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Hello, yes, this filter has IR reduction. 

Hi, if you want put len cap , doesn't need remove the magnetic basic ring, thanks. 

Dear customer, Thanks for this question, we already did instruction picture and tips for "how to remove the lens adapter", plz see the instruction picture in the "Product Description".Hope it helps 

The adapter clicks on the lens. It has a small dark gray colored lever (not the white plastic tab to change aperture), level to the outer edge of the bottom ring accessible when removed from the camera, grab the whole adapter with your left hand and push the lever in with your thumb, and while pushing, rotate the lens with your right hand to remove it. You need to push in that lever to unlock the lens.