Tag Archives: Micro Nikkor 200mm F4.0

Manage the Background – Part three.

I previously discussed managing the background through Depth of Field and through contrasting tone values. This last discussion revolves around the third method of setting off the subject, using contrasting or complimentary colors.

To understand this color concept better, we need to review the theory revealed in the Color Chart. For purposes of discussion in digital photographic terms, we use the RGB (Red, Green, Blue) color chart (below), an additive color scheme.

RGB Secondary Color wheel

In the RGB color chart (above) we see the photographic Primary Colors of Red, Green and Blue labeled in white. You may notice they are spaced evenly in thirds, or 120 degrees, around the wheel. Across the wheel from each of the the primary colors we see the Secondary Colors of Magenta, Cyan and Yellow. These secondary colors are actually made up of equal parts of the two adjacent primary colors.

Colors that are opposite each other on the chart have maximum color contrast, and are called complimentary colors. Two colors commonly found in nature are blue and yellow, a maximum color contrast of two complimentary colors.

In this sunflower photo the yellow flower contrasts perfectly in color with the blue background. This is because the yellow is exactly opposite the blue on the color chart. That makes them complimentary colors and one of the most visible of color contrasts.

Sunflower-2014
_DSC6502-Sm Nikon D2Xs, 200mm F4.0 Micro Nikkor, daylight.

For this cone flower (above) we have the  secondary color of magenta petals against the primary green background. Based upon our understanding of the color wheel these colors are still complimentary, thus of maximum color contrast.

GalliardiaMoth-1533-SmNikon D2Xs, 200mm F4.0 Micro Nikkor, daylight.

However, in the Indian blanket flower photo (above) the reds and oranges are not complementary to the green background. This is because they are not opposite on the color wheel.They are in fact, analogous, meaning adjacent on the wheel. Analagous colors work well together and create a harmonious color scheme. Here, the yellow tips to the flower petals separate it from the background primarily by contrasting tones rather than color.

However , the Shinia moth near the flower  center, a symbiotic insect to the Indian blanket, does not contrast well with the flower. This is actually to the moth’s benefit- a color mimicry trait that protects this moth from predators.

So, what ever the method you can use to separate your subject from the background, it’s a good tool to help attract the viewer’s attention to the subject. If more than one technique can be used in a single image, that’s even better.

Good photographic composition begins with a visual preview of the scene. Do everything you can to find and use as many elements of good design to give your image as much impact as you can within the camera. That will make the task of post processing must easier and allow your images leave the viewer with a lasting impression.

Copyright © 2016 Brian Loflin. All rights reserved.

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Why do macro lenses come in several different focal lengths?

Which one do I need?

TX Bluebonnet-3560-Sm

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.

_BKL6994-Sm

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.

 

 

Understanding the myth of “Crop Sensor” cameras.

Why crop sensor cameras do not produce greater subject magnification than their full-frame brothers.

I am disturbed by a lot of talk over the last few years stating that cameras with “crop sensors” produce larger in-camera subject size to cameras with full frame sensors. This thinking is both incorrect and continues to mislead the photography world. I feel this misleading language comes from two camps: One, the marketing folks who try to tell us that with a 1.6 crop sensor our 200mm lens is now a 320mm lens. And two, the wildlife photographers who want large in-camera images and who use a crop sensor camera believing the crop sensor somehow produces greater subject magnification.

Let me provide a couple of examples of that talk:

“For nature, wildlife and sports enthusiasts, it might make more sense to stick with a smaller sensor. You can take advantage of the crop factor to get maximum detail at long distances.” http://digital-photography-school.com/full-frame-sensor-vs-crop-sensor-which-is-right-for-you/

 “…the Mark IV has the 1.3 crop factor and a higher megapixel count than the D3s, which are nice for telephoto work.” http://www.deepgreenphotography.com/the-gear/

 “Focal length measurements on lenses are based on the 35mm standard. If you are using a crop frame camera the sensor is cropping out the edges of the frame, which is effectively increasing the focal length. The amount of difference in the field of view or focal length with a crop sensor is measured by its “Multiplier.” And,

 “…while a crop sensor DSLR doesn’t provide the same level of image quality as a full frame DSLR, it does [offers] sic. major advantages when it comes to cost. It can also be very effective for telephoto photography for the extra reach gained from the crop sensor multiplier. For example, this can be very useful when shooting sports, wildlife, and other types of photojournalism…” both from: http://www.slrlounge.com/school/cropped-sensor-vs-full-frame-sensor-tips-in-2/

 First let me state two facts: One, images from crop sensor cameras are not inherently of lower quality than those of full-frame cameras and, two, crop sensor cameras produce exactly the same in-camera image magnification as do their larger full-frame brothers.

Before I take this discussion of why these facts are true, let’s understand some things about cameras and their sensors.

First, a full-frame sensor gets its name from the fact that is physical measurements are, in round numbers, 24 x 36 mm. That’s the same size of our old standby, the full-frame 35mm film negative or transparency.

Second, I truly believe that the term, “crop sensor” is a misleading term. It is simply a sensor that is smaller than the full frame cousin. And there are now several sizes of “crop sensors”. They range from the APS-C (15.7 x 23.6 mm), the APS-H (19 x 28.7 mm), four thirds systems (13 x 17.3 mm), and even smaller. So there is really no “Standard” when it comes to identifying a sensor size.

Now let’s talk about the lens for a moment, the image forming device that projects our picture on to the sensor. Lenses have several characteristics. They affect:

  • Image size. This is governed by the focal length. Longer focal lengths produce larger subjectdetail on the sensor at any given distance,
  • Angle of view. This is the area of coverage in front of the lens that the lens may capture and project on to the sensor. It too is governed by focal length. Shorter focal lengths produce a wider angle of view that longer focal length telephotos for example. And finally,
  • Perspective. This is a relationship of components within the image to others within the same image. Focal length affects perspective, but only when the lens-to-subject distance is changed.

Crop sensor-Example 1

Let’s look at the image above to understand the physical relationship. The large frame is that of standard 35 mm film and also that of a full frame digital sensor. The yellow outline represents the area and magnification of an APS-C sensor, similar to that of a Nikon D2X or D7100 series camera body. The image was taken with a Nikkor 80-200 mm F 2.8 zoom lens.

Lenses have physical characteristics in addition to the optical characteristics above. One that is most important here is lens flange-to-sensor distance. This is the physical distance from the rear mounting flange of the lens to the sensor. That distance is specific to allow the lens to be focused at infinity. This distance is somewhat different between manufacturers, but it is standard within a manufacturer family so that all lenses will work properly.

In order for a lens of any particular focal length to produce larger image details on the sensor, the lens must be moved farther from the sensor or closer to the subject. Since the flange-to-sensor distance must be the same for cameras of a particular brand, any given lens (of that brand) will produce an image of the same magnification at the sensor regardless of the sensor dimension. What changes is the area of the projected image, not its magnification.

So let’s look at how this works.

The set-up

A standard, single focal length 200mm prime telephoto lens is mounted on a tripod. A subject is placed at a constant, pre-measured distance from the lens for all images. And two camera bodies, Nikon D90 with its APS-C sensor and Nikon D800 with its full frame sensor, were used.

The Process

Two photos of a mounted scaled quail are made from the same spot. Nothing changes but the camera bodies. Both images are processed in Photoshop in the same manner. A new composite file was made using both images together. Each image was reproduced at the same magnification for comparison. The APS-C image is produced at a six times multiple of its actual size of 15.7 x 23.6 mm, and the full frame image is printed at the same six times multiple of its actual size of 24 x 36 mm.

The Result.

One can clearly see the subject is the same magnification on both sensors and the reproduction sizes of the bird are the same for both sensors. The full frame sensor on the left captures significant additional area than the smaller sensor. This is the source of the term “Crop Sensor”.

Crop-Full Comparison

Left: Full frame sensor, Nikon D800. Right: Nikon D90 APS-C sensor. Initial enlargement (left) = 6 times sensor length 36 mm x 6= 216 mm. Initial enlargement (right) = 6 times sensor length 23.6 mm x 6= 141.6 mm.

The Misconception

When both images are reproduced at the same dimensions, the APS-C subject is reproduced at a larger size. This is only because the image is blown up to be the same reproduction size. This is why some people think there is actual in-camera magnification increase.

When viewed in the camera through the viewfinder or in live-view the smaller sensor frame is filled with the subject at a given distance than the full frame sensor. Therefore, the APS-C camera appears to produce a larger image. This is simply because the frame is filled faster with any given focal length and subject distance. What actually happens here is that the APS-C (crop sensor) image is blown up to match the outer dimensions of the full frame image.

Same enlargement comparison

Left, Nikon D800 full frame sensor. Right, Nikon D90 APS-C sensor.

Image quality

Image quality is not entirely based upon image size at the sensor, but is based upon in-camera processing technology, pixel size and pixel density. Many “crop sensor” cameras have better sensors and processing engines than full frame cameras. But that’s another story. (Maybe later.)

Copyright © 2014 Brian K Loflin . All rights reserved.

Where’s the aperture ring?

ApertureRing-5018-Sm

Modern Nikkor lenses: 60mm F2.8 Micro Nikkor with manual aperture ring (left) and 18-200mm F3.5 – 5.6 VR zoom. Notice the absence of the aperture ring on the zoom. Image made with Nikon D2Xs and 200 mm F4.0 Micro Nikkor and flash.

With today’s electronic technology-driven cameras, many of our exposure controls are as convenient as a finger push on the camera body. And with experience, we never have to remove our eye from the viewfinder.

The shutter speed and aperture selection is controlled electronically through the selector wheel on the camera body. However, in natural science photography there are cases where electronic aperture selection is not possible because the electronic connections between the lens and the camera body are not workable.

Do I mean the camera malfunctions? No, not at all. What I mean is that, through the addition of some components between the camera body and lens, the electronic circuitry is interrupted. This happens with some extension tubes and bellows (below), as well as microscope adapters. This is not uncommon, nor does it really pose a problem when you are aware of what’s really happening.

Tube-1083

Bellows-1727-sm

So without electronic aperture selection, apertures need to be selected manually with the aperture selector ring and the exposures made in Aperture Priority (or Av) shooting mode. The camera will measure the light that falls on the internal metering sensor and set the shutter speed appropriately.

There may be one problem, however. Some lenses do not have a manual aperture selection ring on the lens barrel. Nikon calls these lenses “G” lenses. We fondly call them “gelded” lenses. Many Canon lenses are without the ring as well. So, it ends up that these are not really appropriate for this type of photography. We need to look for those lenses with aperture rings available. There a number of current Nikkor optics with the aperture ring. The 60 mm, 105 mm, and 200 mm macro lenses still have the aperture selector ring. Also the series of manual Nikkor lenses from 20 mm to 105 mm also retain the aperture selector ring.

Fortunately, under the correct circumstances, many older lenses (Canon and Nikon, too) may be used on modern D-SLR cameras. These lenses frequently have the aperture selector ring. And with adapters, Nikkor lenses may be used on Canon EOS series camera bodies. This is a nice option due to the great selection available  of Nikkor optics.

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.

Create shadowless macro backgrounds

In the world of studio photography, it is relatively easy to photograph a subject on white seamless paper and create a bright white background, virtually free from distracting shadows. In the world of close-up and macro photography that task is a little bit more difficult.

Unidentified June beetle (Phyllophaga sp.) photographed 1/2 life-size in the White Box setup.

The difficulty in the high magnification scenario is that we are usually very close to the subject with our lens and don’t have much room for a lot of lights. And too, we really need a lot of light for ample aperture and depth of field. To satisfy that requirement, we often select electronic flash as our light source.

That’s good and bad. The benefit is that it is bright, matches daylight in White Balance and is fast, so that it stops most subject motion. The downside is that it it is highly concentrated as a very small, contrasty light source. Most flash heads are only about 2.5 square inches. We know that soft light requires diffusion and large light sources.

The perfect solution for macro is to build a “White Box”. Building on the idea of a lighting tent, the white box is straightforward, economical cheap and quite portable. It also works well and is easy to make.

To make the White Box you need a sheet of white foam-core board, sometimes called foam project board at the craft stores. You also need a sharp knife, like an X-acto, a ruler straight edge and masking tape. That’s it!

To make the White Box cut two pieces of the foam-core 10 x 20 inches and two pieces 8 x 10 inches. Tape the two longer pieces and a single smaller piece together in an “H” arrangement for stability, as shown below. Then place the second small foam-core piece inside as the floor. A piece of tape across the top will keep the sides from spreading.

For a lighting source an electronic flash in a small softbox like a Lastolight EXYBox Speedlight is perfect. Place the softbox on top of the foam-core construction as shown below.  All done!

There are several softboxes available for electronic flash and they should work just fine. Perhaps however, you may need to adjust the dimensions of your construction accordingly.

Exposures are rather straight forward. I prefer Aperture Priority (or Aperture Value) shooting mode because I am concerned about producing enough depth of field for my subject. At high magnifications, close focusing distances and longer focal length lenses, depth of field drops to ridiculously small dimensions. Usually only a few millimeters.

I prefer to use a longer macro lens for this type of work, usually a 105 mm F2.8 Micro Nikkor, or 200 mm F 4.0 Micro Nikkor because of the longer working distances.

In addition, I need to be certain that my exposure renders white as white, rather than mid-tone. Modern cameras help here, but remember, the electronic meter always attempts to make the world mid-tone or 18 percent gray. So in some cases, exposure compensation in the plus direction may be required to expose correctly.

Fifty caliber civil war bullets found in our family garden in Vicksburg, MS.

In some cases, the all-white background may not be suitable for your subject. An easy solution is to have pre-cut pieces of paper ready to slip into the box as a darker background.

Eggs of Lacewing insect (family Chrysopidae) on cactus spine. Life size.

© 2012 Brian Loflin. All rights reserved.

EntoBlitz-2012

Ento-What? Well, let me explain. Last weekend I had the pleasure to participate in a large, insect-based biological survey and specimen collection. Hosted jointly by the Texas A&M University Entomology Graduate Student Organization and the University of Oklahoma Sam Noble Oklahoma Museum of Natural History, the long-standing Red River rivalry was put aside for 45 entomology specialists to gather at the OU Biology Station on Lake Texoma in southern Oklahoma.

The purpose of the activity is to provide a rapid assessment of the insects found in the selected habitats over the three day weekend. Insects are collected by a wide variety of techniques during the day and at night. After collection, they are properly identified, labeled and curated for continuing study and research. And to a lesser degree, to compare with populations during previous periods.

These entomology specialists collected specimens from pin-head sized mites to much larger wasps, butterflies and moths. Because the weather in the region has been warm with ample rain throughout this year the insects were very abundant. While the collection data is still undergoing processing, the group collected some very unique species records that will be of value for future research.

During the event, many interesting collection techniques were utilized like light-trapping at night.

Here an entomologist uses a mercury-vapor light and a white fabric background to attract insects after dark. Naturally attracted to the light’s wave length, the insects land on the white fabric where they may be visualized and collected.

An entomologist uses a pair of fine-tipped forceps to collect tiny beetles for further identification, examination and study.

An adult antlion lands among a myriad variety of beetles, flies, moths and other insects on the light trap. Most widely seen as larvae in funnels in sandy soils, the adults are weak fliers and often resemble damselflies.

An unusual ichneumon wasp is also attracted by the light. These wasps are in a family with well over 3,000 known species north of Mexico. These wasps are parasites of the pupae of moths and butterflies.

A senior entomologist and student discuss insects that have landed on a beat-sheet. Insects fall to these fabric devices after being dislodged from trees, limbs, and bushes by beating the foliage with a stick or shaking branches and leaves.

Blister beetles are often common and generally consume nectar, pollen or flowers of plants. Some eat the leaves and may damage crops. Their common name comes from the fact that when threatened they exude a harmful skin-blistering irritant.

Field biologists often endure hardships like rain, heat or other environmental discomforts. However this weekend in southern Oklahoma most participants had to watch for poison ivy. In some areas as above, the plants were dense and often head-high.

An entomologist specializing in butterflies and moths, puts on the finishing touches of spreading the wings of freshly collected specimens for his mounted collection.

Insect images: Nikon D2Xs, 200mm F 4.0 Micro Nikkor lens, SB-800 flash. Others: 60mm F 2.8 Micro Nikkor, SB-800 Flash.

Copyright © 2012 Brian Loflin. All rights protected.