DA* 11-18mm and Filters

When I last posted about acquiring the DA* 11-18mm the question of filters was raised.
I've had a little adventure investigating this question.
Not having a suitable set of filters myself I made a call out at the camera club I belong to for a filter set to try with an 82mm connector ring. One lovely member lent me their 100mm Lee set of filters and holder with the appropriate 82mm wide angle connector, happy days.
Alas, this fell at the first hurdle, the connector ring would not screw on to the lens. The plastic end of the the lens, which has the plastic "blobs" for attaching the hood makes it too fat to fit in the groove provided by the Lee connector ring. I wouldn't dare mess about with someones kit so quickly returned them.
We move on and social distancing and isolating became the norm.
I continued reading reviews and looking at filters and holders. Eventually last week I struck a deal on Ebay for a secondhand Nisi V5 pro holder with landscape CPL,two 82mm connectors plus a 77mm and 72mm. It all arrived in great shape at the end of last week. Excitedly I unwrapped it, pulled out the connector ring and, you guessed it, just as the Lee the groove is not wide enough to fit over the chunky end of the lens so the thread will not screw on.
I see two possibilities:-
1. File down the plastic hood retaining "blobs"
2. Try and find an adaptor
I always use the hood provided with the lens, not just to shield from light but to protect the lens when wandering about. I'd rather have a scratch on my hood than the lens element so, I'm not going to permanently alter the lens and ruin the hood attachment. After quite a lot of searching I found two 82mm to 82mm adaptor rings, one from Hong Kong and one from Kood in the UK. The Kood adaptor had a deeper female thread which I didn't want but I knew it would arrive a lot quicker and it was I think £1.10 cheaper. The ring arrived in the post yesterday morning. Straight on to the lens it went the Nisi assembly attaching nicely, hurrah!
But.......
First a control shot with no filter kit assembly



Now with the filter assembly, without the CPL



I know the female thread is longer than needed and so keeping the filter holder further from the camera so with very fine emery paper (polishing grades) I carefully start reducing the Kood adaptor ring. I used such fine abrasive paper so as not to damage the very fine thread which in turn could damage the other threads. Once I'd reduced its depth as much as possible it was time to try again.

No CPL


I'd call that a success, with the holder square to the camera frame and no CPL I see no vignetting however.....

With the filter holder swivelled through about 30-40 degrees to be at an angle. For this shot I removed one of the filter holders from the left side of the holder so on that side it would only hold two filters rather than three as standard as in the bottom right of the image, it makes quite a difference



And with the CPL in place there is still vignetting in all four corners



But zoom to 12mm and there is but the smallest trace in the very extreme corners



All taken at 11mm f8 except the last 12mm all imported to LR as RAW and exported as resized jpegs.
I don't know how anyone will get on with other brands but without the CPL inserted I consider the problem resolved, with the CPL it's not dreadful at 11mm but almost gone completely by 12mm.
I would guess that to get results with no vignetting at the widest end if using a CPL or wanting to twist your holder to be at an angle one would have to step up to a 150mm filter holder set and filters. For myself I think I'll get by just fine.

Nigel,
Thank you for taking the time to answer the question on filters. That is an extremely useful post.
I would not have thought about the lugs for the hood preventing fitting the adaptor ring.
You have done well to find a way around the problem. At such wide angles one is dealing with fine tolerances to avoid vignetting.
There are newer filter holders on the market which are slimmer e.g the Irix Edge. Also the Kase K9 holder has a wider diameter so it can take a 90mm CPL.
The only way to know if they work is to try it on the lens. It gets expensive to keep buying different filter holders and you need a friendly dealer to be able to try them on the lens. In theory they could work but the devil is in the detail....

At the moment that gives me a good reason not to buy the lens!

As a comparison, I have the DA 12-24 lens and use the Lee system with it. The 77mm adaptor easily clears the hood lugs. If I remember correctly at 12mm one can only use 1 filter slot to avoid vignetting, . I did loads of tests with and without screw in filters and CPL and could find those if anyone wanted.
Thanks again for the post.
Paul