When does close focus become macro?

chuckmiller wrote in post #19557082
...I will simply hold a greeting card at the MFD and measure how much of it is viewable.

Done. At MFD (about 5 inches from the front element) the FOV is about 1 3/8 inches wide.
(FF 5D4 body, 100mm f/2.8L IS USM lens)

chuckmiller wrote in post #19557205
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Done. At MFD (about 5 inches from the front element) the FOV is about 1 3/8 inches wide.
(FF 5D4 body, 100mm f/2.8L IS USM lens)
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So then you compare the 1 3/8 inches to the length of your sensor and if they are equal then you are getting true macro capability from your lens.


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gjl711 wrote in post #19557203
I don't know why y'all are dragging sensor resolution into a lens discussion. This has to be from the perspective of the lens alone. Any lens can have tubes, multipliers, or converters on it or you can crop the heck out of the picture so that the final print is the same size as the real object but that defeats the whole point of a macro lens. A macro lens has to be a lens that delivers a 1:1 image circle without modifications, irrespective of what sensor you stick in to. That's my story and I'm sticking to it.

The old (obsolete) definition would say that xeroxing is macro photography, which it is not. At the other end of the scale, there are more and more photographers doing good bug photography with their phones. They are at maybe 1/5 life size and to me it is macro, because the final result on the monitor looks just like macro achieved at 1:1 with 35mm gear.

What I'm suggesting is that macro has to do with how the subject appears. Macro should be defined in terms of field size at the subject plane, not in terms of magnification.

So if you fill the frame with a 1" grasshopper, it is macro to me, regardless of the gear that took it.

I still agree that a macro lens should be capable of 1:1 photography.

Per the Canon website:


Macro lens
What is a Macro Lens?

The Basics:
A Macro Lens is specifically designed for close-up photography. Macro lenses have a higher photographic magnification and maintain high image quality during magnification. They have shorter minimal focusing distances. Different Macro lens deliver magnification factors of 0.5x – 5x.

chuckmiller wrote in post #19557205
Done. At MFD (about 5 inches from the front element) the FOV is about 1 3/8 inches wide.
(FF 5D4 body, 100mm f/2.8L IS USM lens)

A lot easier to just have a ruler in the frame and sees how many mm wide the FOV is at MFD in mm (just take a photo with the ruler in the frame).

A full frame sensor’s active area is 36mm on the long side, or 1.4173… inches (1 and 3.339 eights of an inch).

Tom Reichner wrote in post #19557207
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So then you compare the 1 3/8 inches to the length of your sensor and if they are equal then you are getting true macro capability from your lens.

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Boom. You nailed it. My measurements are handheld and rough. 36mm = 1.417 inches.

Bob_A wrote in post #19557215
A lot easier to just have a ruler in the frame and sees how many mm wide the FOV is at MFD in mm (just take a photo with the ruler in the frame).

TRUE!!

chuckmiller wrote in post #19556897
What defines this as a macro lens?

Archibald wrote in post #19557211
The old (obsolete) definition would say that xeroxing is macro photography, which it is not. At the other end of the scale, there are more and more photographers doing good bug photography with their phones. They are at maybe 1/5 life size and to me it is macro, because the final result on the monitor looks just like macro achieved at 1:1 with 35mm gear.

What I'm suggesting is that macro has to do with how the subject appears. Macro should be defined in terms of field size at the subject plane, not in terms of magnification.

So if you fill the frame with a 1" grasshopper, it is macro to me, regardless of the gear that took it.

I still agree that a macro lens should be capable of 1:1 photography.

All very true, but it does not answer the OP question. If the output is judged, than every lens is a macro lens irrespective of magnification factor as you can simply crop out the portion you want and blow it up or print bigger. Nearly every billboard, big screen tv, large poster are macro because the subject is larger than the original, no? As I said in the previous post, a macro lens has to be judged on it's image ciscle without taking the sensor into consideration.

chuckmiller wrote in post #19556897
What defines this as a macro lens?

'Macrophotography' by strict definition of the past is 1:1 and greater (where 'microphotography' was => 20:1). The term started to get loosened to also refer to 1:2, but in the late 1960's manufacturers of lenses started to get truly non-traditional in labeling lenses with close-focus capability (closer than about 9*FL for its MFD) as 'macro'

The reference to 1:1 means that REGARDLESS OF FILM / SENSOR SIZE, the image is 'lifesize' at the film plane...a 10 x 10mm object (real size) would be 10mm x 10mm image area on 4/3 format, 135 format, 6x6 format, 4x5 format, or 8x10 format.

And macro DOF is identical -- for same magnification images -- regardless of format it was captured with.

To me you're kind of trying to argue two sides here. You point out how the reproduction ratio is becoming meaningless, and then go on to push for that as an enduring standard.

To me, filling a 24MP APS-C frame with an image is exactly the same as filling a 24MP FF with it from a "What is macro?" point of view. Same pixel output; I see no practical benefit to saying one is macro and one isn't. Lenses are part of camera systems that work together. There may be image quality and other differences, but nothing that affect macro-ness.

Canon seems to blend reproduction ratio and MFD into their definition of macro, which is probably more useful in the real world.

gjl711 wrote in post #19557224
All very true, but it does not answer the OP question. If the output is judged, than every lens is a macro lens irrespective of magnification factor as you can simply crop out the portion you want and blow it up or print bigger. Nearly every billboard, big screen tv, large poster are macro because the subject is larger than the original, no? As I said in the previous post, a macro lens has to be judged on it's image ciscle without taking the sensor into consideration.

Anton, I think you missed the point gjl711 made:

"As I said in the previous post, a macro lens has to be judged on it's image ciscle (sic) without taking the sensor into consideration."

IOW it is NOT the output size, but the capture size at the focal plane, regardless of sensor size.

Basically in macro, you shoot close and emulate other macro shooters. Forget about magnification, format size, and so on. Focus accurately and make impressive closeup shots.

AntonLargiader wrote in post #19557243
To me you're kind of trying to argue two sides here. You point out how the reproduction ratio is becoming meaningless, and then go on to push for that as an enduring standard.

To me, filling a 24MP APS-C frame with an image is exactly the same as filling a 24MP FF with it from a "What is macro?" point of view. Same pixel output; I see no practical benefit to saying one is macro and one isn't. Lenses are part of camera systems that work together. There may be image quality and other differences, but nothing that affect macro-ness.

Canon seems to blend reproduction ratio and MFD into their definition of macro, which is probably more useful in the real world.

I am not arguing, just trying to point out that using the final output to judge whether a lens is macro or not is meaningless. When looking at the lens, all that matters is the image at the focal plane. If it's the same size at the focal plane as the subject, it's a macro lens.

What I was trying to show (I'm guessing poorly) is that if you take camera, modifiers, and post processing, one can call the image macro and by inference, every lens a macro lens, but the lens is not. Another example, the two images below. One is the full image. It's about 127mm edge to edge. If I crop out a section 24mmx36mm, the image might be macro, but the lens is not. BTW, this was taken with the 100-400mm lens at MFD.

I think what many are arguing is that the term macro has become ambiguous and one can call just about any lens a macro lens if they figure out a decent marketing reason. Many if not most macro lenses out there are not capable of delivering a true 1:1 but something close but the manufacturer still calls it a macro lens.

Archibald wrote in post #19557260
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Macro should be defined in terms of field size at the subject plane, not in terms of magnification.
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I do not understand what that means. . What do you mean by the phrase "field size". . I have never seen that term before, in any photographic context.
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Archibald wrote in post #19557260
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Basically in macro, you shoot close and emulate other macro shooters. Forget about magnification, format size, and so on. Focus accurately and make impressive closeup shots.
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What then do you use as an absolute and unvarying cutoff point to determine precisely what qualities as macro and what does not? . What is your absolute and measurable standard that you use so that the term is never subjective?


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Tom Reichner wrote in post #19557471
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I do not understand what that means. . What do you mean by the phrase "field size". . I have never seen that term before, in any photographic context.
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What then do you use as an absolute and unvarying cutoff point to determine precisely what qualities as macro and what does not? . What is your absolute and measurable standard that you use so that the term is never subjective?

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"Field size" is the size of what is in the viewfinder at the subject focal plane.

There is no precise definition of macro other than >1x.