Finally...
Tried testing the 70-200mm f4L at different focal lengths and with the nifty fifty 50mm f1.8 Mk1 lens.
From left to right...top row - 50mm f2.8, 70mm, 100mm,
bottom row - 135mm, 200mm all at f4.
(please excuse tracking errors and dubious framing)
As you can see internal reflection persists at all focal lengths.
All I can say is buyer beware if you're considering using a clip in front filter with camera lenses.
Hope this helps somebody...
All the best
Doug (Hutech Guinea Pig)
