September 23, 2014, 04:54:10 AM

Author Topic: Patent: Canon EF 100-400 f/4.5-5.6 DO  (Read 5063 times)

AvTvM

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Re: Patent: Canon EF 100-400 f/4.5-5.6 DO
« Reply #15 on: May 25, 2014, 09:42:38 AM »
So far, Canon DO lenses have never been good enough, small enough, or cheap enough to be of any interest to me. I do not expect this to change anytime soon. 

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Re: Patent: Canon EF 100-400 f/4.5-5.6 DO
« Reply #15 on: May 25, 2014, 09:42:38 AM »

wsmith96

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Re: Patent: Canon EF 100-400 f/4.5-5.6 DO
« Reply #16 on: May 26, 2014, 09:45:24 AM »
So what is special about DO?  I never really paid any attention to those lenses.
What I do today is important because I am exchanging a day of my life for it.

mustafaakarsu

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Re: Patent: Canon EF 100-400 f/4.5-5.6 DO
« Reply #17 on: May 26, 2014, 09:55:59 AM »
So what is special about DO?  I never really paid any attention to those lenses.

This is the idea behind diffractive optics, but at the moment it's more developed for sure.
http://en.wikipedia.org/wiki/Fresnel_lens

xps

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Re: Patent: Canon EF 100-400 f/4.5-5.6 DO
« Reply #18 on: May 26, 2014, 04:47:45 PM »
I hope Canon improves this technology. I owned a 400 DO IS, nearly 10 years ago, but the optical quality was not that, I thougt it would be. There was an aberration in the left upper corner that caused in an distorsion in this area. So I changed to the 300mm 2.8. And that was an very  good decision.

Mt Spokane Photography

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Re: Patent: Canon EF 100-400 f/4.5-5.6 DO
« Reply #19 on: May 26, 2014, 11:15:32 PM »
So what is special about DO?  I never really paid any attention to those lenses.

A DO lens element is able to bend light more sharply without introducing chromatic abberations.  Canon's resin lens can do this, but it is apparently extremely expensive to build.  They probably get a very small yield.
This equates to a very expensive lens, which is not going to sell, just to shave a little weight off.

Rudeofus

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Re: Patent: Canon EF 100-400 f/4.5-5.6 DO
« Reply #20 on: May 27, 2014, 06:51:56 AM »
Can you actually apply an antireflective coating to a fresnel lens like on a normal lens? Would such a coating be effective against flare on a fresnel lens?

rrcphoto

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Re: Patent: Canon EF 100-400 f/4.5-5.6 DO
« Reply #21 on: May 27, 2014, 12:17:23 PM »
So what is special about DO?  I never really paid any attention to those lenses.

A DO lens element is able to bend light more sharply without introducing chromatic abberations.  Canon's resin lens can do this, but it is apparently extremely expensive to build.  They probably get a very small yield.
This equates to a very expensive lens, which is not going to sell, just to shave a little weight off.

it's not weight, it's size that it affects.

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Re: Patent: Canon EF 100-400 f/4.5-5.6 DO
« Reply #21 on: May 27, 2014, 12:17:23 PM »

Mt Spokane Photography

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Re: Patent: Canon EF 100-400 f/4.5-5.6 DO
« Reply #22 on: May 27, 2014, 01:26:10 PM »
So what is special about DO?  I never really paid any attention to those lenses.

A DO lens element is able to bend light more sharply without introducing chromatic abberations.  Canon's resin lens can do this, but it is apparently extremely expensive to build.  They probably get a very small yield.
This equates to a very expensive lens, which is not going to sell, just to shave a little weight off.

it's not weight, it's size that it affects.

It affects length.  That means less weight.  The 400mm DO is shorter asnd much lighter, which makes it reasonable to handhold.  The size and weight go together.

mustafaakarsu

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Re: Patent: Canon EF 100-400 f/4.5-5.6 DO
« Reply #23 on: May 27, 2014, 02:21:24 PM »
So what is special about DO?  I never really paid any attention to those lenses.

A DO lens element is able to bend light more sharply without introducing chromatic abberations.  Canon's resin lens can do this, but it is apparently extremely expensive to build.  They probably get a very small yield.
This equates to a very expensive lens, which is not going to sell, just to shave a little weight off.

it's not weight, it's size that it affects.

It affects length.  That means less weight.  The 400mm DO is shorter asnd much lighter, which makes it reasonable to handhold.  The size and weight go together.

I just looked at Canon website,it says:

EF 400mm f/4 DO IS USM - 1,940g
EF 400mm f/5.6L USM - 1,250
EF 400mm f/2.8L IS II USM - 3850

It's significantly lighter than f/2.8 one, which is not a surprise when considering it's a f/4 lens, also its heavier than f/5.6 now I see no reason to buy DO lens unless its way too much cheaper.

wsmith96

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Re: Patent: Canon EF 100-400 f/4.5-5.6 DO
« Reply #24 on: May 28, 2014, 10:45:17 PM »
So what is special about DO?  I never really paid any attention to those lenses.

This is the idea behind diffractive optics, but at the moment it's more developed for sure.
http://en.wikipedia.org/wiki/Fresnel_lens
Thanks for the info!
What I do today is important because I am exchanging a day of my life for it.

dufflover

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Re: Patent: Canon EF 100-400 f/4.5-5.6 DO
« Reply #25 on: May 30, 2014, 01:29:32 AM »
I just looked at Canon website,it says:

EF 400mm f/4 DO IS USM - 1,940g
EF 400mm f/5.6L USM - 1,250
EF 400mm f/2.8L IS II USM - 3850

It's significantly lighter than f/2.8 one, which is not a surprise when considering it's a f/4 lens, also its heavier than f/5.6 now I see no reason to buy DO lens unless its way too much cheaper.
No duh it's heavier (it can't defy basic physics like 400/4 = 100mm+ opening).
The better comparison is that it's a lot lighter than the aperture/light equivalent 300mm f/2.8L mk1 (2,550g).

The MkII is closer but I wonder what weight saving developments with these II's would make any DO lenses lighter too.
Hurry up Canon and do something with your sensors! :P

AvTvM

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Re: Patent: Canon EF 100-400 f/4.5-5.6 DO
« Reply #26 on: May 30, 2014, 12:49:07 PM »
The MkII is closer but I wonder what weight saving developments with these II's would make any DO lenses lighter too.

I don't care for the DO stuff at all, I'd much rather Canon would come up with an excellent "regular optics" EF 400/4.0 L IS ... half the weight and a quarter of the price of the 400/2.8 L IS II.  :-)

tron

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Re: Patent: Canon EF 100-400 f/4.5-5.6 DO
« Reply #27 on: May 30, 2014, 02:10:32 PM »
The MkII is closer but I wonder what weight saving developments with these II's would make any DO lenses lighter too.

I don't care for the DO stuff at all, I'd much rather Canon would come up with an excellent "regular optics" EF 400/4.0 L IS ... half the weight and a quarter of the price of the 400/2.8 L IS II.  :-)
The DO is half the weight of the 400/2.8 L IS II. A "regular optics" EF would be heavier. But yes, such a lens would be very popular.

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Re: Patent: Canon EF 100-400 f/4.5-5.6 DO
« Reply #27 on: May 30, 2014, 02:10:32 PM »

mustafaakarsu

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Re: Patent: Canon EF 100-400 f/4.5-5.6 DO
« Reply #28 on: May 30, 2014, 02:40:29 PM »
This video explains DO principles pretty good.
http://www.canon.com/v-square/movie.html?id=t005

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Re: Patent: Canon EF 100-400 f/4.5-5.6 DO
« Reply #28 on: May 30, 2014, 02:40:29 PM »