Archived posting to the Leica Users Group, 2000/05/20[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]
The obvious difference below is that the filter is in the middle of the lens... and as such it is more part of the optical formula... as opposed to the real life situation of placing a filter on the front of the lens. I had a Canon lens that had that type of internal filter... The instructions said to always use it... and I had no reason to doubt their wisdom.... So I never tried shooting without it. I figured also figured doing so would be the easiest way to get all sorts of dirt, lint and stuff inside your lens anyhow. I am not certain that the filter had exactly parallel surfaces either... which would throw another variable into the mix. Duane >Many long lenses take into consideration the presence of the filter, which MUST be in place in such lenses (e.g., the >400 f/2.8. The effect is not linear, but depends upon the focal length. Perhaps someone at Leica could enlighten us.