# Canon U.S.A. Inc., to Provide 120 EF 400mm f/2.8L IS II USM Lenses for Expansion of the Dragonfly Telephoto Array Project



## Canon Rumors Guy (Nov 22, 2021)

> Canon USA continues to dabble in space projects along with Canon Inc.  Canon USA is sending Project Dragonfly 120 Canon RF 400mm f/2.8L IS II USM lenses. Project Dragonfly is an international research team consisting of Yale University and the University of Toronto researchers.
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## neuroanatomist (Nov 22, 2021)

Great way to write off old stock now that the RF version is available?


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## [email protected] (Nov 22, 2021)

neuroanatomist said:


> Great way to write off old stock now that the RF version is available?


But I thought they were just gluing adapters to the old stock for the new stock. In a time of great supply constraint, they'd be giving away half their end-product's ingredients.


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## David - Sydney (Nov 22, 2021)

I am surprised that Canon had that number of lenses available...that is a big batch to run through production


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## neuroanatomist (Nov 22, 2021)

[email protected] said:


> But I thought they were just gluing adapters to the old stock for the new stock. In a time of great supply constraint, they'd be giving away half their end-product's ingredients.


Perhaps...I have no idea if Canon is converting previously-made EF MkIII lenses to RF or simply producing RF versions de novo and this is a way to clean out existing stock. It's a bit more than just the adapter – the depth window is gone, and there are electronic improvements that go with the RF mount that may (or may not) require different chips/wiring on the inside, including the dual-power mode for faster AF that works with the RF lens on the R3 (but not with the adapted EF lens).


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## Kit. (Nov 22, 2021)

neuroanatomist said:


> Great way to write off old stock now that the RF version is available?


These are Mk II lenses. There already exist lighter, Mk III EF lenses.


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## neuroanatomist (Nov 22, 2021)

Kit. said:


> These are Mk II lenses. There already exist lighter, Mk III EF lenses.


I missed the II. Makes it more likely they’re writing off old stock.


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## David - Sydney (Nov 23, 2021)

Kit. said:


> These are Mk II lenses. There already exist lighter, Mk III EF lenses.


I would have assumed that they aren't using autofocus but manually focusing 120 lenses would be a pain. Maybe they have a way to focus each electronically together as a group


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## privatebydesign (Nov 23, 2021)

They teamed up with Fro to give a load away as well as a load of 1DXII’s as well as EF600’s.


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## Berowne (Nov 23, 2021)

This is not new. Dragonfly Research dates back to 2014. In their first paper they reported the use of 8 400/2.8 canon lenses. So the "Giveaway" extended over nearly ten years. No need to be envious.


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## David - Sydney (Nov 23, 2021)

I would assume that providing series II lenses is also to match the existing lenses provided years ago - even if they are superseded stock now.


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## Kit. (Nov 23, 2021)

David - Sydney said:


> I would have assumed that they aren't using autofocus but manually focusing 120 lenses would be a pain. Maybe they have a way to focus each electronically together as a group


Hopefully, the lenses need to be focused only once, at infinity. There is also no need in aperture control.

But yes, focus-by-wire of mark III would probably be a pain.


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## sulla (Nov 23, 2021)

wow, what a cool project!


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## kaihp (Nov 23, 2021)

neuroanatomist said:


> I missed the II. Makes it more likely they’re writing off old stock.


The original article mixes RF 400, EF 400mm II, and "latest generation" EF 400mm, which is arguably the Mk III. 
So the confusion is complete.


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## BeenThere (Nov 23, 2021)

Aligning axes of this array would also be a fun way to spend your day.


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## Jasonmc89 (Nov 23, 2021)

Ffs give me one


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## Bonich (Nov 24, 2021)

BeenThere said:


> Aligning axes of this array would also be a fun way to spend your day.


Aligning done electronically, your PS is able to do this job not needing a day.


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## Sharlin (Nov 24, 2021)

Berowne said:


> This is not new. Dragonfly Research dates back to 2014. In their first paper they reported the use of 8 400/2.8 canon lenses. So the "Giveaway" extended over nearly ten years. No need to be envious.



Well, 120 new lenses is news. Before this they "only" had 48 of them.


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## skrubol (Nov 29, 2021)

I wonder what the advantage of using camera lenses over telescopes is for astronomy. 6" aperture telescopes can be had pretty inexpensively.


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## SteveC (Nov 29, 2021)

skrubol said:


> I wonder what the advantage of using camera lenses over telescopes is for astronomy. 6" aperture telescopes can be had pretty inexpensively.



It depends, of course, on what you're trying to photograph.

I have a very ancient Criterion RV-6 Newtonian scope (6" aperture), a screaming bargain when I bought it, still a credible telescope today. But I'll never be able to stick a camera body on it.

In my extremely limited experience if you want to do deep sky you'll want a telescope. On the other hand a telescope is totally unsuitable for "here's the Milky Way at night behind some interesting landscape" shots. (Most people here mean that when they talk about "astrophotography" but to me the term conjures up taking pictures of planets, nebulae, galaxies and the like, for which you absolutely need a telescope. I was an amateur astronomer long before I was any kind of photographer so that affects my perspective.)

On my to-do list is a more modern telescope with a EF mount I can adapt to my Canon bodies.


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## BeenThere (Nov 30, 2021)

skrubol said:


> I wonder what the advantage of using camera lenses over telescopes is for astronomy. 6" aperture telescopes can be had pretty inexpensively.


Stacking them gives extremely large aperture for the focal length. Much dimmer light collected.


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## ColorBlindBat (Dec 3, 2021)

If my brain is working today, they should end up with an effective aperture of ~0.22.


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## Kit. (Dec 3, 2021)

skrubol said:


> I wonder what the advantage of using camera lenses over telescopes is for astronomy. 6" aperture telescopes can be had pretty inexpensively.


The formal rationale is very low lens flare of these particular lenses. Dragonfly studies galactic halos, they need optics with very low scatter.


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