When buying lenses, amongst the myriad of decision you need
to make about focal length / aperture / price, you’re actually presented with
one, slightly more fundamental choice first – the question of primes vs zooms. 

This will be a quick article on the pluses and minuses of
both, particularly as they pertain to me, and why despite the fact that I love
and own zooms, your next lens should be a prime.

Primes are fixed focal lengths. You can’t zoom. It’s how the
entire photography world shot photography before someone put a zoom ring on
them and allowed the focal length to be altered by the photographer. 

The promise of high quality zooms was simple – high image
quality, fast glass coupled with unrivaled flexibility. I am sure there have
been times when, on paper at least, many would have wondered if primes would
even survive the digital age.

But survive they have and in fact, they also prosper. You
see, there are several advantages that primes hold over zoom lenses when it
comes to photography: 

1. Sharpness.
It’s almost always easier to make glass sharper when you don’t have to build in the flexibility of multiple moving elements. When comparing a good prime and a good zoom, you’ll often find the prime is sharper

2. Faster.
High quality primes come with a maximum aperture similar to f/1.2, f/1.4, f/1.8. To date, no one’s made a zoom this fast at any focal length. This means you can shoot in lower ISO (and therefore lower noise) when the light gets low. Or handhold in very low light. An example of the latter follows. This was handheld ISO 3200 and 1/6 – but made possible because I shot wide open at f1/4. The light you see in the sky is moonlight and this amount of light would be unimaginable with a zoom with a slower aperture (assuming no VR).

By Lawrence Ripsher (click for larger version)

3. More shallow depth of field. This isn’t so desireable if you photograph architecture or landscapes, where you do want everything to be in focus, but for almost all other disciplines, subject isolation is one of the keys to great images.

If I had to put in order the most important of those three
benefits, for what I shoot, I’d actually put them in reverse order. Control
over depth of field (and the option to have it razor thing) is one of the most
important aspects to my photography when shooting portraiture. An examples follow that would have appeared very different had the aperture been
different (e.g. f / 4 which would have brought more of the background into
focus).

By Lawrence Ripsher (click for larger version)

Now of course, the above benefits have to be weighed against
the fact that zooms offer significant benefits. For one, you do not have the
cost associated with buying them in the first place. That’s a hard one to
ignore. And it’s not impossible to imagine that in the future, there’ll be zoom
lenses that get close enough to aperture of primes. This is already happening
at the long telephoto range. Also going for zooms is this unrivaled
convenience. Also, to get from a focal length of 35mm to 85mm, you don’t have
to carry multiple lenses, change lenses in a location, etc. Sometimes time is
not an option (nor is moving closer to a subject) and in these cases, there’s
no denying the benefit of a zoom.

However, in many respects, the convenience that zooms offer
can also be linked to arguably the greatest benefit of primes – that the very
inconvenience you’ll face can actually can lead to better photos. 

You see, when you shoot with a prime, you can’t change focal
length – you’re stuck with the image you see in your viewfinder. So what do you
do if you want to “zoom”? Well, you move. You walk closer. Or you walk further
away to get a wider shot. It’s the exact opposite instinct to when you have a
zoom mounted on your camera. Here the first reaction is to change the focal
length – but your point of view never changes. And so with primes, it’s this
moving that changes your point of view. And when you start to do that, you
start to frame creatively and a whole new world of seeing and photographing
opens up. You start to crouch down, climb onto things, move around your
subject, interact with it. These are all things which lead to images that often
surprise and astound. And it also forces you to get closer, which as you may
know, I believe is key to taking great images. Another benefit is that you also
slow down with your photography. You don’t take the same image 5 different
focal lengths, expecting to choose later which is the one you’ll like best.
Instead, you’ll tend to think before you shoot which is best – you’ll walk
around, survey the situation and again, your mind starts to see what you would
not have previously considered.

Now, these things are also possible with a zoom. If you’re
disciplined, you can still get exactly the same benefit – there’s nothing that
says you have to be rooted in a spot and just turning your zoom lens while
taking a picture. And also, the above won’t work for every type of photography.
But instead, just ask yourself if the above does apply to you lately and if so,
stick a 50mm f/1.8 prime – a $100 lens – on your camera for a month and see how
you shoot. It’s what I did when I was learning photography and I probably
learned more about framing and composition in those 4 weeks than I could have
done with 6 months with a zoom. 

So, as I continue through photography, I’ll still get
excited about the first f/2.0 lens mid range zoom that Olympus is planning to
release later this year, or an affordable version of Nikon’s 18-200 VR for
Canon if one should ever appear, or a number of other zooms… But since moving
to primes, my heart and mine is now with fixed focal lengths and it’s with
these lenses that I expect to be able to take my best images with.