2009年6月4日

Reverse Mounting Your Prime Lenses fo...

Reverse Mounting Your Prime Lenses for Affordable Macro Photography

Since purchasing my 50mm prime lens a few years back, I’ve felt like a salesman for it ever since–always telling people how sharp, compact and versatile the little bugger is. Well I have one more reason to recommend it. If you mount this lens in reverse on your camera, i.e. flip it around backwards, you get an affordable and fun way to experiment with macro photography. At a little over $9, I found an off-brand 52mm reverse adapter perfect for my 50mm 1.8 and 1.4 lenses. I took it out for a spin at the National Botanical Gardens. Here are my thoughts and experiences with this fun lens accessory.

Right off the bat, let me say that if you want to get serious about macro (close-up) photography this isn’t the best solution. There are good reasons that lenses are engineered specifically with that type of photography in mind. The downside is of coarse, those specialized lenses come with a price. At only $9 I highly recommend this as a starting point or way of experimenting with macro photography. A surprising secondary benefit I didn’t expect when first using this adapter were the insights it gives you into the relationships of depth of field and aperture. So lets begin.

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Protecting the Lens

If you haven’t used one before, it will seem strange mounting your lens in reverse. Once mounted, you see some of the guts of your lens that are normally not exposed. All of the pins the lens uses to talk with the camera are visible as well as the internal glass element that moves in and out when focusing.

Unfortunately, leaving the lens on in reverse can potentially let dust inside your lens. I highly recommend you use the lens protector cap that comes with your lens to protect it while not shooting. If you plan on using the lens in reverse often, you can buy a bayonet-to-standard filter thread adapter. This lets you screw on a UV type or other filter to keep nature’s elements away from your lens.

You Lose the Camera’s Brain so Use Your Own

If you haven’t already deduced it, seeing that the pins are now facing out, the camera has no way of communicating with the lens electronically. What does this mean to you? You are going to lose all the cozy automatic features of your camera. No auto-focus since there is no talking going back and forth. In fact, with the lens mounted backwards, your primary means of focusing is going to be moving the camera, which will be just inches from your subject, back and forth until the area you want sharp is in focus. No auto aperture either. I’m guessing that many of you have always adjusted the aperture of your lenses electronically. Say good bye to that and say hello to that manual aperture ring you may have never touched before.

Old manual focus lenses work well here regardless of make. Lenses without an aperture ring such as Nikon G-series and Canon EF lenses may not work. Remember that normally the camera keeps the aperture open so you can look through the viewfinder and see what you are taking a picture of. Just before you take a picture, it stops it down to the appropriate size. Now the camera now has no way to open the aperture for your viewfinder viewing pleasure. This leads us to the next point.

Depth and Field and Lighting

I found it amazing to see the depth of field effects in real time and watch them change as you stopped down the aperture. So when using the reverse adapter, as you look through the eye piece and start stopping down the lens, you will see things get really dark really fast. Unless it’s a very sunny day, twist it all the way to f/16 and you’re staring into a black square. (Many digital cameras have a depth-of-field preview button that forces the aperture to the size designated giving you a similar effect.) Set at 1.4, I could look at a flower and see the razor thin focal plan move up and down the flower as I made tiny movements with the camera.

I lugged in my tripod and a few lighting stands but at the last second decided to shoot everything handheld. Shooting this way can be very difficult for a couple of reasons. First, at large apertures with a nice bright image in the viewfinder, you get a very narrow DOF. The smallest shift in your camera position changes what is in focus. It’s extremely difficult to hold the camera steady enough to get consistent shots.

On the flip side of this, some of my favorite images ended up being the more abstract one with things unintentionally out of focus. If you want a sharper image without that aforementioned razor thin focal plane, you can step down the aperture, but again, you’re faced with guessing what is in focus because you can’t see what your shooting in the dark viewfinder. A tripod would be one solution. You could open the aperture, set your focus, then stop it down to take the shot. I did this a few times without the tripod and it worked out fine.

The three pictures below show the dramatic changes that come with changing the aperture on close up images. These are all the same flower, with changes made to the f-stop. On the first image, only the tiny buds are in focus. On the second image, I moved slightly losing the focus of the buds making them essentially disappear. The last image was stopped down to f-16 to get both the buds and the pink pedals in focus.

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This image is of an orchid. You can see how shallow the dof is on the first image and how different it looks in the second which was shot around f/16. All small aperture shots required me to use my flash to compensate for the loss in light. I used it in remote mode and held it in my other hand to get different lighting angles. Leaving the flash on the camera is a bad idea as it usually over shoots your tiny subject and you can’t control the light direction.

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Finally here are a few other images my brother took with this same adapter in his backyard.

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If you want to see the entire collection from botanical gardens, they are on blog.chaselliott.com. Like I said, I found myself liking the soft focus abstract ones and plan on mounting a few of them to frames. If you pick up the adapter, let us see some of your own work.

A few side notes

*This setup would work best in a studio environment. You could use multiple flashes and a tripod or even focusing rails to get pinpoint accurate focusing.

*With this reverse mount technique, you are no longer limited to having a single lens on your camera. A technique called “lens stacking” is popular in some circles where a lens like the 50mm is reverse mounted on the end of a zoom lens. Search around for example shots and explanations.

*You aren’t limited to reverse mounting prime lenses. In fact, you can build your own reverse mount extention tube that will work with any lens. Here are some detailed instructions.

*Reverse mounting a lens is not the only way to get cheap magnifications. If you use the Kenko extension tubes and an AF lens you can maintain metering, autofocus (both AF-s and screwdriver AF), and VR (vibration reduction). A three piece extension tube set will give you up to 6 different magnification ratios plus fine tuning with the lens helix. The reversing adapter will give just one magnification ratio.

*If you already own a nice zoom lens, look into close-up diopter lenses that screw onto the filter threads. The best ones are dual-element made by a few different manufacturers, and cost around $80 each. Some zoom lenses will even work well reversed if you reverse-mount them with the close-up lens attached. In this case, zooming simply changes magnification which is very handy for trimming the composition.

Post from: Digital Photography School - Photography Tips.

Reverse Mounting Your Prime Lenses for Affordable Macro Photography

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