The 77mm Magnetic Back Cap is a filter cap compatible with the Freewell magnetic quick swap filters. Made of metal, it magnetically attaches to a 77mm quick swap filter to protect it in transport. The cap allows you to protect the filter when you don't want to carry the filter in a storage case. It's useful for times when you don't want to carry a storage case with all your filters but rather just want to take the filter(s) you need for the shoot.

For Freewell Magnetic Quick Swap Filters    Protects Filter Outside of Storage Case

Related Questions and Answers

Q: 1. Does this mattebox support partial insertions of filters such as graduated effect filters?

A: The SmallRig Revo-Arcane Lightweight Multifunctional Matte Box Basic Bundle (114mm Back) (B&H# SM3641) uses a system of filter trays with solid black bezels on all four sides to hold rectangular or square filters. You would thus be unlikely to want to use a filter only partially inserted if you wanted to be able to make use of the entire typical 16:9 section of a full frame sensor when using an ultra wide lens such as a 14mm one. However, if you were using a cropped sensor, or if you were using a less wide, normal, or telephoto lens then you might be able to position the filter tray in such a way that it would not be in your shot despite not being fully inserted. Given the small nature of the likelihood of someone being satisfied with that, however, we cannot recommend it.

Q: 2. Will this fit the Canon RF 600mm f4?

A: Yes, Don Zeck C10 Lens Cap for the Canon 600mm f/4 IS Lens is also compatible with Canon RF 600mm f/4 L IS USM Lens.

Q: 3. Fits on elmarit 21mm2.8?

A: Yes. The Elmarit-M 21mm F/2.8 should have 55mm filter threads and this cap will fit when you are not using the lens hood.

Q: 4. So would this only mount to the Sigma 60-600mm f/4.5-6.3 DG DN with 105mm size by "floating" next to the lens on the rails?

A: Using a 114mm to 105mm thread adapter to mount the SmallRig Revo-Arcane Lightweight Multifunctional Modular Matte Box Basic Bundle (114mm Back) to the Sigma 60-600mm f/4.5-6.3 DG DN OS Sports Lens (Sony E) is one solution. Another is mounting the camera, lens, and matte box to 15mm rods and using the SmallRig Silicone Donut for SmallRig Matte Box 2660. See the link below: https://bhpho.to/3oGEkOv

Q: 5. What's the weight limit before a lens support bracket is needed?

A: The Tiltaing Canon RF-Mount to PL-Mount Adapter with Adjustable Back Focus (B&H# TIARFPL2) does not have a stated weight limit before a lens support bracket should be used. Intended motion of the camera (none, slow, or bumpy movement), lens balance, and of course weight are all important. Moreover, the lens mounts and, yes, the adapters themselves also should be taken into consideration, the latter seeming to be the very appropriate point of your question. Assuming little or no camera movement, and also especially when using a lens adapter, experienced cinematographers will typically use lens supports whenever the lens is more than 5 lbs (2.27 kg). However, it is never a bad idea to use one, especially when the lens mount is not of the locking variety. One common misunderstanding is the idea that such a support is only used to keep from damaging the lens mount on the camera. In actuality, any downward flex of the lens mount at all (even one micron) will affect the plane of focus of the lens circle on the image sensor. That's what makes lens supports so important even if no damage will result from not using one.

Q: 6. does this fit with the leica Q?

A: The Match Technical Leica Hot Shoe Cap, is compatible with the Leica "M" cameras. The BH #LEHSCQP2 • MFR #423-116-001-013 is the right cap for the Leica Q, and the Q2.

Q: 7. Can you stack multiple 4x5.65 trays?

A: No, the SmallRig Revo-Arcane Lightweight Multifunctional Modular Matte Box Basic Bundle (114mm Back) has one stage for 4x5.65.

Q: 8. What's the material? Metal? Plastic?

A: The cap would be plastic.

Q: 9. Will it fit the 24-105mm?

A: The Sigma LCF-105 III 105 MM lens cap. fits a Sigma 105mm F/2.8 EX DG OS Macro Lens which has a 62MM filter Diameter. I have a Sony 24-105 mm lens which has a 62mm filter Diameter. It would fit my lens. If your lens is 62MM diameter it will fit. If your lens is any other filter Dia. it will not fit.

Q: 10. Do bolts come with this battery plate? How many? If only two bolts come with the plate, can someone provide a link to buy two more compatible additional bolts?

A: Mounting hardware is included, however we do not sell additional hardware.