The tale of two lenses: the Cann EFS 18-55mm 'kit' lens on the left, which was marketed and sold as a 'starter' lens with many consumer DSLR's; and the Canon 50mm f2.5 Macro on the right, a sharp, beautiful piece of professional glass. Both of these lenses are about five years old. (Copyright 2010 / Andrew Boyd)
I’m always preaching about how ‘it’s all about the glass,’ firmly believing that the quality of the lens you are using is intrinsically more important than the level of high tech gizzmoditry that’s wrapped up in the marketing that came in the box with that smokin’ new camera…but is this true?
I recently had a friend pose the question: if you’re on a budget (and who isn’t?), and you could only buy one item—either a new digital body or a new, professional-grade lens—which would be the right choice?
I went through my usual explanation about the importance of professional glass, if you want professional results, and about how so much of the hype around megapixels is just that, hype. But this discussion got me thinking: maybe I could devise a test to prove this once and for all.
So, here’s what I’m going to do:
I’m going to take two camera/lens combinations: a 6-year-old Canon Rebel with 18-55mm EFS kit lens, and a 5-year-old Canon Mark II with Canon 50 mm f2.8 Macro lens. The cameras and lenses have all been well cared for and are in great condition. Both of these cameras shoot an 8MP image.
I plan to shoot the same scene, at 50mm on the 18-55 zoom kit lens and with the macro, with the lenses on their normal respective mates. Then I’ll switch the lenses around, putting the professional macro on the Rebel and the kit lens on the Mark II.
I’ll end up with four photographs to study and show you here.
Caveats first though: I now have a Mark IV camera, but intentionally kept it out of the test. I wanted the camera technologies to be of roughly the same age and stage of development. Same goes with the lenses, although I think it should be less of a factor there.
Now for the results:
Well, a problem right away: when I went to bayonet the cheap consumer 18-55mm lens on my Mark II camera body, I discovered that it wouldn’t fit! The plastic bayonet on the cheapo won’t even go on the pro body. The professional-grade 50 mm macro, however, did turn out to be ‘backwards-compatible,’ fitting easily and snugly on the Rebel camera body.
So: the test results are limited to a comparison of the capabilities of the two lenses. I thought about this for a millisecond and decided that this would still work ok, since it would either prove or disprove my mantra about the glass being the all-important factor. (All we won’t really see is what the cheap lens on the good camera body produces…)
So here are the results.
The 18-55 EFS lens is on the top, the 50mm macro on the bottom. Taken full-frame like this, the cheap lens does an acceptable job. It's interesting the way the two lenses render the color in the scene slightly differently, with the 18-55 consumer lens creating a warmer tone. (Copyright 2010 / Andrew Boyd)
I first shot a blue gin bottle (no, we’re not big gin drinkers; we have a ‘bottle tree’ in our yard and the blue bottles are great for it) first with the 18-55 EFS lens and then with the 50mm macro. After that , I photographed a leaf from one of our tung trees, placed against white background paper, again first with the kit lens and then with the 50mm macro.
Blowing the same two frames up to 200% yields a strikingly different result, however. Here the cheap lens is on the top, and it shows. All crispness in the lettering is absent in this version. The professional lens on the bottom shows why it's a professional lens: crisp, clear detail, just the way you want it. (Copyright 2010 / Andrew Boyd)
Both of the ‘overall’ versions with the little plastic zoom lens look ok. But when you blow the images up, as I did in the accompanying photos, things really do start to fall apart, literally.
First, the gin bottle. The overall version with the two lenses looks roughly the same, although it’s interesting that the cheap lens renders the light much warmer than the 50mm macro lens. Blown up to 200 percent though, you really see the difference in quality: the lettering loses all edge detail in the kit lens version, with the professional lens retaining crisp detail even at the large magnification.
The inexpensive 18-55 EFS zoom is on the top again in these two leaf still lifes. Here it looks fine, again yielding warmer tones than the 50mm macro, bottom. Taken alone, you'd think the top image was acceptable. (Copyright 2010 / Andrew Boyd)
The same comparison holds up in my second test photo as well. From a distance (the overall shot), the kit lens does ok. But enlarged, it’s all fuzz.
Again both versions are magnified 200 percent. The cheapo lens is the top version, and all detail is falling apart; the Canon 50mm macro on the bottom is still holding together at this magnification. (Copyright 2010 / Andrew Boyd)
This is where you really do get what you pay for: good lenses are heavy. They contain a good bit of metal and glass elements in groups. The kit lens, on the other hand, is mostly plastic, with few elements, making for an easy, cheap product, both in terms of production costs and resulting image quality.So how do you pick out the professional lenses from the consumer junk? It’s not always easy at first glance, with the dizzying number of choices that major camera manufacturers offer. But a couple of points should help guide you.
Go online and take a look at all of the lenses your camera maker offers. You’ll notice that some of the surprisingly inexpensive options have ‘variable’ apertures: that is, the aperture will change as the zoom lens moves through its range, typically getting slower as the lens is racked towards its higher focal length. STAY AWAY FROM THIS LENS. This will be a cheapo.
Lenses with larger apertures cost a lot more to make. Consequently, lenses with f2.8 apertures (except in 50mm focal length, where f1.4 and f1.8 versions are available) tend to be higher quality.
One important tip: fixed focal length lenses are available for a big discount off the prices of their zoom lens cousins. Take a good look at a couple of fixed focal length lenses if your cash is tight. Not only will you save money, but the fixed focal length lenses are always sharper and crisper than the zooms! (It’s easier to optimize a lens at a single focal length, rather than trying to design for sharpness with lens elements that are traveling through space.) I would look at a wide angle in the 20-24mm range, and a telephoto in the 135-200 mm range, if I wanted to cover my bases with fixed glass.
I can hear some of you thinking: what about the ‘off brand’ choices? The Sigmas and Tamrons and Tokinas? Should you consider going this route to save money?
This is a tricky subject, and one that is hard to answer. Name-brand glass IS expensive. But that’s because it’s the name-brand product. Some off-brand glass is pretty good…and some of it is JUNK. Hard to tell the difference unless you can get the thing in your hands and shoot some photographs with it (which usually you can’t do). I would recommend doing some online research about any off-brand lens you’re thinking about, and proceed with caution! Here’s a link to an interesting discussion about off-brand glass in a Nikon Flickr group.
Hi, I’m Andrew Boyd, a.k.a. The Discerning Photographer, and I hope this post has been interesting and informative. Please leave me a comment about it, let me know what you’d like to see more of on the site! You can also sign up for email delivery of all future articles or my RSS feed. Thanks!–DiscerningPhotog
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