So my question is:
How far do Filters influence the quality of a picture.
I have the choice to buy a Hoya PRO1 or a Soligor Polar filter. I have a Sigma 17-70 sDC len. DO I need for this lense the Hoya polarizer or the cheaper Soligor will produce the same quality?
For one thing light has not changed since man invented the digital camera. So when you see this advertising rubbish ignore it:
"The SOLIGOR DHG-coated Filters are optimised especially for digital high- …"
Soligor DHG Cir.Polarizing Filter 49mm Reviews
Most filter manufacturing now days results in great products. I had an exchange with a person on a forum over color casts by cheap filters. I bought the Cokin el-cheapo ND filter knock offs on
eBay and took photos of my white car with the various brands. There was no color cast. Eventually at about 10x the white just got dark due to not enough light getting through. Even when I posted the photos the man refused to believe it. Opinions are entrenched and many refuse to change.
Make sure the circular polarizer is properly coated for flare etc.
The polarizer and ND filters along with the haze reducing UV are the only required filters for digital that can't be duplicated with software so a bit extra cost is not going to break the bank. But there is no need to buy the megabucks filters they are in my opinion just a whole lot of advertising shtick. Here is a link to support the going overboard on the image quality degradation shtick
Dirty lens article
Many people like to add the bragging list after their posts. Seldom are they the cheap gear. Almost always they love listing their big dollar items. They may never use it or use it to potential but they let the world know they have it. Like the guy with a 1972 Corvette that never drives over 65 mph.
If this is you then buy the most expensive and brag about it.
I did a wedding as the primary with a humble Nikon D50 and some rather poor Sigma lenses fitted with a budget SunPak polarizer. I noticed the beginners had outfitted themselves with all the big dollar items. They could afford it so it was no big deal. In conversation after one said he was taking notes as I did my thing and learned I was spinning the polarizer etc. After it was all said and done the wedding party said they liked mine the best. Humble gear in the hands of talent will trump the most expensive gear in the hands of the talent-less every time.
Buy what ever makes you happy and trips your trigger. You have to be comfortable with it.