# Just What Is Magnification Ratio?

## A Numerical Value Indicating the Size Difference

The magnification ratio is a numerical value that indicates the size difference between the actual size of an object and the size of that object captured on the image sensor. For example, if a 10-mm object is captured in a 5-mm size on the image sensor through a lens, that lens has a magnification ratio of 0.5x. If the object is captured in a 10-mm size, the lens has a magnification ratio of 1.0x, which is also referred to as "1:1."

In an article by Apogee Photo Magazine, a f 1:1, magnification ratio life-sized, denotes that a subject real life measures 1 inch long, will also have the identical 1 inch measurement on film, while a 2:1 ratio indicate that the subject will appear as twice its normal size. This numerical progression moving from full life-size to lesser and lesser increments is therefore defined as 1:1, 1:2, 1:3, 1:4, etc. Inversely, a 2:1 or 3:1magnification ratio indicates that the subject under discussion when captured on film will show up as double or even three times its initial magnitude.

Close-up photography magnification ratio ascertains the amount of detail captured in the image. As you move in nearer to your subject, the overall area captured actually decreases, thus magnifying the degree of detail visible. The majority of 35mm thru 50mm optical lenses have the ability to seize a shot at a 1:2 magnification ratio

This is successful for snapshots, smaller paintings, small product shots, flowers, plus cropped portraits, along with other natural objects. Even so, many lenses will need a close-up adapter like an extension tube, that will fit in between your camera and your lens, allowing you to zoom in tighter than a 1:4 ratio.

A more multifaceted concern of the association with shooting close-up photography is depth of field, or that area immediately in front of and in back of your focusing point. Depth of field is a factor of the crispness of the photo. A constricted photo, for example, would naturally contain a "shallow" field depth, while a broader shot would be classified as "deep".

Depth of field is also dependent on three major factors: aperture setting, camera-to-subject expanse and focal length. A general rule of thumb, is that the smaller the opening of the aperture more depth field, while the longer your focal length, your depth of field becomes more restricted, which naturally becomes progressively narrower as you get closer to your subject.

You should choose a smaller aperture opening to expand depth of field, while the tradeoff is employing a slower shutter (with the risk of image blur) or a use higher ISO (with a risk of increased picture noise)." "Noise" in this meaning implies everything from wind to shadows to stray light that could possibly take away from the sharpness and focus of the image.

From a technical point of view, there are a number of formulas employed to calculate a magnification ratio. If you have knowledge of uour lens's focal length, as an example, the formula would look like this: R = (t - f) / f , or magnification ratio = (bellows extension - focal length) / focal length. If t = 200 mm and f = 90 mm, while a numeric expression could be: R = (200-90)/90 = 110/90 = 1.22 meters. Jun 20, 2011