Hack Tip: Using ND Filter Gels with Rokinon Fisheye Lens

My recent video with a fisheye lens has brought up the question about how to block incoming light on a bright day. On a typical lens you would screw an ND Filter to the front. Due to the design of many fisheye and wide angle lenses, they are unable to accept threaded filters.

rokinon Fisheye Lens

On a bright day, you end up stopping down your aperture as much as possible, and sometimes that's still not enough. Simply holding a glass ND filter over the front of your lens can help, but you'll be prone to internal reflections bouncing off the fisheye back to your filter.

So if you run into this problem, here's a simple and yet very effective way to add an ND filter to your fisheye or super wide angle lens using inexpensive gels.

If you want to maintain sharpness, get a decent filter. The Rosco gels are great quality, inexpensive, and as you can see there's not too much loss in sharpness in my tests. Keep in mind i'm using a flat Cine profile on the GH4 with no sharpening added in post. You can punch this image up even more if you think you have the need.

For such a small piece I suggest grabbing the Cinegel Creative Kit (found here) which includes a bunch of different ND filters and creative colored gels.

Rosco Cinegel Creative Kit ND Filters
find-price-button Rosco Cinegel Swatch Creative Kit

If you need a larger piece, those too can be purchased in larger individual sheets (found here)

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find-price-button Rosco Cinegel ND Filter Sheets

6 thoughts on “Hack Tip: Using ND Filter Gels with Rokinon Fisheye Lens

  1. A trick I can recommend when you're footage is shot at a shutter speed that is way too high , is to use a 50 fps timeline. I use FCPX, so when you drop your 25p footage into it, you get 2 identical consecutive frames.
    Retime your footage a little (like 101%), just to trick FCPX in allowing you to select the option optical flow ("Retime" > "Video Quality" > "Optical Flow"). After you switched it on, you can set your footage back to 100% and you will have a new frame, every frame. I admit the intermitting frames look blurry, but check the video a it's playing. You'll be a whole lot happier! It's a life saver. Try it for yourself. A smile will come to your face 😉

  2. Alex

    @urban runoff, adding motion blur in post to a high shutter speed footage will be very different from shooting with a 180 degree shutter, because you simply lack all the intermediate information captured by the slower shutter, the result of the motion blur will be a ghosting effect, which most of the times looks worst than leaving the high speed shutter footage as is, and it is definitively very different from a 180 degree shutter footage.
    @Cfreak, so the conclusion is that it cannot be fixed in post if you lack the information. Also ND filters are very useful to shoot at the desirable f-stop.

  3. urban runoff

    you shoot at higher shutter speed and ad motion blur in post? anybody ever done a side by side comparison? I only do this with action b cameras such as gopro's

  4. urban runoff

    yup we used to do this with Bolex cameras. But they had a special filter insert behind the lens. didn't notice any drop in sharpness either 😉 😛

  5. Cfreak

    Kodak Wratten Filters are more expensive but what Hollywood uses for behind the lens gel filtration. I am sure they are optically better than the free gel swatch books from Rosco or Lee.

    In this day and age, it can be fixed in post, so why spend the money if you don't have to.

    I do get the concept.

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