What to Look for in a Speed Light is the first in a series of articles this year that will look at equipment and hopefully provide some helpful guidance on equipment purchases. However, because what you need comes down to your genre and style of shooting as well as budget, I can only provide general guidance and not unequivocal answers to buying questions. My best advice is to hold whatever it is you are going to buy in your hands before buying and, if you like it and it meets your needs, buy it.

Blue Ridge Workshops held its first off-camera flash class this past weekend and one of the topics was equipment. In most cases, I am inclined to say that equipment doesn’t make the image, the photographer makes the image. However, there is little doubt that, when lighting a subject, good equipment can make capturing the image that you want much easier and, in some case, even possible.

As a general matter, you can buy as much lighting equipment as your budget allows and still find something else that would be helpful when you are using lights. However, the one thing that you can’t do without is a source of light and, while there are bigger and more powerful units, e.g., studio lights, a speed light that supports your camera’s flash TTL metering should be your first purchase.

While there is nothing wrong with a Sigma, Nissin, Metz, or any of the other flash units on the market, I think it is best to buy at least one flash from the company that manufactured your camera, e.g., buy a Nikon flash for your Nikon camera, a Canon flash for your Canon camera, a Sony flash for your Sony camera, etc. Even though the camera maker’s flash will likely be more expensive than an equivalent flash from another manufacturer, you know that a Sony flash will work with a Sony camera.

Moreover, I would recommend that the only flash you attach to the top of your camera or connect to your camera with a TTL extension cord is one made by the camera manufacturer. If you are using your camera manufacturer’s flash, in the event something goes wrong, you won’t void your flash or camera warranty. You will also be able to get technical support from your camera’s manufacturer, which you won't get if you are using a third party flash unit.

One of the key features to look for in any flash is the ability to wirelessly set and trigger remote flash units. You might not think that this is important but, if you need to use multiple flash units to capture an image, this feature will come in very handy, especially if your camera doesn’t have this capability built into it.

Beyond these two items, you should look at the guide number, which is a measure of the light output and higher numbers are brighter and usually better, how many flashes you can get from a set of batteries, and recycling time. See the summary chart below for the Nikon and Canon flash units. However, when looking at the chart, keep in mind that each manufacturer measures these specs differently and, while you can compare a Canon flash to another Canon flash, you shouldn’t compare Canon to Nikon.

Using the criteria above, if you are a Nikon user, you have a choice between the SB-910 (about $550 street) or the SB-700 (about $350 street). You can use either to manage remote flashes so that isn’t an issue. The two major differences are the power, guide numbers of 161 and 121 respectively and the number of groups of flashes that can be managed remotely. Generally two groups is sufficient for most photographs so the SB-910 has no real advantage over the SB-700 unless you are planning to or might use more than two flash units. The big advantage of the SB-910 over the SB-700 is power and, when you are using a flash, it is all about the power of the unit. I’d go with the SB-910.

If you are a Canon shooter, you only have one real choice for your first flash: Canon 580 EX II (about $475 street). Why? The smaller, cheaper unit, the Canon 430 EX II can’t be used to set and trigger remote flash units. The higher end Canon cameras, e.g., the 1D Mark IV and the 5Ds, don’t have this capability built into the camera so, if you have a 430, you are out of luck controlling other flash units unless you spend four hundred dollars buying TTL capable wireless triggers. As an added bonus, you get the extra power of the Canon 580 EX II.

Every photographer needs a flash unit and I recommend that your first unit be the best that you can possibly afford from your camera manufacturer because it will make lighting much easier. Also, a good flash will last longer than a camera body so a small additional investment now will have a big return later when you upgrade your camera.

-- Brian Zwit