Patent: Canon presents some interesting fast zoom lens optical formulas

cpreston

EOS 90D
Mar 22, 2014
132
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Those maximum apertures stops sound more like Cinema lenses then still lenses. Still lenses (rarely) deviate from the typical numbers 1.2, 1.4, 1.8, 2, 2.8 etc… but I’ve noticed cinema lens often end in odd numbers in the decimal.
I would also guess this would be expensive cinema glass. The reason that the T numbers are odd on Canon glass, though, is because they are just taking the even focal length number and adding 0.1. I don't think many companies even measure the transmission, they just add 0.1 since the transmission will never be 100% of the theoretical f stop number. An f/1.5 would likely be a T1.6.
 
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Nemorino

EOS R5
Aug 29, 2020
446
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Those maximum apertures stops sound more like Cinema lenses then still lenses. Still lenses (rarely) deviate from the typical numbers 1.2, 1.4, 1.8, 2, 2.8 etc…
If you have a look at other lens patents, you will see a lot strange aperture numbers like 2.9 or 4.1 etc in the specs. The marketing division will sell them as 2.8 or 4.
For example

And of cause the 300mm ist a 292.53mm in the specs. ;)
 
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EOS 4 Life

EOS 5D Mark IV
Sep 20, 2020
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Those maximum apertures stops sound more like Cinema lenses then still lenses. Still lenses (rarely) deviate from the typical numbers 1.2, 1.4, 1.8, 2, 2.8 etc… but I’ve noticed cinema lens often end in odd numbers in the decimal.
Cinema lenses usually go by T Stop.
For Canon, F Stops are usually even so when they have cine versions of photo lenses those ten to have off F stop numbers.
Like 50 f/1.2 and 50 T1.3 being different versions of the same lens.
Canon has dedicated cinema lenses with both odd and even F stops.
An F stop of 1.5 will probably be a T stop of 1.6 or so.
For comparison, those Sigma f/1.8 zooms have a T stop of 2.
 
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SnowMiku

EOS RP
Oct 4, 2020
221
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If my 2008 self saw those two 1kg lenses as an alternative over a 4.5kg EF 800mm & 5.4kg EF 600mm then odds are I'd get the f/11 copies as I am lazy in carrying things and the risk of being hassled over the gear is reduced to near nil.

I've even had people comment about my gear when I use a 700D and 55-250mm thinking it's professional gear. But when I use the M5 and 18-150mm no one cares. You will still get people approaching you with the RF 600mm and 800mm, but not as much as the big whites.
 
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dolina

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I've even had people comment about my gear when I use a 700D and 55-250mm thinking it's professional gear. But when I use the M5 and 18-150mm no one cares. You will still get people approaching you with the RF 600mm and 800mm, but not as much as the big whites.
That has been my experience as well. You're more likely to see a Ferrari or McLaren than fast white primes.

This will only entificy as fewer and fewer people buy dedicated still cameras into the future.
 
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Aug 7, 2018
519
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As it is Canon, they will likely print "f/1.4" on those f/1.5 lenses. Sadly Canon cheats a little when it comes to specs. A 600mm lens is only 585mm and so on. I wish there were laws that require companies to fulfil at least the promised specs. It seems a few percent of cheating is legal and they alway try to use those few percent to their advantage.

I wish the industry would also switch to T-stops instead of F-stops like it is already done for professional video lenses. There are huge differences between the same F-stops of two different lenses. Only with T-stops the amount of light would always be the same.
 
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koenkooi

EOS 5D Mark IV
CR Pro
Feb 25, 2015
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As it is Canon, they will likely print "f/1.4" on those f/1.5 lenses. Sadly Canon cheats a little when it comes to specs. A 600mm lens is only 585mm and so on. I wish there were laws that require companies to fulfil at least the promised specs. It seems a few percent of cheating is legal and they alway try to use those few percent to their advantage.

I wish the industry would also switch to T-stops instead of F-stops like it is already done for professional video lenses. There are huge differences between the same F-stops of two different lenses. Only with T-stops the amount of light would always be the same.
For prepackaged things we have https://en.wikipedia.org/wiki/Estimated_sign over here in Europe. Nothing is absolute, but it'd be nice to have guidelines on how much leeway there is on specs :)
 
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neuroanatomist

I post too Much on Here!!
CR Pro
Jul 21, 2010
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As it is Canon, they will likely print "f/1.4" on those f/1.5 lenses. Sadly Canon cheats a little when it comes to specs. A 600mm lens is only 585mm and so on.
Your implication seems to be that when Nikon or Sony put out an f/1.4 or 600mm lens, it’s actually f/1.4 or 600mm and not something slower or shorter that’s rounded to the specified value. Do you believe that’s true?
 
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AlanF

Desperately seeking birds
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Aug 16, 2012
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Your implication seems to be that when Nikon or Sony put out an f/1.4 or 600mm lens, it’s actually f/1.4 or 600mm and not something slower or shorter that’s rounded to the specified value. Do you believe that’s true?
The patent for the RF 300mm f/2.8 has it as 292.53mm f/2.9. Are you still going to pre-order?
 
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unfocused

Photos/Photo Book Reviews: www.thecuriouseye.com
Jul 20, 2010
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Not anymore. That sort of behavior is unacceptable for a manufacturer and I'm going to stick it to Canon by not buying their game or their lens.
Careful Neuro. If you don't use the [/sarcasm] tag people will believe you.
 
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