The Movcam 144:100mm Step-Down Ring for Clamp-On MatteBoxes lets you mount 100mm lenses onto 144mm clamp-on matteboxes -- the kinds without a thread on their rear adapter.

The ring is split along a point of its diameter to flexibly widen and mount a mattebox. (A locking pin on the side of the mattebox securely tightens the ring in place.)

Split Ring for Clamp-On MatteBoxes

Related Questions and Answers

Q: 1. Will this lens work with the Canon EOS R5 Mirrorless Camera when using an adapter? Thanks.

A: Yes, works great on an R5 or any other R series bodies.

Q: 2. I want to get into macro photography but I enjoy portrait photography too. Is this good for both? Thank you,

A: YES, Absolutely an incredible lens for both of your Needs!

Q: 3. I am looking to replace the front lens cap for this lens. What size do I need?

A: Canon EF 100mm f/2.8L Macro IS USM Lens has a 67mm front thread accesories to attach lens caps, filters and other accesories.

Q: 4. I've been reading lots of reviews on Macro lenses in the 90-105mm focal length, and I seem to sense that in this focal length range the better it is to look for one with image stabilization. There'll be times when I can use a tripod and not need it, but I like to be able to handhold when I'm out hiking and don't want to lug a tripod with me. I usually stick with Canon lenses since I have an EOS 70D, but I also like affordability. What would be your recommendation between a Sigma macro lens with OS and a Tamron macro with VC in the focal length range I'm interested? I'm pretty sure I want to do more in the macro field as I look for new areas to try and think that I'd feel better about using a designated lens over a close-up lens.

A: Sigma and Tamrons macro lenses in this category are both honestly excellent options. I would have no issues having either in my own kit bag. Of the two I more commonly have used the Tamron in the past for my needs, as I like their sharpness and color rendition. The lens is well constructed and focuses quickly.

Q: 5. Does the Canon MT-24EX Macro Twin Lite Flash attach to (clip onto) this lens?

A: Yup. I believe it attaches itself on the outside on the lens housing on the other side of the filter ring. Be careful if you are shooting objects at the minimum focus distance (12 ). It may not fully illuminate your subject matter.

Q: 6. What improvements have been made to this lens? I have a 15 year old version of this lens, but wonder if the improvements justify buying the new version.

A: I can't help you with personal experience, I've only owned the new EF 100 F2.8L Macro IS USM version. Some users tell me it is easier to find a tripod collar for this model that the older one. I do fine the lens extremely sharp, when I use AF it's accurate and fairly fast. It's my favorite lens.

Q: 7. Is there a Canon 100 Macro that is auto focus

A: The Canon EF 100mm f/2.8L Macro IS USM Lens is an Auto-focus lens.

Q: 8. The Eos R7 is not a full frame camera. Do I have trouble focusing on close-ups (plant, insect, face)? Because this lens is a mirrorless lens designed for full frame camera. Is the focus area narrow?

A: When using this lens on a Canon R7 it will have a crop factor of 1.6x. This will make the equivalent focal length 160mm. This will have no effect on the minimum focus distance though, which will remain 10.2".

Q: 9. Canon EOS Rebel T2i isn't specifically listed in the compatibility screen. Can anyone confirm compatibility?

A: This lens is compatible with Canon T2i

Q: 10. Can canon Ef 100mm f2.8 Marco USM lens use with canon EOS 5D Mark 4?

A: Yes EF lenses are compatible with the 5d Mark IV.