In my experience, any image can be altered (sometimes dramatically) when one changes lenses. A subject can be isolated and the perspective in front of, and behind, the subject flattened with a telephoto lens; while landscapes in many cases look better with a wide-angle lens as the field of focus increases and the view around the subject widens.
I select my lenses depending on what I want to photograph and say about the subject. Because control over my image is important to me I question two items. What am I photographing? And what result do I want?
For close up photography, one will be more successful with a macro lens that is designed to move in close to a subject than a mid range zoom that only focuses ‘sort of’ close, but is really designed for distance work. For those wide expanse landscapes in the interior of British Columbia one may want a lens with wide-angle capabilities. For example, I might select my 18-70mm or 16-85mm as I search for a focal length that helps me include important features.
Last week I discussed lenses with a photographer who wants to get serious about photographing the abundance of wildlife here in the interior of British Columbia. I suggested starting with a 70-300mm and then a longer telephoto in the future. Those lenses have a narrow angle of view, but plenty of magnification for wildlife photography. Most of the 70-300mm lenses available today are lightweight and easily hand held. One can dig into their piggy bank and purchase some of the super telephotos like a 500 or 600mm, but until then moderately priced lenses like the 70-300mm should do.
There are interesting lenses like the 18-200mm that are just great. These multifocal length lenses are lightweight, and excellent for vacations or just walking around. However, for serious enthusiasts there are wide aperture lenses with maximum apertures like f/2.8 that allow much more light in than lenses with f/3.5 or f/4 that are most common. These large aperture lenses give the user lots of light gathering capability and the ability to use higher shutter speeds for reducing camera shake, and help stop fast moving subjects.
To explain that, there is an optimum amount of light that reaches the camera’s sensor for a correct exposure. When the aperture is closed down it lets in less light and one must slow the shutter speed. With large aperture lenses the shutter opening can be increased and let in a lot more light, therefore one has the ability to increase the shutter speed and still get a proper exposure.
All this also affects “depth of field”. Depth of field is best defined as that area around the main subject, in front of and behind, that is acceptably sharp. Photographers like to blur non-essential elements in the background by reducing the depth of field, and do that by increasing the size of the lens aperture. In addition, letting in more light makes shooting in low light conditions less difficult.
So we get back to my earlier question: Do I need another lens? Even though I like the wide range focal length lenses like the 18-200mm for everyday use there are lots of other choices that will better help me visually say what I want when I make a picture. A brief summary might be as follows; a macro for close-ups, a wide angle for landscapes, a telephoto for wildlife and, of course, some lenses with wide aperture for low light and for more control of depth of field.
Each year manufacturers introduce more lenses with different technology, which improves imaging capabilities, and naturally, increases the price. Now you understand why one of the favourite sayings in photography is “it’s all about the glass” as I’ve explained to readers in this short discussion. So, go ahead, check out the many offerings and ask yourself “Do I need another lens?”.