Since, in most cases (unless you are using a microscope), the lens shrinks the object, the magnification value is less than 1.

If you'd like to know more, try our others optic calculators dedicated to lenses, like the thin lens equation calculator or the lens maker equation calculator.

Convexlens magnification

Lenses can focus or "unfocus" light rays. In this tool, we will only consider converging lenses. Their main feature is the ability to focus every ray entering the lens parallel to the optical axis at a specific point, the focus.

In photography, the magnification of a lens is the ratio between the height of the image projected onto the sensor or film of the camera and the height of the real image you are taking a picture of.

When you are snapping a picture, you don't usually know the values of hhh and ggg, but you know the focal length for sure, and you likely know the distance between you and your subject. These two quantities are enough for you to calculate the magnification of your lens!

Magnificationformula for convexlens

A camera is nothing but lenses and a sensor. At least in theory! To understand how it works, we need to explore the world of optics.

Our lens magnification calculator will focus on the world of lenses in photography, finally explaining what magnification is, why it is different from zoom, and much more!

Expand the further magnification properties section to see the variable extension tube. We set it at 0 mm0\ \text{mm}0 mm by default, but change it according to your needs!

Magnificationof convexlensis positive or negative

The perceived magnification of an object, thanks to the use of powerful telephoto lenses, comes from the reduced projection of the object onto relatively small sensors. If that projected image can change the size, let's say by a factor of two, we say that the lens has a 2× zoom.

Since that beast would be too dangerous to photograph at a close distance, we suggest you use a 500 mm500\ \text{mm}500 mm telephoto lens. We advise you to keep your distance, let's say 150 meters (but remember that a kangaroo can reach a maximum speed of 70 m/s70\ \text{m/s}70 m/s). Insert these values into our magnification of a lens calculator, which will return:

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Their lenses are usually manufactured with a focal length of 25 cm25\ \text{cm}25 cm. If you use the lens to look at an object closer to it than that distance, you create a virtual image of the object.

🔎 Lenses and their properties have been known by humanity for a long time. However, only in the 13ᵗʰ century did lens-making skills reach a level of refinement that allowed for the construction of glasses, telescopes, and much more!

Magnificationformula for concave mirror

As you can see, now the rays on the right side of the lens do not converge. We are dealing in terms of virtual images, which originate from the virtual continuations of the rays, creating a non reversed image of the object.

However, when talking cameras, the magnification is usually a really small number. The number followed by a ×\times× is the zoom.

The zoom describes how much the lens's focal length can change by (there are such things as zoom lenses). A typical 18/5518/5518/55 lens will have its zoom defined by:

The magnification of a lens is an absolute value that depends on the focal length of the lens itself, while the zoom is a relative quantity that describes how much you can change the focal length of a lens by, thus changing its magnification.

In the case of violent kangaroos, it may be better to go for the second option: that's why camera manufacturers sell extension tubes, short rings to mount between the lens and the body, which end up increasing hhh by some precious millimeters.

Magnificationformula Biology

Now consider that the sensor is at most a few centimeters wide, while you can take a picture of the Eiffel Tower, which is 330 m330\ \text{m}330 m tall. Even from afar and with a powerful telephoto lens, you'll always get a magnification that is much smaller than you expect when taking pictures with a camera.

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First thing – the upward facing arrow on the left of the image is the object we are looking at. The rays of light coming from it hit the lens. The one parallel to the optic axis (the topmost line) gets focused and so converges on the focus. The ray passing through the center of the lens meets the focused ray on the other side of the lens, which creates a flipped image called the real image of the object.

Imagine you are taking a picture of a huge kangaroo, let's say two meters tall and weighing 95 kg95\ \text{kg}95 kg, like the one that terrorized Brisbane a few years ago.

A dielectric coating consisting of alternating layers of quarter-wave film of a higher refractive index and lower refractive index than the substrate.Such coatings can be made very specific to a reflected wavelength or,by varying the layers’ thickness or film indexes,spread over a wide wavelength interval including high reflection coating(HR) and partial reflective coating(PR).

Magnificationof convex mirror

Magnificationformula forlensin terms of focal length

The magnification of a lens is an absolute measure of how much the height of a real image differs from the object's height. Remember, that in a camera, the real image forms on the sensor (or on the film, if you're old school).

A lens is a device made of a material with a different refraction index to air (there can even be electromagnetic lenses that act on electric currents). This and its shape allows it to bend rays of light as they come into contact with it.

The magnification of a lens with focal length 55 mm at a distance of 100 m is m = 0.0005506. To calculate it, follow the steps:

Formula formagnificationof mirror

The values of hhh and ggg are hidden in the further magnification properties section of our calculator, so if you need to know either of these, just click the button!

🔎 The word "focus" comes from Latin for "fireplace". This is because the Romans believed that their ancestral gods were located in the fireplace, or hearth, and so would direct (or focus) their worship towards it.

Thanks to the properties of similar triangles, we can compute the magnification of a lens also using the distances between the object/image and the lens:

Maybe you expected the magnification to be a bigger number, something like 10×10\times10× or 20×20\times20×, like the values you see on binoculars or telescopes (we made an entire calculator for that, check out our telescope magnification calculator).