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This Simple Conversion Turns Any Zoom Lens Into a Macro Lens

Are you looking for an affordable but also electronic macro lens? Or maybe you have an old kit lens that’s just sitting around, collecting dust since your last upgrade? Well then read on, because in this article I am going to share one cool hack that will allow you to transform almost any kit or standard zoom lens into a capable macro lens!

I am not talking about reversing the lens or mounting it on extension tubes, we’re actually going to convert the lens for good. And it’s incredibly simple.

Believe it or not, this image was taken with the Canon EFS 18-55 Kit lens Version I on a Rebel T7i; no additional equipment was used at all.

The Theory

The basic design of zoom lenses in general is similar: the extendable front element produces a projection of the image into the lens barrel, where the next group of movable elements picks up on this image and projects it further down the lens barrel. The distance between the front element and this inner group, as well its distance to the sensor plane, determines how large the original projection of the front element will be when it arrives at the sensor.

In other words: the distances between the lens groups/elements to each other and to the camera sensor decide the zoom factor. This also explains why the minimum f/number increases as we zoom into the scene—a smaller portion of the image circle leaves us with less light.

But what if we where to remove the front element from the equation? Then we would have a lens that focuses very close. Close enough to shift the focus plane into the extendable zoom tube of the lens barrel.

Remove the zoom tube from the equation as well and we have a capable macro lens.

Note: This a non-reversible procedure in many cases; however, with some lenses you can simply unscrew it, such as in the example below.

I have already modified a few lenses this way and so far it has worked for all of them. The video below shows the conversion by the example of an (otherwise pretty useless) old Sigma 18-50mm f/3.5-5.6 DC lens.



February 2020
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