Category Archives: Botany

New tool simplifies focus stacking

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Many times when producing images of small subjects we find that there is insufficient Depth of Field (or depth of Focus) to render the entire subject sharply from front to back. Insufficient Depth of Field (DoF) is cause by three factors:

First, we understand that, in addition to exposure,  aperture controls DoF. As we increase the F number we add DoF. However we may not be able to make a good exposure with a big F number like F22.

Another factor is that as we increase the focal length of our lens, the DoF becomes smaller. We could select a shorter lens, but that changes perspective and ability to focus close in the case of a macro lens.

The final consideration is that when the lens is moved closer, the DoF also becomes smaller. Thus we are our best enemy and must deal with self-imposed photographic criteria.

Therefore we have learned to use focus stacking to solve this problem. This requires a series of often many images, each made at a different point of focus from front-to-back. The images are blended into on in the computer using specialized software. The image of the bee (below) is an example of a stacked composite of 50 blended images.

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The several images are captured using different points of focus. Some lenses change magnification as the focus is changes, creating alignment problems. The better approach requires moving the camera a measured increment between shots. A geared focusing rail (below) or an automated programmed focusing rail are specialized tools for changing the focal point without compromising image size.

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Another system uses a rail incorporated into a bellows system to change focus but not scale, as pictured below. There are several choices from several manufacturers to accomplish this movement process.

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Now comes the new tool on the market- The Helicon FB Tube. This new idea comes from the producers of Helicon Focus, the industry leader in image stacking software. Essentially it is an extension tube with integrated electronic micro-controller designed to enable automated focus bracketing in single or continuous shooting modes. The measured tube length is 13mm and adds somewhat to the magnification of the lens dependent upon the focal length. Mounted on the camera in the same way as a usual macro extension tube, Helicon FB Tube automatically shifts the focus by one step with each shot thus producing a stack of images of unlimited length that can be rendered into a fully-focused image.

Helicon FB Tube needs no additional hardware apart from conventional cameras and lenses. Helicon FB Tube has no optics and does not affect image quality. Helicon FB Tube settings are configured through an additional application for Android or iOS. The set contains: Helicon FB Tube with IR Receiver and LED Indicator; Front and Rear Caps; IR Transmitter – connects audio port of a smartphone and Extension cable for smartphone and IR Transmitter.

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The unit has been tested and found compatible with a wide number of camera models and lens. Helicon FB Tube is available with mounts for Nikon and Canon cameras and AF lenses with built-in motor.

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I tested the image focusing ability of the FB Tube making 15 focus step images of the acorns below using a step factor of 70. The camera was a Nikon D800 with the FB Tube and 105mm F2.8 Micro Nikkor. Selected aperture was F5.6. Electronic flash in TTL Mode within a softbox provided consistent light.

To set up the FB Tube a couple of simple settings are made on the smartphone device, including lens focal length, crop factor, aperture and step size. this was relatively straight-forward on my iPhone using the available ap:

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The phone then transmitted the data to the FB Tube via an IR emitter plugged into the phone audio jack and aimed at the tubes receiver. as shown below.

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To get started, the first focal point was focused manually at 3.0 CM on the rule. The rest of the images in the series were focused automatically by the FB Tube. Three of those images are shown below -the first, middle, and last- of the 15 image sequence.

Acorn Stack-01FP Acorn Stack-07FP Acorn Stack-15FP

The fifteen images were selected in the computer and rendered in Helicon Focus
Method B (depth map) in a normal manner, rendering sharp focus from front to back. Final adjustments for tone, color and sharpening was completed in Photoshop CC.

Acorn Stack Complete

There are several procedures to make images for stacking. Moving the camera is simple and inexpensive. A manual rail is a bit of an expense, Fully automated, servo motor driven rails and associated accessories are often more than $600. In comparison, the Helicon FB Tube costs $200.

Copyright © Brian Loflin 2017. All rights reserved.

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Why do macro lenses come in several different focal lengths?

Which one do I need?

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Texas Bluebonnet, Lupinus texensis. This flower was photographed  at half life size on the sensor (0.5X) with a Nikon macro lens. Which focal length was used?

True macro (or Micro) lenses allow subjects to be photographed much closer than normal minimum focusing distance, thus greatly magnifying the image size. Often, these are prime lenses of single focal length with various focal lengths available from each manufacturer. And macro lenses produce high quality images. Because these are complete lenses that focus to infinity, many other uses of high quality are possible.

Macro lenses are the more expensive of the alternatives to focusing close. Most retain all automatic features, but have limited magnification range, frequently up to 1:1, or life size. With accessories they can produce magnifications from 1.0 X to 40.0 X life size. Because no lens extension is required per se, little exposure compensation required.

Most manufacturers make more than one macro lens. Canon, Nikon, Olympus and others produce high quality macro lenses. True macro (or micro by Nikon) lenses are produced in various focal lengths, commonly from 40mm upwards to 200mm. And they may all focus very close; most focus to life-size or 1.0X. (Also called 1:1.) Essentially, they all do the same thing.

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Three Nikon macro optics (clockwise, from near left) 60 mm F 2.8 AF Micro Nikkor, 200 mm F 4.0 AF Micro Nikkor, and 105 mm F 2.8 AF VR Micro Nikkor.

So if that is true, why would there be a variety if they all do the same thing? The answer is simple: working distance. Working distance is the actual distance between the subject and the camera’s sensor when the lens is focused. As the focal length of the lens increases, the working distance also increases at the same image magnification.

Let’s look at the working distances provided by three popular focal lengths above: the 60mm, 105mm and 200mm macro lenses. All these lenses below are accurately focused at life size or 1.0X and the reproductions are at the same scale. Canon has lenses in similar focal lengths; the 60mm F2.8, 100mm F2.8 and the 180mm F 3.5 lens trio. All are magnificent optics to be sure.

Nikon Macro Lens

This lens is the 60mm F2.8 Micro Nikkor focused on a small portion of the flower at life-size. It focuses to 1:1 at 8.6 inches.

Nikon Macro Lens

The second is the 105mm F2.8 Micro Nikkor. It focused to 1:1 at 12 inches.

Nikon Macro Lens

This last lens is the 200mm F4.0 Micro Nikkor. It will focus at 1:1 at a distance of 19.2 inches.

Working distance is important to macro photography. Greater working distance allows several advantages. These include the freedom from making a shadow on the subject, the ability to get ample light or lighting fixtures onto the subject, the ability not to frighten or run off a live subject and the ability to work at a safer distance from a dangerous subject.

One additional attribute to remember is that the angle of view of any lens gets smaller as the focal length increases. So as a result, a 200mm lens focused at 1:1 will have an area of coverage of one half that of a 100mm macro lens at the same magnification.Three Focal Lengths-Sm

These three images were made with the macro lenses described above.  In making the photographs, emphasis was given to producing the flowers at the same size in each frame in the camera when shot. To do so the image with the 60mm lens is made from fairly close; the 200 mm lens much farther away.

The resultant images look the same, but upon close inspection there are notable differences. First, the longest lens tends to compress the image more than the other two. The distant flower looks closer to the close one. This is an example how the focal length of the lenses affects perspective. The second difference is an apparent difference in angle of view. Notice the black form in the upper right of the images. We see less of it in the 60 mm view and it tends to move and get larger as the lens focal length gets longer. Otherwise, there is little difference perceived in the three images. Because the subject size is the same in the three images, the Depth of Field is also the same. All images were shot at the same F5.6 aperture.

So, to answer the question: The lens that’s right for you depends upon your most common use. If you need a lot of accessory lighting like flashes, diffusers and other modifiers in your set up, you may enjoy the freedom of the longer focal length/longer working distance. If you want a real compact lens, then the shorter lens may be perfect. A good compromise and my recommendation is the 105 mm F2.8 AF VR Micro Nikkor.

Copyright © 2014 Brian Loflin. All rights reserved.

 

 

June Macro Photo Workshop

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Ten avid participants from as far away as Minnesota discovered great surprises as they developed new skills in the exciting small world of macro photography. The workshop was held in the heart of the Texas Hill Country at the historic Mo Ranch Conference Center in Hunt. Everyone expanded their understanding and skills through classroom instruction, and intensive, hands-on field and lab photography sessions.

Participants said their macro images are much better than any they would have taken before this instruction.  Most participants were also in for a big surprise as they learned precisely how little DOF their macro lens has. All appreciated learning how to use flash to improve their work and learning to use Live View for better focusing on tiny objects.

Of special interest was the use of a macro focusing rail, focus stacking, flash for additional depth of field and techniques for mitigating wind.

Mo Ranch was a really great place to hold the workshop–very relaxing and lots of nature to photograph. Participants would definitely recommend this workshop to others.

Several of the images from the workshop are shown below:

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Photos:© Melody Lytle, Rose Epps, Steve Houston.

See more participants small world images on Facebook at https://www.facebook.com/pages/Brian-Loflin-Macro-Workshop/469018396566911

Copyright © 2014 Brian K. Loflin. All rights reserved.

New Photography Workshops for Fall and Winter

Three new workshops are slated for the months ahead including one Macro Workshop and two South Texas Bird Photography Workshops.

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Field Macro Photography Workshop • October 10-12, 2014
MO Ranch, Hunt Texas

Join us in the very heart of the magical Texas Hill Country for a three-day macro photography workshop geared to shooting in a field setting. This workshop will be packed with hands-on instruction to help you grow your photographic abilities with new found skills, techniques and proficiency.

The historic, 500 acre Mo Ranch is located in a beautiful setting on the North Fork of the Guadalupe River. Here, habitats include: aquatic, riparian areas, grasslands, oak-juniper woodlands, and limestone hills. We will make use of all of them.

The workshop will feature hands-on learning and demonstrations with native flora and fauna of the area and will cover many subjects including discussions on: Equipment for getting close, Tools to make macro work easier, Wide Angle Close-Ups, Lighting with Flash, High Speed Flash, Focus Stacking, Extreme Macro, and much more.

Don’t miss out on this workshop. Only four slots remain.
(The June workshop sold out in ten days.)

For more information see: http://www.thenatureconnection.com/files/Macro_Photography_Workshop_in_the_Field-Oct_2014.pdf

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South Texas Bird Photography Workshop •Laguna Seca Ranch Edinburg, Texas
• October 23-26, 2014
• February 27-March 1-2015

This instructional, hands-on bird photography workshop is located in the heart of the South Texas flyway. The workshop features a half-day of hands-on instruction and a day and a half shooting (or two and a half days) in some of the best South Texas birding habitat available where neotropical South Texas varieties abound.

The workshop will be held at the Laguna Seca Ranch north of Edinburg, Texas in the heart of the lush Rio Grande Valley. The facilities of the 700-acre ranch are purpose-designed for photography and preserved with all native species. It features four constant-level ponds, each with permanent photography blinds oriented for the best use of light. A fifth blind is set up specifically for raptors.

Each location has been hand-crafted to provide the most outstanding bird photography opportunities. With nearly eighty species found on the property, Laguna Seca Ranch clearly offers a uniquely outstanding South Texas bird photography adventure!

For more information, see: http://www.thenatureconnection.com/SoTxBirdPhotoWS.html

Six great tools for photography

How many times have you been asked the question, “What kind of camera do you use?” Or, “Is that made with a prime lens?” I hear that all the time. Many of my students are always focused on the cameras and lenses. And sometimes, not much else.

While the image capture apparatus is certainly important, how you make the picture is even more so. And as a follow-on to that statement, the little regarded accessories often save the day.

While it is true that we need a variety of tools that may be specialized or single- purpose, I have several basic tools in my armamentarium I would not like to do without. Each one is very inexpensive, quite handy and readily available through most hardware stores.

Nikon D2Xs, 60 mm, F2.8 Micro Nikkor lens, electronic flash with softbox and reflector.

These six tools include “A” style spring clamps, ball bungees, blocks of wood cut to a variety of dimensions,  bungee cords of various lengths, carabiners with a rope loop, and spring-style wooden clothespins.

The “A” clamps will hold a lot of things like backgrounds, reflectors and flags and are useful for making tents from foam core boards.  Ball bungees tie up extension cords, secure lighting cables to overheads and booms and of course, to stretch tarps, silks and butterflies to frames. One photographer claims to mount his speedlights on furniture with them.

Blocks of wood in a variety of sizes make their home propping up or elevating objects in still life or table top arrangements. I have a large bucket of pre-cut pieces from 1/2 x 1 x 1 inch to 2 x 4 x 8 inch material.

In my outdoor photography of plants and flowers, bungee cords work well to pull back vegetation and other unwanted material from the subject area. These are also great for stretching as a clothes line to support fabric backgrounds and diffuser material. I also use them to make light stands behave in their closet.

Carabiners are exceptionally handy, spring closing, safety clamps originally designed for mountain climbing. But, small light weight “beeners”, when married to a short loop of rope, are handy for hanging set weights, corralling coils of extension cords and safely securing lighting fixtures when in use.

And of course, the wooden spring clothes pin has many magical uses. More commonly, close pins are used for clamping gels and sheets of diffusion material to barn doors of lighting fixtures. Called C-47s in the movie industry, it is thought they received this highly technical nomenclature because they were once located in Row C-Bin 47 in the lighting department’s grip storage.

So remember, when you admire nice photography there may be just a few dollars worth of these special tools holding a very expensive set together in front of the camera and lens.

© Copyright 2012 Brian Loflin. All rights reserved.

Table-top macro background holder

Many times it becomes necessary to use a card or other two-dimensional material as a background or light modifier for small scale table top photography.

Mounting these materials has been a previous challenge. The use of “A” spring-type clamps, wooden blocks and other mounting schemes is only somewhat successful. As illustrated below, some of these devices may get in the way on the table top.

The solution that really works is an adjustable clamp that will hold a variety of cards, plate glass or other materials vertically and securely. These adjustable clamps are very simple and easy to construct out of common, low-cost materials.

In use, these clamps allow the easy, yet secure, positioning of light modifiers such as glass, scrims, flags, reflector boards, and background cards or prints. They also require little space on the table top so they don’t interfere with positioning of the subject or other props.

MATERIALS :
(All dimensions, inches.)
1 ea-  1/2 X 1 1/2 X 12 clear lumber
2 ea-  3/4 X 1 1/2 X 12 clear lumber
1 ea-  1/2 X 1 1/2 X 12 clear lumber
1 ea-  3/8 X 4 inch coarse thread (all thread) carriage bolt
1 ea-  3/8 coarse thread recessed Tee nut.

CONSTRUCTION:
Assembly of the holder is straight forward. Measure and cut all wooden stock to size. Drill a hole through one piece of the 3/4 inch stock at its center and mount the Tee nut as shown below. Screw and glue the two larger pieces to the base as illustrated. Insert the carriage bolt into the side piece to secure the smaller clamping board. In use, simple finger pressure is sufficient. Position the bolt side of the assembly away from the camera on the table.

My specifications suggest 12 inch long materials. Background holders of other dimensions may be desired depending on the required use.

Sample table-top macro with a mounted color photographic print as a simple background.

Silk iris and bud. Nikon D2Xs, 200 mm F 4.0 Micro Nikkor. Two SB-800 Speedlight electronic flash with background, reflector and diffusers.

Copyright © Brian Loflin. All rights reserved.

What color are cactus flowers?

Many people are lovers of cacti- or cactophiles- you might say.

There are many reasons for this fact. Cacti are most interesting plants. They grow in many  shapes and sizes. They have spines in many diverse shapes, patterns and numbers. They reproduce easily. And maybe the number one reason for enjoying cacti, is that they take very little effort.

Cacti are a New World plant group and are mostly found in arid parts of this side of the globe.They thrive from the high, cold and dry Altacama Desert of Chile, to the hot southwestern United States. In fact, cacti occur naturally in each of the mainland 48 states and into Canada.

Because they are xerophytes, they require little water or time-consuming care as do other vascular plants. That makes cacti real user-friendly.

But an additional reason to enjoy cacti are the many variety of flowers. When a cactus gets moisture in nature, it believes that it’s time to reproduce and puts out its flowers in hopes of polination by bees, moths, bats and other critters of cactus country. Again, cacti are show-offs. They may frequently flower with large multi-colored, spectacular flowers, or put out only a few. And some produce blossoms larger than the plant itself. Sometimes, because of the plant’s natural camouflage, these flowers and the bees that they attract are the only method to find the cactus itself.

So what color are their flowers? Every color except blue!

© Copyright 2012 Brian Loflin. All rights protected.