Yes but with two caveats.

1. If you are going to crop the image, you need to use a smaller CoC in proportion to the amount of crop. For example, a 1.5 crop would need to use a CoC of about 0.02 mm, just as if you were using a crop sensor.

2. If you plan to print and view at a not-standard size you also need to adjust the CoC. For example, "standard" means making an 8x12 inch print to be viewed from about 10 inches, or an 8x10 foot image to be viewed from 10 feet or similar print size and viewing distance proportions. If you plan to view from closer than normal distance, you need to use a smaller CoC. If you plan to make only a smaller print to view from further than normal you can get away with a larger CoC.

These two consideration are usually overlooked in any discussion of depth of field.

Ok, guys, help me out here. I teach an introduction and intermediate digital photography classes at a local contemporary photography museum. In intro, I just teach them what one member posted, the smaller the hole, the more depth of field. Enough said for a ten hour intro class. But for intermediate, we want them to be able to also use the effects of focal length and distance to control depth of field. I use the 1/3, 2/3 "myth" as a rule of thumb. I also tell them they get twice as much depth of field behind the focus point than in front of it. I point out the depth of field charts on lenses, but most of their lenses don't have that any more. I recommend using the depth of preview button, but most of their cameras don't have one. Most enjoy the science of how their cameras and lenses work, but how much is too much. Our emphasis is fine art, so the power of the image is the main thing we are trying to teach them. Where do I draw the line?

Yes, a smaller aperture or a shorter focal length will provide you with more DoF, all things being equal - which they never are. Conversely, a wider aperture blurs more of the foreground and background and that's important for a fine arts class. After all, still life and landscape have different requirements.

But you need to learn more about DoF before you give your students the wrong information. Do a little research with a DoF calculator.

The 1/3-2/3 ratio is really a myth. It only works when you focus at 1/3 of the hyperfocal distance. It does not work for any other focus distance. It clearly does not work when you focus at the hyperfocal distance since the DoF extends to infinity and half way back toward the camera. The closer you focus to the camera the nearer you approach a ratio of 1:1 for DoF in front of and behind the focused distance.

But as I implied in my initial post, the devil is in the details.

Ok, guys, help me out here. I teach an introduction and intermediate digital photography classes at a local contemporary photography museum. In intro, I just teach them what one member posted, the smaller the hole, the more depth of field. Enough said for a ten hour intro class. But for intermediate, we want them to be able to also use the effects of focal length and distance to control depth of field. I use the 1/3, 2/3 "myth" as a rule of thumb. I also tell them they get twice as much depth of field behind the focus point than in front of it. I point out the depth of field charts on lenses, but most of their lenses don't have that any more. I recommend using the depth of preview button, but most of their cameras don't have one. Most enjoy the science of how their cameras and lenses work, but how much is too much. Our emphasis is fine art, so the power of the image is the main thing we are trying to teach them. Where do I draw the line?

While both concepts are based on sound mathematical principals, they are fundamentally flawed by an assumption and a misunderstanding:

1. That Depth of Field (DoF) is a range of distances from the camera over which the image is equally sharp.
2. That everyone understands and agrees on the definition of the Circle of Confusion (CoC).

The first assumption is close but there is a difference between being equally sharp or acceptably sharp.

There will be only one distance at which an image is perfectly sharp. Consider a point source of light such as a star. If you set the focus at infinity, the star should project a point of light on your sensor that is smaller than a single pixel. The same would apply if the point source of light were much closer to the camera, for example 20 feet from the camera or much closer. When in focus, the point on your sensor could still be smaller than a pixel. If it were slightly out of focus it might be as large as a whole pixel and your camera would not know the difference.

How big is a pixel? A full frame 24x36 mm sensor that produces an image of 4000x6000 pixels or 24 MP – 24 mm divided by 4000 (or 36 mm divided by 6000) is 0.006 mm. Disregard for the moment that this may be either a red, blue or green pixel and that your lens might not be capable of projecting a point source that precisely. A CoC of 0.006 mm is much smaller than you normally need. If you were to aim at a star with a 50 mm lens at f/11, you might get the point of light to stay within a single pixel if your focus was anywhere from about 125 feet to infinity.

A common assumption for the size of the CoC is about 0.03 mm for a full frame sensor or film with the same format. That would mean that a point source of light could actually spread out to cover a diameter of 5 pixels and still be acceptably sharp. The star that is in focus at infinity will cover less than 5 pixels with a 50 mm lens at f/11 if you focus at any distance longer than about 25 feet, the hyperfocal distance for a 0.03 mm CoC.

Why 0.03 mm? Someone with normal eyesight can resolve a detail that is about 2 minutes of arc or 30 cycles of black/white stripes per degree. That works out to about 0.0291 mm for a 24x36 mm film or digital format.

The common assumption is that you will be making a print that is about 8x12 inches using the entire image and viewing it from about 10 inches with normal eyesight – or 8x12 feet and viewing it from 10 feet or any other ratio that keeps the print dimension proportional to the viewing distance. But if you crop the original image, view it from a distance that is different, with eyesight that is different from normal, use a loupe or magnifying glass, then 0.03 mm may no longer be appropriate.

So you need to know something about how your image will be viewed before deciding on the size of the CoC. If you are going to display it within the parameters described in the previous paragraph the 0.03 mm will work. If you will be displaying the whole image on a smart phone, tablet or printing it smaller than 8x12 inches then 0.03 mm will be more than adequate. But if you plan to enlarge it, crop it, pixel peep, print it large and look at it closer than normal viewing distance, you will need to use a smaller CoC.