Travel Photography - Any advantage to a wide aperture when conditions allow a broad choice?

Let's say you don't need depth of field, and don't have a shutter speed problem (or blur benefit) if you use a wide aperture. Is there any reason to favor a wide aperture? I've heard that lights may look better using at least f8, but what about other subject matter?

If you're not looking for the creative effects of a wide aperture (selective depth of field or freezing motion), then most lenses aren't at their best wide open.

As a general rule of thumb, two stops down gets you to peak performance - it avoids the challenges of redirecting light from the edges of the lens but isn't a small enough aperture to cause the blurring effects of diffraction.

There are various testing sites that show the levels of resolution/sharpness at different apertures for lenses, but when in doubt, f/8 is always a great place to start. I tend to try f/5.6 for f/2.8 or faster lenses, and f/8 for slower lenses, but the differences between 5.6 and 8 are typically minuscule.

In fact, one of my Custom Settings is ISO 100, Aperture Priority, f/8, mirror lockup, timer on. That's my default setting for tripod-based landscape shooting (which I used quite a bit today).

A possible benefit in digital cameras (doesn't apply to film, unless you carry multiple bodies loaded with different film types - not too likely) is that it lets you shoot at a lower ISO rating. Depending on your sensor, but especially if you have a small sensor and you'd otherwise be toward the upper end of your camera's ISO range, that may reduce noise. The benefits of that may be greater than what you lose by opening up the lens.

Personally I love taking at full aperture. I have a Canon 50mm f/1.4. It's tricky but great results and only for specific subject matter - close ups. Depth of field at max aperture is very small so setting your a/f spot is key and so is setting your metering zone. It really helps with that to just take as many shots as you can per subject.

Advantages and rules for me: pin point focus (aim for the eyes, not the nose - especially if someone has a big nose) so close up face work only, colours are muted and more natural looking IMO, lighting is softer and with my EOS 20D I think duller (except with external flash), everything else foreground and background is really blurred - which really picks out people and makes special shots.

Disadvantages: pin point focus not forgiving when poeple move slightly, if using flash it has to be external Speedlite and set to high speed sync, many wasted shots. If you set AP on your camera and you swap lens remembering to crank it back to P... Getting best results as per advantages means you have to be close to the subject.

Best thing is to experiment and take variations of the same shot and see what you like.