Customized Ring Kit for Any Lens

I had never ordered a 3d-printed product before and was a touch skeptical, but I am impressed. Delivery was fast. Setup was easy. It is well made, and fits well. I haven't had any failures or issues. The rings are very sturdy. I don't have any concerns with them at all. I think the EAF mount could benefit from being a bit sturdier. It flexes noticeably, but I didn't have any issues with functionality. (my focus ring is a tad stiff so take that with a grain of salt)

Overall this is a great system and I can tell a lot of thought has gone into the design. The real winner for me was being able to "window shop" this product, enter measurements for my random lens, then a few days later get a version sized to fit. It's very convenient!

For starters nrstellar’s customer service is great. I had several questions during the process and they were quickly available and had answers to my question ready to go.

Read the store page guide and follow the diagrams and drawings and the process is pretty straightforward.

The materials are well packed and everything is super sturdy. I’ve worried about the quality of 3D printed materials in the past but everything in the kit is well built and feels rock solid. The connections points have embedded metal threads and everything feels like it can hold the loads being placed on it. And the foam used in the rings is very grippy. Your tube will not move once secured.

I bought a custom ring set for my redcat 51 v2. If you’re looking for a ring kit for the redcat with helical focuser this is the one to go for. My main purpose for purchase was obtaining a geared EAF setup and the EAF setup is fantastic. I personally would recommend placing your front ring on the dew shield just ahead of the focus tension adjustment ridges.

Everything went together smoothly and with no real issues. Though I will note that if the helical focuser you’ll be attaching the EAF gear to is much smaller than the radius of your front or rear tube-end you may have issues getting the focuser gear onto the focuser. This is not an issue for the redcat. You may also consider buying the risers for smaller radius OTAs to avoid your accessories interacting with your dovetail saddle.

This is my second purchase from nrstellar and I’ll readily do so again. I sincerely think that what you’re getting, both customer support and the end product, is well worth the price.

Noah was fast, friendly and helpful. The custom ring kit turned out perfectly, and I'm really enjoying my new imaging setup.

Custom mounting rings for Canon EF 100-400mm f/4.5-5.6 L IS II USM lens

TLDR: if you have this lens and want to use it for astrophotography, get this ring set and EAF bracket and gear set. Best thing you can do!

I have been using this lens coupled to a QHY168c for a year or so. Originally purchased for bird photography, I was very pleasantly surprised by how well it works as an astrophotography tool. My AstroBin gallery has several examples. The variable focal length makes framing targets just the way you want them very simple and even used wide open at f/4.5 the stars are not horribly distorted. A pass through BlurXterminator on correct-only mode makes them just about perfect! The lens holds focus well at all focal lengths, but needing to focus with a Bahtinov mask is a significant drawback, once you have enjoyed electronically assisted focusing. The biggest attraction of this ring system is the incorporation of an EAF bracket and gear system. I contacted Noah at nrStellar about making rings for this lens. After sending in measurements and photos, Noah created a cutout to accomodate the foot pad and the rotating collar lick knob as well as customizing the ring spacing and focusing ring gear system. Once we confirmed all the measurements, he printed and shipped it all and I had it in hand in days.

Assembly was simple and straightforward and the fit was perfect for the rotating collar in terms of spacing, but I needed to put a thin shim of material under the upper part of that ring to ensure a completely rigid mount. I don't think that there would be any movement without the shim, but there is definitely no movement with it in place. Noah has printed a new upper rear ring that reduces this space, but a small shim is still required as before. I suspect that I could easily get away without it, but it is such a simple fix, I will keep it. The attached image shows the cutout for the collar foot and rotation lock knob. Two accessory mounting plates are in use, one for the Quieter3c and one for the SV210 power distribution box. Gude scope mounting shoe and the EAF mounting bracket can be seen, but the focus ring gear is not seen in this view.

Using a ZWO EAF, the mounting bracket and gear system works just as expected. Wrapping the focus ring gear onto the lens' focus ring is simple and secure and the gears mesh easily and securely. I tested it with the manual controller in daylight and it worked perfectly. Under the stars, I was able to work out a step size quite quickly using NINA. The critical focus zone of my version of this lens is fairly broad, making selecting a step size that works well a bit of a challenge, especially for dualband filters and their longer exposures, and using autofocus is therefore still a work in progress. However, it is easy to get to optimum focus with a few iterations and because the lens holds focus so well, with little noticeable effect of changing temperature so far, this doesn't seem to be a big issue.

With its wide range of focal lenght choices, it will make your widefield imaging of just about any target easier than you could ever hope for. You will read lots of opinions claiming zooms can't hold a candle to prime lenses when used for astrophotography. Well, this is an awfully good zoom right off the hop, and even without using RC AStro's BlurXterminator it captures very good images. Just about everyone uses BXT now anyway even with premium imaging setups--it's a no-brainer. Adding the capability of focusing from a remote connection is also a no-brainer. See my AstroBin page for some examples of images created with this lens using nrStellar mounting ring system!

At the price and with the quality of the product and customer service, I highly recommend this mounting system for the Canon EF 100-400mm L IS II lens.

Norman Hey
Sudbury, ON
Canada