Stacking Your Lenses
Flipping the lens around boosts your magnification. Putting the flipped lens instead of attaching it directly to the camera body boosts your magnification even further.
To stack lenses you start with a regular lens attached to your camera (preferably a prime lens) and then you add a male-to-male coupling ring–essentially an aluminum ring threaded on both sides with no filter glass in it. This male-to-male coupler allows you to thread a reversed lens onto your existing lens. Thus you can stack a reversed 50mm lens onto a regularly mounted 50mm lens.
You set this up the same way you set up the reversed lens in the previous section but instead of screwing the reversed lens onto the camera body with the bayonet-to-threading mount, you screw it onto to the regularly mounted lens with an appropriate male-to-male adapter. We still recommend using the reverse ring kit pieces that allow you to protect the rear lens element.
A little scratchpad calculation can show you what kind of magnification power you’re going to get out of your lens arrangement. When you stack lenses the formula you use to determine the strength of the magnification is the focal length of the stacked lens divided by the focal length of the normally mounted lens. Thus a 100mm lens reverse mounted onto a 50mm lens would have a 2x magnification (100/50 = 2).
First, let’s take a look at a full frame capture from our stacked 50mm <-> 50mm lens setup:
In addition to the very shallow depth of focus we saw in the reversed 50mm lens photo, there is a new photography aberration to consider now. In the upper corners and edges of the photo you’ll notice a darkening of the photo reminiscent of old fashioned photographs. This darkening, or vignetting, is a side effect of the lens stacking. By adding extra optical elements to our lens setup we’re losing a little bit of light and that light lose manifests itself in the darkening of the edges of the photograph.
Continuing with out comparison of full frame capture sizes, the original 50mm setup captured 6″ within the frame at minimal focal distance. The 50mm to 50mm lens stack captures roughly 1″. Let’s take a look at the results from our stacked lens setup at 100% crop–back to looking at President Lincoln’s dreamy eye:
At this point we’re so close that you can see how the individual cotton fibers have absorbed the ink placed onto the surface by the printing press and the hash marks the etching artist used to define the pupil.
Extending Your Focal Length with Extension Tubes
The final technique we’re going to look at today is the use of extension tubes to turn a regular lens into a macro lens. An extension tube kit is exactly what it sounds like, a tube (or series of tube pieces) that you attached to your camera to extend the lens away from the camera body.
Why do you want to extend the lens away from the body? A regular camera lens, say our trusty 50mm lens, has the ability to focus to infinity but a rather limited ability to focus up close (as close as we would like to get for macro photography). As we move the physical lens away from the body, we increase the magnification while simultaneously decreasing the minimum focal distance. It’s possible to add an extension tube so long that the minimum focal distance results in the object you’re trying to photograph actually touching the lens of the camera.
In order to attach your extension tubes to your camera, simply remove the existing lens and attach the extension tube like you would a camera lens (using the bayonet mount on the end of the tube). Then attach the actual lens to the end of the extension tube like you would attach it to a regular camera body.
Be aware that you’ll need to switch your camera to manual mode as inexpensive extension tubes have no electrical contacts to pass information between the lens and the camera body. You can purchase extension tubes which do have this feature, but you’ll spend $150-200 for the extension tube set instead of $12. Furthermore, given that macro work requires extensive manual camera adjustments anyway it’s silly to spend all that extra money when you’ll most likely be operating manually regardless.
Let’s take a look at what kind of magnification we can enjoy if we extend our 50mm lens with all the extension tube segments that came with our extension tube kit (you don’t have to use all the segments, but we’re demonstrating how much magnification the whole kit can provide). Here is a full frame look at our $5 bill using the full extension tube:
Not bad, our full frame view at this point is less than an inch, without even zooming in to 100% crop we’re so close we can see the single red security fiber embedded in the cotton currency (at the top of the bridge of President Lincoln’s nose). Let’s check out the full 100% crop to see how close we can get:
We’re close enough in this full size view to see how the ink from the rings of Lincoln’s iris has bled into the surrounding fibers via capillary action. What looks like wrinkles (or waves) in the picture is actually the contrast between the peaks and valleys of the paper itself.
If you’re looking to get even closer to your subject you can combine techniques. Here is a crop at 100% of the $5 bill with an extension tube topped with a 50mm lens which in turn has a 28mm lens stacked over it:
We’re now so close to that security fiber on Lincoln’s nose that we can see it wasn’t just a single red fiber but a red and yellow fiber.
Tips, Tricks, and Going Further with Your Macro Photography
Now that you’ve learned the basics of DIY macro photography, let’s look at some simple steps you can take to increase the quality of your photos and your enjoyment of the process.
As we mentioned at the start of the tutorial, a tripod and a remote shutter release are invaluable. Because the depth of field in macro photography is paper thin the slightest change in the position of the subject or the camera can radically shift the focus. This is why macro photography in the field can often be very frustrating for new macro photography enthusiasts–the tiniest breeze is enough to move a flower out of focus and ruin a photo.
When you’re photographing your subject, it’s usually easiest to move the subject to adjust the focus rather than to move the camera. Standard camera tripods don’t have the kind of fine-tooth adjustments necessary to shift the camera lens 1mm but you can easily scoot your subject a hair closer to the camera. If you find yourself really getting into macro photography, you may find it a worthwhile investment to pick up a macro focusing rail (a special tripod attachment that allows you to make very minute adjustments along an X/Y axis).
When it doubt, take extra photos. Ultra-thin depth of field makes it difficult to determine via the viewfinder if you’ve nailed the shot you want. It’s always better to fire off a few extras than to get back to your computer and discover that you managed to get every part of the insect you were photographing in focus but the eyes–which was the shot you really wanted.
Finally, one of the best tips we can offer in regard to macro photography is to relax and enjoy the process. Consider capturing that perfect shot of an insect or flower pistil to be a sort of meditative pursuit that occurs at the intersection of practice, technique, and serendipity.
The photo of the bee above, for example, is my favorite macro photograph of all the ones I’ve ever taken precisely because of that last bit–serendipity. It looks like the kind of photo that I must have taken a great deal of time to prepare for and set up, but in reality the photo came about simply because I pulled myself out of a bed on a chilly Sunday morning in September to meander around my back yard looking for something interesting to photograph. The cold had left this bee essentially stranded on the closed-up thistle bud upon which it had landed the night before. It was a perfect opportunity to fire off a bunch of hand-held macro photos without worrying about my subject flying away in a huff.
It’s not the best photo I’ve ever taken, nor is it the most interesting macro photograph in my collection. It always reminds me, however, of the importance of getting out there and enjoying photography.
Don’t get caught up in having the best lens or the perfect technique. Go buy that $5 reversing ring. Go look for old and cheap but serviceable lens at garage sales and second hand stores to play with and stack on your macro rig. It’s far more satisfying to snap a really cool photo with a MacGyver’d rig than it is to sit around waiting for the day you can buy your dream equipment.
Jason Fitzpatrick is warranty-voiding DIYer and all around geek. When he's not documenting mods and hacks he's doing his best to make sure a generation of college students graduate knowing they should put their pants on one leg at a time and go on to greatness, just like Bruce Dickinson. You can follow him on Google+ if you'd like.
- Published 04/17/13