Thursday, 4 August 2011

Selling your photography

Selling your photographs can be tricky in the world. Where do you start?

Everyone has to start somewhere, and one good place to get your feet wet is Zazzle.

If you haven't heard of it, Zazzle is a great online shopping place with tons of original and unique designs, ranging from hard-to-find products made by professional brands, to original designs by small-time artists. Not only that, but *anyone* can be a zazzler. If you fancy yourself as a budding photographer, zazzle can be your playground to get creative and use your photos to start designing clothing like t-shirts, hats and even shoes!, mugs, magnets, bags, stamps, stickers, greeting cards, mouspads and more. If you're more of a purist photographer, you can stick to posters, postcards and canvas-style prints.

So check Zazzle out! 

If your photos are good, you may even be featured on some zazzle-related websites that display the "bests" of zazzle like the site Zazzle Pizzaz.

Wednesday, 1 June 2011

What is acutance?

Acutance is how sharp an edge is.

Low acutance is a blurry edge that merges into the next thing in the photo.

High acutance is a sharp edge that is well-defined and clear.

What affects acutance?
Acutance is dependent on the quality of your lens, and on post-processing techniques (e.g. sharpening tools and blurring/ unsharpening tools).

What is a "bit" in photography?

In computing, a "bit" is an abbreviation for a "binary digit", which is smallest unit of data (in binary code) in which computers store information.

What has this got to do with photography?

Digital cameras store photos in bits too. The colours of the shot are interpreted by the computer chips in terms of binary code of 0s and 1s. The "bit depth" of a picture describes how many colours can be stored as information for a photo, or more usually, it describes how many colours can be stored as information for one pixel of a photo.

Each pixel of colour is made up of different percentages of the primary colours: red, green and blue. Each one of these primary colours within a pixel is called a "colour channel". The information for the intensity of each channel is stored in bits (bits per channel), and the information that records the combination of the 3 colour channels together is also stored in bits (bits per pixel, bpp).

Usually each channel has 8 bits available for information storage. i.e. a computer reads it as a series of 8 figures of zeros and/or ones. This means that each of the three channels can have up to 256 different permutations of zeros and ones, and 256 different shades of their primary colour. Since there are three of these channels, if you calculate the total number of permutations with all 3 channels together it comes out to 16,777,216 different possible colours you can obtain.

The number of bits per pixel varies depending on the settings of your camera and digital equipment.
  • For black and white images, or monochrome (ie a range between two colours, like black and white, or dark red to white), you only need 1 bit per pixel.
  • For 4 colours (called CGA), you need 2 bits per pixel
  • For 256 colours, (VGA) you need 16 bits per pixel
  • For 16,777,216 colours (SVGA or "true colour") you need 24 bits per pixel. This is more than the eye can detect because the eye can only perceive about 10,000,000 colours so for most purposes 24bpp is as high as you'd need.

Tuesday, 31 May 2011

What is white balancing?

White balancing is where you ensure that the white in your photos really is "white" and not cream or blueish white or any other shade of white. Digital cameras may have an auto-white balancing (AWB) function but with all the different lighting conditions with their different shades of white, it's usually not as good as the human eye, so the photographer sometimes has to intervene and take action to ensure that the white of the photos is indeed white.

Sometimes the camera can be confused if a shot is mostly one shade of colour, say green, it may mistakenly think that the scene is being lit by a green light and will auto-white balance accordingly, so the photographer has to step in and make sure this doesn't happen.

How can a photographer intervene to do white balancing?

1.) Take RAW shots

Taking photos in RAW format enables you to manipulate the white balancing after the shot is taken. After taking the photo, the camera usually shows you a screen with a colour slider, where you can adjust it manually to white balance the shot. Depending on your camera, an alternate way to white-balance is to click on the part of the photo which you see to be pure white, and it will adjust the rest of colours of the photo accordingly.

2.) Ensure you have a sample of white in your photo

To allow you to white balance a shot, it's helpful to have white in the shot. This isn't essential and some photos don't have white reference points in them, but if there isn't a white reference point, white balancing is more tricky and your camera is more likely to struggle with auto-white balancing.

3.) Carry with you a white card to show you what white is

If your shot has no white in it,  you can have a reference card or object with you to help you white-balance by eye. You can buy photographer card kits for a range of colours, including different ranges of greys, to help you white balance by eye.

Friday, 27 May 2011

What is Shutter Speed?

Shutter speed is the amount of time the camera's shutter stays open, allowing light in, before taking a shot. It is usually measured in fractions of a second so is seen as a fraction like 1/125, or 1/2000. The larger the denominator, the faster the shutter speed (because the fraction makes up a smaller part of a second).

The standards figures for shutter speeds are: 1/1000 s, 1/500 s, 1/250 s, 1/125 s, 1/60 s, 1/30 s, 1/15 s, 1/8 s, 1/4 s, 1/2 s, 1 s, and a few settings for super-long exposure.   Each increment (apart from the super-long exposure) roughly doubles or halves the amount of light entering a shot. The fastest shutter speed available is 1/16,000 which is found on high quality DSLRs.

A fast shutter speed (eg 1/16000-1/1000) means that there is little time to let light in, so the picture will appear darker. This setting is suitable if you're in high light conditions or have other settings on the camera set to allow light in.

A slow shutter speed (eg 1/125 - 1/2) gives more time for light to get into the camera, so the shot will appear lighter and brighter.

Because of it's relationship with light, shutter speed is also known as "exposure time". A fast shutter speed is a short exposure time and a slow shutter speed is a long exposure time.

Effect of shutter speed on exposure vs the effect of aperture size on exposure

If you compare how much brighter a shot is made by a low shutter speed or by a large aperture, you find that doubling the aperture has a more dramatic effect on light than shutter speed:
  • halving the shutter speed doubles the exposure (ie it increases the exposure by a unit of 1 EV, where EV stands for exposure value ), 
  • halving the f-number (ie. doubling the aperture) increases the exposure by a factor of 4 (or by 2 EV units).  
Shutter speed and aperture have such a closely linked relationship that you could effectively get the same exposure of the shot at wildly different settings, by  considering this relationship. For example, all the following settings will have roughly the same exposure:
  • shutter speed of 1/250 s and f/8 
  • shutter speed 1/500 s and f/5.6, 
  • shutter speed 1/125 s and f/11.  
Advantages of fast shutter speeds
  • It allows more light into a shot which can be useful if you need to boost exposure without changing aperture or ISO.
  • It allows you to capture things in motion without a motion blur. The fast shutter speed snaps a super-brief moment in time, so it can capture a movement that occurs in a fraction of a second. The less time there is to allow light to enter the shot from the next part of the movement, the less blur there will be. This can be useful in capturing wildlife mid-flight or mid-run, catching subjects in races and sporting events, and generally capturing anything in motion. For example, if you want to capture someone mid-jump with both feet in the air, fast shutter speed is ideal.
Advantages of slow shutter speeds
  • Creating artistic motion blurs: This can be fun if you're using flashlights or photographing moving cars at night. It can create almost abstract shots.  It can also create magical looking effects like when you shoot running water with slow shutter speeds, the resulting motion blur gives the illusion of flowing fog sometimes. The amount of blur depends on the speed at which the object is moving, as well as on the distance the object is from you and the amount of zoom you're using (or focal length). Zoom accentuates motion blur.
Disadvantages of slow shutter speeds
  • It's very easy to get a blurry shot even if you don't intend to. Any movement of the camera can result in a blur. It's really advisable to use a stabilizer like a tripod to steady the camera and prevent camera shake in anything slower than 1/60. 

What happens if you change the zoom whilst a picture is being exposed with a slow shutter speed? 

This is a photographic trick called "zoom burst" where you set the camera to a long exposure/ slow shutter speed, and whilst the shutter is open, you zoom in on the object you want to capture. The result is a sharp object in the centre (as long as it is still and not moving during the long exposure), and a radial blur in the surroundings from the motion of the zoom.

    Red Eye in Photos

    What causes red eye in photos?

    I've written a post about this on my website which you can check out here:

    What is resolution?

    What is resolution on a camera?

    Resolution in digital photography  relates to how detailed and high quality your picture is. The detail is determined by the number of pixels in your photo.

    Every digital image is composed of little pixels. Each pixel in a photo is smaller than a computer screen pixel. Computers usually display about 72 pixels per inch, whereas on paper you may print off a shot with 300 pixels per inch. The more pixels there are per a photo, the higher the quality of the image. For this reason, resolution is often measured in megapixels (millions of pixels per image). The resolution is determined by the quality of the camera's technology.

    A camera that captures images that are 1920 pixels high and 1080 pixels wide is said to have 1920x1080 resolution, or around 2 million megapixels. Incidentally video quality is also measured in this pixel-related resolution, and 1080 pixel width (1080p) is the common image width for high quality blu-rays and some HD discs.   Most DVDs are 720x480 pixels (720p) and normal  analog TV broadcast is around 500x480 (480p). Youtube videos allow you to set your resolution from 240p to 480p.

    Still cameras generally have higher resolution than 2 megapixels with the best ones having up to 8 or more megapixels.

    The higher the resolution, the  higher the quality of your shots, so you can zoom in on a shot and still retain detail, and you can blow a photo up to a large size and it'll still look good.  So really, the higher the resolution, the better.

    Can you change your camera's resolution for individual shots? 
    Yes. On my camera there are settings for:
    • Large (L) which is high resolution at 3264x2448 pixels (ie 8 megapixels)
    • Large to medium (L/M); Medium (M); and Medium-to-small (M/S) settings which vary in resolution
    • Small (S) which is the lowest resolution at 640x480 pixels (ie 3 megapixels)