photodoc16

Dear Hogosphere,
I have used my DOF calculator for a while and thought I understood it. However, what I probably have not used is the "focal distance" scale. If the Focus Distance is not the same as the hyperfocal point, then the question is how do you use both numbers? Does it mean that while I know the HP I choose to focus on something else? The HP, however, changes as I put in the focus point. I do try to focus on the HP and read where my near and far DOF are located for composition purposes. What then is the Focus Distance and how do I use it?
Thanks,
Photodoc16

Apaflo Loc: Anchorage, Alaska

Here is a really nice web site with several calculators. A DOF calculator is at the top.

http://www.tawbaware.com/maxlyons/calc.htm

Most of the time you probably don't need to be concerned with the hyperfocal distance. The graph will help you understand it. Hyperfocal distance changes with aperture and the focal length of the lens, but does not change with focus distance.

Winslowe

Here is another calculator you may find useful: http://www.dofmaster.com/dofjs.html

BHC Loc: Strawberry Valley, JF, USA

Deleted

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

The HP is the focus distance setting that results in the greatest depth of field for a given aperture and focal length. The focus distance is used when you want to focus at a point different from the HP. For instance, you may want to do a portrait of a dog, with the nose and eyes in focus, but you don't care about the rest. You would figure out a distance that you will be shooting at, and select an aperture that will give you about 12" or so of DoF. Or select the aperture first, then find the distance that will result in the DoF and composition that you want to have.

The only time the focus distance is the same and the HP is when you want the maximum depth of field, which will be from 1/2 the HP focus point distance to infinity.

selmslie Loc: Fernandina Beach, FL, USA

There is no practical use for the Hyperfocal Distance. It is a mathematical concept and it is the first step in calculating DOF.

The first consideration is practical. Even if you know the value of the hyperfocal distance it is unlikely that you will be able to locate an object in your scene at that distance on which to focus.

In the second place, when you focus on anything, only something at that specific distance will actually be in focus. Everything else, closer or further from the camera, will be progressively more out of focus until you can actually notice this in your final image or print.

As I posted once before:

Take a look at the DOF calculator at Cambridge in Colour (click on show advanced). There are seven factors that go into the DOF calculation:

1. Max print dimension
2. Viewing distance
3. Eyesight
4. Camera type (sensor size or film format determines initial COC diameter)
5. Aperture
6. Focal length
7. Focus distance

#4 is only a starting point, assuming that you don't crop the resulting image when making the print. As soon as you crop, the COC gets smaller and this reduces the DOF.

Simply put, you cannot determine DOF as precisely as the calculators imply. It's a fuzzy concept.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

Apaflo Loc: Anchorage, Alaska

No practical use for the hyperfocal distance???

Just the literally millions and millions of fixed focus point and shoot cameras that have been sold since Kodak offered the Brownie...

That was sort of practical, eh?

selmslie Loc: Fernandina Beach, FL, USA

A lot of masterpieces created with a Brownie? Get real!

I guess I will have to add hyperfocal distance the list of stuff you don't understand.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

Yup, those fuzzy 4x6 snapshots really filled a practical need . . . maybe for you . . .

Scotty is right, hyperfocal is more hype than practical.

On another note, I came across a quote that reminded me of you, "There’s one thing about an extreme narcissist, they don’t take criticism well, nor being either defied or denied. And when they reside in an alternative reality, where their words and actions are always correct, and they’re never at fault for anything . . .".

It was about a certain public figure, but . . .

Bill_de Loc: US

I was taught years ago that for maximum depth of field, set the focus ring so the infinity symbol lined up with the aperture you were shooting at. I realize that is impossible to do with most of today's lenses. Was that method valid at the time?

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Apaflo Loc: Anchorage, Alaska

Kodak and several other companies used the principle of Hyperfocal Distance to make millions of dollars. That happened because it is a very practical principle.

Nobody said, and there need not be concern, that a Brownie camera does or does not take pictures that rise to the level of great art. That is obfuscation with a Non Sequitur just meant to hide how silly the claim was about no practical use.

Here is another little tidbit to think about... where to you think Andreas Gursky focused when making the negatives for Rhein II?

Apaflo Loc: Anchorage, Alaska

That would pretty much nail focus at hyperfocal distance on a lens with DOF marks. If you absolutely wanted objects at the horizon to be sharp it was best.to go just past the infinity mark. And if closer objects were more important it might be better to be just shy of infinity.

Incidentally that is a very practical technique for landscapes...

selmslie Loc: Fernandina Beach, FL, USA

Nobody who does landscapes would do that.

Apparently you do not anything about the subject of landscapes or DOF.

rehess Loc: South Bend, Indiana, USA

So, how should I set focus to guarantee that objects "on the horizon" will be in focus?