Stock Photograhy Lesson - Quality Requirements for Online Stock Photograph Sales

by Sean David Baylis - Date: 2007-01-20 - Word Count: 1248 Share This!

Most online stock agencies require that your images be submitted in TIFF or JPEG format at resolutions high enough to be printed at A3 or bigger. In order to do this you will have to have shoot the image on a camera with at least 6 megapixel this will give a file size of at least 17MB at 8 bit. You are then required to Interpolate (upsize) your image to at least 48MB before submission. Use Adobe Photoshop CS/CS2 camera raw to open your RAW files. This allows maximum control over the editing process. Camera RAW is a photoshop plugin for CS/CS2.

The difference between RAW, JPEG and TIFF.

RAW files are the camera's data from the three sensors RGB (Red, Green, Blue) recorded as independently editable data. As the three colour chanels are not combined you have much easier editing capabilities over exposure, contrast, saturation and white balance, than if you had shot in JPEG. Shooting in RAW will also allow you to interpolate your images in Camera RAW allowing you to escape the tedious process of having to upsize using Genuine Fractals. (See appendix: Genuine Fractals). All professional photographers shooting with digital cameras shoot in RAW. JPEG is a file format used by most point and shoot cameras that combines the three colour chanels and compresses the image using a mathematical algorithim. Most point and shoot camera only allow JPEG files. There is a certain loss of image quality with JPEG compression and it becomes more noticeable the higher the compression ratio. Loss of image quality is a bad thing, which is why we always shoot in RAW. TIFF files are the same as JPEG except that they do not compress the image and therefore have much larger file sizes. There is no loss of image quality with TIFF files. Images are usually sent into the agency in TIFF format.

Dust, Scratches and Noise

Beware of getting dust in your camera. Todays DSLR cameras have one problem that the manufacturers are working to eliminate. Dust getting onto the sensor. When this happens you get blemishes or spots on your photos that show up especially in the areas of same colour like the sky or someones face. They are very unsightly and must be removed in an image editing program like Photoshop, before you submit to the Stock agency. If you are still shooting film and want to scan your negatives, make sure you scan them at double the resolution you want to save them as. If you want a 50MB file you will have to scan the slide at 100MB to achieve a desirable resolution. Drum scans from a professional output lab are best, but some fine desktop scanners are also available. The Nikon DS4000 is a good choice, the Minolta Dimage 5400 is a better one. These scanners come quipped with DIGITAL ICE a software program that uses the data from the sensors to see where the dust and scratches are and to then correct the image, or in other words, it does all the photoshopping for you. When scanning slides make sure you have DIGITAL ICE or you will have to spend hours touching up. Digital noise is the effect of colour patterns and texture that show up in images that are underexposed or shot on a high ISO (film speed). Basically these unsightly patterns and textures, that show up in the darker areas of images not badly affected or in all areas of more severe images, are caused by the over sensitivity of the sensor. On long exposures the light enters the camera, hits the sensor then small amounts of it are bounced back onto the back end of the lens to then be reflected back onto the sensor, creating colour and noise patterns and textures. With high ISO settings the same principle applies except it is magnified into a shorter time by the high sensitivity of the sensor. On a slow ISO of 100 with a proper exposure the sensor only picks up the direct light from the subject. Underexposed images can be brought up to the proper exposure but with very severe noise effect.

Each agency will have its own specific requirements, as you may chose to submit your images to more than one agency you will want to have the highest possible image quality as some agencies demand higher quality than others. Always aim to achieve the highest image quality with your digital camera or scans, file sizes of 50-70mb are standard for most agencies.

What kind of camera will I need?

Selling stock photography on-line requires that you have a high resolution camera that has at least 6 megapixels. Cameras with lower resolution create images that when blown up to a large size turn to Jaggies (INSERT JAGGIES IMAGE). DSLR (Digital Single Lens Reflex) cameras are very popular with photography enthusiasts as they allow you to control the many camera functions such as shutter speed and lens aperture as well as the use of different lenses and accessories. They also allow you to shoot in RAW a very important feature for the serious amateur.

Two popular manufacturers of DSLR cameras are Canon and Nikon (chose one or the other, stay away from anything else). One of the best places to buy a DSLR is at The Canon 400D is a very popular camera having won the prestigious TIPA award for 2005. Retailing at Amazon for $828 this camera is a steal compared to what was available just a few years ago. The 400D uses Canon's acclaimed CMOS technology, for outstanding image quality and 10 Megapixels resolution. This camera has all the image capture power you will need for any stock agency online. It is light weight, easy to use and is full of all the features you will need to take great photographs. It can shoot in RAW or JPEG mode, we always recommend shooting in RAW. More on RAW later.

Quality Lens the most important part of your kit.

The most important part of your camera is the lens. It is the lens that gathers and focuses the light from the subject on to the sensor (film). The quality of the material the lens is made out of determines the quality of the image captured. Expensive lenses refract the light in a cleaner manner, rendering the detail in an image with the highest possible clarity. Cheep lenses tend to make images look blurred or flat. If you are starting out and want to get a great kit, buy a cheeper body such as the 400D and spend more on a decent lens. Today you can find great lenses from third party vendors such as Sigma and Vivitar that cost a fraction of what the Canon lenses cost. As you may have gathered by now we favour Canon, not saying that Nikon is a poor choice, just that we have been using Canon forever and love them. It used to be said that Nikon was the choice of the top professional, but when they failed to switch to a digital lens mount backing the 80's they fell behind when the advent of digital hit the market. Nikon make great cameras, Canon make slightly better ones. For entry level the 400D kicks the D40.

And as this is not an expose on what camera to use. Our final words, no matter what camera as long as it meets the minimum pixels count requirements and it not noisy you images will have a good chance of passing the agencies editing processes.

Related Tags: hong kong photographer stock photography

Hong Kong Photographer Sean David Baylis is a full time commercial and event photographer in Hong Kong. Coming soon lesson 3 in our series.

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