Flektogon ie Wide angle with filters

I have two 35mm Flektogon lenses: one in Ekakta mount, the other in Werra mount. I seem to recall using a Yellow contrast filter and getting vignetting. This happened on the small Yashica zoom and definitely on the Werra mount version.

I guess it makes sense as the acceptance or rather the "wide" angle properties are made to the glass specifications and using a filter even with small apertures tends to make the corners darken.

I recall reading somewhere , in reference to the Werra mount, there was indeed a yellow filter that compensated for this wide angle. Does anyone have particulars as I find this focal length to my liking and using the filter for the sky is my desire.

I have had similar issues with other wide angle lenses and found that getting a step up adapter and a larger filter size solved the problem.

Huuhh ?? Is it that easy.. well I will try that out here immediately... I was concerned that any "extension" ie simply the height of the ring itself would cause the vignetting..

Huuhh ?? Is it that easy.. well I will try that out here immediately... I was concerned that any "extension" ie simply the height of the ring itself would cause the vignetting..

Should work, if the step-up ring fits properly. It should only add the thickness of one layer of metal, which is not enough to cause problems in 99.99% of all cases. Even "thin" or "slim-line" filters are much thicker than that one layer of metal.