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Reversed Lens Article

Contents

1. Purpose 3. Depth Of Field & Exposure 5. Bounced Flash & Lighting 7. "L" Brackets
2 .Reversed Lens  4. Prime and Rev. Lens Settings 6. The Macro Buggin' Setup 8. Bug Hunting

                                                   

                

 

Purpose:

In March 2003, I began researching Macro work at extreme magnification.  I found several articles on the internet, some very enlightening and others having little matter of fact. 

There are various methods used to achieve extreme magnification.  High end macro lenses with extension tubes or bellows, and stacked diopters are just a few of the tools available to magnify and capture subjects just viewable at the very ending limit of our vision.

There is also the reversed lens technique which has been used by photographers for many years with film based cameras, and currently being used successfully in digital work.  In my estimation, it is probably the least expensive, with excellent results, and most challenging.

 

The Reversed Lens:

Film based camera lenses can be used as quality magnifiers for digital camera lenses.  This magnification property can be seen by viewing an object through the end of a lens normally closest to the subject toward the film plane end of the lens.  You will also notice an extremely narrow depth of field while trying to focus the hand held lens.

The degree of magnification is dependent upon two factors.  First, the prime lens which is on the camera, and  second, the reversed lens.  If the prime lens of a digital camera at maximum digital zoom is assumed to be at 150mm, and the reversed lens is a fixed 50mm then 150mm/50mm = magnification +3.  

For additional magnification a teleconverter such as the Nikon TC-E2 may be added to the prime lens before adding the reversed lens.

For more in depth information regarding magnification of reversed lenses and teleconverters, please visit a most informative web page by  Dr. Ching-Kuang Shene of Michigan Tech.  Dr. Shene has also published several in depth pages regarding the Nikon line of digital cameras and accessories.  Please click on the image below for visual information about assembling the reversed lens to the prime lens.

steprings.jpg (46639 bytes) Information regarding the various sizes of step up rings and macro coupler is noted upon the image (The macro coupler has male threads on both ends).  The sizes depicted are used to adapt the lens shown in the photograph. Your lens may have a different filter thread size.  The Nikon standard 50mm manual lenses have 52mm threads.  You must check the filter thread size on your Prime and Reverse Lens to determine proper ring sizes in order to couple them together. 

These small parts may be purchased from B & H Photo for about $8.00 each plus shipping.    If they are out of stock, get creative and figure out another combination.  If you already own a standard lens in the 50mm range, then the first step toward making macro images is almost complete.  Can you use a larger or slightly smaller lens? The answer is yes of course, resulting in a change in magnification.

 

Depth Of Field And Exposure:

One of the major problems encountered when using reversed lenses for imaging is D.O.F. (depth of field).  If you have already viewed an object through the reversed lens, then you have already experienced the difficulty in focusing upon a subject.  In most imaging situations, unless the subject size is slightly smaller than the Depth Of Field, part of the subject will be out of focus. 

palpusfly.jpg (68502 bytes)As an example, the fly in the image on the left was photographed for it's damaged facial feature. If you look closely, you will see that the immediate foreground is out of focus as well the area immediately behind it's head.  The entire length of this fly is about 7mm.  His head is about 2-3mm in length.  The shallow DOF here can only be increased by a decrease in digital magnification (zooming out).  In this situation I wanted to capture his face with the damaged palpus.  The image was captured while the camera was hand held, which made focusing even more difficult.

Another problem you will encounter with reversed lens photography is the gathering of light through the reversed lens.  The lens used in the previous photo is at it's largest aperture opening of F3.5.  Even though it is usable and has produced some quality images, good exposure with this lens is difficult.  Ideally, you would want to use a lens with a maximum aperture of F1.2 or 1.4.  The closer the lens is moved to the subject, the less light you will have for viewing and exposure.  While adding additional magnifiers to your prime lens, such as Diopters, and Teleconverters to provide larger images, focusing will become even more problematic, as hand held imaging becomes more difficult.  All Focusing is done by moving the camera physically toward and away from the subject.

 

Nikon E995 Digital Camera with Prime and Reversed Lens settings:

The optimal settings used most of the time for the equipment that I am currently using is as follows:

1. Reversed 50mm Nikkor 1.4 lens  = Aperture F1.4 - Focus at Infinity

Nikon E995 digital camera         = Full Manual Mode, Aperture F7.9 - F10.3, Focus set to   Manual at Infinity. Shutter Speed 1/250th or 1/125th. (These settings are only valid with the external SB-18 flash turned On)

 

Bounced Fill Flash and Controlling Light:

The above settings are used in conjunction with a bounced fill flash from an Nikon SB-18 speed light which is synched with the camera.  I set the External flash to Automatic, and Internal Flash to Off.  It is a rare occasion, or very sunny day, when the sensor shuts the external flash off.

  macrocomponents.jpg (34382 bytes) As with all photography, having control of light as much as possible determines the degree of success or failure of the image. After trying different combinations of fill light, I found that by using the bounce reflector and moving the flash toward and away or tilting it from side to side, greatly increased the quality of light used in exposing macro images.  The reflector also acts as a constant shade for the exposed areas and thus in part may explain the reason for the relatively stable camera settings and even subject lighting.

The basic exposure technique in the above photo has been used for decades by photographers, particularly in studio work. It is simple, inexpensive and it works well. When the reflector gets damaged just throw it away and cut out another. If you leave the reflector at home, stop off at Dunkin' Donut, pick up a dozen donuts, and use the lid off the box.

I would also like to mention Color Cast Problems which are curable in Photoshop,  but time consuming. Prevention is the best solution.  I find that the colorcast usually occurs when foliage gets between the Fill flash system and the lens. The light seems to acquire the properties from whatever object through which it passes.

The nature of  this setup is that it is a bit bulky to be poking into bushes in pursuit of insects, hence some missed imaging opportunities.

 

The Macro Buggin' Setup: 

 

macrobush.jpg (66513 bytes)This entire system works reasonably well when mounted on a tripod or monopod.  I find that the use of a Macro Slider allows me to achieve superior focus as compared to only tripod support.  Hand held imaging at this level, is very difficult, but it can yield images that would normally be long gone, by the time the tripod is setup and adjusted. I shoot both ways, but prefer the tripod method.  If you have enough flexibility in the tripod and the macro slider, it becomes another extension of your body. 

The Velbon macro slider is moderate priced and is able to transport the entire setup forward approximately 2 1/2" inches from its home position. It also is capable of movement from left to right.

Tripod support is a Benbo Trekker with swivel ball mount. This tripod is ideal for all of the manipulating that has to be done for subject positioning. There are nine combined adjustments available that can be made for fine tuning light exposure, and image composition. Six adjustments can be made to the tripod, two on the slider, and one on the Speed Light.

 

Assembly and Flash  Information

Two L  brackets were fashioned from 1/8" x 1" aluminum bar available at Home Depot and most any hardware for about $5.00.  

Flash is Nikon's SB-18 Speed Light (No longer in production), mounted to a Mini Bogen 3009 swivel in order to use the SB-18 for Bounce Flash.   This flash can be purchased on E-Bay when available via bid at about $30.00 auction price.

All holes are drilled and tapped for 1/4 - 20 threads and lock washers added. Machine screws and washers added to secure Bogen 3009 ball swivel and quick disconnect.  An additional 1/4 - 20 added to mount flash on right side for portrait shots, when in the vertical position.

Provision for a shutter release cable was not necessary due to an earlier purchase of the Nikon MC-EU1 remote.  The shutter release provision could be made with a short piece of pre-formed aluminum bar with a hole drilled and tapped for a cable.

 

 

Hunting For Insects:

Until March 2003, I had no idea that I would be trying to photograph a Fly or an Ant.  I had just broken my left arm, and was looking for something to keep me occupied until I fully recovered, which I have.  Like many others, I had no appeal for insects, especially flies.  

So, what is the big attraction for taking pictures of bugs?  For me it began with the challenge.  Trying to poke a lens in a fly's face at two inches without it flying away.

Lesson number one is that it requires patience.  Flies don't like shadows or fast movements.  Some species have sat in front of the lens for as long as twenty minutes with very little activity.  Others, will groom themselves, or blow bubbles.  Yet others jump onto the lens.  The fact is that they are never seen in detail, they are always flying or just a spec on a wall.  

applauding.jpg (98785 bytes)The fly in the picture on the left really isn't applauding, he is cleaning his front legs with his internal mouth parts.  An insect activity many of us have never seen with clarity.

 

sorgumhead2.jpg (36828 bytes)Ant's are difficult to photograph because they are so very active.  If they find a good food source they will stand and feed for quit awhile.  The image on the left shows an Ant eating Sorghum from a leaf.  I put it there as bait for an image.  Their world is really very busy, and through Macro photography, I have been able to view a part of their daily routine.  I am sure that there will be other images that satisfy the curiosity which makes us want to peak into their world.......Which makes me wonder who is peaking at us through that fine membrane in space?

 

Good Luck Hunting and satisfying your curiosity.

Richard Flake

 

Copyright 2000 2011 Richard Flake All Rights Reserved