What's the benefit of a tiny aperture?

Question

In this answer to another question Rob Clement wrote:

Think background first. What story do you want to tell? Epic background, big mountains. Looking to deliver a sense of grandeur with your subject. Go big! f/22 or higher if you have it.

I understand that he's using depth of field to talk about keeping the background sharp. But even at a modest f/8, the hyperfocal distance for most common scenarios is only a few tens of feet... more than enough to get a mountain range in.

I also understand that wider apertures reduce sharpness... but a few stops down from wide open is usually enough.

And obviously, you can use a smaller aperture to reduce the light. But f/22 seems pretty tiny even for a bright day.

So what other reasons for using a tiny aperture exist?

Answer 1

Those kind of apertures often show up in macro work because the DoF is razor thin, so every fraction of a mm you can get matters. However, you also can be diffraction limited at such a aperture and actually end up with less sharpness. Cambridge in Colour has a good article on this very topic.

Answer 2

You know those shots of cars driving and the head lights are streaking all over. Well in order to shoot that you have to keep the shutter open very long. You would need a small aperture to cope with the long shutter in order to not overexpose the picture.

Answer 3

Smaller aperture can be used for reducing lens flare. Ok, nothing I really ever did, but it comes to mind if you eliminate the other reasons ;)

Answer 4

f/22 is perfectly appropriate for medium format. In fact, f/64 was a common aperture for 8x10" landscape shooters, hence the name of Ansel's group. For 35mm/full-frame you'll usually be at f8-f16 and for APS-c a stop or so wider is fine.

At least, I assume that's what he meant. If you didn't have any ND filters handy you might use f/22 in dawn light to get blurred water, I suppose.

Answer 5

I realize the question pertains to selecting a particular aperture on a lens capable of, say, f/1.7 to f/22.

But another way of looking at it is What benefits might a photographer have if they only used tiny apertures?

One big advantage is that such lenses are much smaller and lighter. The diameter of lenses is driven by the maximum aperture. A lens capable of only f/16, f/22, and f/32 would be very tiny and light, perhaps using 5% of the glass of one capable of f/2.

But the choice of aperture is a balance between useful depth of field versus diffraction-induced fuzziness. See this.

Answer 6

The usual answer from photo manual is to take panoramic pictures with tiny aperture to get the maximum deep of field, no flares and highest sharpness. This is how the theory goes.

The reality is really different, I tried myself several shots with several "semi-pro" range lens (500-1000$ price range) with my Nikon 300D. All of them showed a marked drop of sharpness after f16, with the best results at f8. I think the problem is the irregular shape of the shutter hole when reduced causes many diffractions. I could be that with special or more expensive lens the problem is not present.

As results I'm using tiny aperture only if I need long exposures (and I don't have ND filters with me) or for high macro snaps (where dof is really important).

On a side note, pinhole cameras with film are very funny to use, I bought mine for 20 pound and it's done of cardboard. :)

Answer 7

A tiny aperture can be useful if you want a blurred picture of a bright waterfall.

Answer 8

In addition to reducing the amount of light and increasing the depth of field, tiny apertures can also be used to produce a starburst effect on point light sources in the frame.

Answer 9

Larger aperatures (assuming you shorten the exposure time to compensate) tends to also lead to harsher light and shadows. This tends to only be noticable for very, very fast shutter speeds, and therefore only with wide-open apertures as well.