Vignetting on CV 15/4.5 with Milich filter holder

[tvleeskr]

Originally Posted by chris_tribble

Check that you have Lens recognition on + that your lens has been coded + that you select the CORRECT lens length when the menu comes on. If you do that, no vignetting. If you don't - DARK corners.

I was caught out - it's annoying quirk of the M8.

This just confirms JLM's position that the tolerances are a bit too tight. I checked this with mine of course and the vignetting does not go away.

[jscottyk]

Originally Posted by jlm

I'm looking into it. the present design was arrived at by making several prototypes, enlarging the opening until vignetting just disappeared. It looks like I need more of a saftey margin. Regarding centering and axial alignment, the attachment to the lens is less than ideal, given that it can only fit around the existing petalled hood and be side clamped with a set screw.

I will probably increase the opening and set it to match a standard lens cap.

as far as choosing a larger filter, uh-uh, tolerances are too tight.

Does anyone know if the design has been updated? I sent a private message to jlm several weeks ago inquiring but haven't heard.

[lars_bergquist]

Originally Posted by jlm

I'm looking into it. the present design was arrived at by making several prototypes, enlarging the opening until vignetting just disappeared. It looks like I need more of a saftey margin. Regarding centering and axial alignment, the attachment to the lens is less than ideal, given that it can only fit around the existing petalled hood and be side clamped with a set screw.

I will probably increase the opening and set it to match a standard lens cap.

as far as choosing a larger filter, uh-uh, tolerances are too tight.

It sems to me that with a larger filter (which would of course entail an entirely new hood) tolerances would actually be less tight! But if you can solve he problem, I'm in line for a new hood. BTW, it seems to me that with superwide lenses, lens shades are more or less psychotherapeutic devices. The 'petals' of the lens are for protecting the bulging front element, they don't shade anything.

The old man from the Age of Visible Light

[Ecar]

Originally Posted by jscottyk

Does anyone know if the design has been updated? I sent a private message to jlm several weeks ago inquiring but haven't heard.

I asked him the same question a couple of weeks ago. Answer is yes - design seems to have been updated to "minimize" vignetting. Not sure it means it's fixed, but I have ordered it and should receive it shortly. Will post my impressions then.

[jscottyk]

Thanks for the update ecar. I look forward to your report.

[Ecar]

Originally Posted by jscottyk

Thanks for the update ecar. I look forward to your report.

I did a few quick tests today, so this is only preliminary. In addition to proper coding and software settings (lens detection On+UV/IR, then select 16mm) the trick is to screw the filter in the adapter as much as possible (I'm using a Leica filter). This seems to enable the adapter to fit closer to the lens and minimize vignetting. The important word here is indeed "minimize" (see my previous post quoting JM's response), as you will definitely see some vignetting. Tolerances are very tight, and you may get slightly different results depending on how you fix the filter on the petal hood using the nylon screw.
Need to play with the adapter and do a bit more tests at different apertures when I have some spare time. Will post examples here.

[lars_bergquist]

I still think a larger filter would be in order. Just 41 or 43 mm would be enough.

The old man from the Age of Print Vignetting