Why you should consider getting an external flash first before anything else
For many new photography enthusiasts, upgrading to a fast 2.8 zoom lens will be their first priority and their main reason is for low-light shooting capabilities.
There’s nothing wrong with that, it’s a legitimate, worthwhile investment for those who can afford it and need it for their assignments.
Make sure you check out my Comprehensive Flash Buyer’s Guide as well.
Flash is Cheaper
Those of us can’t afford fast zoom lenses without going through some serious budgeting will need to real consider the reasons to get one as when we do buy such a nice piece of equipment, most users fail to realize that a fast lens does have trade-offs as well, especially when it comes to depth-of-field and max shutter speed issue.
For most casual users, investing on a flash gun is a much better decision, in my opinion. A flash gun allows your basic kit lens to function well in low-light and fast-moving subjects regardless of lighting conditions.
Unless you shoot in very good light and with a tripod most of the time, a flash will be more beneficial than a fast lens.
Limitations and Compromise of Large Aperture
If you’re shooting a group of subjects in low-light, using a wide aperture (f/4 or larger) usually won’t let you get a sharp image beyond the person your camera focused on.
You’ll most probably need f/6.3 to f/11 in most group shots – something even your fast lens won’t be able to cope with in terms of shutter speed. Even high ISO won’t help much, not to mention the loss of detail due to noise.
If you’re a daytime-only or landscape photographer, then a flash may be less advantageous to you, but for most people, read on.
A flash will allow you to keep a high shutter speed (usually above 1/100) while keeping the aperture opening small (f/5.6 or smaller).
E-TTL systems calculates exposure pretty accurately and if you have the experience, you can always manually mix and match your flash-cam settings.
In addition, the AF assist system of most external flash guns are superior to on-cam flash assistance units especially in near-total darkness.
We’ll take a look at practical applications on the advantage of having a flash gun on the next page