Depth Of Field Question: After reading quite a bit on DOF, still not sure about one thing. Say your hyper focal distance is 25ft. If I move the focus point out beyond 25ft (say to 50...

BrettOssman Loc: near Tampa, Florida

After reading quite a bit on DOF, still not sure about one thing.

Say your hyper focal distance is 25ft. If I move the focus point out beyond 25ft (say to 50 or 100ft), will the DOF still reach to infinity. Or as you move the focus point farther out, does the far end of the DOF move in accordingly?

I think I pretty much get the rest of the DOF concepts, just wasn't sure about the above.

dirtpusher Loc: tulsa oklahoma

http://www.youtube.com/watch?v=T1cd3GZG5tE

BigBear Loc: Northern CT

DOF is the distance that is in focus in front and behind your subject.
DOF is determined by your aperture.
The more open your aperture is, ie: the smaller number, the shallower the DOF will be. And the opposite is true as the smaller your aperture, the larger the number, the greater your DOF.
Each lens has it's own DOF. The shorter lenses tend to have more DOF at certain f-stops compared to longer or telephoto lenses using the same settings.

lighthouse Loc: No Fixed Abode

BrettOssman wrote:

After reading quite a bit on DOF, still not sure about one thing.

Say your hyper focal distance is 25ft. If I move the focus point out beyond 25ft (say to 50 or 100ft), will the DOF still reach to infinity. Or as you move the focus point farther out, does the far end of the DOF move in accordingly?

I think I pretty much get the rest of the DOF concepts, just wasn't sure about the above.

If your hyperfocal distance is 25ft and you focus at 50 ft you will be doing the Buzz Lightyear focus - to infinity and beyond.

In real terms, if you focus at 25ft you will be in focus from about 12.5 ft to infinity.
If you focus at 50ft you will be in focus from about 20ft to infinity.

But - if you focus at 24ft then your far acceptable focus point will move in dramatically - probably from infinity to a couple of thousand feet. (Very rubbery figures used here just to give example)

BrettOssman Loc: near Tampa, Florida

lighthouse wrote:

If your hyperfocal distance is 25ft and you focus ... (show quote)

Thanks that answered my question. :mrgreen:

johneccles Loc: Leyland UK

Hello Brett, I understand that anything beyond a 100' is infinity any way. For the best DOF I use between F8 and F16 (never any higher) Then I manually focus on something about 100' away or more. The resulting image will have an excellent DOF from 25' to infinity. I try to get something in the foreground about 15-25' away to make the DOF more obvious.
This in my method.
John

BrettOssman Loc: near Tampa, Florida

Thanks all.

Got the answer to my question. Seems the best way to think of it is the hyper focal distance is the minimum distance to get focus to infinity. You don't lose any depth moving out farther. :thumbup:

jackm1943 Loc: Omaha, Nebraska

Yes, as long as you do not change the aperture.

BrettOssman wrote:

After reading quite a bit on DOF, still not sure about one thing.

Say your hyper focal distance is 25ft. If I move the focus point out beyond 25ft (say to 50 or 100ft), will the DOF still reach to infinity. Or as you move the focus point farther out, does the far end of the DOF move in accordingly?

I think I pretty much get the rest of the DOF concepts, just wasn't sure about the above.

BrettOssman Loc: near Tampa, Florida

jackm1943 wrote:

Yes, as long as you do not change the aperture.

Yes, I'm just talking about different focus point distances, nothing else.

Thanks

georgevedwards Loc: Essex, Maryland.

So by shortening the focus pt to 24ft you lose the focus on things on the horizon line? Whereas at 25ft and over you always have that. I have heard about a "mythical" perfect depth of field setting. My brother, a photography teacher in a public school system, said what most people don't realize is that if you focus on a certain distance, I remember him saying the 22 number on the focus ring, that everything from about 10 ft to infinity would be in focus. I have had problems testing it myself, and something tells me I may have to be concerned about aperture? I am still a little confused on this DOP concept too.

lighthouse wrote:

If your hyperfocal distance is 25ft and you focus ... (show quote)

BigBear Loc: Northern CT

BrettOssman wrote:

Thanks all.

Got the answer to my question. Seems the best way to think of it is the hyper focal distance is the minimum distance to get focus to infinity. You don't lose any depth moving out farther. :thumbup:

You have to consider the lens you are using also.
The longer the lens, the shallower the DOF will be compared to a shorter lens using the same settings.

BrettOssman Loc: near Tampa, Florida

BigBear wrote:

You have to consider the lens you are using also.
The longer the lens, the shallower the DOF will be compared to a shorter lens using the same settings.

Sure, was just wondering about the moving the focus point.

Thanks again all. I'm out.

emmons267 Loc: Arizona, Valley of the Sun

[quote=lighthouse]If your hyperfocal distance is 25ft and you focus at 50 ft you will be doing the Buzz Lightyear focus - to infinity and beyond.

If you focus at 50ft you will be in focus from about 20ft to infinity.

I would interested in knowing how you arrived at this conclusion. Could you please explain that. I am quite familiar with dof/hyperfocal.

johneccles Loc: Leyland UK

I agree with lighthouse, just focus on about 50' and everything will be in focus from 20'

amehta Loc: Boston

johneccles wrote:

Hello Brett, I understand that anything beyond a 100' is infinity any way. For the best DOF I use between F8 and F16 (never any higher) Then I manually focus on something about 100' away or more. The resulting image will have an excellent DOF from 25' to infinity. I try to get something in the foreground about 15-25' away to make the DOF more obvious.
This in my method.
John

Would this depend on your lens?