A Closer Look At the Awesome Canon EOS R Drop-In Filter Mount Adapter

One of my favorite accessories that debuted with the new mirrorless Canon cameras is the EF-EOS R Drop-In Filter Mount Adapter. This mount adapter allows Canon EF lenses to attach onto the RF mount, but also adds a variable neutral density or circular polarizer into the mix in one product.

For this video, Potato Jet takes a spin with the Canon EF-EOS R Drop-In Filter Mount Adapter and gives his thoughts on its design and performance. The variable neutral density filter is controlled with a small dial on the side of the mount adapter and is capable of blocking 1.5 to 9 stops of light. Canon also makes a circular polarizer version which operates the same way, allowing for variable strength of polarization.

The biggest downside with the Drop-In Filter Mount Adapter is that it does not come with any way to remove the effects filter and close the gap in the adapter. Instead, a separate $129.95 purchase is required to buy the clear drop-in filter. As with the clear drop-in filter, the variable neutral density and circular polarizer drop-ins are available as add-ons as well.

Do you own the drop-in filter adapter? Share your experience in the comments below.

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Andrew Morse's picture

I love the idea (especially considering this can let you filter with lenses that don't have any other reasonable options) but the price seems a bit out of touch for me, especially for the clear drop in filter.

canon should include one with every RP.

For $99 you have an adapter with no filter that is also much more durable than the insert in a bag.... just get a plain ef-rf adapter. This is why I have both.

Ryan Stone's picture

Being able to add ND or CP to an 11-24 is amazing, and no different sizes or step rings needed. Probably the coolest accessory for the new cams. That said, I’m using the control ring adapter and love it in a Fuji kind of way for my remaining EF lenses.

Marcus Joyce's picture

The killer video feature for sure. Makes you wonder what they have planned for bodies down the road

I went for the adapter with the polarizer. Love it. One filter from 8-600mm. Plus I don’t have to turn the camera off to change the lenses with the curtain closed. The filter prevents any dust from getting to the sensor

Iain McLean's picture

I have the ND filter and it has a horrible brown cast on the bottom right and top left corner, wish I never bought it.

Ryan Mense's picture

Does turning the filter have a hard stop to it? This is the effect you see with variable ND filters that don’t have a hard stop and are spun too far beyond the limits. If it does have a hard stop, I’m wondering if there was a manufacturing error with yours where the two pieces of glass weren’t aligned correctly?

The drop-in ND filter do have max-min stops.

So now I have tested the filter on my EOS R. I does have a quite pronounced blue color shift close to and at max bit is is consistent over the whole frame. So nothing like your picture.
Using a camera/lens calibraion tool and white balancing is recomended to get accurate colors.

A pre and post color and white balance correction. There is a 1-stop difference between each picture from Min to Max

If you do by an additional drop-in filter separate it does come with a plastic case.