I always keep a filter on a lens. Most of them have nice, multicoated filters. Schneider, B&W, Nikon, Leica, Tiffen, Hoya. The images are sharp enough to cause aliasing on the M8 and exceed resolution of C41 film. So the addition of the filter does not produce a detectable difference in the image.
Now- using something like a scanning densitometer or other scientific instrument, and running a 2-D Fourier Transform of the image, I'm sure that some difference could be detected. But the only person that I know that has done that at home is my wife.
Now- using something like a scanning densitometer or other scientific instrument, and running a 2-D Fourier Transform of the image, I'm sure that some difference could be detected. But the only person that I know that has done that at home is my wife.