Patent: Canon EF 300 f/4L IS II

[Canon Rumors]

New Patent
Canon has filed a patent for the optical formula of a new EF 300 f/4L IS II.

Patent Publication No. 2012-159726

• 2012.8.23 Release Date
• 2011.2.1 filing date

Example 3

• F = 300mm focal length
• Fno. 4.0
• Tele ratio 0.68
• Inner Focus
• φr = 68.8mm
• φg1 = 67.8mm
• φg2 = 70.2mm

Canon EF 300 f/4L IS at B&H Photo

Technical background

• When the miniaturization of the optical system, longitudinal chromatic aberration, chromatic aberration of magnification is remarkable
• As the focal length becomes longer, the telephoto lens system, chromatic aberration is noticeable
• There is a method of correcting the aberrations of a material having an anomalous dispersion resin, the resin is difficult to produce high-precision thick
• There is a method of sandwiching a thin glass resin material, the bonding peeling distortion problem bonding at high temperature

Canon patent

• Joining three or more optical elements
• The outer diameter of the resin is increased to reduce the distortion at the time of bonding
• Not adhere to each other resin outer glass element
• Between the optical element of the outside is gone, adhesive, the thickness of the adhesive distribution occurs
• Using a sealing agent to prevent change in shape of the resin and the refractive index change due to moisture absorption
• Do the black outer peripheral portion of the glass element
• Prevent flare and ghosting resin at the outer periphery
• Surface resin glue is not good

Source: [EG]

cr

[Rienzphotoz]

Just out of curiosity ... how long does Canon generally take from Patent to Production?

[hammar]

If  this lens becomes reality and is decently priced and optically awesome, I would definitely swap it for my 70-200 f/4 IS.

[Daniel Flather]

$2499

[Daniel Flather]

Just out of curiosity ... how long does Canon generally take from Patent to Production?

One to ∞ year(s).

[hmmm]

I'm interested in this lens... I just hope they do not use too much surface resin glue.  That is not good.

[hammar]

$2499

You think? How about Canon being a little friendly for once and consider the poor L-lens users

[candyman]

Interesting.


What do you think? Will it be followed by a patent for a new Canon 400mm f/5.6 ? And, maybe coming with IS?

[AdamJ]

I'm interested in this lens... I just hope they do not use too much surface resin glue.  That is not good.

 

[Bosman]

yawn

[mortadella]

Here is a patent filing that made CR over a year ago....

http://www.canonrumors.com/2011/05/patent-ef-300-f4l-is-ii/

The current version was released in March of 1997, so an update would be nice sometime within the decade.

Price-wise, look on the bright side, however much the II costs ($2000+ ??) went does get released it will be a fraction of what you would have to pay to get your hands on a 200-400 1.4x.  We should all be happy that there are a few big whites we can get our hands on under $3000, and count our lucky stars there are a few under $2000 (at least for now)... right Canon? right?

[Gcon]

I'd much rather use the 7-200 f/2.8 IS II USM plus the 1.4x extender than this lens - so much more flexible.

[Viggo]

I'm sure a used mkI 2,8 IS will be my alternative.

[tron]

It will be hard for Canon to beat the quality of the 300mm f/4L non-IS. We'll see...

[wickidwombat]

i just hope they keep the integrated lens hood, I love the 300 F4L IS
More modern IS and full weather sealing would make great improvements as well as the more modern coatings supressing flare and CA, depending on cost I would look at an upgrade. although the sigma 120-300 f2.8 is really tempting even if i got it the 300f4L would stay just for its super well balanced and convenient sized when used with a 5D body