V.I.O. POV ND Filter

**carvemeister** · 02-10-2010, 10:04 PM

Thought this might be worth a new thread after being discussed [ame="http://www.tetongravity.com/forums/showthread.php?t=157836"]here[/ame].

As a precaution for extremely bright days (which some POV users reported), I rigged up what seems to be a pretty good ND Filter on my 1.5.

The fit is very secure and the filter seems to be of superior quality. It wasn't cheap at $32, but it is very thick (much thicker than your standard camera lens filter). I'm sure it would take quite a shot to crack this filter, especially being so small. At the same time it's good protection for the cam lens.

I'm not sure how much I need this yet or if its a stop too dark at 1.0 density (ND8), but it's very simple to pop out later and put a lighter one in. At the same time, it fits snug inside the cut out cap and won't come out without a firm push. I have yet to have it outside on a sunny day.

Thanks to Thorlabs for a nice filter of the perfect size (25mm or .98"):
PRODUCT PAGE
SPECS

The cut out in the lens cap was a bit of a chore. I used a small box cutter type razor but an exacto knife would have been better if I had one.

You need to get very close to cutting the whole center out to prevent vignetting. I still have a very minute bit of that but I don't have the patience to try and cut any closer.

**carvemeister** · 02-11-2010, 10:08 AM

Update:
I tried it out briefly today after 14" of wet pow and blazing sun appeared. Works perfectly with noticeably less washed out area when pointed toward the sun. This should be perfect for all but the darkest of ski days. Nice little filter -optical quality is outstanding.

Now I just need to fashion some kind of lens cap to fit over the whole shebang.

**Sphinx15** · 02-11-2010, 10:45 AM

Care to post up a sample vid?

**carvemeister** · 02-11-2010, 10:55 AM

Originally Posted by Sphinx15

Care to post up a sample vid?

I'm at work right now but just happen to have the VIO in my car. If I get a chance I'll shoot a test clip or two when I go out for lunch and post them in the next day or two.

**Sphinx15** · 02-11-2010, 11:15 AM

Very cool - looking forward to it

**carvemeister** · 02-11-2010, 11:21 PM

I did a brief test today and will post a few still captures from the VIO while the video clip is being rendered (and degraded) by Vimeo. I still have some vignetting and will have to do some more careful trimming, but it does help identify when the ND filter is ON. Also the large object in the lower left is the mounting bracket.

I was very surprised to see that adding the ND filter not onlt kept the highlights from blowing out, but seems to significantly reduce compression artifacts and/or noise.

All the following are clips using the same Color Optomized Exposure setting with ND filter ON and OFF. I didn't take the time to find if there was a better exposure setting but this seems to show the clear benefit of a ND filter.

ND OFF:

ND ON:

ND OFF:

ND ON:

ND OFF (CROPPED & ZOOMED):

ND ON (CROPPED & ZOOMED):

The last comparison is the shocker. This was evident in almost any area I looked at.

Postprocessing could certainly brighten up a clip with the ND filter if needed since highlights aren't blown so I'll be using the ND filter for sure and will correct color and/or exposure a bit later if needed.

I will post the video clip when it's up.

**carvemeister** · 02-11-2010, 11:58 PM

OK, video is up:

[ame="http://vimeo.com/9394536"]Test of ND Filter on V.I.O. POV 1.5 on Vimeo[/ame]

Note - In the last segment, I "corrected" the brightness and reduced the contrast a bit in post processing just to see what could be done. It could be better, but that's as far as I'm going to experiment for now.

SB · 02-12-2010, 09:04 AM

Nice results. Thanks for posting.

**Sphinx15** · 02-12-2010, 09:46 AM

Originally Posted by scottyb

Nice results. Thanks for posting.

Yup - looks great, thanks

**backcountry1pr** · 02-12-2010, 10:18 AM

thats awesome

**carvemeister** · 02-12-2010, 10:40 AM

Thanks for the kudos.

Just remember that if the snow appears a bit dark with the sun in the frame, that's OK, at least it has the ability now to stop down far enough to avoid blowing out the detail. The real benefit is shown when the sun is not in the frame where you can see that the exposure appears perfect with the apparently added benefit of less noise.

Why that is, I'm not sure. Maybe more noise is created by a stopped down aperture on the filterless cam. Maybe this will all go out the window the first time a storm rolls in, but I don't think so.

I may send a link to this to VIO tech support and see if they have any info to provide on this. If any further oddities surface, I will advise.

**grskier** · 02-12-2010, 02:53 PM

Impressive.....

**carvemeister** · 02-13-2010, 06:36 PM

I picked up a cheap little exacto knife at Home Depot and after a few minutes of careful trimming I was able to completely eliminate the vignetting problem and the filter is still as secure as it was before.

Here's the before & after look:

BEFORE:

AFTER:

**Roo** · 02-15-2010, 09:26 AM

Pisses me off that VIO don't offer one of these.

**carvemeister** · 02-15-2010, 09:45 AM

Originally Posted by Roo

Pisses me off that VIO don't offer one of these.

Yeah, It doesn't really make sense.
If they did though, they'd probably charge you more than the homemade job cost.
All things considered, it's quite easy to make one yourself. This really works perfectly now and is simple to make with a good sharp exacto knife.

**brownmonkey** · 02-17-2010, 03:49 PM

Sweet mod - seems incredible to me that Vio do not offer an option for this, especially considering one of the primary uses marketed for the Pov.1 is skiing - where very bright scenes will be the norm.

**Dirty Hoar** · 02-24-2010, 01:17 PM

Hey Carvemeister... excellent solution.

FYI - if you unscrew the protective housing from the camera body you can easily gain access to the protective glass cover. It can be replaced with an ND filter of the same size. The actual diameter of the glass is 21mm. This would be the best solution. The problem is finding an ND filter with those dimensions.

If anyone knows of an inexpensive source for custom cut glass optics a group purchase may be in order. Something under $5 would be ideal. I need at least 20 of them to start. Polarized version too?

**carvemeister** · 02-24-2010, 01:58 PM

I thought about that, but doing so could void the warranty on the cam. In fact, I now think my solution works better anyhow (although more time consuming and expensive) because I can just pop the ND filter off in a second if I suddenly end up in a deep dark glade somewhere, or in Julia Mancuso's closet.

I found a nearly perfect solution for a lens cap to cover the whole deal too. I'll post pics when I get a chance but I simply took an old plastic film container and cut it halfway down. Threw away the top half, turned it over and it's almost a perfect fit. I just put two tiny pieces of sticky backed very thin velcro on the inside of the film container to snug it up and it now works perfect. Stays on tight, comes off easy. Done.

I took a second film container and put some cut foam in the bottom half. When I don't need the ND filter, I stick in in there and put the top on it for a tight, no scratch holder which I'll carry in my pocket if I need to remove the filter.

Originally Posted by Dirty Hoar

Hey Carvemeister... excellent solution.

FYI - if you unscrew the protective housing from the camera body you can easily gain access to the protective glass cover. It can be replaced with an ND filter of the same size. The actual diameter of the glass is 21mm. This would be the best solution.

**Dirty Hoar** · 02-24-2010, 06:56 PM

Originally Posted by carvemeister

I thought about that, but doing so could void the warranty on the cam. In fact, I now think my solution works better anyhow (although more time consuming and expensive) because I can just pop the ND filter off in a second if I suddenly end up in a deep dark glade somewhere, or in Julia Mancuso's closet.

Ya, I see your point.

I'm not too worried about the warranty. I'm more worried about scratching the glass and rendering the camera head useless. So it's good to know that it can easily be replaced.
The protective lens shields they sell are quite dorky, large, and scratch really easy. So that's why I was intrigued by your solution. Killing two birds with one stone... ya know.

I just ordered up some some linear polarizing sheets w/ adhesive. They also have a slight grey tint to them. I'm going to stick this directly to the glass. This should help with toning down the bright conditions, glare, and protect the glass.
I'm not familiar with the stuff so we'll see. But from what I've read it sounds like good stuff, and is not too expensive. Apparently, it's used to cover LCD screens which apparently require the use of a polarizer to view correctly. And they also provide resistance to scratching.

As you mentioned, the downside is not being able to take the filter off while in use. I"ll post an update when I get it done.

**Colorado_Freeskier** · 03-28-2010, 02:28 PM

1st off great work! Also a Dremmel tool would be great to cleanly remove the center of the lens cap. So do you have any ski video posted up where you used your ND filter? I'd like to do this for my POV 1...anyone know if the POV 1.5 camera head is the same size as the POV 1?

I can't believe what a POS the firmware 1.4 upgrade is. I've got a POV 1 and took it out on a sunny day in CO, set it to "color enhanced" mode which per their website is supposed to darken the picture. Turned out that 100% of the footage is completely useless and, as expected, I can't recover anything in FCE. Much worse than before the upgrade. VIO needs to get their head out of their ass.

**carvemeister** · 03-30-2010, 09:10 AM

Right now, I don't have any software capable of editing the POV's video files. I guess the POV software might have done that but it was such crap that I uninstalled it. I was using a 30 day trial of Edius 5 which was great but it's expired. I have to buy something soon.

The files I have are too big and too long to upload at the moment. I'll see if I can find time later this week to upload something.

The ND filter worked very well. Maybe a bit dark on very overcast days, but otherwise in bright sun, etc. it was perfect.

I had no problems using color optimized with mine at all, but I have the 1.5. I also don't think that setting was supposed to darken things much, if at all. The front end diameter on the 1 and 1.5 are the same BTW. I verified that when I called VIO to order an extra lens cap.

Originally Posted by Colorado_Freeskier

1st off great work! Also a Dremmel tool would be great to cleanly remove the center of the lens cap. So do you have any ski video posted up where you used your ND filter? I'd like to do this for my POV 1...anyone know if the POV 1.5 camera head is the same size as the POV 1?

I can't believe what a POS the firmware 1.4 upgrade is. I've got a POV 1 and took it out on a sunny day in CO, set it to "color enhanced" mode which per their website is supposed to darken the picture. Turned out that 100% of the footage is completely useless and, as expected, I can't recover anything in FCE. Much worse than before the upgrade. VIO needs to get their head out of their ass.

**carvemeister** · 03-30-2010, 02:39 PM

Originally Posted by Colorado_Freeskier

So do you have any ski video posted up where you used your ND filter?

OK, I just downloaded another software trial version (Edius NEO 2.5) so I could edit and upload a quick clip. Nothing special except for some great pow in the 1st minute of the clip. This was from Monarch Cat skiing and one of the only clips that I was able to get without the Invalid Clip problem.

It came out a little bit dark with the ND filter on so I just bumped the exposure up a small bit when editing. Very simple.

Here's the clip:

[ame="http://vimeo.com/10561598"]Monarch Cat Skiing 3/9/10 on Vimeo[/ame]

**Colorado_Freeskier** · 03-30-2010, 03:08 PM

Thanks. I'm going to give this a shot, so hopefully in the next couple of weeks I can post up some ski footage in bright sunlight.

**carvemeister** · 03-30-2010, 03:45 PM

If I get a chance later, I'll try to post a shot from bright sun segment with the ND on.

**carvemeister** · 03-30-2010, 07:51 PM

Ok, I posted a small sample from a very bright day, March 6th at Telluride. Just cruising down to the lift line. Wish I had a more worthy clip for you, but I just wanted to grab a quick example.

I actually had to bump the exposure up a smidgen on this too because it looked a little dark to me. Maybe its my monitor?

[ame="http://vimeo.com/10569682"]ND Filter Test on Vimeo[/ame]