Macro: DIY Lens-Reversing Technique

Posted by CWade in How-To | Tagged | 1 Comment

razorblades at 4.2X magification
As promised in An Excursion Into Macro Photography, what follows is the [semi-ghetto] method I’ve been employing to capture true macro (1:1 or greater) images without the use of a dedicated macro lens.To be technical, what I’m doing is really a combination of lens reversing and lens stacking. Many people simply invert a prime lens directly onto the camera body, but I like to stack the reversed lens onto my telephoto zoom for greater magnification.

This is by no means the only way to make macro photos on a budget; many people also use extension tubes or bellows, teleconverters, close-up filters – or some combination of any of the aforementioned.

First, I’ll just walk you through the equipment I’m using:

Nikkor AF 70-300m f/4-5.6

In my macro setup, this telephoto mounts normally onto the camera body.

Next, a 50mm prime lens:

rear element & mount of the Nikkor 50mm f/1.8, showing the aperture control lever

The aperture control lever is also referred to as the “stopdown lever,” for good reason: it simply controls the size of the aperture (your f-stop). I have no idea whether or not Canon lenses also operate this way.

At any rate, you need to make sure that the lens you’re reversing stays open at it’s maximum aperture. This is really important, as a lot of light is lost when you stack lenses.

By default, the lever remains at the smallest aperture (f/22 on this lens) when not mounted to a camera body. We need to manually open it up all the way.

I do this by making a tiny splint out of thick card stock:

Nikkor 50mm f/1.8 with makeshift card stock splint holding aperture lever open
The white you’re seeing is the folded card stock splint inserted into the space the lever occupies, functionally keeping the aperture fully wide-open. All of the purple area visible through the rear element is the aperture at f/1.8- notice you can’t see the diaphragm blades.

Be careful splinting the lever; you don’t want to wedge the card stock in so far as to be irretrievable.

Now we need a way to mount the lenses in the unconventional, reversed configuration. Here is where adapter/ coupling rings come into play:

Nikon BR-5 Mount Adapter Ring, Generic 52mm Macro Coupler (male to male)

Another look at the BR-5 (I had to lean it up against something)

The BR-5 is basically what’s known as a step-down/ step-up ring. On this particular ring, one side is threaded at 62mm, and the other is 52mm. They’re also handy in non-macro applications, allowing use of any type of round photographic filter on more than one lens.

The generic macro coupler threads onto the front of whatever lens you’ll be reversing- like this:

Nikkor AF 50mm f/1.8 with threaded male-to-male coupling ring

Keep in mind, you’ll need to get coupling rings in the correct size for the lenses you’ll be using. The filter diameter can usually be found on the inside of the lens cap.

Next, the BR-5 step-down ring screws onto the front of the 70-300mm which has a filter diameter of 62mm. This allows the 50mm prime lens (with coupler) to be mounted inversely onto the 70-300mm, since the BR-5 “steps down” to the smaller 52mm filter diameter.

*I’ll apologize in advance for the following photos- they were taken with a point & shoot. I’ve actually no idea how to make nice images with a p&s, having never owned one.

There are no controls aaaaaaagh!

Here’s a shot of the lenses connected by the coupling rings:

Left to Right: inverted 50mm lens, generic 52mm coupling ring, BR-5 step-down reversing ring, 70-300mm Nikkor zoom.

Here’s the setup all together:

In principle, this lens configuration uses the inverted 50mm like a magnifying glass. The further you move a magnifying glass from your eye, the greater the magnification.

I usually end up taking the battery grip off of the D80 because its extra weight stresses the lever that holds the tripod shoe (and thus the camera to the tripod).

I shoot all my macro subjects in the DIY lightbox I created, way back in this post. You need as much light as you can possibly get when stacking lenses, and having a white box for light to reflect around in really helps. In the near future, I’ll probably cave and buy a real fabric light tent and better lights, because portability and durability are nice things which are lacking in cardboard and tissue paper. ;-)

Here’s the tripod and setup in question:

tangent:

That tripod has served me well so far, and actually can become quite tall (taller than my line-of-view into the camera viewfinder). I originally bought it for its portability and its completely awesome hybrid joystick ball-head, which simplifies the composition process since you don’t have >2 levers to adjust vertical, horizontal, and tilt placement, ect.

The only complaint I have with this tripod is the quick-release lever that holds the shoe in place; it really can’t take the weight of an SLR+ longer lenses, especially when you start tilting it at odd angles. (However, it was only designed to support 2.2 lbs or so, so I cannot fault it for this.)

/tangent

So, once the tripod, lightbox, and lights are in position, I change some essential settings:

  • Set focus to manual on the camera body
  • Make sure the reversed lens has its focusing ring dialed to infinity
  • Stop down the camera-mounted lens considerably: usually between f/22 & f/38
  • Enable the remote shutter release (some shutter speeds will approach ~1 second)
  • Double-check shooting mode is in RAW file format
  • Set ISO to 100
  • Set a custom white balance, OR-
  • be lazy and use the incandescent setting (which is approximate), and fine-tune later in post.

Important things to know:

  1. In all likelihood, your camera won’t know how to meter accurately, so keep an eye on the exposure and figure out what works through trial-and-error. (yay, digital!)
  2. Magnification levels are measured by dividing the normally-mounted lens’ focal length by the focal length of the reversed lens. So, in my case, if I had the telephoto zoomed out fully to 300mm, it would be 300mm/50mm = 6x magnification.

You can see that the working distance from the subject to lens is quite small! It depends on the focal length of the telephoto, but generally I find that the subject needs to be less than 3cm from the rear element of the inverted 50mm lens. Generally in macro photography, it’s easier to move the subject slightly instead of manually focusing with your camera-mounted lens. In reality, I find myself doing some combination of both. There’s a technique involved, and it takes practice, as the depth of field is measured in millimeters- and sometimes even less.

Even when shooting with a real macro lens, the concept remains the same; people utilize specialized focusing rails so that the camera can be positioned precisely. This alters the focus by changing the distance from the subject.

You’ll also notice how close the lights are to the subject (a beer bottle cap) and the lens:

It looks a little crazy, but at such a small f-number, that’s the only way I’ve found to throw enough light onto the subject. This technique will be greatly improved by the addition of an off-camera flash or speedlight.

Sometimes, the subject will need to be propped up. That’s ^ just a beanbag I use to stabilize the camera in low-light situations when I don’t feel like carrying a tripod.

And, that’s about it.

There are definite drawbacks to the reverse lens macro approach, some of which are:

  • Not suitable for insects or anything that’s going to move on you (This excludes the most interesting macro subjects, unfortunately!)
  • Difficult to obtain tack-sharp focus
  • Vignetting is likely- especially if a zoom is used as the normal mount
  • Nearly-impossible to use in the field; I think you really need a studio-type setting, where the camera can be stabilized and the light controlled.
  • In general a highly-finicky process, approaching tediousness: lots of room for error

Since I’ve never shot with a macro lens, I’m sure there are even more drawbacks (by comparison) inherent in this method to which I’m just naive. Ah well, some day.

However, If you posses a 50mm prime (or any prime, really), and any other lens, reverse mounting and/or lens stacking is a really accessible way to experiment with macro photography. I spent about $40 USD on the BR-5 step down adapter ring, which considering the average price-tag of any dedicated macro lens, is virtually nothing. You’d probably be able to locate a generic adapter/ step-down ring for less, as well. The other coupling ring was dirt cheap because it’s a (plastic) generic, yet the threading on it is flawless, and it works just fine for my purposes.

All in all, this experiment’s been a little like having a microscope in the house- which is super nerdly-cool, if a little frightening at times.

Checking focus and exposure

Here, the focus was soft and it was a little overexposed, so I repositioned the bottle cap and lights, and eventually came up with this:

Beer bottlecap at 6X magnification

A collection of my macro photos made using reverse lens stacking can be viewed in this Flickr set:

 

I hope this has been useful to some of you!

If you need clarification or have questions, please ask away in the comments.

Good Links:

Macro With a Reverse Mounted Lens

Reverse Lens Macro Photography

Reverse Mounting & Reverse Stacking

One Response to Macro: DIY Lens-Reversing Technique

  1. CIOPhoto says:

    Wow girl – you certainly don't need no stinkin' macro lens. ;) You are getting amazing macro results with this technique. The DIY blog post is great. If you don't mind, I think I'll try to do one similar with Canon gear. BTW – can't wait for my April Wallpaper.

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