[RayGunn]

I was reading the thread “Sigma APO Macro 180mm F2.8 EX DG OS HSM”, located within General Pentax Forums: Pentax News and Rumors, when, near the end of the thread, the discussion turned to a different topic which seemed to me to concern the difference between the terms “Magnified” and “Enlarged”.
Perhaps I am simplifying the discussion but that is only because of the complexity of the arguments and my failure to understand the issue and its resolution. The URL for this discussion is:

https://www.pentaxforums.com/forums/pentax-news-rumors/177856-sigma-apo-macro...dg-os-hsm.html

Since I found the discussion examples to be of little or no help to my understanding, I ask the participants of that discussion to please answer my questions, using my examples, the first of which is:

Example 1: I have a postage stamp on my desk top. I take a magnifying glass out of my desk drawer to more closely examine the postage stamp. When I look through the magnifying glass at the postage stamp, I see an image of the stamp ‘in’ the magnifying glass. This image appears to be larger than when I look at the stamp with only my naked eye.
Questions re: Example 1: Is this larger image a “magnified” image or is it an “enlarged” image?
In this particular case, may the terms “magnified” and “enlarged” be used interchangeably or are they mutually exclusive?

[RioRico]

As I understand the common usage of the last few decades:

* Magnification happens as the image is captured.
* Enlargement happens as the image is displayed.

So with macro lenses, we measure the ratio of a captured image's size to the actual size of the subject -- and that's the magnification. If an object 48mm wide fills an ~24mm-wide APS-C sensor, then the magnification is 1:2 or 0.5x. If the object is 24mm wide and fills the frame, it's 1:1 or 1x. How the captured image is displayed is irrelevant here. Magnification is capture:reality.

Once we have the image, and we display it, then we can talk about enlargement. If a 24mm-wide image at 1:1 magnification is printed or projected to 2.4m, then enlargement is 100x. If a 24mm-wide image of a 48mm-wide object (1:2 magnification) is projected to 2.4m, enlargement is 50x. Enlargement is display:reality.

[JinDesu]

As I understand the common usage of the last few decades:

* Magnification happens as the image is captured.
* Enlargement happens as the image is displayed.

So with macro lenses, we measure the ratio of a captured image's size to the actual size of the subject -- and that's the magnification. If an object 48mm wide fills an ~24mm-wide APS-C sensor, then the magnification is 1:2 or 0.5x. If the object is 24mm wide and fills the frame, it's 1:1 or 1x. How the captured image is displayed is irrelevant here. Magnification is capture:reality.

Once we have the image, and we display it, then we can talk about enlargement. If a 24mm-wide image at 1:1 magnification is printed or projected to 2.4m, then enlargement is 100x. If a 24mm-wide image of a 48mm-wide object (1:2 magnification) is projected to 2.4m, enlargement is 50x. Enlargement is display:reality.

Exactly my understanding here. And I know nothing of the subject!

Magnification is to change the size of an object as optically portrait on the sensor for capture.
Enlargement is the size of the print/display - in the event of an electronic display, it is in reference to resolution.

[Blue]

Quick! Lock the thread.

[Bob from Aus]

Defining words also needs to be in the social current context as language is dynamic and has a life of its own changing all the time. The only languages that don't change are dead ones like Latin. So an accurate technical definition is useless when 90 % + of people use the word differently.

At the end of the day the process of taking a photo with a macro lens, processing it by enlarging it has magnified the image by nearly everyone's definition. It is a similar result as looking down a microscope.

So if you are interested in all technical aspects of photography then definitions can be very important. If you want to communicate with non technical photographers then you need to use their language to communicate.

[Blue]

Exactly my understanding here. And I know nothing of the subject!

Magnification is to change the size of an object as optically portrait on the sensor for capture.
Enlargement is the size of the print/display - in the event of an electronic display, it is in reference to resolution.

Resolution can refer to a specific sensor or in the case of film, a specific emulsion. For example, Kodachrome 64 and Tri X Pan 400 each have different (had in the case of Kodachrome) capabilities regarding resolution.

[RayGunn]

Sorry my questions were so difficult to understand , so let me try a restatement.
... please answer my questions, using my examples, the first of which is:
Example 1: I have a postage stamp on my desk top. I take a magnifying glass out of my desk drawer to more closely examine the postage stamp. When I look through the magnifying glass at the postage stamp, I SEE (not capture) an image of the stamp ‘in’ the magnifying glass. This image appears to be larger than when I look at the stamp with only my naked eye.
Questions re: Example 1: Is this larger, non-captured (photographically) image a “magnified” image or is it an “enlarged” image? Please answer either magnified or enlarged or, perhaps, both).
In this particular case, a non-photographic case, may the terms “magnified” and “enlarged” be used interchangeably or are they mutually exclusive? Please answer interchangeably or mutually exclusive.
Thank you.

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Last edited by RayGunn; 04-09-2012 at 03:15 PM. Reason: clarification

[baro-nite]

an accurate technical definition is useless when 90 % + of people use the word differently.

No, it is still accurate, and 10% of people use it correctly so it isn't useless. All specialists have their technical jargon and it is generally opaque to outsiders. Shouldn't be used to an outside audience without explanation, and even then one should avoid jargon as far as possible.

To the OP, in photography and particularly macro photography, magnification means image size at the sensor. (Some say "reproduction ratio" instead.) It's a simple standard for expressing the relationship between subject size and image size. It is, however, non-intuitive to outsiders, who naturally expect magnification to refer to the size of the image as viewed on a screen or a print.

I see an image of the stamp ‘in’ the magnifying glass.

Well, I'd say you aren't seeing an image (except insofar as all seeing is images, on the retina and in the mind). You're seeing light reflected from the actual object and refracted through a lens. But at no point before it reaches your eyes is this light projected onto a surface that I would call an image.

[riff]

Magnification - Wikipedia, the free encyclopedia

Magnification is the process of enlarging something only in appearance, not in physical size.

[Philoslothical]

Sorry my questions were so difficult to understand , so let me try a restatement.
... please answer my questions, using my examples, the first of which is:
Example 1: I have a postage stamp on my desk top. I take a magnifying glass out of my desk drawer to more closely examine the postage stamp. When I look through the magnifying glass at the postage stamp, I SEE (not capture) an image of the stamp ‘in’ the magnifying glass. This image appears to be larger than when I look at the stamp with only my naked eye.
Questions re: Example 1: Is this larger, non-captured (photographically) image a “magnified” image or is it an “enlarged” image? Please answer either magnified or enlarged or, perhaps, both).
In this particular case, a non-photographic case, may the terms “magnified” and “enlarged” be used interchangeably or are they mutually exclusive? Please answer interchangeably or mutually exclusive.
Thank you.

The magnifying glass in your question is analogous to the macro lens. The strength of the magnifying glass in dioptres determines how magnified the image appears. The important point to take away from this is that you're using the magnifying glass to magnify the subject, so you can see smaller detail on it. If you were to hold that magnifying glass in front of a printed picture of the subject, you're only magnifying the ink dots of the print - that's analogous to enlargement that you do in your graphics editor.