Macro shots with lenses reversed?

I was looking at some macro shots and noticed some photographers talking about reversing a lens. I'm just thinking about this, is it just prime lenses that can be reversed? Sorry if this is a silly question, I did some searches and didn't find the exact explanation that I was after.

If not primes, what lenses (Nikon) can be reversed for macro?

Good question. I have a reversing ring for my 50 prime. Nikon has a reversing ring and the reverse of that so you could add a filter on the camera end that has become the filter end except Canon doesn't have such a thing so I am really just babbling. I still think its a good question though, I think I'll go see if they make a 72mm reversing ring to a Canon body. Or maybe a reducer adaptor...

What was in those brownies??? Are there any more left?

The same can be done with reversing one lens on another. You will still have the lens talking to the body. I made a reversing ring for my 35mm and 18-55 lens using 2 old filters that I glued together.

Lenses are designed to make a large field of view smaller to fit on the camera sensor. Reversing a lens does the opposite, it magnifies the image on the sensor. The shorter the focal length of the lens the greater the magnification achieved. Realistically, the best focal lengths for reversing are less than 100mm according to my books on the subject, with most suggesting 20-50mm as being best.

Theoretically, at magnifications greater than life-size, a short focal length lens should give better image quality too. The lens is designed to work best when the lens-to-subject distance is greater than the lens-to-sensor distance. At high magnifications with a lens mounted on extension tubes this is not the case and reversing the lens restores the best ratio.

All my sources say to use primes, not zooms, but I'm having trouble finding much explanation of why. Here's one guy who says he has good results with a reversed zoom but I don't know what his standard of "good" is. Short primes tend to be a very good optical quality, better than zooms, so there's one argument for primes. Depending on your point of view, since focusing involves moving the whole camera, the added variable of varying focal length with zooms could be viewed as a benefit or a complication.

In reversing a lens you lose all connections to the camera, auto-focus (not that you need that at high magnification), exposure, etc., so any good prime should be fine. It doesn't have to be your camera brand, but it does need to have an aperture ring, which many modern lenses don't have. I'd tend to look for an old manual focus lens of high quality which should be cheap on eBay and sim if I didn't already own a suitable lens.

That is interesting, I'm curious why reversing lenses under 100mm are better than reversing something larger. So let's say you have a 105mm with extension tubes, will you get closer to your subject with this or a 50mm reversed?

Such good answers, thank you all for helping me out with this question.

SJM wrote: That is interesting, I'm curious why reversing lenses under 100mm are better than reversing something larger. So let's say you have a 105mm with extension tubes, will you get closer to your subject with this or a 50mm reversed?

Such good answers, thank you all for helping me out with this question.

It may be harder to control the lens, the aperture with longer lenses. I don't know.

SJM wrote: That is interesting, I'm curious why reversing lenses under 100mm are better than reversing something larger. So let's say you have a 105mm with extension tubes, will you get closer to your subject with this or a 50mm reversed?

Such good answers, thank you all for helping me out with this question.

It's been a long, long time since I've used a prime + extension setup. I now use dedicated macro lenses but am considering trying my hand at high magnification pics again, so you've tweaked my interest with this question. The "why" is definitely hard to come by.

When using extension (lens not reversed), magnification = extension/focal length, according to John Shaw's classic Closeups in Nature . When a 105 mm lens is used at 1:1 then there is essentially 105mm of extension built into the lens. To get twice life-size magnification you need to add another 105mm of extension. that's a lot of extension. Higher magnifications at longer focal lengths require rather unwieldy combinations. Supporting the combo and keeping the setup steady becomes a challenge. Shorter lenses can achieve higher magnification with less extension and are more managable. I suspect a similar argument is true for reversed lenses, though the numbers will be different.

I've been thinking of using a reversed lens on extension tubes. Another option is to use a reversed lens as a high quality diopter/close-up filter stacked on another lens. That's a different issue.

You gotta be careful when using reversed lenses as the lens will be right on top of your subject & it is easy to damage the exposed rear element. If you are shooting Nikon use a BR3 adapter as that will allow you to use a 52mm filter on the outermost end, thus offering some protection of the rear element. When you get the BR2 reversing adapter, it comes with literature that tells you what the magnification ratios you can achieve with different focal length lenses...