Hi,
  I see that ND filter for OP always sold in package. Some of the package contains ND-64 (which is 6-stops of light). Just wondering if you ever use ND-64? or ND-16 or ND-32 is good enough for daylight ?
Thanks.

I bought mine only for time lapses but 6 stops does not give you much outside low light conditions (sunsets/sunrises etc.) If we get 1 second or less time lapse options in the future, it might come in handy.

Of course, with any shutter speed above 1/2500 you will need a ND64 in bright daylight IF you're shooting at 24fps and want to keep your 180 degree rule Shutter Speed, meaning - in case you don't know it - double your fps in order to get a smooth video. in this case 1/50sec.
Spring is in the corner and soon Summer. Unless you plan to use the OP only at daw or dusk you will definetely need it.

You can get away with the ND32 if you are willing to shoot at higher fps (48fps and above).

Hi, thanks for the inquiry. Hope that you could get the best feedback that you may need in regards to your query. Please let us know if you need our assistance.  Thank you for continued support.

Thanks all for the info.  Looks like I need ND64 as I will use it mostly at the beach in the summer. I was about to return OP due to AF , but then I did more test. I  realize the OP is not perfect but also the way I use it. I feel more comfortable with it now. However, I hope OP will improve it with more firmware in the future.

I use an ND64 quite regularly during midday on a sunny day, especially if I'm shooting at 1/50 (for 25p frame rate). If I'm shooting towards the sun's direction I still need it sometimes even when shooting at 1/100 shutter speed.