2filter no longer supplies Hoya in the above picture. 2filter is offering a Japanese supplier making perfect thin ringed filter products at normal prices called Marumi
New products not in above picture include Tiffen's Digital HT mount, B+W's XS Pro Mount 3.5 mm, Marumi Super DHG mount only 3mm

Do I need a slim or thin filter ring for my lens?

This is our number one question at the 2filter tech department.

First, we always recommend you shoot through the least amount of glass as possible. Use one filter at a time. The protective, UV or clear will not enhance the polarized image when used along with a circular polarizer in the world of digital. So take off the extra glass

The ring dilemna starts with many of our customers being new to DSLR cameras. Many image makers making the switch from film to digital, Many DSLR owners are remembering the lenses of the past. The film full frame 18mm super wide lenses always needed special filters. Today with the popular digital SLR Camera, the smaller image sensor. The 10's 14mm's lenses are now considered the super exotic wides.

On a digital zoom lens 18mm to 200mm any circular polarizer in the market today works perfect, some even with many of the wider 12mm to 24mm zooms.

All of the current circular polarizer’s offered by 2filter.com from Japan, Germany or the USA are perfect for this style of digital SLR or HD slr camera lens.

Here’s a simple point of view, no maker of high quality circular polarizer’s on earth have offered for sale to the public any rotating/ screw mount version in less than a 5mm high ring with or without front threads. still true now 10+yrs in 2011

No quality SLR lens manufactures in the high tech world have ever produced a popular zoom range lens that was not able to accept the use of a polarizer ... So

Don’t pay more for a slimmer ring
it will not make any digital image file better.

If the lens you own takes a circular polarizer, and most do, a 4 mm high protective, clear camera filter will be fine.