One of the most foolish allegations that has taken legitimacy among photographers is that it is great to protect your costly lens with a protective filter, and even better with UV. It is even better if it is a multilayer illumination made of the highest quality optical glass.
Many people are submitting to the “reasonableness” of such “convenient” allegations by the manufacturing companies without considering whether this is not another commercial number ?!
The truth is that each filter affects the optical qualities of each optical system – a lens.
1. The lens is considered from the first to the last optical surface, without any number of bills changing the number of optical surfaces of refraction. Any such change causes serious damage to optical quality. And it inevitably leads to a worse end result.
2. The optical surface of your front lens is specially designed to last for a long time without mechanical damage. Modern low and medium-grade lenses have a short life of the materials they are made of. A lot earlier than the time at which the front optical component would be affected, they would be out of order. Each chemist will explain you extensively, how and why, how long – polymers lose their elasticity and strength and when deformities begin. And the ads will affect you, buy a new, much better and better quality lens – though from 1949. optical circuits have not undergone any significant development.
3. The filter is enclosed in its own housing, and in the case of the best manufacturers, the parallelism is distorted by more than 3 microns, and as we know that the maximum error between the system, the camera lens should not exceed the limit of 5 microns. You should know that this is not the case with very expensive modern lenses. A mistake above this limit starts to affect image quality. Moving from one end to the other with 10 microns is already a problem. And if you have a medium-sized lens, it can make a very serious mistake.
4. High quality filters cost a lot of money … and the others are very dangerous for your pictures in any way.
Finally, filters should be used only when the benefits of these filters outweigh their damage or when there is no other possibility, as is the case with the polarization filter.