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56 vs 90: Who is more versatile? Discuss.

Started Aug 10, 2018 | Discussions thread
Advent1sam
Advent1sam Veteran Member • Posts: 9,089
Re: 56 vs 90: Who is more versatile? Discuss.

Truman Prevatt wrote:

ScottD1964 wrote:

You can always crop an image from the 56 to a 90mm perspective. Can't do that in reverse though.

Scott

Actually you can't. The axial magnification of a lens is determined by the focal length and the axial magnification of a 90 is greater than a 56. The formula is available on the internet.

The axial magnification impacts how the background looks and it looks different in a 90 and 56. You often hear that long focal lengths "flatten" the image - which is the effect of the axial magnification.

https://photography.tutsplus.com/tutorials/exploring-how-focal-length-affects-images--photo-6508

In this series the foreground is identical ( a woman sitting on a bridge rail). However the background is vastly different as a result of the axial magnification.

Not sure that proves anything!

To frame something the same for its required focal length, lets say upper body at 8ft will require 12.5ft on the 90mm, now if we crop the 56 to 90mm the dof will also be cropped too, so you will get exactly the same dof of the 90mm from a 56mm 1.2 cropped by 1.6x, you just have to remember to step back 1-2 strides to make sure you can get the same framing as the 90!

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