Putting filters on ultra-wide-angle lenses isn’t usually an easy or inexpensive task. Sure, it’s possible, but you need to get some pretty large filter holders and filters to match. The trend amongst some lens manufacturers lately has been to support rear “gel” filters. Filters that sit behind the lens that you attach before you mount it to your camera.
Aurora Aperture has recently announced their “next-generation” of rear mount filters. And best of all, they actually work with lenses that don’t have built-in mounts as the system uses its own magnetic mounts, tailored specifically to your lenses. Now, they’re available on Kickstarter and they’ve already doubled their goal.
Putting filters behind the lens instead of in front of it means that you can go much thinner with the glass. In fact, it’s pretty much a necessity that you do, minimising the risk of refraction and other issues that you often see with front-filters (particularly the really cheap ones). It’s become a popular way to attach filters for those lenses that support them.
Aurora Aperture’s made filters for these lenses in the past, but their new system takes things up a level, by completely replacing existing rear filter mount holders, and adding them to lenses that didn’t previously have one. Some slight modification to the lens is required, although it’s easily reversible. Essentially, you just unscrew a ring on the rear of the lens and replace it with their magnetic one.
The filters are then able to quickly be attached to the rear of the lens using magnets and removed just as quickly when done. At the moment, about a dozen lenses are supported with the new system including…
- Canon EF Rear Mount
- Nikon AF-S 14-24mm f/2.8G ED
- Sigma EF Rear Mount
- Sigma 14-24mm F2.8 DG DN Art
- Sony FE 12-24mm F4 G
Three different types of filters are available to fit these systems, including neutral density (ND), graduated neutral density (GND) and Light Pollution Reduction (LPR) filters.
- ND0.6 / ND4 ND Filter
- ND1.2 / ND16 ND Filter
- ND1.8 / ND64 ND Filter
- ND2.4 / ND256 ND Filter
- ND3.6 / ND4096 ND Filter
- GND0.45 / GND3 GND Filter (soft transition at 60% of frame height)
- GND0.75 / GND6 GND Filter (soft transition at 60% of frame height)
- GND1.05 / GND12 GND Filter (soft transition at 60% of frame height)
- Light Pollution Reduction Filters:
- Hα (656nm) 99.3%
- Hβ (486nm) 91.66%
- O III (496nm & 500.7nm) 88.82% & 81.37%
- S-II (672nm – 92.54%)
- 572nm 0.65% (High-Pressure Sodium Lamp Spectrum Peak)
- 585nm 0.28% (Metal Halide Lamp Spectrum Peak)
It’s an interesting system, especially as it can add the ability to attach a rear filter mount to lenses that don’t natively possess it. It may even offer some new life to those older lenses you’d previously abandoned.
If you want to find out more, you can head on over to Aurora Aperture’s Kickstarter. Items are expected to ship in September 2020.
[via Canon Rumors]