Art Alley - Up Close and Personal

The fallowing photos are a study in textures and colors. All are photographed with a 90mm Macro lens approximetly 1/2 inch away from the piece of art.

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HDR a basic overview

HDR

High dynamic range (HDR) imaging is a set of techniques that allows a photographer to capture and display a greater range of exposure than can be captured in traditional film or digital imaging techniques. The consept of exposure range to a photographer represents the values between light and dark areas in the scene being photographed. Factors effecting the range which a photographer can capture is a function of the medium being used; the sesitivity of the film, paper, and digital sensors. HDR has been recognised for decades but its use was limited due to a lack of computer processing power. However with todays powerful computers HDR is now emerging into the general population.

HDR images contain digital information which corasponds to the physical luminance that can be obsevered in the real world. This is differant than traditional digital images which represent information as it should appear on a monitor or papaer. Thus the data stored in an HDR image is often called scene-referred and the data stored in traditional digital images is called device-referred.

The human eye can see a much greater range of lumanace than a camera can. For an image to come close to this range the photographer must make a minimum of 3 exposures of the scene to collect all the data neaded. A photo to record the bright areas one to record the dark areas and one the records inbetween the two. The more exposures made the higher the dynamic range.

in this example we see that 4 images were used with exposure values of -5, -2, +2, and +5.

These exposures are then blended together using computer softwere such as photoshop or photomatrix. However there is one problem, that is in viewing the image. CRT, LCD, prints, and other ways of viewing images have a limited dynamic range. There are however various methods that have been developed to convert the HDR image into a viewable format, the most common of which is called Tone Mapping.

Tone mapping is a technique which employs a computer to map one set of colors to another with the result of approximating the appearance of HDR images. When an HDR image is displayed on a non-HDR display it has a strong loss of contrast, tone mapping adds contrast to the image while retaining the image details and color appearance.


here we see the above images blened together and tone mapped.

Here are the other HRD images I have made.

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Color, How We See Light

this was originally published on my webpage 3 years ago, enjoy =)

Introduction

Light is a form of radiant electromagnetic energy which, for our purposes, travels as a wave. While this is not exactly correct it is all we need to concern ourselves with to understand color.
The color we see is dependant on the wave length of the light that reaches our eyes.
Visible light is a range of electromagnetic wave lengths that the human eye is sensitive to. The range is about 400 to 700 nm (nanometers). Below 400nm we find ultraviolet radiation, X-rays and Gamma-rays. Above 700nm we encounter infrared radiation, radar, television, and radio.
White light is a combination of all visible wave lengths. Black is an absence of light.

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Bending the Light
If you take a beam of white light and shine it into a prism the prism will bend the light. The shorter wave lenths will bend more than the longer wave lengths thus the white light will be spread out into a visible spectrum.


By placeing filters in the path of the light we will only see the light waves that are passed by the filter. A red filter will only pass red light. Green passes green. Blue passes blue.

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The Additive Property
The next step in our understanding of color is called the additive property. Imagine if you would the next image being created by three projectors projecting white light. Projector 1 has a red filter, 2 has a green filter and 3 has a blue filter on it. When the lights are arranged so they overlap the colors will blend into new colors. Red and green blend to create yellow, green and blue create cyan, blue and red blend to create magenta.

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Subtractive Property
Now again we are going to imagine the three images below are a white light with red, green, and blue filters on it and we are going to hold a different color filter over the red, green, blue.


Much like Red Green and Blue light can be added we can use Yellow, Cyan and Magenta light subtractivly.


Think about it like this, white is all the light together. Printers subtract colors from the white paper using yellow, cyan, and magenta pigments.
We create images on our black (lightless) computer screens by adding red, green and blue light.

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Painting with Light

A fun experiment for any photographer is light painting. The concept is very simple, light painting is a technique were the exposure is made in a dark area by selectively illuminating parts of the subject with a movable light source. The light I use is often a flashlight or a camera strobe with different color gel filters.



The above photo was taken in the dark of night. It is a 1/2 second exposure at ISO 1600 and the light comes from a passing car... I was going to use a flash to fill the photo but the car beat me to it. But this shows how lightpainting can be done to make interesting patterns in an otherwise standard photo.


A very simple use of lightpainting, this exposure lasted 15 seconds at ISO 200. As the moon backlit the scene I moved to the right side of the picture and holding a magenta gel over the flash popped off a few bursts of light. Yes it is that simple.


Another much longer exposure (116 seconds) from the same shoot, you can see the movement from the model. In this photo I used a cyan filter on the left side and popped off about 3 bursts of light. I then moved to the right and popped off 1 burst of light with a yellow filter. Just before closing the shutter I added some green light which I bounced off a screen to the ground.


Light painting can also be done by moving a point light source in the photo itself. In this image Amanda just held her position while I moved an LED flashlight around her.


In this photo which can be seen at the top of the page uses two colors with the flash a heavy blue gel just to the right and slightly above the camera and a magenta gel directly to the right of the model at her eye level. The red on Sam's boot comes from a large red neon light located on the roof of a building behind her.

So here are the basics of what you need to do this yourself. First you need a camera that you can lock the shutter open, this is normally called bulb mode. Most cameras will also need a shutter release cable. I have had some exposures go for multiple minutes. You will therefor need a sturdy tripod to set your camera on.
A light source, this could be a flashlight or a strobe and some color gels are nice to have also. The gels I use are the same that are used for stage lighting. They come in sheets that can be cut to fit the flash. You can order them online or they can often be found at your local music store.
After that you just need to use your imagination.


A simple lighting scheme using 3 filters cyan, red, and light orange.


Here I planed out this shot to take advantage of Laurens placement in the yellow flowers and the light gray colored rocks knowing that a cyan flash would make the yellow pop out and the rocks would take the color of the flash. I strategically placed Mat, the demon, so that the red flash on him would compliment the red tones in the sky. The purple in the middle of the photo was a consequence of the red and cyan flashes adding together.


This is also a bit more complex photograph. Lauren and I coordinated her slowly standing up while I popped off alternating colors of green-blue and red-orange.

I hope this will encourage you to try something new and different with some of your photos. The worse that will happen is you will get a blur or nothing at all. However when these photos work the results can be amazing.
After years of playing around with this technique I can now do it like second nature and I always end up with a great photo shoot.

Coming soon I will talk about how light and color work which should help with blending color filters in a photo and how they will affect objects and each other. However the best thing you can do is just go out and play around with it. Learning by doing is key in photography.

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Introducing Fizzgig

Fizzgig, 10% Cardigan Corgi, 90% Attitude.

Age 2
From an early age Fizzgig was a natural rock climber.

Fizz loves to run at the dog park. He was runing to go see his puppy buddy Booger a big Rottweiler.

There is Booger his sister Snot and the white one is Cracker. Fizzgig refuses to play with dogs his size believing he is the size of a small horse.

Age 3
Fizzgig's first encounter with a turtle...
a few seconds later he stuck his nose underwater to sniff it, hehe.
Poor dog has had a minor fear of water ever since.



Age 4


He loves to hike. We can go for miles on end.

Is that a smirk?


Age 5
He is most happy in the wilderness, just like me.

This is his Rin Tin Tin pose

Dont tell me dogs can't smile..



Age 6




Rabits.. he has a weak spot for them...
he is hunting around in this photo.



Age 7


He is pretending to fly =)

He is now 8 years old. I will have to get more photos soon.

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