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Author Topic: EF 24-70 f/2.8L II Patent Published  (Read 28505 times)

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EF 24-70 f/2.8L II Patent Published
« on: April 24, 2011, 10:18:09 AM »
It’s coming, really! We posted the filed patent of a 24-70 f/2.8L II way back in October. However it has now been published as of April 21, 2011. The big omission appears to be IS. I think it’s safe to say the lens is coming soon.

Other Lenses in the Patent A couple of other lenses appear in the patent. A 70-300 f/4-5.6L IS, which has been released. Also appearing is a 55-250 IS lens. This could be a version II of the current lens. It could also shrink to 200mm at the long end.

Patent Information

  • Patent Publication No. 2011-81062
  • Published 2011.4.21
  • Filled 2009.10.5

24-70 f/2.8L II

  • Focal distance f=24.74 – 67.50mm
  • Fno 2.92 – 2.91
  • Half angle of view 41.17 – 17.77 deg.
  • Lens length 206.42 – 177.53mm
  • Back focus 38.43mm
  • Aspherical 2
  • zoom ratio 2.73x
  • MOD 0.38m

70-300 f/4-5.6L IS

  • Focal distance f=72.21 – 299.52mm
  • Fno 4.65 – 5.85
  • Half angle of view 16.68 – 4.13 deg.
  • Lens length 142.64 – 201.84mm
  • Back focus 37.77mm
  • Aspherical 1
  • zoom ratio 4.15x
  • MOD 1.4m

55-250 f/4-5.6 IS

  • Focal distance f=55.60 – 203.11mm
  • Fno 4.16 – 5.88
  • Half angle of view 13.80 – 3.85 deg.
  • Lens length 162.05 – 202.41mm
  • Back focus 58.79 – 82.03mm
  • Aspherical 0
  • zoom ratio 3.65x
  • MOD 1.5m

Egami notes the 24-70 patent shows possible performance issues. You can check out their findings here.

Quote

The performance does not seem to be so good. The spherical aberration is delivered to less than +-0.2mm in all conditions at the outskirts. The astigmatism exceeds 1mm extremely badly in the short distance. The distortion is -4% of barrels type in the wide side. In the short distance, the distortion is +5% of lozenge type in the tele side. The chromatic aberration of magnification is corrected well.

cr

« Last Edit: April 24, 2011, 10:38:10 AM by Canon Rumors »
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EF 24-70 f/2.8L II Patent Published
« on: April 24, 2011, 10:18:09 AM »

tivoboy

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Re: EF 24-70 f/2.8L II Patent Published
« Reply #1 on: April 24, 2011, 11:24:02 AM »
just curious.  WHY do you think that the 55-250 will only be 55-200?

Roroco

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Re: EF 24-70 f/2.8L II Patent Published
« Reply #2 on: April 24, 2011, 11:24:58 AM »
The Mark I of this lens is so good, I don't see why they are releasing a MarkII without IS.  With video being a big focus with DSLR, I think IS is becoming a requirement at this focal length in a zoom...

mathino

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Re: EF 24-70 f/2.8L II Patent Published
« Reply #3 on: April 24, 2011, 11:33:50 AM »
just curious.  WHY do you think that the 55-250 will only be 55-200?

...maybe because of what is written in the patent :-) :

Focal distance f=55.60 – 203.11mm
6D (on the way) | 450D | EF 28 f/1.8 USM | EF 40 f/2.8 STM | EF 85 f/1.8 USM | 430 EX II | wishlist: EF 24-70 f/2.8 L II USM, EF 135 f/2 L

dilbert

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Re: EF 24-70 f/2.8L II Patent Published
« Reply #4 on: April 24, 2011, 01:43:23 PM »
24-70 f/2.8L II
  • Focal distance f=24.74 – 67.50mm
  • Fno 2.92 – 2.91

70-300 f/4-5.6L IS
  • Focal distance f=72.21 – 299.52mm
  • Fno 4.65 – 5.85

55-250 f/4-5.6 IS
  • Focal distance f=55.60 – 203.11mm
  • Fno 4.16 – 5.88

How does Canon get away with advertising a 70-300 as f/4-5.6 when it is really a f/4.5-5.6? Full 1/3 slower!

Or a 24-70 when it is a 24-67? 7% difference there.

Do they not care because almost nobody will shoot with it wide open anyway?

Or do they tweak the lens a bit post-patent to get the extra numbers?

LFG530

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Re: EF 24-70 f/2.8L II Patent Published
« Reply #5 on: April 24, 2011, 02:24:10 PM »
what the *? I don't get it why would they release a II without IS and with performance issues, the first one is already sharp and is a pretty good lens generally?

traveller

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Re: EF 24-70 f/2.8L II Patent Published
« Reply #6 on: April 24, 2011, 03:05:27 PM »
The only aspects of the current 24-70L that most people had cause to complain about were the lack of IS and the wide open performance at 50mm and above (other than the price and weight).  Why on earth would Canon release a lens that addresses neither of these complaints (and will probably be worse on both of the other accounts too).  This really doesn't make any sense... Oh wait sorry, I forgot this is Canon we're talking about!

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Re: EF 24-70 f/2.8L II Patent Published
« Reply #6 on: April 24, 2011, 03:05:27 PM »

gene_can_sing

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Re: EF 24-70 f/2.8L II Patent Published
« Reply #7 on: April 24, 2011, 03:28:15 PM »
Just because IS is the number ONE requested feature on the 24-70, why should Canon address that? Hmmmm......

I think they are making a serious mistake by not offering IS in the 2nd version because there would be no reason to buy it, especially for video. And with it being optically worse? Makes no sense, but then again, Canon makes no sense.

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Re: EF 24-70 f/2.8L II Patent Published
« Reply #8 on: April 24, 2011, 03:38:20 PM »
It appears to me that Canon is compromising by sacrificing properties that can be fixed by in-camera software, or in post processing for properties that cannot.   They seem to be giving priority to center, corner and edge sharpness and to eliminating chromatic abberation.  Distortion at the wide end or long end can be fixed by software, while sharpness and LOCA's cannot.

This formula might also be applicable to a new 24-105 mm lens, just because it is not in the examples does not mean it won't happen.

In any event, it is a very complex lens, moving three or four lens groups at a time and with extreme precision will mean tighter tolerances, and higher prices.  Be ready for $$$$.

Simply constructed primes are looking better and better.  I've nothing against zooms, but as mechanical complexity increases, so does the possibility of misalignment or malfunctions. 

Chewy734

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Re: EF 24-70 f/2.8L II Patent Published
« Reply #9 on: April 24, 2011, 04:42:19 PM »
It appears to me that Canon is compromising by sacrificing properties that can be fixed by in-camera software, or in post processing for properties that cannot.   They seem to be giving priority to center, corner and edge sharpness and to eliminating chromatic abberation.  Distortion at the wide end or long end can be fixed by software, while sharpness and LOCA's cannot.

How can lack of IS be "fixed" by in-camera software or in post-processing?  You could just say use a tripod, but then I'm not sure why Canon would make a MKII of this lens if the first one does so well?  I know I can't be naive and think Canon hasn't been listening to those of us who want IS in a lens, or better ISO performance in a body, but at the same time it seems like they dropped the ball on this one.

I'm sure it'll cost more than the MKI with maybe a small %age increase in IQ that probably won't be worth it for most people.  IS on the other hand would've been a fantastic feature to have (along with the improvements you suggest).  That would given people who have been waiting a long time for this lens a real reason to upgrade.

macfly

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Re: EF 24-70 f/2.8L II Patent Published
« Reply #10 on: April 24, 2011, 05:27:48 PM »
I did tell anyone who'd listen Canon took a real step backwards with the G12 from the G10, and from this it looks that it is about to do it again. I keep looking here to see if there is some great reason to stay with Canon, but more and more it looks like they are just missing the point.

GMCPhotographics

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Re: EF 24-70 f/2.8L II Patent Published
« Reply #11 on: April 24, 2011, 07:58:49 PM »
I think we need to actually see and use this lens before we get bent out of shape over this theoretical design. I have an excellent copy of the existing version and in my opinion the mkII has a lot of live up to, if not...then I'll keep my current version. It's a great lens.

gmrza

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Re: EF 24-70 f/2.8L II Patent Published
« Reply #12 on: April 24, 2011, 08:10:23 PM »
It appears to me that Canon is compromising by sacrificing properties that can be fixed by in-camera software, or in post processing for properties that cannot.   They seem to be giving priority to center, corner and edge sharpness and to eliminating chromatic abberation.  Distortion at the wide end or long end can be fixed by software, while sharpness and LOCA's cannot.

How can lack of IS be "fixed" by in-camera software or in post-processing?  You could just say use a tripod, but then I'm not sure why Canon would make a MKII of this lens if the first one does so well?  I know I can't be naive and think Canon hasn't been listening to those of us who want IS in a lens, or better ISO performance in a body, but at the same time it seems like they dropped the ball on this one.

I'm sure it'll cost more than the MKI with maybe a small %age increase in IQ that probably won't be worth it for most people.  IS on the other hand would've been a fantastic feature to have (along with the improvements you suggest).  That would given people who have been waiting a long time for this lens a real reason to upgrade.
I don't think scaleusa was referring to IS when discussing factors that can be "fixed" in software.  What he was referring to, I think, was more the factors in terms of optical quality, which can be "fixed" in software - for instance, peripheral illumination and barrel/pincushion can be sorted out either in camera or or in post.

As for IS, it might be worthwhile if somebody could comment on the technical feasibility of fitting IS into a package that is not too bulky for this lens.  I am not sure whether that might be too much of a challenge.

If I were Canon, and planned to release a 24-70mm with IS, I would also market a non-IS version.  Purely commercially, I think you would find that this is a lens where you could sell both versions.  For stills shooters, many people need to use shutter speeds fast enough to ensure that there is no blur due to movement of the subject.  This is unlike the 70-200 category, where shooting at speeds less than 1/200s is essential, whereas many photographers may not need/want to shoot at less than 1/80s - especially press or event photographers.  As has been mentioned, this may be different for videographers.
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Re: EF 24-70 f/2.8L II Patent Published
« Reply #12 on: April 24, 2011, 08:10:23 PM »

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Re: EF 24-70 f/2.8L II Patent Published
« Reply #13 on: April 24, 2011, 09:20:06 PM »
Quote
How can lack of IS be "fixed" by in-camera software or in post-processing? 

There is nothing wrong with a lack of IS, it does not need to be fixed. 

However, since you mentioned it, there is software on the market that supposedly can repair blur caused by vibration.  I am doubtful that it works very well ... yet.  There are lots of patents for methods to do this as well.

http://www.focusmagic.com/


My guess is that the IQ hit taken by the 24-70mm f/2.8L by adding IS as well as increased size and weight is a problem that Canon has not solved and still managed to keep prices within reach.

thien135

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Re: EF 24-70 f/2.8L II Patent Published
« Reply #14 on: April 24, 2011, 10:44:36 PM »
I decided to sell my old cropped sensor camera and wait for 5D mark III and this lenses. However, my friend told me to buy 70-200 2.8 is mark II instead. So , 24-70 mark 2 or 70-200 would be best pairing with a FF camera?????? I'm looking to do a lot of portraits and some family events.

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Re: EF 24-70 f/2.8L II Patent Published
« Reply #14 on: April 24, 2011, 10:44:36 PM »