View Full Version : Lenses and Filters

05-19-2005, 06:01 PM
I am new to DSLR cameras and recently I bought a Canon EF 75-300 IS USM lens to go with my new Rebel XT. To help protect the lens I also got a Cokin UV filter.
Well the image results were poor ( soft ) until I removed the filter, now the images are fine.
What I'm wondering is, would it be a poor quality filter that is causing the problem of soft images or is it the way this lens auto focus works with any filter attached?
I'm happy to purchase a "quality" filter to protect the lens, however it would be a waste of time and $$$ if the images just turn out to be soft again.

05-19-2005, 06:43 PM
I'll direct you to a thread I started a few days ago: UV/Polarizer Filter Comparison (http://www.dcresource.com/forums/showthread.php?t=7912) and heres another article on the subject: The Filter Flare Factor (http://www.luminous-landscape.com/columns/sm-feb-05.shtml)

05-19-2005, 09:07 PM
the higher quality the filter, the better the results. Usually unless you have to use it I would recommend taking it off. The polarizer filter may double as a color saturator/light intensity reducer and lens element protector.

But once again, for normal picture taking I would take the filters off.

05-20-2005, 05:25 AM
BlueDog and Juan-

I agree that filters are, in most cases, not needed. However, when you live directly on the ocean (it less that 120 feet away from where I am sitting), you can see lens coatings affected quite measurably over a period of time of about a year.

Sarah Joyce