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In praise of the 50mm Lens



The advent of digital SLR’s brought with it a dearth of std focal length lenses, sure camera makers had 28mm lenses and 35mm lenses, but neither were really equal to the 35mm cameras std 50mm lens and worse still unless you paid up big time they were quite slow compared to 50mm lenses of old.

More recently Sigma has got serious and released a fast 30mm lens to fill the gap for APS-C sensor cameras but frankly the price is anything but cheap, though reportedly the performance is top drawer.

For the purposes of this conversation though lets think of the 35mm film standard of 50mm and the APS-C’s 30mm as being roughly equal in terms of application.

The standard lens has quite a few advantages that belie its rather basic and, some would say unexciting design, so lets just look at these in context.

First they are typically pretty fast, f1.8 being a fairly standard sort of maximum aperture, but faster ones are also available at reasonable prices. But unlike many other focal lengths the speed does not come at the cost of performance and universally most are the sharpest, best performing lenses that any manufacturer has within their catalogue, except perhaps for short telephotos and purpose made macros lenses.

In most instances they are critically sharp around 1 and half stops down from wide open, which means around f 3.5, whereas most zooms and wide angle lenses are critically unsharp at such apertures. A good example of the atrocities of a bad zoom is the original 18 to 55mm zoom that came with the first Canon 300D, this piece of chopped optical liver needs to be stopped down to about f11 to become almost sharp, but by this point diffraction has started to rob the image of critical sharpness and your selective depth of field options have been totally deselected.

Std focal length lenses tend to have few problems with vignetting and in most instances are only darkening the edges of the frame by half a stop or so even wide open, but wait there’s more, chromatic aberration and pretty much all the other forms of optical distortion and degradation are generally missing in action. So what’s not to like.....nothing in my opinion, its just that they are not that sexy.
I can honestly say I have never had a standard focal length lens that did not perform at least very well and the two I have at the moment, a Canon f1.8 and Nikon f1.8 are really excellent in all respects.

But lets just consider a few issues and see if we can change your attitude a bit to this plain vanilla optic, I know I can hear you saying, yeah but Brad they might be stellar performers but isn’t a standard focal length a bit limiting?

Now consider wide angles, and these days they are very wide indeed, these things create images that on first sighting can look pretty interesting, they do after all get more in, and they can certainly tart up the work of the average shooter, but let’s think about the cost you pay other than the financial drain.

First they tend to distort horribly, and I am not just talking about curved lines that should be straight, I mean edges that are soft and blurry like mashed potato with too much milk, they vignette terribly, your depth of field options are very limited, the sharpness varies widely across the field of view, chromatic aberration abounds...and all this applies to the good ones; the bad ones, well just don’t think about it. As a breed there is also substantial variation from example to example, and the net abounds with stories of photographers who have tried several identical lenses to find one that was actually sharp.

But on top of all those negatives, you end up with images that scream, “Hey this Photographer is not very clever so he is using a wide angle lens”, they are in short the cliche of the lens world. And then to compound things you end up with shots that have nothing on top and bottom and all the detail in the middle. Its not that wides can’t take great shots, they certainly can for the “right subject” but generally as a breed they are abused and used to compensate for poor creative technique.

Now I mention all this because if your real reason for going wide is indeed to get more in, maybe the standard lens would be much better. If you use image stitching software and careful technique you will likely end up with a vastly superior result, and this applies whether you start with digital or film and works a treat if the subject is stationary.

It’s simple really, first of all, you’re going to end up with a vastly larger image once the bits are stitched, but beyond that you will avoid the empty sky and foreground syndrome. The really cool thing is that you will have an image that is truly sharp and undistorted even on the edges.

There is however an even neater advantage, you will have real control over depth of field, for example you can focus on some foreground elements and use a shallow aperture to create a panorama which has the background really nicely out of focus, with a standard wide angle this is impossible.

Great, but what about the telephoto end, well now, you may have noticed this, but just in case you haven’t, attached to your body are these two long appendages called legs, when you use them to walk closer to the subject you get a tighter view, I know I am being a bit silly there, but often the zoom or tele is used when it was not the best option. The fact is however that today’s digital cameras and even films are so sharp and detailed that a bit of cropping is hardly an issue at all, and normally the bit you are keeping is the middle (I hope), is the sharpest part.

Even for mild Macro work a standard lens can be useful if cropping is used, the images will still be sharp enough, maybe more so due to better depth of field as a result of the lower magnification, casting shadows on the subject is also less of an issue. Of course you could always buy a macro lens in the standard focal length, and other than a smaller maximum aperture there is no trade off at all, in fact they are typically the sharpest of all optics.

Finally I feel that shooting with the standard focal length forces the photographer to really think more about the photographic process, it stops you falling foul of the trendy wide angle look, prevents you from becoming zoom lazy and generally can make you a better photographer. Trust me on this, fit a standard lens to you camera and keep it there for a month, you might be pleasantly surprised at just how good your images can be when you really learn to work within the limitations of the optic.

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