Points in Focus Photography

3DP Ideas Wide Angle Replacement Filter Slots for Lee Holders Review

I’ve spent a good amount of time looking for the right solution to using 100mm filters on wide-angle lenses—namely my 16–35mm zooms. From changing systems, to designing my own, I’ve tried a number of solutions to the problem. 3DP Idea’s are another option in the arsenal of tools that seek to address these problems.

First some backstory and disclosure.

Full disclosure; unlike my normal reviews, I didn’t purchase these at retail, they were provided to me at no charge by the manufacturer to test and evaluate, at no cost to myself.

A number of years ago, the idea was brought up by a Norwegian gentleman who had designed and built a non-vignetting filter holder that achieved that by separating the filter slots units into two columns that were moved apart outside of the lens’s angle of view. I quickly made the observation that while doing that worked, all of the slots didn’t need to be moved, and the solution he came up with was somewhat inelegant because of that—of course his solution worked, and worked well for him, and there’s nothing to fault in that.

Part of that discussion involved Hector, of 3D Printed Ideas. He and I, mostly independently but we did talk over ideas and problems, ran with the idea of building a smaller more integrated filter slot component that could be retrofitted onto an existing Lee holder. I banged out a design in Sketch Up and had a prototype made, stated playing with it, and considered taking it to market. However, the costs and an open question about durability of the 3D printed part were something that I wasn’t ready to address and I quietly abandoned the project.

Hector, however, didn’t abandon his work, and to be perfectly honest, I’m glad he didn’t, because I really didn’t want to get into the manufacturing and distribution business to support selling something like this.

In any event, Hector sent me a couple of his slots to test and provide him with feedback earlier this year. It’s those parts that I’ll be discussing in this review.

I would also point out that not all lenses with the same labeled focal length have exactly the same angle of view. I’ve tested these filters on a Canon EF 16–35mm f/4L IS USM lens, since that’s the lens I have and use now. However, it’s important to remember that the entire point of this design is to shave just enough material off in just the right places that they don’t vignette. This is all about tolerances, and keeping them as tight as possible.

Moreover, these slots don’t work alone. You still need to have the right mounting ring and, if you use a protective filter, a thin enough filter too.

3DP Ideas wide-angle filter slots show mounted on a Lee holder on a Canon EF 16-35mm f/4L IS USM lens.
3DP Ideas wide-angle filter slots show mounted on a Lee holder on a Canon EF 16-35mm f/4L IS USM lens.


The entire point of these replacement slots is to reduce or eliminate vignetting on wide angle lenses without having to use larger than 100mm filters. The premise is to carefully removing the parts of the slots that vignette while retaining both 3 slots and an appropriate clamping situation so you don’t drop filters.

Obviously there are limits to just how far a holder like this can go; at some point there’s no getting around needing a bigger filter. So how well does the 3DP Ideas slots work at dealing with vignetting?

I tested the 3DP slots on a Canon EF 16–35mm f/4L IS USM, at both close focusing and infinity focus. The Lee holder was mounted to the lens using Lee’s 77mm wide angle adapter ring. I also ran the tests both with a B+W XS-Pro protection filter (3mm) and without. The two focus positions are do the fact that the EF 16–35mm f/4L IS USM is not a parfocal lens, and at the closest focus setting the angle of view is somewhat wider than at infinity focus.

So the burning question, how well does it work?

Vignetting 16mm no filter
Vignetting 16mm no filter
Vignetting 16mm B+W XS-Pro Filter
Vignetting 16mm B+W XS-Pro Filter
Vignetting 16mm B+W XS-Pro Filter + Lee wide angle adapter ring
Vignetting 16mm B+W XS-Pro Filter + Lee wide angle adapter ring
Vignetting 16mm B+W XS-Pro Filter + Lee wide angle adapter ring, + Lee holder and 3DPI Slots
Vignetting 16mm B+W XS-Pro Filter + Lee wide angle adapter ring, + Lee holder and 3DPI Slots
Vignetting 16mm B+W XS-Pro Filter + Lee wide angle adapter ring, + Lee holder and 3DPI Slots rotated ~45 degrees
Vignetting 16mm B+W XS-Pro Filter + Lee wide angle adapter ring, + Lee holder and 3DPI Slots rotated ~45 degrees

As seen above, with the EF 16–35mm f/4L IS USM, there is no vignetting from the filter slots at 16mm at both infinity and close focus. With this specific lens, there’s slightly more vignetting at the minimum focus distance, however it’s not due to the slots but either the filter or wide angle adapter on the filter.

That said, this isn’t an exhaustive test. I only had my EF 16-35mm f/4L IS USM to test the slots on. Other 16mm wide angle lenses may very well perform differently.

That said, the slots do exactly what they were designed to do, allow you to shoot use wider angle lenses with more filters in the slots.

Holding Force

One of my lingering concerns with replacing the Lee slots is whether or not these slots would provide enough holding force to keep a filter from slipping out when in use. I tested these very crudely by putting them on a scale and pushing the holder down allowing the filter to slide as constantly as possible. The reading on the scale was approximated to an average of what I was seeing, and the force was calculated from that.

Slot 3DPI Lee
Inner 3.4 3.1
Middle 3.9 3.3
Outer 2.3 3.1

There’s a lot of confirmation of things we already knew, at least about the Lee slots. The performance is quite uniform, which is to be expected for filter slots that are all the same. The 3.3N measurement may be measurement error, or it may be a result of me only having really used 4 of the 6 provided slots since with the Lee slots I can’t shoot at 16mm without vignetting.

Likewise, the differences in the 3DP Ideas’ slots isn’t unexpected either. Each of the 3 tracks have had their spring positioning customized to insure that the middle section of the outer most slot to prevent vignetting.

Sure the outer most positions value of 2.3N is worse that the other two positions and the Lee slots. However, if I’m shooting 16mm with the Lee slots, I can’t have 3 slots in use anyway. Slightly lower holding force for an extra slot seems like a fair trade off to me. Moreover, even though the holding force is lower, 2.3N is still enough to hold a filter without it sliding unless you start shaking the camera.

What I was quite pleased to see, is that in this test, the 3DP Ideas slots perform every bit as well as the Lee slots.


In my testing, the 3DP Ideas’ filter slots do exactly what they set out to do. I can shoot with my 16–35mm lens at 16mm without worrying about the filter slots causing vignetting, which is a marked improvement compared to the stock Lee slots. Since getting my pair of these slots, I haven’t even bothered putting the Lee slots back on my holder.

Buy Wide-Angle slots from 3D Printed Ideas


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