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Patent - EF 300 f/4L IS II

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Canon Rumors:
Share EF 300 f/4L IS II Canon patent for EF 300 f/4L IS II
* Patent Publication No. 2011-70032
* Published 2011.4.7
* Filled 2009.9.25 Specifications
* Focal Distance: 294
* Fno: 4.14
* Half angle of view:4.08
* Image Height: 21.64
* Lens Length (mm): 225
* Back Focus (mm): 83.12
* Aspherical: 1 Needed? Not really. However the 300 f/4L IS is a great performer and a decent seller for Canon. Adding updated IS to the lens would make most buyers very happy. Not sure it would be upgrade worthy. cr Canon EF 300 f/4L IS $1399 at B&H

awinphoto:
Is it just me or the Fno's not quite what they are claiming to be?  This lens, for instance is 4.14 but advertised as F4... similar with the 35mm patent and 24mm patent?  The 50mm appears to be 1.3 but advertised as F1.4.  With these minor differences, when the cameras metering system calculates the exposure on what the lens SHOULD be letting through, (especially since the lenses are wide open when they are metering and focusing and not stopped down) then it seems to me some of the lenses would be a hair darker and lighter than you would expect once you shoot the scene. 

c-law:
You'll also notice that almost all the focal lengths are out. This one is actually 294mm not 300mm.

Pretty much all specifications are translated into marketing speak. To produce a lens that works they build it to whatever tolerances are required to make it sharp, focus, contrasty, etc. Rather than building it to set lengths and apertures and hoping it turns out sharp.

However that doesn't sell well to have an EF 294mm f/4.14. It is just to complicated so they use big round numbers to approximate what it actually is.

Just like how a 300GB hard drive or 8GB CF card are never that much. A real GB is 1024 MB but that makes things complex and not big and round so all storage is approximated to 1GB = 1000MB because that markets better.

Chris

hmmm:
I am definitely interested in this lens -- at a reasonable price.   

Hopefully they can keep the price hike at or below 15-20%.

dgsphto:

--- Quote from: hmmm on May 26, 2011, 01:15:05 AM ---I am definitely interested in this lens -- at a reasonable price.   

Hopefully they can keep the price hike at or below 15-20%.

--- End quote ---

Or they can leave it at the current price. Just because it is a revision does not mean the price has to rise.  It amazes me as so how society is generally very receptive to the notion a revision warrants a price increase!

(Not to pick on you. On the contrary, you bring up a good point.)

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