When Hyperfocal Distance Fails, Part 2

A few days ago, I wrote a blog post about some widely held misunderstandings about hyperfocal distance and concluded with this question:

What does this mean? Is hyperfocal distance useless, or of limited use? Should we limit ourselves to small prints, when we use it?

In this follow-up post, I want to give an answer to this question, suggesting some possible solutions.

Solution 1: Ignore the problem

Henri Cartier-Bresson is credited with saying “Sharpness is a bourgeois concept” and I will readily confess my sin of pixel-peeping, when I examined that photo at a 100% enlargement. Can we really see the softness in normal viewing conditions? Is that softness important?

As with everything, the answer is “It depends.” If we shrink that image down to web size or print it at a small size, probably not. However, our monitors are getting bigger and bigger, larger prints are becoming cheaper every day, and we are getting accustomed to seeing sharper prints.

Moreover, we spend thousands of dollars on multi-megapixel sensor cameras and computer-designed lenses that are sharper than everything that came before. Why spend all that money, if we are going to lose sharpness because of bad technique?

Perfect sharpness is not always necessary or even desirable, but it is important to be able to achieve it, when needed. In any case, always keep in mind that, according to Ansel Adams:

There is nothing worse than a sharp image of a fuzzy concept.

Solution 2: Use a smaller aperture

The image I used to illustrate these concepts was taken at an aperture of f/5.6. I used that because my hyperfocal distance calculator app assured me it was enough and it is the sweet spot, in terms of sharpness, of the lens I used. However, I could have used f/8 to get more depth of field and still acceptable overall sharpness. At f/11, my camera-lens combination starts showing some signs of diffraction. At f/16 diffraction causes a perceptible softness. At f/22, it gets really bad.

Stop down the aperture, if you really must, but be careful. If you recompute the hyperfocal distance using the new aperture, the new value will be closer to the camera’s position. You will have more depth of field in front of your subject, but the same as before behind your subject. In other words, distant objects will still be fuzzy, possibly even more due to diffraction.

So, compute the hyperfocal distance at, say, f/5.6, then stop down to f/11 but focus at the same point as before.

Solution 3: Change the factors

As I wrote in part 1, the formula used to compute the hyperfocal distance is based on conventional values for enlargement and viewing distance. These values are used to compute the so-called Circle of Confusion (CoC). A typical CoC value for APS-C sensor cameras is 0.02mm. For full frame cameras, 0.03mm. Here’s the kick:

Using a smaller value for the circle of confusion will yield more conservative values of the hyperfocal distance.

This is simply because the CoC is used in the denominator of the fraction used in the formula, where it is indicated by the symbol c:

Hyperfocal distance formula

The smaller the CoC, the longer the hyperfocal distance H and the sharper your distant objects will be (possibly at the expense of objects really close to the camera).

So what value of c should we use in practice? Again, that depends on enlargement size and intended viewing distance and you could certainly compute an adequate value based on larger prints viewed closer. I am sure there are formulas somewhere.

However, I have a better solution.

Solution 4: Trust the manufacturer

Once upon a time, lenses used to have depth-of-field markings on the barrel, but those times are mostly gone. We live in the digital age, though, and our cameras have amazing high-resolution LCD displays that display all sorts of information. Couldn’t camera manufacturers give us a distance scale and a real time depth-of-field indicator in the LCD or the viewfinder?

Well, my camera does and I am sure many others do too.

A neat feature of Fuji X cameras is that you can enable the display of a distance scale with a marker of the focusing distance and a blue area corresponding to the range of distances that are in focus. Want to focus at the hyperfocal distance? Easy as pie: just rotate the focusing ring on the lens, while in manual focus mode, until the right limit of the dark area reaches the end of the scale. The focusing distance marker in the middle now indicates the hyperfocal distance, no smartphone app required.

Distance scale on the Fujifilm X-E2

Distance scale on the Fujifilm X-E2

Now, here’s what I have discovered:

The formula Fuji employs in its display is much more conservative than the conventional one.

As you can see from the screenshot above, the hyperfocal distance indicated on the LCD is at around 3.5m and the near limit is a little less than 2m, much farther away than the 0.89m and 0.65m, respectively, computed using the conventional CoC.

This means that, if you trust it, objects that fall within the range of distances contained in the blue area will be really sharp enough. No need to fudge the circle of confusion or stop down the aperture too much unnecessarily. Thank you, Fujifilm!

There are cases, however, when you have objects so close to the camera that their distance falls out of the range of acceptable focus and you don’t want to stop down too much, in order to avoid the effect of diffraction. In this case, you might want to use my fifth solution, but this post is too long already, so I am going to reveal it in the next post, to be published soon.

Update: Part 3 has been published here.

Comments 1

  1. Pingback: When Hyperfocal Distance Fails | Ugo Cei Photography

Leave a Reply