On Sat, 19 May 2001 20:36:56 -0400, "Ira Wilner" wrote:

>Hello fellow denizens of this newsgroup.
>
>I have a question for those who have had the pleasure of using the better TV
>zoom lenses such as the newer internal focus IF series from either Canon or
>Fujinon.
>
>My "stock" Fujinon, the model provided with the JVC GY DV500, besides having
>some flare issues is especially sensitive to dust on the surface of the
>front objective as well as any filter in front of it. This is far more so
>than I recall from 35mm lenses I've used. Any particulate results in a
>small blurry gray circle that can be seen when shooting a brightly lit scene
>with a fairly uniform background. Cleaning the lens with an air bulb brush
>usually eliminates the problem.
>
>With 35mm photography I rarely had dust show up as visible artifacts as the
>surface of the lens and/or filters were so far away from the focal point as
>to be virtually invisible. Is this sensitivity to an occasional dust
>particle on the front element a characteristic of most 1/2 inch video zoom
>lenses? Or are the newer, more expensive IF lenses more immune?
>
>Thanks for any first hand experience you can offer.

With the much smaller sensitive areas and the physically
much longer (relative to angle of view, at the short FLs)
lenses for video, the front element surfaces are much more
likely to be nearly within the DOF range of the most
commonly used focus distances (with lens zoomed short),
so dust on the front elements will often show. This problem
is especially bad when WA front lens converters are used (I
blow off the front before every scene, but I still sometimes
get "the blobs"...).