Uploaded November 2020 | Updated September 2026, 2 hours ago
Comparison view of the William Optics GT71 refractor APO triplet telescope (420mm) with 4x Kenko teleconverters vs the Canon RF800mm lens with 2x extender. It’s not the best time of year to do this with the planets so low in the sky but a few people wanted to see the difference. So even though they’re not great shots, we can see how well they performed at the same time in the same sky conditions at approximately the same extreme focal lengths. I think they were nearly equal in performance with my usual pushing the limits with teleconverters. Daytime photos of 1600mm at 7:32.
Pros of the GT71 telescope - it has a mid range focal length of 420mm at F/5.9 (F4.7 with flattener on at 336mm) in prime focus for deep sky objects, and can be used with barlows, Powermates, and even teleconverters for extreme reach to the planets, with loss of quality and light of course.Weighs 5.12 pounds (8 pounds with my current teleconverter setup). The feather smooth fine adjustment focus knob. Comes with a dew shield attached and a bahtinov mask in the dust cap.
Pros of the Canon RF800mm lens - it's very very light! 5.11 pounds with the camera and heavy dot sight attached. You can even auto focus with the 2x extender on at 1600mm (F/22) which I think is insanely good. Also, it's portable and can be shot handheld.
They're both nice lenses and similarly priced. :)
1/60 shutter speed, ISO 800. F/23.66 on the telescope and F/22 on the RF800mm lens.
5:52pm to 6:35om, Sunday Nov 8th, 2020, NE Ohio (USA), SW Sky, 53°F (13°C)
Telescope Footage Filmed through the Canon Ra Mirrorless Camera
Canon RF800mm Lens & 2x Extender on the Canon R Camera
Recorded onto the Atomos Ninja Flame 7” & 5” Monitor/Recorders in 1080p - Upscaled to 4k
Stacking Done in Pipp, AutoStakkert, & Registax through Parallels for Mac
Photos Processed in Lightroom Classic
Everything put together in Final Cut Pro X
~Jayling
(Ohio is in the Eastern Time Zone)
My Photos & Videos Website:
jayling.smugmug.com
--------------------------------------------------------
Here's the equipment used in this video:
-William Optics GT71 APO Triplet Refractor Telescope: highpointscientific.com/william-optics-gt71-f-5-9-gold-triplet-apo-refractor-w-flattener-and-dual-side-dovetail-a-f71gtii-ap
-Canon EOS Ra Astro Camera: amzn.to/3gmSJFB
-Kenko Teleplus HD 2x Teleconverter: amzn.to/2jEFitp
-Atomos Ninja Flame 7" 4K Field Monitor/Recorder: amzn.to/34a4Xv9
-Benro C373T Carbon Fiber Tripod Legs: amzn.to/2XzddGz
-SkyWatcher AZ-GTi Alt-AZ Telescope Mount: amzn.to/2YFiVDm
-Orion SynScan V5 Hand Controller: amzn.to/2JyzxYp
-Canon EOS R Mirrorless Full Frame Camera: amzn.to/2Wn8dkF
-Canon RF 800mm F/11 Lens: amzn.to/35n9tuz
-Canon RF 2x Extender: amzn.to/3k01VC9
-Atomos Ninja V 5” 4k Recorder/Monitor: amzn.to/2Wt2D1K
-Manfrotto MT055X PRO3 Aluminum Tripod Legs: amzn.to/2lc1wDH
-Astromania Dot Sight: amzn.to/2L0IJom
-Tascam DR-100 MK III Audio Recorder: amzn.to/2LwwqQT
-Tascam TM-2x Mic: amzn.to/2LNADRL
-SkySafari Pro App: skysafariastronomy.com
Links to my gear are for Amazon. I'm an Amazon Associate for which I earn from qualifying purchases. If you click on them, thanks in advance. Additional equipment I use is listed over at my website: jayling.smugmug.com/Equipment
Comparison view of the William Optics GT71 refractor APO triplet telescope (420mm) with 4x Kenko teleconverters vs the Canon RF800mm lens with 2x extender. It’s not the best time of year to do this with the planets so low in the sky but a few people wanted to see the difference. So even though they’re not great shots, we can see how well they performed at the same time in the same sky conditions at approximately the same extreme focal lengths. I think they were nearly equal in performance with my usual pushing the limits with teleconverters. Daytime photos of 1600mm at 7:32.
Pros of the GT71 telescope - it has a mid range focal length of 420mm at F/5.9 (F4.7 with flattener on at 336mm) in prime focus for deep sky objects, and can be used with barlows, Powermates, and even teleconverters for extreme reach to the planets, with loss of quality and light of course.Weighs 5.12 pounds (8 pounds with my current teleconverter setup). The feather smooth fine adjustment focus knob. Comes with a dew shield attached and a bahtinov mask in the dust cap.
Pros of the Canon RF800mm lens - it's very very light! 5.11 pounds with the camera and heavy dot sight attached. You can even auto focus with the 2x extender on at 1600mm (F/22) which I think is insanely good. Also, it's portable and can be shot handheld.
They're both nice lenses and similarly priced. :)
1/60 shutter speed, ISO 800. F/23.66 on the telescope and F/22 on the RF800mm lens.
5:52pm to 6:35om, Sunday Nov 8th, 2020, NE Ohio (USA), SW Sky, 53°F (13°C)
Telescope Footage Filmed through the Canon Ra Mirrorless Camera
Canon RF800mm Lens & 2x Extender on the Canon R Camera
Recorded onto the Atomos Ninja Flame 7” & 5” Monitor/Recorders in 1080p - Upscaled to 4k
Stacking Done in Pipp, AutoStakkert, & Registax through Parallels for Mac
Photos Processed in Lightroom Classic
Everything put together in Final Cut Pro X
~Jayling
(Ohio is in the Eastern Time Zone)
My Photos & Videos Website:
jayling.smugmug.com
--------------------------------------------------------
Here's the equipment used in this video:
-William Optics GT71 APO Triplet Refractor Telescope: highpointscientific.com/william-optics-gt71-f-5-9-gold-triplet-apo-refractor-w-flattener-and-dual-side-dovetail-a-f71gtii-ap
-Canon EOS Ra Astro Camera: amzn.to/3gmSJFB
-Kenko Teleplus HD 2x Teleconverter: amzn.to/2jEFitp
-Atomos Ninja Flame 7" 4K Field Monitor/Recorder: amzn.to/34a4Xv9
-Benro C373T Carbon Fiber Tripod Legs: amzn.to/2XzddGz
-SkyWatcher AZ-GTi Alt-AZ Telescope Mount: amzn.to/2YFiVDm
-Orion SynScan V5 Hand Controller: amzn.to/2JyzxYp
-Canon EOS R Mirrorless Full Frame Camera: amzn.to/2Wn8dkF
-Canon RF 800mm F/11 Lens: amzn.to/35n9tuz
-Canon RF 2x Extender: amzn.to/3k01VC9
-Atomos Ninja V 5” 4k Recorder/Monitor: amzn.to/2Wt2D1K
-Manfrotto MT055X PRO3 Aluminum Tripod Legs: amzn.to/2lc1wDH
-Astromania Dot Sight: amzn.to/2L0IJom
-Tascam DR-100 MK III Audio Recorder: amzn.to/2LwwqQT
-Tascam TM-2x Mic: amzn.to/2LNADRL
-SkySafari Pro App: skysafariastronomy.com
Links to my gear are for Amazon. I'm an Amazon Associate for which I earn from qualifying purchases. If you click on them, thanks in advance. Additional equipment I use is listed over at my website: jayling.smugmug.com/Equipment
