It is quite evident today that computers can do almost anything with images. Whether it is digital photography or film photography, everything can be manipulated in post processing, so what is the need of using those troublesome filters? Why should you go through the hassle of buying such filters and storing them when you can manipulate your images at the click of a mouse?

Well, the answer is a little complicated because sometimes after effects can not get the same effect as the filters and sometime vice versa. For instance see the following images. The first image on the right has been taken without the filter, the second one on the left with a filter, and the third one below on the right has been manipulated in Photoshop.

In the first image the details of the red bushes and leaves are lost due to low exposure, but the contrast is good. After using a colour enhancement filter to enhance the red colour of leaves and maintain the exposure, we can see that there is a reddish cast on the entire image. Now what is the use of the filter if even after using it you will need to correct it in computer software? But if you see the third image, which has been digitally manipulated using Adobe Photoshop Elements 7, the reddish tones have been enhanced but the beauty of other colours is retained without any colour casts. So there are some filters like colour correction, contrast enhancement, sepia, diffusion filters and net filters, whose effect can be attained digitally.

However filters like UV filter, polarizer filters and ND filters can not be compromised with, as they help in getting the right picture and exposure and not enhancing the image.