Schoee Loc: Europe

I understand if I use a macro lens and get a 1:1 image on the sensor then a one inch long item will be one inch on the sensor. If we assume my crop sensor is one inch by 2/3 of an inch (that is pretty close to the actual size) and the resolution is 6000 x 4000 then the one inch long item occupies 6000 pixels.
Now if I print at 300 ppi the printout of the whole sensor area will be 20 inches long side by 13 and a 1/3 the short side.
Do you say that the image on my printout is at 20 times magnification or 400 times?
A one inch line will be 20 inches long but if we consider a little rectangle that would cover the sensor (1 x 2/3 inches) it could now be placed on the printout 400 times (20 rows of 20).
In a similar vein when someone says they are using a 5x lens for macro does that mean a line is reproduced 5 times as long as real life on the sensor or the square root of 5 times as long (approx 2.24 times the real length).

bleirer

I believe magnification is something the lens does, independent of the sensor or print size. A one inch object in the world at 1x or 1:1 would still be the same 1 inch on a half inch sensor or a quarter inch sensor or any size sensor. it would just appear cropped and you wouldn't see all of the one inch.

I was a little confused by your print example but I think in your example it you could print at 6000 pixels per inch it would be a 1 inch print.

User ID

Stick with one dimension. 20x20 does equal 400 but that is an area measurement. You want linear measurement if you want to state magnification.

Back to your original idea of a 1 inch object being 6000 pixels long on the sensor at 1:1. YES !!! “... pixels long ...”. “Long” is a linear measure.

Back the camera away from the subject so the image of the object is only 2000 pixels long. Now you’re at 1:3 and NOT 1:9 even though you can gather 9 of those 1 inch subjects together in a 3x3 array and photograph all 9 in a single frame.

At 1:3, total AREA of the frame contains 9 such objects but each object is rendered only 1/3 as LONG as the frame and thus 1/3 as long as the real object. (In this case the real object and the sensor are both 1” long.)

Repeating:
Magnification (and reduction) ratios are LINEAR, meaning “one dimensional”.

Schoee Loc: Europe

Thanks, that clarifies it.

sippyjug104 Loc: Missouri

Regarding macro...and micro, the magnification is considered to the the ratio of the image on the camera sensor to that of the real size of the subject.

A typical macro lens is considered to be a 1 to 1 ratio which means that whatever size the area is viewed of the subject that it is projected to occupy the same size area on the sensor. When we move up to a 5X (five times magnification) the size of the subject viewed is projected to five times that size on the cameras sensor.

Magnification can be accomplished in several ways such as a lens designed to produce it including using microscope objectives as the camera's lens, extending the focal length by using extension tubes, bellows or a helicoid, reversing the lens, or adding magnifying accessory lenses on to the camera lens are all some of the most common methods.

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