# The perfect lens…

…doesn’t exist. There is a way to determine which is the best lens available to you that I like to call the Pyramid Theory. Essentially it works in a similar way to calculating speed, distance and time, or at least the way I learned it at school.

To calculate the speed of, say, a moving vehicle, you need to know the distance it has travelled in a given time then do a calculation. We always used a pyramid with D at the top, S on the bottom left and T on the bottom right. This way you would be able to remember which variables you needed to do the calculation. For this you would always need two of the variables to get the third.

The three main ideals for the perfect lens, of any mount, focal length or age, is for it to be fast, cheap and high quality. Whereas with the maths analogy above you need two variables to get the third, with this you can only have two variables and the third cannot apply.

For example, the Nikon 24-70mm f/2.8G AF-S IF-ED, announced in 2007 with the launch of the D3 and the D300, retails at around £1,000. The build and optical quality is excellent, it is a fast lens at f/2.8 through the focal length range but it’s not cheap.

The Nikon 70-300 f/4.5-5.6G AF-S VR is a great lens and gives a photographer that extra reach over a 70-200 or 80-200 that is lost on FX bodies. It is fairly cheap, at around a third of the price of the 70-200 f/2.8, has very good build quality but it’s a slow lens.

I could play this game all day long and would struggle to find a lens that matches all three points in the equation. The main thing to learn from this is that when you are looking for your next purchase and can’t find that perfect lens, you must be prepared to dig deeper into your wallet, accept lower quality or avoid the fast f/2.8 lenses.

Unfortunately the disappointment in the search for the perfect lens doesn’t end there. Pick up something like the 24-70, after you’ve found that extra £700 you forgot you had, and you’ll notice that the other sacrifice you have to make is for a lightweight camera system/bag. Fast glass doesn’t come cheap, but it’s also damn heavy!

Happy shopping, folks!