| 
If I use a filter on my lens, will my image quality suffer?
This is a very common question that we get asked, and one that isn't so straight forward to answer! There are two main variables to consider, one is the optical quality of the lens and the other is the optical quality of the filter being used.
The fact is that whenever you place a piece of glass in front of your lens, there is a possibility that your image quality will suffer depending on the optical properties of the glass. However, if you use a quality filter that has better optical properties than that of the lens then the images should be unaffected.
So how do we choose the right filter for our lens?
A simple rule we can all apply when choosing a filter is that of price and brand. In most cases the price is a reasonable reflection of the quality of the filter. So if you're lens is a low end model, then it would be overkill to go out and buy the most expensive filter because the optical properties of the filter would be far superior to that of the lens. Likewise, if you have a high end professional lens then you wouldn't use a $10 filter on it.
By following this "rule of thumb" and you sticking to commonly known brands of filters, you are very unlikely to have a problem.
After you purchase your filter, it is easy to do some comparison shots with and without the filter for your own piece of mind.
Camera Clinic have seen a few cases of varying degrees of softness due to filters with most being very subtle, we have however also seen many severe cases. Below is an example of a severe resolution issue due to a bad filter.
Inferior Filter No Filter