I am a bit confused... I'm not sure if the cokin system will work on my lens, as my lens doesn't have threads for a filter.
I've found that placing a Z series cokin filter in front of the lens will cover the area of vision on my D5100, but I'm not sure how placing a flat piece of glass or plastic in front of the lens will affect the optics (vignetting, bending, sharpness), as this lens is seeing much more than what's directly in front of it, even though the filter does cover the vision area.
Is there an ideal distance the filter should be from the lens? Or perhaps if I created a bubble shaped filter not just in front of, but extending behind the lens? Something just feels wrong... the front of my lens is a circular shape. And it's looking out of a flat piece of glass placed in front of it.
I'm just trying to place a blue filter in front of my camera so it captures moonlight at night. And I do not want to use white balance or Photoshop to mimic the effect. Thanks a lot for the help.