ND filter?

[Jim Michael]

Please suggest an ND filter density for the following: I need to blur the prop on an airplane. The prop is 72 inches in diameter and rotation speed varies from 1500-2600 RPM. I get rolling shutter artifacts with no ND filter on a sunny day. Camera is a GoPro Hero HD.

[Ian Newland]

We have had success with as little as ND 1.2, i just depends on the amount of light on the day. But reducing the shutter below 1/250 should do the trick.

[Jim Michael]

Thanks Ian.

[Tom Hardwick]

Jim, your rolling shutter artifacts will be there regardless of the shutter speed the GoPro uses. ND will only reduce the shutter speed, and by introducing motion blur will reduce the staccato.effect of the GoPro's high shutter speeds in sunlight.

[Ian Newland]

I don't think Jim is talking about jello wobble, he specifically mentions the effect rolling shutter has on the prop. However, if you are also suffering jello wobble, shoot in 50/60fps to reduce jello by about half of the 30/25fps modes.

This is a very interesting experiment one of our members did with regard to jello, we determined in the end the reduction/elimination was mostly due to the added mass/weight of the adapter and ND filter. However, the ND does seem to have some effect also.

GoPro Jello fix - R5 mode on Vimeo

[Ian Newland]

How's this for an ND or filter solution as well as an antifog solution and a flat lens fix.

BlurFix GoPro Adapter Independant Review on Vimeo

Here's the full review i did.

This single Product fixes 3 common issues with the GoPro HD Camera
1. The underwater focus
2. Inability to attach filters
3. Fogging



I found the adapter and filter very easy to install, taking no longer than 10mins, just follow the well written and pictorial instructions included. (See Video below)
I was very impressed with the build quality, the BlurFix is machined from a single piece of Aluminum billet and is Anodized to prevent reflections.
The two most popular modes R3 720 and R5 1080 show no signs of vignette, however if your GoPro camera is not perfectly aligned within the case you may see a small vignette on one side in R3 mode, simply ensure your camera is seated correctly. My one year old camera had a slot worn in it where it had vibrated against the case locating lugs at some point, so needed the wear slot fixed, my newer cameras had no issues. There is vignette in R4 960 mode, but it's not a mode most people use underwater. The high quality filter that came with the BlurFix has the outer threads machined off to make it low profile, so stacking filters is not possible, but you have the option of changing the filter to say a CY filter, polarized etc. If want to use your own filters, they must also be low profile. Or there is a range of quality low profile filters available from BlurFix.

The video below confirms underwater sharpness is now optimal and you have the option to remove the filter for above water shooing if required and leave the adapter in place. I tested the unit to 50ft over 1 hour with a line and anchor and it remained completely watertight. I have no reason the believe it won't go lower, the manufacturer has tested to 130ft.

I found the anti fogging beads worked perfectly, not once did i see any fogging and i assembled the GoPro and filter in midday 22 degree, 65% humidity conditions. For comparison i also had an unmodified GoPro accompany the test unit and it fogged. Be aware though, you must ensure the O ring, adapter and filter is free of any water/sweat inside the cavity for the beads to do their job of absorbing moisture in the air.

Pros and Cons

Pros

Easy to fit
Glass not Plastic
Precision made from solid billet (one piece)
The flat black anodizing eliminates reflections
Original case dome lens remains intact so does your main case waterproofing.
Can be fitted with most 55mm filters (polarized, ND, UV, Grad etc)
No Fogging - replaceable desiccant beads
Completely fixes the focus issue in 720 and 1080 modes (no vignette)
Does not interfere with camera operation - buttons etc.
Optimal focus in or out of the water
Can be used above water with no vignetting in all modes (including R4 960 and stills) when filter and o-ring are removed (adapter stays)


Cons

Requires assembly (application of silicon)
Will require maintenance to prevent filter threads from sticking (lube)
Overall Slightly more added weight.
Slight vignette in Stills mode and R4


Highly recommended for the following uses

Underwater Video and Stills
Canoes and Kayaks for the anti fogging attributes and water droplet repelling flat lens.
Airplanes or situations where an ND, polarizing filter or other filters are required.
Shutter speed control.
You could get very creative with Graduated ND filters, especially in Snow or Timelapse videos.


You could use it for motorsports as long as you're aware the filter glass may break if hit hard enough.

I have not been paid for this review, the supplier simply shipped me a single product unit to independently review.

[Annen James]

I just tried one of the above mounts for 55mm lens, and used some Tiffen ND's. Was VERY disappointed in the image quality. It lost tons of sharpness without fixing much of the blowouts. Returning ND's now. It is nice to use underwater with a clear UV, but I had high hopes for the ND fixing a lot of issues. Jello is not a concern, so .... damn.

[Ian Newland]

Yes the ND's on the GoPro do nothing to fix blown highlights, actualyl i've found they blow the highs even more. There is too much dark foreground in that image for yhe GoPro to handle bright sky. Grad ND's do work ok though but are expensive. Funny but a polarizer actually works better than an ND, but i suspect that may be due to the coloring more than the polarizing effect..