2X Tele Extender

[Zipper] I use this for my Canon 2x tele-extender. Perfect fit.

Bought to use in my Celestron Tele-Extender as it fits and was cost efficient. I have not been disappointed.

[6mm] Bought to use in my Celestron Tele-Extender as it fits and was cost efficient. I have not been disappointed.

[Glass] There are many A+ reviews about the 2x Extender from Explore Scientific! Add my opinion as A+. Okay, so the glass is excellent and the machining of the unit is exemplary - fit & finish unbeatable. What puts this above & beyond are the instructions are easy to read & understand, and the box from ES is an amazing work of art and utility! Seriously! The box alone is probably worth keeping & displaying at any gathering! The extender is hefty and is packed well within; a given. The covering is based on Wil Tirion's Uranography & Graphic Design! My wife was more impressed with the boxes, than the gadgets! Guys, ponder it. I may survive this purchase. LOL!

There are many A+ reviews about the 2x Extender from Explore Scientific! Add my opinion as A+. Okay, so the glass is excellent and the machining of the unit is exemplary - fit & finish unbeatable. What puts this above & beyond are the instructions are easy to read & understand, and the box from ES is an amazing work of art and utility! Seriously! The box alone is probably worth keeping & displaying at any gathering! The extender is hefty and is packed well within; a given. The covering is based on Wil Tirion's Uranography & Graphic Design! My wife was more impressed with the boxes, than the gadgets! Guys, ponder it. I may survive this purchase. LOL!

[Canon EF] As a rule, I have never found 2X tele extenders to meet my expectations with regard to resolution. I am happy to report that this one surprised me. I use it both on my Canon 6D and EOS 5M along with my Sigma 150-600 Contemporary. While this lens will not auto-focus on the 6D, it will do so on the EOS M5, it being a mirrorless camera. Consequently, I most likely will be using it the majority of the time on the M5. I can unequivocally recommend this extender.

[18.2mm] I used the Tele Vue 2x Powermate to image the planets, as well as doing some visual observing. As usual, Tele Vue optics never disappoint! Highly recommend this great addition to your eyepiece line up!

[1/2" Bayonet] The Extender RF 2x does what you'd expect it to do - doubles the focal length of the lens and doubles the minimum f-number. Optical quality is good; when used together with an RF 100-500mm f/4.5-7.1 L IS USM lens, there's only a small loss of sharpness, and some of that may be unavoidable due to diffraction. Autofocus continues to work with the extender, but image stabilization can become unreliable.

[Zipper] Well made. I wanted a bag for my Canon R5 w/ 100-500mm lens plus 2X extender. Perfect size.

I use the 2 2X Explore Scientific Focal Extender with 2 Eyepieces in 25, 30, 35mm (70 degree FOV Bressers) primarily for viewing Deep Sky Objects: Clusters, Nebulas and Galaxies. My scope is a Meade LX 90 8 inch. The results with the 2 extender are pretty amazing. I begin by using a 20 or 25 mm eyepiece without the extender to find the object. Then for the increased magnification I switch to the 2 extender with either the 25 mm or 30 mm 2 eyepiece . Before getting the 2 extender I used a 1.25 2X extender (also Explore Scientific) with Plossls for viewing the deep sky objects. For the most part, with that setup the objects were bright and clear but, with the narrow FOV of the Plossls, not as dramatic. With the 2 extender and the 2 Bressers the clusters and nebulas are bigger, brighter, well defined objects. The clusters especially are bright and clear with many well defined points of light. The Galaxies are still fuzzy objects, but magnified. If there is a downside to the use of the 2 extender for me, it might be the weight. The combination of the 2 Extender, a 2 Diagonal, and a 2 eyepiece is heavy. But, so far, the scope performs just as it did with the 1.25 setup. Also, the 2 setup prevents the scope from going to zeinth. A 1.25 adapter is included with the extender so it is not necessary to have both the 1.25 and the 2 extenders. I am completely satisfied with the extender.