What does a lens’s maximum reproduction ratio mean?
Asked 7/23/2012
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A lens review says: “Minimum focusing distance 20cm and maximum reproduction ratio 1:7.4.” What does maximum reproduction ratio mean, and what does 1:7.4 tell you in practical use?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
14y ago
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The reproduction ratio means the largest that you can make a subject on the film/sensor compared to its real-life size. In the case of your lens, it means that the image on the film plane will be 1/7.4, or 5/37 of the actual size of the object when it is as close as you can possibly focus the lens.
If your camera has a full-frame (24x36mm), an object would have to be at least 177.6mm by 266.4mm to completely fill the frame using that lens at its closest focusing distance. A Nikon/Sony/Pentax APS-C (DX) sensor would be filled with an object 118.4mm x 177.6mm; a Canon APS-C would be filled with an object 111mm x 166.5mm. In this case, on a μ4/3 camera, that reproduction ratio will fill the frame with an object 99.9mm by 133.2mm.
A lens of this class is rarely used for extreme close-up or macro work due to the very small working distance between the lens and the subject, even if it could be made to focus more closely. (You can, however, achieve very high magnifications with short-focal-length lenses like this one by mounting them reversed on the camera using a special adapter, with or without extension tubes or bellows.) The lens can be considered a "short normal" or a "moderate wide angle", depending on who you ask, and is intended for general photography. In larger formats (35mm, medium and large format), a "normal" lens can often be pressed into macro service, but the "normal" focal length of the 4/3-sensor world means that the lens-to-subject distance gets very small, and keeping the camera from shadowing the subject becomes difficult.
Macro photography is a term used to describe reproduction ratios at or around 1:1. That is, the image on the camera's film/sensor approximates the actual size of the object. Lenses labeled "macro" usually have a reproduction ration of at least 1:4; many photographers wouldn't consider a lens to be a "true macro" unless it goes to at least life size (1:1). Microphotography refers to reproduction ratios significantly greater than 1:1 (the old definition used to start at 10:1; I don't know what the standard is today).
Originally by user2719. Source · Licensed CC BY-SA 4.0
user2719
14y ago
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Generated from our catalog & community — verify before relying on it.
Maximum reproduction ratio is the largest size a subject can be recorded on the sensor compared with its real-world size, usually when focused at the lens’s minimum focus distance.
A ratio of 1:7.4 means the image on the sensor is 1/7.4 of the subject’s actual size. So if your subject is 74mm wide, it would appear about 10mm wide on the sensor.
Practically, it tells you how much close-up ability the lens has. The closer the ratio is to 1:1, the better the lens is for close-up or macro work. A 1:7.4 ratio is fairly modest, so this lens is not a true macro lens.
Another way to think about it: at its closest focus distance, the smallest object that can fill the frame is still relatively large. On a full-frame camera, it would be roughly 178 × 266mm. On smaller sensors, the frame-filling subject would be somewhat smaller, but still not tiny.
So in everyday terms, 1:7.4 means the lens can focus fairly close, but it won’t give strong magnification for small subjects like insects or jewelry.
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