This is kind of stupid but..I just "Got it"!

[Leigh]

The "equivalent focal length" concept is just a new and improved way to confuse people.

Ignore it. Pretend the phrase was never invented. It's nonsense.

- Leigh

[Steve Smith]

I noticed that the smaller the piece of film I use, the smaller the picture I get.

Then you need a bigger enlargerificator.


Steve.

[RichardSperry]

The effective focal length never changes, ever. The perspective doesn't change, either, unless you move the camera. The part of the image you record on film is what changes.

The images will look different.

E., What is the acceptable word for that difference?

Or do you say that only a wordy paragraph works, for explaining something obvious that one word will do?

[RichardSperry]

The "equivalent focal length" concept is just a new and improved way to confuse people.

Ignore it. Pretend the phrase was never invented. It's nonsense.

- Leigh

Likewise to you, Leigh. What is your acceptable word for the difference?

You know that the two images will look different, everyone does. What is your word to describe the difference?

[sully75]

The "equivalent focal length" concept is just a new and improved way to confuse people.

Ignore it. Pretend the phrase was never invented. It's nonsense.

- Leigh

confusing? Really? Seems totally simple to me.

[RichardSperry]

Your observation is incorrect. The focal length does not and can not change. This is very important to know, if you wish to be a competent photographer.

I think a competent photographer should know that an image made with a 300mm lens will look different on an 8x10 camera back versus a 4x5 back. It's something a beginner photographer would notice off the bat, a layperson would notice the difference.

This whole discussion is merely a terminology debate. Some like to include all the details of image circle or DOF or whatever, unnecessary. If all you did was agree on what word works to describe the obvious difference, then the debate would be settled. And then it would be clear to everyone, instead of debating something that no one is arguing(it is beyond obvious that the focal length does not change, why argue that point). There is a difference, and you certainly don't have to jump down Cletus' throat for noticing it, He doesn't know the word or term, and is politely asking what that word or term is.

So am I. What is your word to describe the difference, E.?

[Leigh]

confusing? Really? Seems totally simple to me.

The concept of "equivalent focal length" is based on an invalid premise, specifically,
the idea that a photographer will know intuitively the angle of view of a specific focal length on a 35mm camera.

Back in "the day", when digital first came out, it was assumed that everyone was familiar with 35mm lenses and what image they would produce.
Therefore it made sense to convert the true focal length into an "equivalent" FL that would yield the same image on 35mm as you got on digital.

That assumption is no longer valid.

Couple that with the fact that the aspect ratios are different for 35mm and LF, and any suggestion of "equivalence" becomes invalid.

- Leigh

[Leigh]

...an image made with a 300mm lens will look different on an 8x10 camera back versus a 4x5 back.

Disregarding the actual image circle diameter, every 300mm lens will produce exactly one image of a given subject,
and that image will be identical for every 300mm lens regardless of what, if any, film or sensor is behind the lens.

This is absolutely obvious since the lens has no knowledge of what's behind it, so there's no way to adjust the image for the medium.

The medium will determine what portion of that image is captured for future use.

If you shoot a picture on a piece of 8x10 film, you get an image containing some portion of the subject.
If you then take a pair of scissors and cut out a 4"x5" section of that negative, that's what a 4x5 camera would capture.
Then take the scissors and cut a 6x6 section out of that negative, and that's what an MF camera would capture.
Then cut out a 24mmx36mm section of that negative and you have the image from a 35mm camera.

The image thrown by the 300mm lens has not changed in any manner whatsoever.
The only change is what portion of that image you choose to retain.

- Leigh

[RichardSperry]

Leigh,

How about sticking with Cletus' first example.

Take an 8x10 camera with a 300mm lens. The camera has an 8x10 back and a 4x5 back. The image produced will be different for each back, obviously. What term do you use for this difference, Leigh?

It's the same camera, same aspect ratio, same lens, same distance, same DoF, same image circle, same field of view, same angle of view. But the image is different, what is this called?

[RichardSperry]

Disregarding the actual image circle diameter, every 300mm lens will produce exactly one image of a given subject,
and that image will be identical for every 300mm lens regardless of what, if any, film or sensor is behind the lens.

This is absolutely obvious since the lens has no knowledge of what's behind it, so there's no way to adjust the image for the medium.

The medium will determine what portion of that image is captured for future use.

If you shoot a picture on a piece of 8x10 film, you get an image containing some portion of the subject.
If you then take a pair of scissors and cut out a 4"x5" section of that negative, that's what a 4x5 camera would capture.
Then take the scissors and cut a 6x6 section out of that negative, and that's what an MF camera would capture.
Then cut out a 24mmx36mm section of that negative and you have the image from a 35mm camera.

The image thrown by the 300mm lens has not changed in any manner whatsoever.
The only change is what portion of that image you choose to retain.

- Leigh

You have just described something that has a name, a term; cropping.

I am not debating that. I am asking you for the word to describe two different images taken with two different sizes of film, with all other things remaining non variable.

What is that word, or term, or phrase that describes that difference.

If you don't know it, just say so.