Inspire 1 ND filters Part 2 – Renaat filters
Since posting my review of the Polar Pro filters the DJI Inspire 1 I’ve purchased another set from a guy named Renaat in China. I read about his filters set on the InspirePilots forum, for more information he can be contacted via email at firstname.lastname@example.org
I paid a total of $84 including delivery for a set of four filters from Renaat including ND8, ND16, ND32 & ND64. The filters were delivered in 2 days using DHL so they are extremely good value.
The filters come really nice individual filter boxes that secure each filter against a piece of soft foam, that alone is a big positive for this set. Each filter has a series of dots printed on the side denoting it’s level of filtration, 3 dots for ND8 through 6 dots for ND64. As you can see in the photo below the design of these filters is also a lot closer to that of the original DJI filters so the camera gimbal won’t be stressed.
So lets start with a similar setup to part 1 and see how these filters perform. Lets start with a shot without any filter to gauge levels.
So without any filters correct exposure is being achieved at ISO 100 with a shutter speed of 1/640 th of a second.
Next up, the Renaat ND8 Filter…
As with the previous tests each ND level should half the current exposure meaning that ND8 should produce results as follows…
Clear = 1/640
ND2 = 1/320
ND4 = 1/160
ND8 = 1/80
ND16 = 1/40
This puts the resulting 1/100 Shutter speed close enough to be considered correctly labeled. Colour wise there seems to be a slight red bias over the clear lens. This is likely the result of Infra Red pollution which often becomes an issue with ND filters. On larger camera systems this can sometimes be corrected with an additional IR filter but as it’s not possible to stack filters on the Inspire 1 as we don’t have that option. Next up the ND16.
Going from ND8 to ND16 is one stop so the resulting shutter speed of 1/50 is exactly where it should be. Colour stays very similar to the ND8 with slight bias in to the reds from the IR light.
In order to test the ND32 I increased ISO to 400 to better simulate brighter conditions. here’s the result with a clear lens.
And now with the Renaat ND32 Added.
Again lets look at where each level of ND should take the exposure
Clear = 1/2500
ND2 = 1/1250
ND4 = 1/640
ND8 = 1/320
ND16 = 1/160
ND32 = 1/80
So as you can see the resulting 1/80 shutter speed produced with the ND32 seems spot on in terms of filtration offering 5 stops of reduction. We are beginning to see more colour shifting with the ND32 however with blacks becoming brown and the sky becoming noticeably more purple. The Inspire 1’s sensor has a tendency to allow Infra Red light to effect the image which is usually noticeable on black fabrics. This IR pollution becomes more apparent as more ND is added because the Infra red light not being filtered whilst the visible light is being reduced by the filter.
For the final ND64 Filter I increased the ISO to 800 lets lets start again with a clear filter.
So the theory seems to be working correctly as doubling the ISO had doubled our shutter speed to 1/5000, lets see how the Renaat ND64 deals with that.
Clear = 1/5000
ND2 = 1/2500
ND4 = 1/1250
ND8 = 1/640
ND16 = 1/320
ND32 = 1/160
ND64 = 1/80
ND128 = 1/40
With a resulting shutter speed of 1/40 the filtration results actually put the ND64 closer to the results I’d expect from an ND128 but when this many stops are involved it’s very easy to be a stop out. IR pollution is starting to become extreme at this level of ND.
At a cost of only $84 (USD) these filters are extremely good value, they are built to match the Inspire 1 perfectly using a similar lightweight frame as the DJI filters. The included cases for each lens is another welcome addition.
I would certainly be happy using the ND8 and ND16 in combination with the DJI ND4 filter. The Renaat ND32 is also going to produce usable results but will definitely require some additional attention with colour correction. I wouldn’t however feel comfortable using the supplied ND64 filter as the IR pollution is just too extreme. While some correction could be made in post I’d rather have a higher shutter speed than have to deal with this much of a colour problem in post.
There are ND filters on the market for larger cameras that include IR filtration, I’ve seen these priced in the hundreds for each filter though so we’ll have to wait and see if a set becomes available for the Inspire 1.
If you’d like to find out more about these filters then contact Renaat via email at email@example.com and please let him know you heard about them here.