On macrophotography and "1:1" image magnifcation

[Doug Kerr]

As an "aside" in a recent thread, I reminded us that the notion that an image magnification of "1:1" as the criterion of "true macro performance" of a lens* is not all that meaningful.

*We note here that it is of course not actually the lens properties alone that determine the magnification, but rather the properties of the whole camera "setup" The lens, in our sock drawer, has no maximum image magnification.​

Here is a "grab shot" of an SR626SW watch battery I happened to have laying on my desk, taken with my Panasonic Lumix FZ1000 camera (with its "permanent" lens) in its greatest image magnification state:

Douglas A. Kerr: SR626SW watch battery​

Note that no attention whatsoever was given to the lighting!

The battery has a diameter of approximately 6.80 mm. On the sensor, its image had an approximate diameter of 3.86 mm. Thus the approximate image magnification was 0.36 ("1:2.78").

The sensor size of that camera is 13.2 mm × 8.8 mm.​

If the point of a photograph of this object was just to document the face of the battery, in the highest available resolution, it might have been desirable for the setup to have yielded a magnification of perhaps 1.18 ("1.18:1"). That would have made the image 8.0 mm diameter, snugly almost filling the 8.8 mm high frame.

But of course I could have cropped the existing image:

Douglas A. Kerr: SR626SW watch battery​

Now suppose I had instead shot this battery with a camera with a full-frame 35-mm sensor size (36 mm × 24 mm). Then to make the image of the battery fill that same fraction of the frame height (so as to make best use of the available resolution) would require a setup with an image magnification of 3.20 ("3.20:1").

Woof! Get out the extension tubes

So what image magnification do I need to take a "macro" photo of that battery?

Hmmm.

Best regards,

Doug

 

[Asher Kelman]

As an "aside" in a recent thread, I reminded us that the notion that an image magnification of "1:1" as the criterion of "true macro performance" of a lens* is not all that meaningful.

.......We note here that it is of course not actually the lens properties alone that determine the magnification, but rather the properties of the whole camera "setup"...........

Hmmm.

Doug,

Ignore the camera. Magnification is merely a property of the lens. It doesn't change with sensor size! All the sensor does is receive some or all of the image in the focal plane!

Asher

 

[Doug Kerr]

Hi, Asher,

Doug,

Ignore the camera. Magnification is merely a property of the lens. It doesn't change with sensor size! All the sensor does is receive some or all of the image in the focal plane!

No, it does not change with sensor size - I never suggested that it does.

But it is determined by the lens and how it is fit to some body. For example, the maximum magnification of a certain Canon lens on a Canon 80D body depends on whether the lens is mounted directly to the body or by way of an extension tube. The lens, body, and (if present) extension tube constitute the camera - that's what I meant. (Perhaps I was not clear enough about my meaning.)

We note that the maximum magnification of a view camera depends on the focal length of the lens and the available extension of the bellows - that is, it is a property of the camera (which comprises the "body", the lens, and the bellows). Thus we cannot say what is the maximum magnification of a certain view camera lens of itself.

Of course the magnification of a camera equipped with a certain lens is a function of the distance to the subject. The maximum magnification then depends on the minimum distance at which the camera (with that lens aboard) is able to focus. (Whcih is why I am always careful to say "maximum magnification" when that is what I mean.)

Of course, when we say that the maximum magnification of a certain Canon lens is so-and-so, we mean when it is mounted on a body for which it is intended and without any further apparatus such as an extension tube. That is a reasonable practice. But the simplicity of that can misdirect us from all the factors that are really at play.

For example, the maximum magnification reported for my Canon FD 50 mm macro lens (which is based on the assumption that it will be mounted on an FD-mount body) will not obtain if I mount it in the only way I can (with an adapter) on an EOS body. In other words, the maximum magnification of that lens is not solely a property of the lens. (It will in fact be greater than "stated" when on the EOS body.)

Thanks for your observations.

Best regards,

Doug

 

[Asher Kelman]

Doug,

It is much simpler for me to consider that magnification only depends on the lens. If it has an extension added to it, then "that" is now the modified lens and can be moved to any camera. All one has to do is to get the focal plane of that lens to coincide with the film or sensor plane. Size of the latter does not figure into this at all, the magnification will remain the same.

?

Asher

 

[Doug Kerr]

Hi, Asher,

It is much simpler for me to consider that magnification only depends on the lens. If it has an extension added to it, then "that" is now the modified lens and can be moved to any camera. All one has to do is to get the focal plane of that lens to coincide with the film or sensor plane. Size of the latter does not figure into this at all, the magnification will remain the same.

Sure.

Best regards,

Doug

 

[Asher Kelman]

Hi, Asher,



Sure.

Doug,

"Sure"?

You can't give in that easily. Did I exasperate you! There must still be conditions and exceptions that are significant!

Asher

 

[Tom dinning]

Doug,

"Sure"?

You can't give in that easily. Did I exasperate you! There must still be conditions and exceptions that are significant!

Asher

Asher, you should know better.

When Doug feels a lack of understanding with us of lower intellect, he simply responds with: "sure".

In other words, there is no point in discussing further.

I'm still coming to grips with memories of Grade 9 physics when the professor, a Doug like character called Mr Baldwin, would elaborate on the complexities of lens geometry and wonder why we were more interested in the view through the window ( a cluster of secretary students heading for the local college).

Now, bow nicely to the gentleman, admit your defeat and move to something less mathematical before you are reduced to a set containing nothing at all.

 

[fahim mohammed]

Tom, Asher, Fahim....

Perhaps the following would be more useful. A photographer I admire, a reviewer I respect, and a teacher who can relate to the real world of photographers.

Show and teach

 

[Tom Robbins]

Does anyone recall the wild early days of digital when lots people were just getting their photography feet wet? I especially remember the DPReview forums where it was a good idea to put on a helmet and pads before entering. Remarkably inventive ideas about focal length, depth of field, and such were freely offered. Those who knew the scoop would sometimes try to enlighten the masses only to eventually give it up as a hopeless task.

Not sure what brought this memory back, maybe it was Doug's comment about the sock drawer.

 

[Doug Kerr]

Hi, Asher,

Doug,

"Sure"?

You can't give in that easily. Did I exasperate you! There must still be conditions and exceptions that are significant!

If we consider "system" lenses (e.g., Canon EF mount lenses, Sony E-mount lenses, etc.), then your outlook is apt.

I will assume that by "focal plane of the lens" you mean what I would more rigorously (and tediously) describe as "the plane, considered with respect to the lens, where we expect the focal plane of the camera to be when the lens is mounted." (In the case of a Canon EF-mount lens, that would be 44.0 mm to the rear of the register surface of the mount flange; for an MFT lens, 19.25 mm.)​

My comment with which you took exception was intended to generalize my discussion to also work for the view camera paradigm. If we have a view camera lens "in hand" (perhaps even mounted on a lens board), it does not have such a plane defined. We do not expect that when it is mounted, the focal plane of the camera will be at a certain place measured with respect to some place on the lens, or lens board. In fact that distance changes as we, by moving the front standard of the camera and the lens with it, change the focus distance of the camera.

And, if we consider a certain view camera lens, of itself, it does not have a certain maximum image magnification.

But once that certain lens is mounted on a certain camera, on which the front standard can be moved forward only to a certain place (a certain "bellows extension"), then we do have a certain maximum image magnification.

Although you allude to this in your comments, I did not say, and certainly did not mean to suggest, that for a certain lens the maximum image magnification depends on the sensor size. You are quite right that it does not.

My point was wholly this:

While we may speak of an image magnification of 1:1 as being the pivotal (if arbitrary) criterion of "real macrophotography", it really is no such thing.

Most commonly, in macrophotography, our interest is in having the image of some particular object occupy some desired portion of the frame. The image magnification required to achieve that goal depends both on the size of the object itself and the frame size of the camera.

On a full-frame 35-mm sensor size camera, an image magnification of 1:1 will allow us to fill, for example, about 75% of the frame height with a United States dime coin. On an MFT camera, a lesser image magnification of 1:1.8 is needed to do the same thing.

Now, is the ff35 camera performing "real" macrophotography, and the MFT camera not?

And consider an 8" × 10" view camera, set for 1:1 image magnification, taking a shot of a ladies' shoe in which the image "well fills" the frame. Is it performing "real macrophotography"?

Best regards,

Doug

 

[Doug Kerr]

Hi, Fahim,

Tom, Asher, Fahim....

Perhaps the following would be more useful. A photographer I admire, a reviewer I respect, and a teacher who can relate to the real world of photographers.

Show and teach

Very nice piece. Beautiful work. Thanks for commending it to us

Of course, you will realize that I find this passage:

"Simply, macro refers to 1:1 or greater magnification . . ."​

to be "problematical".

He is of course absolutely correct that this is an "accepted definition". I just find it not particularly good.

Again, taking an extreme but presumably included case, I find it hard to think of what an 8" × 10" view camera, arranged for 1:1 magnification, does as being "macrophotography". (Recall that we, in an interesting perversion of the etymology, before we get into technical ratios, use "macrophotography" to mean "the photography of small objects").

Perhaps we should say that "Macrophotography is photography with an image magnification of 1:1 or greater by a camera that is not really big".

Best regards,

Doug

 

[Doug Kerr]

It may be instructive in this matter to consider what we mean by the term "macrophotography" - not in terms of some arbitrary criterion of image magnification but in terms of an actual genre of photographic tasks.

We use the term to refer to the photography of "small" objects - coins, rings, watches, mechanism parts, insects. Of course there is no criterion for what constitutes a "small" object. A bearing jewel from a watch movement probably is, and a battleship probably isn't.

The term itself is paradoxical, since its root - "macro" - means "large". This curiosity has a simple, but perverse, explanation.

Scientists often characterize an object as being either "microscopic" (meaning, essentially, so small that it cannot be seen effectively by the "naked eye", but rather requires seeing through an instrument called a microscope, "micro" meaning "very small") or "macroscopic" (meaning, essentially "large enough to be seen effectively by the named eye", "macro" meaning "large".) Yes, a battleship is a macroscopic object.

The parallelism with "microscopic" suggests that we have to see them through a macroscope, but of course it doesn't really mean that.​

An interesting branch of photography is the photography of "microscopic" objects. This essentially means taking a photograph with a camera through a microscope. This is called micro-photography (or in some cases, to recognize that the optical heavy lifting here is done by a microscope, photo-microscopy).

Now suppose we move on to work with a somewhat larger object, one that is no longer microscopic but rather macroscopic. This now, sensibly, becomes "macrophotography". But by custom, we do not apply that term when the object becomes "actually big" (like a breadbox, or a battleship). We limit the term to things that are "bigger than microscopic but not a lot bigger". Said in the other direction, we use the term to mean "the photography of small objects, but not so small that they must be photographed through a microscope".

Wonderful!

Best regards,

Doug

 

[Doug Kerr]

Finally, hopefully to clarify my point, let's assume that our task is to take a high-resolution film image of a US dime coin. We will do this with an 8" × 10" format film camera.

Since this certainly sounds like macrophotography, we will plan to arrange for our camera to have an image magnification of 1:1 (using a lens whose aberration corrections work well in that situation, an aspect of "macro" lenses I had not previously mentioned).

We take the shot, and find that the image of the dime is about 18 mm in diameter, or only about 9% of the 8" dimension of the film frame.

Well, that's hardly what we set out to do. But where did we go wrong? Gee, we arranged for an image magnification of 1:1, said to be the minimum needed to do macrophotography.

Best regards,

Doug

 

[fahim mohammed]

To be honest Doug, I do not know what you are trying to explain. More importantly, why?

Are you questioning the terminology used in this particular type of photography?

Or are you suggesting that Nikon should rename their Micro-Nikkor lenses?

I do not understand what need made you start this thread?

Take care.

p.s And would it make a difference to my photography with the 60mm Micro-Nikkor?

 

[Doug Kerr]

Hi, Fahim,

To be honest Doug, I do not know what you are trying to explain. More importantly, why?

Are you questioning the terminology used in this particular type of photography?

Or are you suggesting that Nikon should rename their Micro-Nikkor lenses?

I do not understand what need made you start this thread?

Sure.

Best regards,

Doug

 

[Doug Kerr]

We often think of the photography of coins as an example of macrophotography.

Here is a "grab shot" of a US dime coin, taken with my trusty Panasonic FZ1000:

Douglas A. Kerr: US dime coin, shot with Panasonic Lumix DMC-FZ1000​

As before this was a very "agricultural" shot, with no attention paid to lighting.

I framed it so as to take the best reasonable advantage of the camera resolution.

Now, what image magnification was in effect for this shot? Well, a little reverse engineering shows that the image magnification was about 1:2.6. Not even near 1:1.

Wow! This was not macrophotography at all!

Well, suppose I borrow a nice full-frame 35-mm size sensor camera, equipped with a nice "macro" lens capable of giving an image magnification of up to 1.1:1. I take a shot of the coin, adjusting things to get the same framing as above. The image would look about like this (a simulated image, of course):

Douglas A. Kerr: US dime coin, simulated shot with full-frame 35-mm sensor camera​

Well, what image magnification was in effect for this hypothetical shot? Again a little reverse engineering shows that the image magnification would have been about 1.04:1.

Great! A real macrophotographic shot this time.

How curious that the second image constitutes macrophotography, but the first image doesn't!

Best regards,

Doug

 

[Doug Kerr]

Hi, Fahim,

To be honest Doug, I do not know what you are trying to explain.

I'm sorry that my didactic capabilities are not up to the task.

More importantly, why?

If I told you why, what would you do with that information?

Are you questioning the terminology used in this particular type of photography?

I am pointing out that the notion that macrophotography only occurs when the image magnification is 1:1 or greater is a silly notion.

Or are you suggesting that Nikon should rename their Micro-Nikkor lenses?

No.

I do not understand what need made you start this thread?

I understand.

Best regards,

Doug

 

[Michael Nagel]

Time to add some practical aspects to all this theory.

You will find dedicated macro lenses for film/sensor formats from MF to smaller formats - where it makes sense.

And consider an 8" × 10" view camera, set for 1:1 image magnification, taking a shot of a ladies' shoe in which the image "well fills" the frame. Is it performing "real macrophotography"?

No idea where this narrow definition leaped at you. The macro definition is pretty fuzzy. There is a definition that says that macro covers all from an image magnification of the lens of 1:10 to 1:1 or even 2:1 - anything with greater magnification of the lens would be considered as micro-photography (not to be confused with photomicrography). There are many other definitions with varying limits.

Now, what image magnification was in effect for this shot? Well, a little reverse engineering shows that the image magnification was about 1:2.6. Not even near 1:1.

The value of 1:2.6 would be within the above noted definition.

And consider an 8" × 10" view camera, set for 1:1 image magnification, taking a shot of a ladies' shoe in which the image "well fills" the frame. Is it performing "real macro-photography"?

Did you consider to check the DOF possible in this configuration - would it be practical at focal lengths providing a normal angle of view?

Douglas A. Kerr: US dime coin, shot with Panasonic Lumix DMC-FZ1000

Douglas A. Kerr: US dime coin, simulated shot with full-frame 35-mm sensor camera​

Not very precise - did you consider the aspect of equivalence here - it is also valid for macro photography.

Ignore the camera. Magnification is merely a property of the lens. It doesn't change with sensor size! All the sensor does is receive some or all of the image in the focal plane!

Starting with the lens magnification is - from a practical point of view - a good start to get quickly to a complete view. Adding the sensor size, focal length, distances (object and sensor to lens) and f-stop will complete the picture (literally and metaphorically).

The overwhelming part of macro-photography is done at film/sensor sizes ranging from Kleinbild to mFT - where the 1:1 criterion makes more than just a little sense.

Best regards,
Michael

 

[Doug Kerr]

Hi, Michael,

No idea where this narrow definition leaped at you.

Please see below.

The macro definition is pretty fuzzy. There is a definition that says that macro covers all from an image magnification of the lens of 1:10 to 1:1 or even 2:1 - anything with greater magnification of the lens would be considered as micro-photography (not to be confused with photomicrography). There are many other definitions with varying limits.

Well, and of course that all makes sense.

But, as I said at the outset of this thread, I was speaking of the widely-cited definition that macrophotography occurs for an image magnification of 1:1 or greater as an absolute criterion. (Note for example the stating of this in that lovely paper cited in this thread by Fahim.)

The overwhelming part of macro-photography is done at film/sensor sizes ranging from Kleinbild to mFT - where the 1:1 criterion makes more than just a little sense.

Indeed. Although the "1:1 or greater" criterion is arbitrary, we have many other arbitrary"cutoff" definitions - for example, what format sizes constitute "medium format" and what ones constitute "large format". And I suspect the "1:1" criterion was first "adopted" in the context of the Klenibild format (as for many conventions, including the matter of defining the magnification of a TTL viewfinder with a 50 mm lens aboard).

What concerns me is the carrying forward of that "criterion" to substantially different format sizes, so that its implication is substantially inconsistent.

For example, if we take a photograph of an object 22 mm in diameter on a Kleinbild-format camera and it fills the (short dimension) of the frame, then we meet the "1:1 or greater" criterion.

But if we take a photograph of an object 22 mm in diameter on an mFT camera and it fills the (short dimension) of the frame, then we aren't even close to meeting that criterion. And that doesn't make sense to me.

Perhaps we would be better off to say that macrophotography occurs when we can fill the frame "height" (short dimension) with an object of diameter 24 mm or less.

Thanks for chiming in.

Best regards,

Doug

 

[Doug Kerr]

Mea Culpa

My sincere apologies to those here whom I may have insulted, offended, irritated, challenged, confounded, or awakened from a nap in the course of my Quixotic quest into the dark land of what is and is not "macrophotography".

I should know better than to poke in the eye a notion that has evidently well served the Crown lo these many years.

I shall return to (privately) studying the behavior of a camera that some feel is, and some feel is not, truly parafancratic.

Best regards,

Doug

 

[Tom dinning]

Mea Culpa

My sincere apologies to those here whom I may have insulted, offended, irritated, challenged, confounded, or awakened from a nap in the course of my Quixotic quest into the dark land of what is and is not "macrophotography".

I should know better than to poke in the eye a notion that has evidently well served the Crown lo these many years.

I shall return to (privately) studying the behavior of a camera that some feel is, and some feel is not, truly parafancratic.

Best regards,

Doug

What the FUK is parafancratic?

 

[fahim mohammed]

Don't get him going again,Tom. Please.

What the FUK is parafancratic?

 

[Asher Kelman]

I myself have been puzzled by nomenclature. There is inherent value in checking what we mean in our common terminology and this is the correct section for doing so.

Re-reading it as often as you want, won't generate actual pictures. That is not the O.P.'s purpose or interest. It is what it is and nothing more.

This thread is being paused.

Asher