Introduction to Cameras for Nature Photography Part 1: Lenses

Merrimac Farm BluebellsThis is the first of several posts that discuss how to  select  and use a camera for nature photography. The emphasis is on fundamentals. If you wonder why your photos never seem to capture a scene quite the way you intended, this series is for you. If you are an experienced DSLR shooter you probably will not gain much here and you may even be able to give me some pointers!

In the first two posts of this series, I will discuss lenses. You may be asking yourself why start there? Isn’t the camera the most important part and the lens is just an accessory? Well the answer is no. The lens is by far the most important piece of the system. It is the primary factor in how much of the scene you will be able to capture, how close you can get to your subject, how much light you will need to get a proper exposure, and the overall quality of the sharpness and color correctness of the image.

It is a huge and important subject. So let’s get started.

A camera lens is basically a metal or plastic tube which holds in position several optical quality glass or plastic elements which are designed and shaped to direct light reflected from the subject to a precise point inside the camera where the film or digital sensor is placed (whew!). All lenses have two variables that you can control to affect photo quality: aperture and focus. Some lenses also allow you to vary the length, which I will discuss in Part 2.

Aperture, simply, is the size of the opening in the lens that the light is allowed to pass through. Obviously in bright sunny conditions you do not need to have as large of an opening as you do in cloudy or shady conditions, so good quality lenses allow you to vary the aperture. The opening is expressed as a ratio of the length of the lens to the size of the opening and is call an f number. For example, in simplified terms, a 100 mm lens at f4 would have an aperture opening of 25 mm (1/4 x 100 = 25). This is why the smaller the number, the larger the opening. Thus an aperture of f2  is larger than f16. The f2 setting will allow more light to enter the camera. Because it will allow acceptable images with less light and other characteristics, all other things being the same, the larger the maximum aperture (the smaller the f number) of the lens,  the better the lens. (Translate this as more expensive!)

The other variable found in all lenses, except the most basic of cameras, is focus. Focus is the movement of some or all of the glass elements in the lens to achieve a sharp, clearly defined image. These elements can be moved manually by turning the barrel or a ring on the lens, or more commonly today, by very small motors located inside the lens or camera body.

The ability of a lens to achieve “tack sharp” focus depends on the preciseness of focus and the quality of the glass. This varies tremendously and is the major reason you can pay upwards of $15,000 for a lens to take the picture of a sparrow.

Aperture and focus are just two of the variables that you need to understand in order to get the most from your camera and to decide which camera is best for you.  I will discuss another effect of aperture size as well as the relationship between aperture and shutter speed in future posts.

Next: Focal length types and what they are used for.


4 comments so far

  1. […] this summer: picking the right camera to capture all of your outdoor nature shots. Area blog Your Piece of the Planet has posted some tips for budding […]

  2. Dirk Nienaber on

    Helpful blog,

    Nature video on DSLR’s

  3. Photography on

    I have just bought a lens for £1,500 which is pretty good and which I am hoping to use for wedding photography initially, however, when I came across the shot you took above, I noticed how much more striking it was than the shots I am able to take with the lens I have just bought, would you be able to advise how much you paid for the lens which took the above nature shot?

  4. Ernie Sears on

    That image was taken with a Sigma 10 – 20 mm 4 – 5.6 DC HSM. on a Nikon D300.

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