A student recently asked me to explain to his or her spouse (anonymity will be preserved) why it is worth investing in lenses.

Michael in The Plaid Chair

And indeed I am happy to do this. Not because I have any stake in selling lenses (I teach, at various venues including Henry’s School of Imaging, but I have no stake in selling anything anywhere). But because:

1. I strongly believe the lens is the most important part of photographic equipment between you and a great picture.
2. A lens keeps its value much better than a camera does.

Let me explain.

• The lens determines how sharp your picture is. Good lenses are simply sharper, and with today’s sensors this difference is noticeable.
• The lens determines how fast your shutter speed is. And hence, how blurry the image. A faster lens (“fast” means “how wide is the aperture”, i.e. “how low is the minimum F-number this lens can go to”) means more light can get in – which means faster shutter speeds are possible at the same ISO.
• The lens determines how blurry you can make the background. An f/2.8 lens gives you, if you want it, a much blurrier background than a consumer-grade f/3.5-5.6 lens. A “prime” (fixed) f/1.4 lens, even more so.
• Good lenses focus faster, are quieter, have better “bokeh” (look better where they are out of focus), are water- and dust-sealed, and so on.

Those are very important factors whose importance it is almost impossible to overstate. Photojournalists like me use f/2.8 zoom lenses and f/1.4 primes. for a reason. For several reasons.

And finally- a lens keeps its value. A camera – not so much (next year it is worth half; a afew years later it has $0 value). A good lens keeps its value for decades.This is because 20 years from now it will still do what it does today (let through photons), and because the intrinsic value of the optical glass is a larger part of the value of the lens.

This is why lenses are worth buying. They make much more difference to images than the camera does, and they are a much safer investment.