It’s easy to think that shallow depth of field is somehow better. Who doesn’t want an f/1.0 lens, or iPhone portrait mode, to blur out the background. For that ‘professional’ look.
It wasn’t that long ago that the opposite was true. There was very little emphasis on achieving a shallow depth of field in photography. Why lose information? Journalists especially would want as much as the image as possible in focus. Many street photographers still use zone focusing so they can preset a focus distance and remove the need to focus at the time of the image. A narrow aperture gives you a much deeper zone of focus to work with, so you have a better chance to get your subject in focus in a fast-moving environment and even fast autofocus might not be quick enough.
I’ve found myself instead becoming lazy with using a wide aperture. I often use the Fujifilm 56mm f/1.2. And it’s so tempting to often lean on that f/1.2 (which is more like f/1.8 on full frame). It lovely for portraits, it’s great for isolating one element of a scene. But then you tend to forget about the rest of the scene. Distractions become less of a distraction so you’re less concerned about them. It’s easy to get lazy and careless and assume that the wide aperture will make a good photo.
Aside from the trend of ‘professional portraits’ with blurred background, I do think there is one strong argument for a shallow depth of field. And that’s because it’s the way we see. We don’t see everything in focus at once. We see with a shallow depth of field. It also draws the attention of the viewer. Our eyes are drawn to the sharpest part of an image just as they are to the highest contrast or the brightest area. Movies use shallow depth of field for the same reason.
Except that with a still image we have time, if we allow it to ourselves, to browse and absorb an images. Let our eyes wander around the scene and absorb the little details. Look at the very best photographs. The greatest ever photographs. The great landscape and portrait and humanitarian and documentary photographers. Not many use of a shallow depth of field. Some, not many.
That’s partly why I bought an f/2.5 Voigtlander lens rather than the faster options. (And it was cheap). But I thought it would be good to have more limited options. I can’t throw the background out of focus enough to not worry about it. Like the rest of the Leica experience, I want to slow down a little and take more care with each image.