How often do you calculate the depth of field?

How often do you calculate the depth of field for a particular photographic situation, or do you rely on other ways to determine if it will be adequate (such as experience, depth of field preview on the camera, trial and error)?

By calculate, I mean use a DoF calculator app, a DoF table, the DoF scale on a manual lens, etc.

my scientific calculations.

perfect dof = guesstimation

😁

HAND.

Not a situation. For a approach, general plan or discipline, when chosing a lens, strategically. Not for a shootout at place.

Hi,

I have always used the scales on the lenses. This, beginning in 79 when I bought a Nikon FE. And so, this means the manual focus lenses which have useful DoF scales. Focus on the near point and note the distance. Focus on the far point and note the distance. Then choose the aperture which covers both distances and set the focus to make that so. Snap.

Yes, there are more precise ways. This one works well enough for me.

Now, the more modern lenses don't do so well with their scales. Fortunately, I have a rather large bag of the older prime lenses for when I want to work this way.

Stan

This is pretty much the same conclusion I came to. Given one of the variables is the "acceptable" circle of confusion, these calculations are less objective reality and more subjective preference. I can get to my subjective preference faster through a combination of experience and instant feedback from a digital camera.

This is not a downside, it is a strength.

It's only a downside if the CoC is indeed arbitrary.

BTW, it's easy to derate DOF marking on lens barrels. Two stops down halves the CoC.

The problem with a DoF calculation is that you can't really do one at the time of capture.

DoF relies on human perception, embodied in the circle-of-confusion number. The problem is, CoC is dependent on the viewing condition of the final image. Since the photographer can't control at capture time the way the final image will be viewed, the CoC and hence the DoF is unknown at the time of capture. This is why DoF preview, either with the stop down button on an SLR or with an EVF doesn't really work well.

That said, a rough idea is possible to calculate or to estimate via viewing through the viewfinder. For example, you can find out if (for example) the entire frame will have a CoC that's smaller than a pixel, meaning the DoF calculation is meaningless and the sharpness isn't limited by that source (out of focus blur). Or you can find out it's going to be very thin across the frame and most of the frame will be out of focus. That sort of thing.

Many times at the time of capture, I have a good idea of what the final form of the image and the viewing conditions will be.

Very good point!

Yep. Gotta love all those lens reviews where diffraction "sets in" at some exact f/number ...

I suppose that's possible. But if you think about it, even if you are the only viewer and the only view is going to be a print hanging on the wall, your distance to that print will change probably every time you view it - as you walk by, sitting down, whatever. Every change in distance is a change in CoC. Viewing pictures I took on my 40 inch 4k is a factor of 4 different (in CoC) than viewing the same shot on my phone. It's pretty easy to see how things can change a lot, but especially if you send it to other people to view however they are going to view them.

HAND.

Cool.

How to change your DOF ... resize the image ...

Another way is to apply Sharpen AI.

Calculate? ... almost never.
Estimate? ... almost always.