Nowadays, digital imaging device has become a popular item of our daily life. Even a cell phone can gives a high density image. People can enjoy taking a photo at anytime and anywhere, but such a mechanically simplified imaging device usually cannot mount an optical lens filter. Therefore the digital filtering effect is needed. Many image effect filters have been released by image processing soft maker or digital camera manufacture, but most of them were made just for funny, the resulting image is unnatural. This research focuses on the digital filtering effect, and it is realized according to a real optical lens imaging system. In this work, we prepared several optical filter lenses, and take photos with or without using them. Assuming the photo without using a filter is the real object, and then the photo using the filter is the observed filtering image, the digital filter can be derived by a division theoretically. Using these digital filters, the resulting filtering images are gotten. From these result, we find that some of the filtering effect is good, but some of the effects were not enough. Therefore, assuming the cause of these problems from the experimental results, show the direction for future research such as improving experiment approach or adopting nonlinear algorithms is also attempt.