What Lens Should I Buy?

Posted on: July 30th, 2011 0

I get this question a lot. And I think most novice photographers agonize over which lens will allow them to take amazing photos. Let’s set the record straight up front. A lens, like a camera doesn’t take great photos……the photographer does. In a very real sense, the camera doesn’t matter….any one who knows me knows that I say that a lot…..and mean it. However, I feel that LENSES are much more important than camera bodies.

So Which Lens Should You Buy?

The answer here is pretty simple. If you’re Canon shooter, get the 50mm f/1.8 full-frame lens. You can get it here. If you’re a Nikon shooter, get the Nikon 50mm f/1.8. You can get it here. However, if you own the Nikon D40, D60, D3100, D3000, or D5000, you’ll loose Af (auto-focus). If AF is important to you (I swear by it), think about getting the Nikon 35mm f/1.8 DX (not full-frame) lens. You can get it here. If you have a cropped-sensor camera (every Canon model except the 5D and 1D lines, every Nikon except the D700 and D3 line), the 50mm lens will give you an effective focal length of @ 75-80mm. The 35mm lens will give something very close to a 50mm focal length. Both the Canon and the Nikon 50mm f/1.8 lenses are a total steal at roughly $120-$130. The Nikon 35mm is still not bad at @ $200.

What If You Don’t Have a Canon or Nikon Camera?

If you own a camera body by most of the other major camera makers like Sony, Pentax, Olympus, et al, it’s a bit more complicated. Sony makes a 50mm f/1.8 lens for @ $150. You can get it here. as far as Olympus and Pentax, I was unable to find anything under $200 by either maker, but you CAN get adapter ring mounts that will allow you to attach another maker’s lens to your camera body. There are such adapters available fore both Pentax and Olympus cameras.

OK. You can stop reading here if you want. I’ve given you what I (and many others) feel is the best lens to get for both Nikon and Canon, gave you a link to find out more, and and briefly explained what the effective focal length will be on your camera (unless you own a full-frame body, in which case, 50mm will be, well, 50mm!). If you want know WHY this particular lens is so often recommended, read on.

What Is So Great About A 50mm lens?

Look. I never said a 50mm (or 35mm) f/1.8 lens was “great”, but it turns out it is! Since “great” is a relative term (it wouldn’t pass existential muster without “crappy”), let’s put it in context. I am making several assumptions. Assumption One is that you are using a variable focal-length (commonly known as “zoom”), variable-aperture lens that goes from f/3.5 (or f/4) to f/5.6 depending on the focal length you set. Assumption Two is that you DO NOT have a full-frame sensor in your camera. Assumption Three is that you are just beginning to see that camera companies lie about stuff…..especially when that stuff pertains to what you can expect from the camera you bought from them……especially when one of those expectations was that you could take photos in low-light.

Enough with the assumptions already! The fact is, based on Assumption One, your lens is NOT a good low-light performer. If you are using the normal 18-55mm kit lens that came with your camera, and if you zoom to 55mm, you only have access to f/5.6. If you don’t know WTF I’m talking about, suffice it to say f/5.6 is a mid-range lens opening that won’t let in enough light to take a picture in low-light conditions. A 50mm f/1.8 lens, if you stop up to f/1.8, lets in almost 8x as much light than the normal kit lens….f/5.6 is over 3 stops away from f/1.8. Plus, at f/1.8 you’ll get a narrower depth of field, which can be bad or good, depending on what you’re after. In low-light, you need to open up to grab as much light as you can, but if you want a photo with lots of depth, you’re gonna need to take into account the proximity of the focal plane to the lens. The farther away you set the focal plane (the distance to what you are focusing on), the deeper your depth of field. So at f/1.8, which has an inherently narrower DoF than any other f-stop on that lens, you’ll need to avoid any close-focusing. The bottom line is, you give up a wide DoF for a much larger aperture in low-light. Not that big a deal. I mean, would you rather take a photo with a relatively narrow DoF, or not be able to shoot at all? Kind of a no-brainer isn’t it?

As far as Assumption Two, that you don’t have a full-frame camera, well, these 50mm lenses from Canon and Nikon ARE full-frame lenses, so it’s a moot point. It’s just that on a cropped-frame camera the effective focal length is about 75mm, because the image circle the lens throws is made to accommodate a larger sensor than those found in consumer DSLRs, so the sensor isn’t picking up as much of the available image. It turns out that the factor by which the sensor picks up less of the image is about 1.6…..known as the Crop Factor. All of which probably makes no sense to you, so think of it this way; if you have a smaller sensor than what the lens is made for, it is AS IF you’ve zoomed in, which in effect gives you a narrower field-of-view. It turns out that the amount that you “zoomed in” by is about 1.6……hence 75-ish mm instead of 50mm. Now, all this is pretty-much useless geek-speak, since all you really need to do is look in the viewfinder and compose a shot. At that point, who cares what the “effective focal length” is?

On to Assumption Three…..you were lied to. You were told if you buys this amazing (insert your camera model here) camera, you would take amazing photos. Its that deeply-held American idea that all you need to do to improve anything is throw more money at it, commonly known as “consumerism”. After cameras crossed the 6 MP threshold, anyone that knew how to shoot could get great photos. Cameras don’t take great images….people do. Knowing how to compose, understanding light, understanding exposure, and knowing how to use THE GEAR YOU HAVE are much more useful than buying a new camera. Now the latest craze is making cameras with stupid-high ISO values. Nikon is now claiming you can shoot in low-light without a flash!!!! YIPPEE! I shoot in low light without a flash all the time, and I use a Canon 5D….a 5 year-old camera. I do so cuz I know how to shoot in low-light, and one of the things I know is that a lens that will open up to f/1.8 will allow me to shoot in MUCH lower lighting conditions than one that only goes to f/5.6. So either run out and buy a new camera for @ $1000, or buy the 50mm f/1.8 for @ $120 and stick it on your camera. The choice is yours.


If you are learning about exposure, there is NO BETTER tool than a fixed focal-length, fixed maximum aperture lens. You won’t have to deal with all of the confusion that arises when you can set f/3.5 at 18mm, but only f/5.6 at 55mm. Everything on the 50mm lens if fixed….no zoom, and no variable aperture….so you can concentrate of setting the right f-stop for the scene, instead of wondering why you could dial in f/3.5 but when you zoomed in you git f/5.6.

A 50mm f/1.8 lens is simple to use and simple to understand.

Besides price, besides performing much better in low-light, besides ease-of-use, there are still other advantages. Different focal lengths yield different kinds of images. Wide angle focal lengths, say 12-24mm, tend to elongate the scene front-to-back. Telephoto lengths, say 120mm and up, tend to compress the scene front-to-back. A 50mm lens gives you the very least amount of this type of distortion, so it tends to render your scene more proportionally accurate than shorter or longer focal lengths do. On a full-frame camera, a 50mm almost goes into “wide-angle” territory, so you really can’t get very close to your subject without introducing some distortion. On a cropped frame camera, this isn’t a problem at all due to the effective focal length being closer to 75-80mm.

The Bottom Line

The bottom line is this; most novice shooters look at FOCAL LENGTH when shopping for a lens. I look at the MAXIMUM aperture, or f-stop, that the lens allows. If it is a zoom, I want that aperture to be FIXED across the entire zoom range, not vary with the focal length. Unfortunately a fixed-aperture zoom in expensive. So this is really the only real down-side to a fixed 50mm f/1.8 lens. It does not have the convenience of zooming. However, this is easily overcome by zooming with your feet. Here’s how it’s done. Sit in a chair, take your shoes off, and while you are looking through the viewfinder lift your feet up until both feet are on opposite sides of the new 50mm lens you just bought……..OK….I’m kidding. If you want to “zoom”, just move in tighter……..walk towards your subject!!

There’s a lot to like about the 50mm f/1.8 lens….price, low-light performance, distortion-free images…..did I mention price? Both the Canon and Nikon 50mm f/1.8 lenses are very highly-rated in terms of sharpness and overall performance. Why are they so cheap? Well, they are not built like tanks…. mostly plastic…not able to withstand real punishment. Just be careful, don’t drop the lens, and you’ll get years of use out of it. Just go get one…..you’ll love it!

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