So you have your first SLR. Congratulations! Now comes the hard - and important - part: lenses. In these days of digital, your camera likely came with an 18-55 or 18-70 lens as part of the kit. Maybe the salesperson showed you that light, little lens that offers a whopping 18-200 or 28-300mm of coverage. Excited by the choices, you've browsed over to your favorite online retailer to see what other options you had, and.... holy mackerel! The range, the prices and ohmigod, THE PRICES! Why does a prime (i.e., fixed focal length) 300mm lens sell for $3,500 when you can get a 28-300mm zoom for only $200? What's good? What's crap? What should someone get to start out with?

Well, read on for more info.

About focal lengths

Let's begin with a standard lens. In the old days, this used to be a 50mm prime lens - this provided a perspective that was similar to that seen by the human eye. A focal length less than this was called a wide angle - it provided a broad, sweeping vista. Focal lengths more than this were telephotos - they magnified the image and brought distant subjects closer.

With the advent of modern AF cameras and improvements in the quality of zooms, the 50mm lens was replaced by a 28-80 or 28-105mm lens. This was a very useful focal length - it had a good mix of wideangle and short telephoto, allowing the photographer to shoot a wide range of subjects.

With today's DSLRs, there is a complication. Odds are good that the DSLR you bought uses a smaller sensor than film. So it only captures the central portion of the image projected by the lens. As such, it captures a smaller angle of view than what is projected by the lens. In terms of effect, the focal length of the lens appears magnified by 1.5 (Nikon) or 1.6 (Canon).

All recommendations in this section are based on this crop-factor. If you have a full-frame camera (ie, it has the same size sensor as film), then multiply the lens focal lengths by 1.5 or 1.6

What focal length do you need to start with?

The Kit Lens: The most useful focal length for someone starting out is the range of the kit lens that comes with the camera - 17-18mm on the wide end and going up to 55-85mm on the long end.

As we discussed earlier, this focal length is the most useful for general photography, and covers a wide range of shooting situations - landscapes, portraits, buildings and architecture, street and more. Because of the importance of this lens, it well worth investing in a high-quality lens covering this focal range.

A Wide-Angle: If you do landscapes, indoor photography or buildings, you'll find that the angle of view provided by a 17mm lens on a crop body is is often not wide enough. In that case, you need an ultra-wideangle lens. These cover a very wide angle of view (so put away those clown shoes), allowing you to fit into the image a grand landscape, the entire palace or a large group of people indoors. Very dramatic results are possible with ultra-wideangles; however, it needs skill and practice in order to be able to use a wideangle effectively: only some scenes benefit from ultra-wideangle treatment. I am a "wideangle" sort of person, in the sense that I naturally relate to compositions that lend themselves to super-wide treatment. Even then, I find that I rarely go wider than 24mm [in old film terms - corresponding to 15mm with DSLRs] when shooting.

As an aside, keep in mind one thing - when it comes to wideangles, every wider mm of focal length makes a significant difference in the field of view (ie, what is captured by your sensor or film). So there is a big difference between a 15mm lens and the 17 or 18mm on the zoom that you have.

A good lens to buy at this stage is a 12-24mm zoom.

There are also new lenses now starting at 14mm and going up to 50mm or so, which actually combine all the benefits of a standard zoom and a wideangle in a single lens. As a single-lens solution, these are quite promising and it is worth researching the quality of the optics before making a purchase.

A Telephoto: More so than ultra-wideangles, most people find that their most immediate need after a standard zoom is to get a telephoto - something that lets them get closer to their subject. A short telephoto, starting at 70-100mm on the wide end and going up to 200 or 300mm on the long end is a perfect complement to the standard zoom and a very versatile lens - it lets you shoot landscapes, portrait, candids, details, animals and more. No wonder that there is a plethora of offerings in this range, starting from $200 to $2000.

The above 2-3 lenses will cover the above ranges will cover pretty much most photo opportunities, with the exception of wildlife (see my article on "Equipment f or wildlife photography" if that's your main interest).

However, there is more to this than merely focal length. You will need to consider a few more issues as well.

How fast is your lens?

Mine goes from 0 to 100 in 5.5 seco-- oh wait, not that kind of fast. Not that other kind of fast either (lens-swapping, anyone?).

Speed, in a lens, refers to how much light it lets in. This is a reference to its maximum aperture. Lenses usually come in a notation that looks something like this: 28-105/3.5-4.5. This means that the maximum aperture of the lens at 28mm is 3.5 (sometimes written as f3.5), and at 105mm, it is 4.5 (or f4.5). A detailed explanation of apertures is outside the scope of this article - I refer you to the excellent online tutorial at photo.net as a good place to start. However, what you need to know is that a bigger aperture lets in more light - this allows you to use a faster shutter speed, which comes handy when you are trying to capture a moving object, or shoot in dim light. A bigger aperture also allows you greater control over depth of field - in other words, you can get the sort of shots where the subject is sharp and stands out prominently against a blurred background. For a bunch of reasons, the smaller the aperture number, the bigger the actual aperture. So f3.5 is a bigger aperture than f4.5. Lenses with larger maximum apertures are called fast lenses. Thus, a f/2.8 lens is faster than an f/4 lens.

With lenses, bigger apertures generally come at a greater cost. Sometimes, this cost can run up to several thousands of dollars. For example, a 50/1.4 lens costs around $250, while a 50/1.8 lens, which is only marginally slower, sells for around $70. A Canon 300/4 lens sells for around $1000, while their 300/2.8 lens goes for almost $3500!

Faster lenses, especially zooms with fixed maximum apertures throughout their range (eg, 70-200/4 or 24-70/2.8) also tend to be of significantly higher quality than variable aperture zooms - and also heavier and more expensive. However, the differences diminish substantially once you go down a few stops - so a 28-105/3.5-4.5 lens is going to be very hard to differentiate from a 28-105/4 lens, costing 5 times as much, at f8 or smaller.

Whether or not this incremental performance is worth the extra dollars for you is not something I, or anyone else can say. I certainly have seen spectacular shots taken with consumer zooms; at the same time, most professionals tend to use fast, fixed-aperture zooms. So there are good arguments to be made for either choice.

Zooms verus Primes

Let's clear up some misconceptions about zooms: in olden days, zooms were consistently crap... and a lot of today's perceptions of zooms are still affected by those days. Modern technology - in both design and manufacturing - has come a long way. A top-of-the-line pro zoom will get you very, very close - or equal - to the performance as a set of primes, albeit at a price.

At the entry-level, however, the old truism still holds true. A $200 prime is going to be superior to a $200 zoom lens - either in terms of quality, or speed, or both. If you shoot mostly at lower apertures, then this gap is a lot less. However, if you shoot wide-open (either due to low light or to blur the background), then a prime will certainly you better quality: more sharpness, more contrast, less flare.

Depending on your needs, you may find it worthwhile to consider trying out prime lenses. A 50/1.8 prime lens only costs $70 or so, and gives you a taste of the quality that the 35mm medium is capable of as well as what it feels like to photograph with prime lenses. Whether or not you think this improvement is significant or worth the trouble of pursuing remains up to you, but at least you are now in a position to make an informed decision for yourself.

Personally, I rarely use primes for general photography - my zooms give me excellent sharpness, detail and contrast and are more than adequate for my purposes.

Third Party Lenses

One question that used to stir up a lot of emotion is the issue of buying third-party lenses - lenses made by Sigma, Tamron and Tokina. Some people used to think that if it didn't carry a Canon, Nikon, Pentax or Minolta tag, it was crap. Other people swore that these lenses offered similar performance to Big Four lenses, but at cheaper prices.

These days, this debate seems to be dying down, thankfully. Sigma, Tokina and Tamron - the big 3 third-party lens makers - seem to have gotten over their teething and quality control problems and are making very innovative, high-quality lenses at prices that are significantly lower than Canon and Nikon's - and without sacrificing any significant image quality. Third party lenses are now a viable alternative, provided you choose carefully (emphasis on the last part, which also holds true for lenses made by Canon, Nikon and the rest). However, where Canon and Nikon still hold an edge is in autofocus performance & build quality.

Ignore the reports you hear on the Internet about the so-called sample variations. In my very biased and subjective opinion, quite a lot of the stories about sample variations came about as an easy way for people to agree to disagree, and over time, this idea has acquired a life of its own. I am sure there are a few cases of misaligned lenses out there, but it is by no means in the volume that the Internet would have us believe. An example - I bought a Sigma 10-20mm lens, which many people claim suffers from softness on one side. I took a few shots, looked at them at 100% and sure enough - they appeared soft on the left side. However, to double-check, I decided to be more rigorous - I taped a newspaper on the wall to ensure everything was in the same plane and took the shot again - and what do you know? Everything was crisply focused.

My suggestion is - do your research and don't get caught up in brand marketing. If you need emotional peace of mind, get a Canon and Nikon. If you want to maximize the value of your dollar, investigate the third party alternatives - there are some real steals there.

Do note that older Sigma lenses used to have problems with newer Canon bodies - Sigma re-chips the lens once free of charge, but after that, you have to pay. Whether this is an issue for you or not depends on how often you upgrade bodies and how easy it is for you to get the lens chip upgraded. Of late, it appears that Sigma has reached some agreement with Canon, because I have not heard of any recent incidents involving compatibility problems.

If you foresee yourself upgrading your lenses every so often, keep in mind that third party lenses - especially zooms - tend to depreciate more than the manufacturer brands, although the better-reputed lenses hold their value much better. Balance this against the substantial cost savings at the time of purchase. My personal belief is that the up-front savings more than compensates for the extra depreciation (if any).

Superzooms

A highly popular lens these days is the 18-200 or 28-300 zoom costing $200-$300. Generally speaking, 10x zooms are not known for their optical quality (exceptions: Canon's new 28-300L IS , Sigma's 50-500 and Nikon's 18-200VR, but they are significantly more expensive than the budget 28-300 zooms).

Whether or not you should buy these lenses depends on your needs. If you are traveling and need a light lens that can do everything - go for it. If you don't take very large prints, go for it. If you are on a tight budget, go for it. On the other hand, if you can break this range up into 2 or more lenses, you will probably get better optical quality or save some money.

Recommendations

The following are some lenses that I recommend and which are, in the grand scheme of things, very reasonably priced as well. By default, they are slanted towrds Canon, a that is the system I am most familiar with. However, it does not by any means imply a particular endorsement for Canon over Nikon - Nikon has a very high-quality system as well.

- Ultra wideangles: Sigma 10-20/4.5-5.6, Canon 10-22, Tokina 12-24/4
- Standard zooms: Tamron 17-50/2.8, Sigma 18-50/2.8, Sigma 17-70/2.8-4, Canon 18-55/2.8IS, Canon 17-40/4L
- Telephotos: Sigma 50-150/2.8, Canon 50-250IS, Canon 70-300IS

These are by no means exhaustive, and I have not tested every single one of them (although I own some of them). But these are the lenses that generally do get the most recommendations on Usenet and seem to offer the best value for money. I have listed only Canon above because that is the brand I am familiar with, but Nikon also has a corresponding range of lenses.

Putting it all together

One trap that a lot of people - myself included - fall into is obsessing about gear (or "measurbating"). Measurbators can be recognized on forums espousing the virtues of the megabuck lenses and sneering at anything that falls short - and typically, these are the people with either no photos in their portfolio, or boring snapshots of their cat or backyard. I actually read an article on a popular web forum where one person was talking about the differences between two iconic lenses when viewed under a microscope!!!

Given this, it is easy to start believing that you need pricey lenses to take good photos. Don't buy into that thinking. I have sold images taken with my 28-105/3.5-4.5 and the older 75-300/4-5.6 IS lenses, and I've taken absolutely terrible photos with my 500/4L IS.

When I have displayed my images, I seldom have had people stick their noses to within 6 inches of the print and go "hmm, the image is lacking a little in critical sharpness - did you not use an L lens"? Almost always, the subject and the composition are what get discussed. If the image is powerful, my lens choice has never come up; on the other hand, if the image was weak, not even the most amazing contrast and sharpness has ever redeemed it.

That does not mean that you can get the same results with an el-cheapo zoom as you would with a high-end lens. There is a reason people buy expensive lenses: larger apertures give you the ability to shoot in lower light or to blur backgrounds (great for portraits or to make the subject pop out). Better quality glass also does give you sharper images - great for enlargements or for when you have to crop the image.

I don't rush out and buy the most expensive lens out there - I try out various lenses and compare the results to my existing kit. If there is a noticeable improvement in results - in other words, if my glass and not my abilities are now the limiting factor - then and only then do I upgrade - if not, I stay with what I have. What I save in lens cost can be spent on film, travel or beer (or all three!).

So what does this mean for you? Well, after reading this article, you should now have an idea of what your options are. If budget is not a constraint, by all means feel free to invest in what lenses appeal to you the most.

However, if budget is an issue, hold off on dumping your kit lens and spending lots of money on the lenses listed above. Spend some time shooting with that kit lens. It isn't as bad as the Internet would have you believe. And as you shoot and get to know your needs, you can then decide what it is that you need the most. Do you need a faster aperture for lower-light shooting? Do you need a wider lens? A longer lens? Ability to make sharp poster-sized prints? Once you know what factors are important to you, you can then base your purchase on your specific needs.