Monday, July 27, 2009

Nature

Discussion Forum

Guides and Reference Articles

Field Ethics

Equipment Reviews

Nature Reviews

Travel and Locations

If you would like to contribute an article to these pages, please take a look the article contribution page.

I would like to thank all those who have sent in contributions to these pages and, of course, Philip Greenspun without whom these pages would not be possible.


Top Photo: © Copyright Robert M. Atkins, All rights reserved.
Western Coyote, Yosemite NP, Canon EOS system, EF 300/4L lens.

Article created 1998

Thursday, July 23, 2009

Characteristics

Pinhole images are softer – less sharp – than pictures made with a lens. The images have nearly infinite depth of field. Wide angle images remain absolutely rectilinear. On the other hand, pinhole images suffer from greater chromatic aberration than pictures made with a simple lens, and they tolerate little enlargement.

Exposures are long, ranging from half a second to several hours. Images are exposed on film or paper – negative or positive; black and white, or color.

Pinhole optics, by the way, are not only used in photography. There is one animal in nature which uses a pinhole for seeing – the mollusk Nautilus. Each eye has an accommodating aperture – the aperture can enlarge or shrink. In this drawing, originally taken from a book published by Arthur Willey in 1900, the eye is the oval opening to the upper right.

History

Early Observations and Experiments

The basic optical principles of the pinhole are commented on in Chinese texts from the fifth century BC. Chinese writers had discovered by experiments that light travels in straight lines. The philosopher Mo Ti (later Mo Tsu) was the first – to our knowledge – to record the formation of an inverted image with a pinhole or screen. Mo Ti was aware that objects reflect light in all directions, and that rays from the top of an object, when passing through a hole, will produce the lower part of an image (Hammond 1981:1). According to Hammond, there is no further reference to the camera obscura in Chinese texts until the ninth century AD, when Tuan Chheng Shih refers to an image in a pagoda. Shen Kua later corrected his explanation of the image. Yu Chao-Lung in the tenth century used model pagodas to make pinhole images on a screen. However, no geometric theory on image formation resulted from these experiments and observations (Hammond 1981:2).

In the western hemisphere Aristotle (fourth century BC) comments on pinhole image formation in his work Problems. In Book XV, 6, he asks: "Why is it that when the sun passes through quadri-laterals, as for instance in wickerwork, it does not produce a figure rectangular in shape but circular? [...]" In Book XV, 11, he asks further: "Why is it that an eclipse of the sun, if one looks at it through a sieve or through leaves, such as a plane-tree or other broadleaved tree, or if one joins the fingers of one hand over the fingers of the other, the rays are crescent-shaped where they reach the earth? Is it for the same reason as that when light shines through a rectangular peep-hole, it appears circular in the form of a cone? [...]" (Aristotle 1936:333,341). Aristotle found no satisfactory explanation to his observation; the problem remained unresolved until the 16th century (Hammond 1981:5).

The Arabian physicist and mathematician Ibn al-Haytham, also known as Alhazen, experimented with image formation in the tenth century AD. He arranged three candles in a row and put a screen with a small hole between the candles and the wall. He noted that images were formed only by means of small holes and that the candle to the right made an image to the left on the wall. From his observations he deduced the linearity of light. (Hammond 1981:5).

In the following centuries the pinhole technique was used by optical scientists in various experiments to study sunlight projected from a small aperture.

Pinhole Photography

History, Images, Cameras, Formulas by Jon Grepstad

Introduction

Pinhole photography is lensless photography. A tiny hole replaces the lens. Light passes through the hole; an image is formed in the camera.

Pinhole cameras are small or large, improvised or designed with great care. Cameras have been made of sea shells, many have been made of oatmeal boxes, coke cans or cookie containers, at least one has been made of a discarded refrigerator. Cameras have been cast in plaster like a face mask, constructed from beautiful hardwoods, built of metal with bellows and a range of multiple pinholes. Station wagons have been used as pinhole cameras – and rooms in large buildings. Basically a pinhole camera is a box, with a tiny hole at one end and film or photographic paper at the other.

Pinhole cameras are used for fun, for art and for science.

Designing and building the cameras are great fun. Making images with cameras you have made yourself is a great pleasure, too. But in serious photography the pinhole camera is just an imaging device with its advantages and limitations, special characteristics and potentials. By making the best of the camera's potential great images can be produced. Some of the images could not have been produced with a lens.

Panasonic Lumix DMC-LX3 – "мыльница" за 69900 р

В августе нынешнего года компания Panasonic представила несколько новых цифровых фотокамер, среди которых особенно выделялась модель Lumix LX3, созданная как компактное дополнение к зеркальной фотокамере. На днях же Panasonic сообщила о поступлении в продажу эксклюзивного «премиум-сета» Lumix DMC-LX3, состоящего из одноименной компактной цифровой камеры и широкого набора аксессуаров.



Напомним основные достоинства камеры Lumix LX3. ПЗС-матрица DMC-LX3 способна воспроизводить изображения, записанные при установке объектива 24-60 мм, в любом из трех форматов – 4:3, 3:2 или 16:9 – для динамичных, выразительных снимков с обширной перспективой. Кроме того, режим макросъемки позволяет делать четкие изображения с расстояния от 1 см. Благодаря новому, 24-мм сверхширокоугольному объективу LEICA DC VARIO-SUMMICRON со светосилой F2.0, фотокамера Lumix LX3 способна снимать неплохие кадры даже при слабом освещении.



В набор входит широкоугольная конверсионная насадка, которая обеспечивает угол съемки 18 мм, а возможности создания изображений также улучшают ND-фильтр и новый PL-фильтр. Внешний алюминиевый оптический видоискатель должен пригодиться при съемке в солнечную погоду. Дополняет набор футляр из натуральной кожи и пригодный для хранения SD-карт чехол.

Спецпредложение ограничено и будет доступно только в России. Стоимость Panasonic Lumix DMC-LX3 составит 69 990 рублей.

Friday, July 17, 2009

Accessories


For a camera body and one lens, the average professional photographer would not use a case at all. To hold a camera system, you should probably find a nearby professional camera shop and experiment to see how your gear fits. I usually end up preferring Tamrac and Lowe cases. Here are a few ideas:

Recommended Starter Nikon SLR Systems

Glen Canyon Dam (Arizona/Utah border)

Average family:

Serious photographer:

Pentax Af540

Pentax AF 540 FGZ Flash ($340)

Product Details

Pentax AF 540 FGZ Flash

The AF 540FGZ Electronic-Flash unit features a large guide number of 54 (at ISO 100) and provides a variety of advanced flash applications, including advanced P-TTL auto flash, high-speed synchronisation and wireless P-TTL auto flash (when mounted on a Pentax SLR camera). When mounted on a Pentax auto-focus SLR (after the Z-10 and including digital format models) equipped with an FA-, FA J-, DFA- or DA- series lens, the AF540FGZ automatically adjusts its angle of discharge to the lens' focal length. The AF540FGZ auto-flash unit also features a newly provided 'Digital' position on the focal-length conversion scale of the zoom head which can accommodate digital SLRs, Bounce Flash function with adjustable angles of -10 to 90 degrees vertically and up to 180 degrees horizontally, and Power-zoom flash head to cover angles of view for 24mm to 85mm lenses (in 35mm format). It is compatible with a range of batteries, and is able to run on either 4x AA alkaline batteries, 4x AA lithium batteries or 4x AA Ni-MH batteries. We advise using rechargeable batteries. External LCD indication - Format; Flash mode; Zoom; Channel; ISO speed; Discharge level compensation; Spotbeam; F number; Discharge level; Wireless mode; Bounce flash warning; Sync mode; Discharge distance; Out-of-coupling-range warning. LED illumination available

Flash

Photo.net Review Excerpt

Photography is about creating images with light. For indoor, night, fill light, or certain special effects, using electronic flashes to generate light becomes an important component in modern photography. Nikon’s current flash technology is called i-TTL, and they offer five different external flash options. So far all of those i-TTL flashes have three-digit model numbers in the form of SB-n00 (e.g. SB-600, SB-900 and there is also an SB-R200) while the older, non-i-TTL flashes have two-digit model numbers (e.g. SB-28 and SB-80 DX). Therefore, it is very easy to determine which ones are i-TTL compatible. This article provides a brief history of the evolution of Nikon TTL flash technology and a guide to those five i-TTL flashes.

The intro image demonstrates the size differences amongst the SB-900, SB-800 and SB-600.

The Introduction of Digital and D-TTL

Nikon introduced the TTL (through-the-lens) flash technology to its film SLRs (Single-Lens Reflex Cameras) in the mid 1980’s. The major advantage of TTL flash is that flash exposure is measured during the actual exposure, as the amount of light reflected off the film is detected by sensors placed inside the mirror box. When a sufficient amount of light is detected, the flash is electronically shut off instantaneously.

Wednesday, July 15, 2009

Nikon part 6

i love nikon

Nikon part 5

Telephoto Zoom Lenses

These are good complements to a normal lens when traveling. The long end may not be useful indoors due to a small maximum aperture.

Wide-angle Zoom Lenses

Good for general-purpose dramatic wide angle photography. More distortion than wide-angle prime lenses, which makes them less suitable for photographing architecture (though many kinds of distortion can be fixed by a PhotoShop wizard).

Nikon

Wide-to-Telephoto Zoom Lenses

Atlantic City Boardwalk, New Jersey

A wide-to-tele zoom is what you get as a standard "kit" lens with a cheaper digital SLR body. The range goes from moderately wide through normal to moderately telephoto. They are good when you are too busy to change lenses, e.g., at a wedding reception. The 24mm perspective (full-frame) will capture a table of guests; the 70mm or 105mm long end is good for a flattering portrait. The main weakness of these lenses is that the cheaper ones have a very small maximum aperture, e.g., f/4 or f/5.6, and can only be used in bright light, on a tripod, or with a blast of on-camera flash that gives everyone a moon face.

Nikon Digital SLR System part 3

In terms of flare, contrast, and sharpness, these are the highest quality lenses that you will ever attach to your camera. If you can do the job with a normal lens, as many of the 20th Century's greatest photographers did, you can save yourself a lot of weight and cost. There are good zoom lenses, but they are very expensive and heavy.

Nikon Digital SLR System part 2

    in-production

  • Nikon F6, $2399 (review), autofocus, probably the best 35mm film SLR that will ever be made
  • Nikon FM10 with 35-70 lens, $310, manual focus, designed for students in intro photography classes
  • discontinued

  • Nikon F5, $1100
  • Nikon F100, $550 (review), much lighter and smaller than the F-series and almost as durable; this was the standard "second body" that professionals carried in the film days
  • Nikon N80, $217 (review), mostly plastic body, reasonably good autofocus and autoexposure systems; rememeber that it is the lens that determines image quality (might actually be cheaper as a kit with a crummy lens: Nikon N80 with 28-80 lens, $300 (review))
  • Three incredibly cheap, all plastic, not very good bodies: Nikon N55, $150;
  • Nikon N65, $488 (review); Nikon N75, $129
  • Nikon FM3A, $800 (review), hard to find; Nikon came out with this all-metal manual focus body in 2001. It is a beautifully balanced camera and, with a 50/1.4 lens, will take much better pictures than what 99 percent of digital camera owners capture with their cheap kit zoom lenses.

Nomenclature

F-number: lower is better.

VR is "vibration reduction", a technology lifted from camcorder image stabilizers. The lens electronically compensates for unsteady hands. VR is especially important at long focal lengths, e.g., 200mm and above, because the lens magnifies camera shake at the same time it is magnifying the subject. A VR lens will allow you to use slower shutter speeds without introducing camera shake. The alternative to a VR lens would be mounting the camera on a tripod or using a high ISO setting, which reduces image quality but allows the use of higher shutter speeds.

"ED" is "extra-low dispersion" glass, a more expensive and higher quality glass that reduces chromatic aberration, in which light of different colors takes different paths through the lens, which would result in a dot of white light being fuzzed up by the time it reaches the film or sensor.

"IF" is internal focus, meaning that the lens does not change physical length as you focus on subjects that are closer or farther away.

"DX" are Nikon's lenses that only work on its small-sensor digital SLR bodies, i.e., they don't cast a large enough image circle to be used on a film camera.

"FX" refers to the full frame sensor

"G" lenses are Nikon's newest lenses. They don't have an aperture ring, which is a shame because it means that you are forced to adjust the aperture with a command wheel on the camera. The G lenses don't work on older bodies.

AF-S is "silentwave motor". Old-style Nikon autofocus lenses did not have motors in the lens, but relied on a screwdriver blade in the camera body to turn the focus ring. An AF-S lens has a built-in ultrasonic motor, a technology copied from the Canon EOS system. When using an AF-S lens, the photographer can push the shutter release (or a button on the rear of the camera, if a custom function is set) and let the autofocus system do its best, then touch up the focus manually by twisting the lens ring. The AF-S lenses also focus faster and more quietly.

Normal Lenses

Shirley Greenspun.  Manhattan 1995.

A normal or standard lens is light in weight and approximates the perspective of the human eye. Normal lenses have large maximum apertures, indicated by small f-numbers such as f/1.4 or f/1.8, and thereby gather much more light than zoom lenses. It may be possible to take a photo with a normal lens in light only 1/8th or 1/16th as bright as would be required for the same photo with a consumer-priced zoom lens. Another advantage of the large maximum aperture is that the viewfinder will be correspondingly brighter and therefore easier to use in dim light. (SLRs keep the lens wide open for viewing and stop down to whatever aperture you have set just before taking the picture; this is why the viewfinder always looks the same even if you switch from f/1.4 to f/8 to f/16.)


Nikon Digital SLR System

a photo.net guide by Philip Greenspun

Motorcycle convention in North Dakota Brooks Falls, Katmai National Park

The Nikon system of digital single-lens reflex (SLR) bodies and lenses is a popular choice among serious photographers worldwide. This page makes it easy to shop for Nikon digital bodies and Nikkor lenses. Every component manufactured by Nikon is covered, plus a few exceptionally good third-party components. If you are new to photography, you might want to start with my article "Building a Digital SLR System".

This article goes through every section of the Nikon system and concludes with some starter system recommendations.

Nikon Camera Bodies

Most Nikon digital SLR bodies incorporate a "small sensor" or "APS-C" sized sensor. This is smaller than the standard 35mm film frame and effectively multiplies the magnification of any lens attached to the body. A small sensor is good for telephoto work, such as wildlife photography, where a 300mm lens that is too short for bird photography on a film camera becomes a 450mm (effective) lens. In November 2007, Nikon added the D3, their first full-frame sensor DSLR professional camera to their arsenal of DSLR bodies. The full-frame sensor bodies are good for wide angle photography, low light photography, and optimum image quality.

  • Nikon D40, 18-55mm kit, $423 (review), 6 MP and good enough for most family photography; best user interface of any digital SLR, with example photos displayed on the rear LCD to show appropriate situations for different settings. Note that the D40 requires SD memory cards rather than the standard CF cards used by other Nikon bodies
  • Nikon D40x, $590 (review), same idea, but 10 MP; if you care about image quality, pair with Sigma 30mm f/1.4 EX DC for Nikon, $439
  • Nikon D60, $561 (review), 10 MP, Nikon's latest addition to the line of small-body DSLRs, an upgrade to the D40/D40x
  • Nikon D80 (review), 10 MP, Nikon's answer to the Canon Digital Rebel XTi; the kit zooms are reasonably good, but too slow for indoor usage
  • Nikon D90, $949 (review), 12 MP, Nikon's latest prosumer model, includes GPS and a movie mode capable of capturing 1280x720 pixel images at 24 fps HD with sound.
  • Nikon D200 (review), 10 MP, the camera for most advanced amateurs
  • Nikon D300, $1570 (review), 12 MP, released at the same time as the D3, a fast camera with 51 AF points
  • Nikon D2HS, $5987 (review), only 4 Megapixels but tremendously fast; intended for sports photojournalists
  • Nikon D2Xs (review), 12 MP, before the full-frame sensor cameras came along, this was Nikon's top-of-the-line camera
  • Nikon D700, $2350 (review), 12 MP, D3 image quality at about half the price
  • Nikon D3, $4600 (review), 12 MP, Nikon's first full frame sensor DSLR
  • Nikon D3X, $7299 (review), 24.5 MP, D3 image quality with about double the resolution

For nostalgia buffs and collectors, Nikon still makes film bodies: