get those nice street photographs, but telephotos have the reach to get the awesome action. Always keep in the back of your mind – optical extraction saves time in the editing process!