Five reasons not to buy a digital SLR

Lots of people will offer you - fairly poor - reasons to buy a digital SLR in preference to what Flickr have rather annoyingly called "point and shoot" cameras. (I'd label them "compacts", personally.) Instead, I'm going to offer you five reasons not to buy one- or at least, to consider not buying a cheap one.

They're expensive, or compromised

The Nikon D40 - and the recently announced minor revamp, the D40x - have major compromises, in order to keep the price low. There are far fewer autofocus points than on professional DSLRs that cost more, but also fewer than on compacts that cost less. The EOS 400D has no LCD display on the top of the body. One could argue that's something you don't realise you need until you've seen a better model, but it does make things more finicky. There are also very few SLRs with live displays on the back, and for people who've got used to using digital cameras at arm's length rather than through a viewfinder, that's pretty jarring.

To avoid these problems, you need to be looking at the level of SLRs above the entry level- the D80s and D30s, in other words. These will cost you nearer £800 than £500; for that you could get any compact you wanted, or even both an ultracompact and a more able model.

Compacts perform nearly as well

There are surprisingly few photographs that an SLR is capable of taking that a compact isn't, and, perhaps surprisingly, the converse is true; there are things compacts can do that SLRs can't (especially not the body+kit lens combination that many people end up with).

In the first category, there are some low light shots, long exposures, and the use of narrow depth of field. However, the first of these is increasingly the focus of improvements in compacts; ISO 800 and 1600 are becoming common on them, as is image stablisation. Neither Nikon nor Canon offer in-body IS yet; both make it a feature of the lens instead, and you'll need to spend around £300 on a lens that supports it.

Narrow depth of field remains a differentiator for SLRs, but it's also easy to overdo it when you first get a lens that's capable of it (I certainly did), and as I've noted before, kit lenses aren't significantly better at it than compacts. Wide angle is also becoming common on compact cameras now.

A field where compacts typically outperform SLRs is zoom range. Even ignoring the "superzoom" class - cameras like Canon's PowerShot S3IS and Panasonic's DMC-FZ7 - the average compact has a 4x zoom, whereas the Canon 350D comes with a kit lens that only does 3x zoom (a range of 18-55mm). Obviously, the point of SLRs is that you can swap out lenses, but then you're, once again, looking at a few hundred pounds to replicate a camera that you could have bought for not much more.

The one point where SLRs can claim a true advantage is sensor size: they're much closer to 35mm film than the 1/1.8" sensors commonly found in compacts. On the other hand, people are evidently happy with cameras in phones, even though they're even tinier; if you post to the web, do you care that pixel-peeping will reveal a bit of fuzziness?

Size

SLRs are pretty big and heavy, and that's just with the kit lens. When you start packing a second (or third) lens and a couple of filters, you're suddenly moving around a lot of stuff. Most owners of SLRs pack them for special occasions, but don't carry them around every day. (I'm a bit odd in that I do carry mine, but I got used to carrying a laptop around, and that's even heavier.) Compared to that, a compact that can fit into a pocket - or at least a shoulder bag - is a lot more likely to be on you when you need it.

Extensibility - blessing or curse?

Obviously, one of the biggest selling points of SLRs is that you can replace the lens, and therefore get the ideal camera for every occasion. This is true, but it carries with it drawbacks. As noted above, there's both the expense of multiple lenses, and the annoyance of carrying them around.

Even the camera manufacturers have (finally) acknowleged another drawback of changable lenses: sensor dust. Every time you swap your kit lens and the 50mm prime, you let in dust to the body, and some of this will settle on the sensor. There are cameras with shake mechanisms to remove the dust, and also with software that detects and repairs it on taken photos, but it's still a problem that needs to be worked around. Unlike on compacts.

One final point - shared by a few, but not many, compacts - is that the file sizes of photos taken with SLRs, especially raw files, might be bigger than you're used to. It's not uncommon to produce a gigabyte of photos on a good day out, and when laptop hard drives are still mired around the 150GB mark, that's a big chunk of your space gone, just in one day.

Video

SLRs don't do video, which is increasingly becoming a flaw that people don't want to tolerate. There are good technical reasons for this, but it's still going to be a bit of a shock for people who've come to expect that option on their digital cameras. It's something I've missed, too; there are some things where motion is a part of what you're trying to capture, and while it's possible to do that if you're a great photographer, it's harder than shooting a quick movie.

In Conclusion

Before spending your £500 on an SLR - and remember my previous advice that you should probably be budgeting that amount again to get the most out of it - have a look around at some of the digital compacts. You could save money and be happier, with only a little less.