must you use THIN filters with slr magic 12MM to avoid vignette?

[texcam]

I am about to order a filter set for my 12mm slr magic.
Now they recommend a stepup to 77mm to avoid vignetting.
But is a thin filter also required or is regular thickness ok?

[MKFilm]

Hello !

I just bought a 12mm slr magic for my gh2. Yesterday I tried some Outdoor-Timelapse-Shots. I had some bad vignetting on the sides. I used a 62mm lcw fader mkII with a´step up ring. Now I readed this comment of seb farges on vimeo:

"There is in my test a small vignetting in the outside shots due to the use of a 62mm L.C.W variable ND filter (with a 58mm/62mm step up ring). To avoid the vignetting you'll need a 67mm or a 72mm filter with the right step up ring, because remeber this is a wide lens ! I'll try with this combination later XXX "

Did any one tried it like seb recommanded ?? 12mm Noktor with lcw Fader 67mm or 72mm ?? No more vignietting ??

This Information would be really helpful for me ??

Thank you ..

Marco

[Axel]

You can have a vignette-free (vignette-[i]visibilty[/i]-free) image  with an ND fader just the size of your lenses filter mount. You can have it with the cheapest as well as the most expensive and best coated ND fader. You can have a very pleasant-looking vignette, one that actually makes the video look better. There are a lot of conditions that contribute to these things. One is a very sharp angle of backlight (the SUN!) in which the front filter pane is hit. This may produce an asymmetric vignette like the various gloss contours in Photoshops [i]bevel & emboss[/i] layer style - and make the shot unusable. It may cause a hefty color shift. It may cause lens flares. It may cause chromatic aberrations.

Let me put it this way: If you take the cheapest ND fader without step up rings on a sunny day the chances are good you capture [i]all[/i] of the positive and negative effects mentioned above rather sooner than later.

With bigger diameter you will lessen the problems.

With better coating you will lessen them further.

With a single ND filter (ND2, ND4, ND8) you will eliminate the vignette-problems and lessen the reflexes and color shifts.

With a single ND filter in a mattebox you will have no more problems.