Amazingly sharp Olympus 45mm lens has the tendency to flip nose up when mounted on unpowered camera. Most gimbals can handle this little off-balance, some may protest with warning buzz requiring an counterweight ring on front. 37mm Variable ND filter by Promaster's seems to be a solution, adding 13.7G to balance the lens perfectly. Moreover, the variable density works within generous ND3 and ND400 range. Circular ring moves smoothly, although the excess of silicone lubricant need to be wiped off and maintained to avoid dust contamination. Highly recommended.
http://www.mcbaincamera.com/productdetail.php?mcbain_id=2100314

I purchased the attached polaroid lens on amazon and it too worked perfectly.   $35.00 free shipping

https://www.amazon.com/Polaroid- ... /ref=cm_rdp_product

The only issue which is not a big deal is finding another lens cap.  The original will not fit, too small.

Ed

In Sky Aerial S Posted at 2016-7-18 03:11
I purchased the attached polaroid lens on amazon and it too worked perfectly.   $35.00 free shipping ...

This does seem to be a great way to get balance and exposure functionality all at once. Thank you for sharing.