Two interesting observations about "equivalent focal length" (Page 8): Your demonstration was flawed by your incomplete understanding of DOF. If you knew what you were talking about...

selmslie Loc: Fernandina Beach, FL, USA

Ysarex wrote:

The poster I responded to said: "Depth of field depends on the magnification of the image on the sensor and the selected f number." I demonstrated that is incorrect. ...

Your demonstration was flawed by your incomplete understanding of DOF.

If you knew what you were talking about your response would have been better.

Ysarex Loc: St. Louis

selmslie wrote:

Your demonstration was flawed by your incomplete understanding of DOF.

I did not intend to present a treatise on DOF. I only intended to demonstrate that DOF depends on more than just "the magnification of the image on the sensor and the selected f number." I succeeded in that.

I don't otherwise care what you do or don't know. Are you claiming that the poster I responded to is correct? Are you making some other claim? Is there a reason you can't answer a simple question?

selmslie Loc: Fernandina Beach, FL, USA

Ysarex wrote:

I did not intend to present a treatise on DOF. I only intended to demonstrate that DOF depends on more than just "the magnification of the image on the sensor and the selected f number." I succeeded in that.

I don't otherwise care what you do or don't know. Are you claiming that the poster I responded to is correct? Are you making some other claim? Is there a reason you can't answer a simple question?

You were both wrong. You failed to supply a useful response. If you really understood DOF you could have provided a more appropriate response.

If you prefer to remain ignorant about DOF that's your problem, not mine.

Ysarex Loc: St. Louis

selmslie wrote:

You were both wrong. You failed to supply a useful response.

My response is useful in that it demonstrates the original claim is incorrect. That's all I intended to do and in that I succeeded.

So the poster I responded to is not correct. I believe that's what I said. Are you making some other claim about DOF?

selmslie Loc: Fernandina Beach, FL, USA

Ysarex wrote:

My response is useful in that it demonstrates the original claim is incorrect. That's all I intended to do and in that I succeeded.

So the poster I responded to is not correct. I believe that's what I said. Are you making some other claim about DOF?

You did not succeed because your response was not appropriate.

The point I am making about DOF is that I understand it and you don't. It is beyond your comprehension, above your pay grade. Your ignorance is bliss to you.

Since I can't teach someone who is unwilling to learn I don't need to respond to you any more on this topic.

Ysarex Loc: St. Louis

selmslie wrote:

You did not succeed because your response was not appropriate.

My only intent was to demonstrate that the poster I responded to was incorrect. You agree he was incorrect -- what I posted showed that. To show that the claim made was incorrect was not inappropriate. If the poster I reponded to has any questions I'll be happy to answer them.

selmslie wrote:

The point I am making about DOF is that I understand it and you don't. It is beyond your comprehension, above your pay grade. Your ignorance is bliss to you.

That's not a point about DOF.

selmslie wrote:

Since I can't teach someone who is unwilling to learn I don't need to respond to you any more on this topic.

You are inappropriate with your rude and juvenile insults -- no news to any of us though. Now are you making some other claim about DOF or do you just want to keep throwing juvenile insults?

selmslie Loc: Fernandina Beach, FL, USA

Ysarex wrote:

My only intent was to demonstrate that the poster I responded to was incorrect. You agree he was incorrect -- what I posted showed that. To show that the claim made was incorrect was not inappropriate.

The fact that you don't know why it was wrong points to your lack of understanding of DOF. If that's a problem for you I suggest you learn more about the subject.

I can't teach you if you refuse to learn.

Ysarex Loc: St. Louis

selmslie wrote:

The fact that you don't know why it was wrong points to your lack of understanding of DOF.

I'm well aware of why it was wrong. And like I said if the poster has questions I'd be happy to answer them. Point specifically to what I said that indicates I don't know why the poster's statement I corrected was wrong.

Now are you making some other claim about DOF or do you just want to keep throwing juvenile insults?

selmslie Loc: Fernandina Beach, FL, USA

Ysarex wrote:

I'm well aware of why it was wrong. ...

Maybe you do now but you didn’t realize it when you posted it.

The only other explanations would be that you couldn’t take the trouble to respond appropriately or that you were being deliberately misleading.

Which was it?

Ysarex Loc: St. Louis

selmslie wrote:

Maybe you do now but you didn’t realize it when you posted it.

Had I not understood it was wrong and known why I wouldn't have corrected it. And I see you have been unable to point to anything I said that indicates I don't understand. Didn't stop you from claiming otherwise though.

selmslie wrote:

The only other explanations would be that you couldn’t take the trouble to respond appropriately or that you were being deliberately misleading.

Misleading how? The correction I posted demonstrates that at the same magnification and f/stop DOF can be substantially different. The poster I responded to said: "Depth of field depends on the magnification of the image on the sensor and the selected f number."

I was satisfied with an example that showed the statement incorrect. If the poster had questions I'd have been happy to answer them.

Now are you making some other claim about DOF or do you just want to keep throwing juvenile insults?

selmslie Loc: Fernandina Beach, FL, USA

Ysarex wrote:

Had I not understood it was wrong and known why I wouldn't have corrected it.

Corrected what? Your post? That's what I am referring to. You never corrected that. All you have done is to make excuses for it.

And now you are repeating yourself. We know what that means. You have painted yourself into a corner and don't want to admit that you are wrong.

I am not going to continue this circular game of yours. Goodbye.

Ysarex Loc: St. Louis

selmslie wrote:

Corrected what?

The statement of the poster to which I responded: ""Depth of field depends on the magnification of the image on the sensor and the selected f number." That's what I corrected.

Now are you making some other claim about DOF or do you just want to keep throwing juvenile insults like a chimp throwing poop?

SuperflyTNT Loc: Manassas VA

Ysarex wrote:

Misleading how? The correction I posted demonstrat... (show quote)

selmslie wrote:

Corrected what? Your post? That's what I am referring to. You never corrected that. All you have done is to make excuses for it.

And now you are repeating yourself. We know what that means. You have painted yourself into a corner and don't want to admit that you are wrong.

I am not going to continue this circular game of yours. Goodbye.

The title was a lie. The OP’s initial observations were neither interesting or accurate. You two have done nothing to make it more interesting.

Ysarex Loc: St. Louis

SuperflyTNT wrote:

The title was a lie. The OP’s initial observations were neither interesting or accurate. You two have done nothing to make it more interesting.

I'm only trying to defend myself from a baseless attack. I'll be happy when it stops.

Although I'd still like an answer to my question: Misleading how?

selmslie Loc: Fernandina Beach, FL, USA

Ysarex wrote:

I'm only trying to defend myself from a baseless attack. I'll be happy when it stops.

Although I'd still like an answer to my question: Misleading how?

There's actually nothing wrong with the statement you objected to, "Depth of field depends on the magnification of the image on the sensor and the selected f number."

The problem is that you selected the same f/number for both examples. The poster (and I) would have selected a different f number for each which would have made the statement correct.

Try your example with different f numbers. I bet you can figure out which pair works and how they are related. If you can't, anyone with a DOF calculator can find them for you.