A poll about depth of field

[J A C S]

Let me remind you that my objections started with the original photograph and people claiming that because the camera was focused to infinity then the DOF was infinite. If that was true nothing would be out of focus and that certainly was not the case in the original photo posted by Sybersitizen.

If that were true, which it is, an infinite (unbounded) range would be in focus, which is the case.

 

[JustUs7]

Good grief. Focus on the building. Focus on the stars. Focus merge in post. Done.

 

[tbcass]

Let me remind you that my objections started with the original photograph and people claiming that because the camera was focused to infinity then the DOF was infinite. If that was true nothing would be out of focus and that certainly was not the case in the original photo posted by Sybersitizen.

If that was true, which it is, an infinite range would be in focus, which is the case.

Oh brother. That is not DOF in the true sense. You are simply being sophistic.

 

[Tom Axford]

Let me remind you that my objections started with the original photograph and people claiming that because the camera was focused to infinity then the DOF was infinite. If that was true nothing would be out of focus and that certainly was not the case in the original photo posted by Sybersitizen.

You are remarkably persistent in making statements that are completely untrue.

Infinite depth of field does not mean that everything is in focus.

 

[tbcass]

Let me remind you that my objections started with the original photograph and people claiming that because the camera was focused to infinity then the DOF was infinite. If that was true nothing would be out of focus and that certainly was not the case in the original photo posted by Sybersitizen.

You are remarkably persistent in making statements that are completely untrue.

Infinite depth of field does not mean that everything is in focus.

It does by every definition I know. Prove me wrong.

"What is Depth of Field?

Depth of field is the distance between the closest and farthest objects in a photo that appears acceptably sharp. Now your camera can only focus sharply at one point. But the transition from sharp to unsharp is gradual, and the term ‘acceptably sharp’ is a loose one! Without getting too technical, how you will be viewing the image, and at what size you will be looking at it are factors that contribute to how acceptably sharp an image is. It also depends on how good your vision is!"

You can interpret it any way you want to prove your point but to me the meaning is obvious. At infinity, it is between the closest object in focus and infinity.

--
Tom

 

[JustUs7]

Disney made this one. Not me.

 

[Phil A Martin]

Disney made this one. Not me.

I already cracked that joke

https://www.dpreview.com/forums/post/65313690

 

[J A C S]

Let me remind you that my objections started with the original photograph and people claiming that because the camera was focused to infinity then the DOF was infinite. If that was true nothing would be out of focus and that certainly was not the case in the original photo posted by Sybersitizen.

You are remarkably persistent in making statements that are completely untrue.

Infinite depth of field does not mean that everything is in focus.

It does by every definition I know. Prove me wrong.

"What is Depth of Field?

Depth of field is the distance between the closest and farthest objects in a photo that appears acceptably sharp.

If the moon is the closest object in focus and every other object farther away also is, then that distance is infinity, therefore, the DOF is infinity.

Q.E.D.

 

[JustUs7]

I already cracked that joke

https://www.dpreview.com/forums/post/65313690

Darn. Missed it in the deluge of semantics being discussed. Nice work!

 

[mamallama]

Let me remind you that my objections started with the original photograph and people claiming that because the camera was focused to infinity then the DOF was infinite. If that was true nothing would be out of focus and that certainly was not the case in the original photo posted by Sybersitizen.

Yes, of course. That is why I said the poll makes no sense with that premise as a background. Amazing that few responders to the poll even noticed.

 

[tbcass]

If the moon is the closest object in focus and every other object farther away also is, then that distance is infinity, therefore, the DOF is infinity.

Q.E.D.

No, it isn't and you aren't as smart as you think you are because you did not prove your point.

 

[tony field]

Sometimes in certain fields, but not in this conversation, where DoF was defined multiple times as a single number (distance) and then mixed up with range defined as two points.

Defining DOF as a single distance number is wrong because it's useless. If I say DOF is 100 feet what does it mean? 10 feet to 110 feet? 1000 ft to 1100 feet? No, because that number has no practical value.

Of course it has practical value. Typically it is assumed that the DoF is about equally split around the point of focus. Clearly, it is better to know the exact near limit and far limit, but if we know the DoF is 100ft and our subject has depth (as measured along the axis to the camera) of only 20ft, then we will easily be able to get it all in focus.

To derive the single number we have to know what the near limits and far limits are first. Since we know what those two distances are what good it to express it as a single number. If I just say the DOF is 10 feet what good is it unless you know the distances. Even giving a single distance of 100ft won't help because you won't know if it's 90-100 or 100-110 ft or 95-105 ft. In all my photographic life DOF has been expressed as a near and far number for a reason.

The only time I am concerned about this fuzzy concept called dof is when shooting showjumping or dance. It turns out that I am only interested in the depth of the subject and the focus distance. I always know what the f number I am going to be using. From that point on, I will simply guess how to combine the variables. My usual rule of thumb computer running around in my feeble brain is actually pretty reliable.

I don't really care about the near and far point of the d o f: I am much more interested in how thick is the area of sharpness.

The simple formulas used by dof Master are easy to follow if you understand the basic nature of Optics and definitely provide some insight into the nature final image sharpness