We know that an RF-S wide angle zoom lens is coming later in 2023 to take the place of the EF-M 11-22mm f/4-5.6 IS STM and EF-S 10-18mm f/4.5-5.6 IS STM. A much needed type of lens for any crop sensor camera. There are two optical formulas covered in this patent, and it’s nice to
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Full frame is about 24mm in height isn't it?I would love too see an 9-18mm lens for APS-C, but the image height quoted on these patents, doesn't that points towards lenses for fullframe format?
21.64 is full-frame.Full frame is about 24mm in height isn't it?
Lenses always cover a greater area than ultimately needed for the respective format, so this looks in line with apsc
They are also fixed aperture f/4I would love too see an 9-18mm lens for APS-C, but the image height quoted on these patents, doesn't that points towards lenses for fullframe format?
The patent is going down towards 19 mm at the wide end. Looks like another "streched" FF lens.21.64 is full-frame.
Wide-angle lenses are sometimes a little less and use image stretching.
Fixed aperture would normally point towards FF and L lens, wouldn't it?They are also fixed aperture f/4
In total, yes.The patent is going down towards 19 mm at the wide end. Looks like another "streched" FF lens.
But still much more than the about 13.4 mm a Canon APS-C sensor would need.
Fixed aperture would normally point towards FF and L lens, wouldn't it?
The image-height in patents ain't measured the way you instinctually would measure it. I saw it explained once, but can't remember the details. BUT I'm pretty sure 21.64mm is for fullframe. And then some optical correction is needed in the wider ends where image-heights are lower (as Canon is making a habit in new wide zoom-designs :-/ ).Full frame is about 24mm in height isn't it?
Lenses always cover a greater area than ultimately needed for the respective format, so this looks in line with apsc
The maths behind it is the that the diameter of the Image circle must be at least as large as the sensor diagonal.The image-height in patents ain't measured the way you instinctually would measure it. I saw it explained once, but can't remember the details. BUT I'm pretty sure 21.64mm is for fullframe.
Enjoy your vacation Hope you find some time to go out and shoot some picsI corrected the post. A third party wrote the article as I am on vacation.
Yep, as @Exploreshootshare said, ...... as I am on vacation.
Personally, I don't blame you or CR or third party for misinterpreting the patent, but having fun in discussing the technical detailsEnjoy your vacation Hope you find some time to go out and shoot some pics
Has been already corrected - by the users as well as by Craig (@Canon Rumors Guy )apsc constant aperture? too good to be true
Because when you shoot manual with wide open aperture you don't want the exposure changing while zooming in (getting darker) and back out (getting brighter again).I never quite understood why anyone think it is so great to have constant aperture in these days of automatic cameras?
It only comes at the expense of a more favorable f-number at the wide end!
So i.e. a 9-18 mm f/4.0 constant aperture might as well have been 9-18 mm f/2.8-4.0.
You could just dial in f/4.0 aperture for you manual exposure and the camera should make sure you get that no matter what focal length you zoom to.Because when you shoot manual with wide open aperture you don't want the exposure changing while zooming in (getting darker) and back out (getting brighter again).
For example, I really do look forward to the Tamron 35-150 f2-2.8 coming in RF mount as it would be the perfect do-it-all wedding lens instead of having two bodies with a 24-70 and a 70-200; but if that will come, I would directly use it as a f2.8 constant aperture, because I don't want to mess with changing exposure constantly.
I actually do have a variable aperture lens, the 28-105 f3.5-4-5 which is my emergency back up wedding lens if the 24-70 dies unsuspectedly, and my holiday/backpacking lens; when I use it, I directly set it at the minimum common brightest aperture (f4.5) because it's easier to work with. SO even if I can get f3.5 at the wide end and f4 around the 35mm/50mm mark, I never exploit it, for me it's just a f4.5 constant lens (which for only 50€ is btw just 1/3rd stop darker then the 24-105 L's, so perfectly able to do a wedding in emergency; and no, it doesn't suck, I have an incredibly blessed copy which is as sharp as the 24-70 L II /24-105 L II at comparable apertures, while it's much better then both Mk I versions).
No professional would "want to pay extra to get rid of it", if get rid is transforming a f2.8-4 lens in a constant f4 lens; a professional would pay extra to buy a lens that is directly constant f2.8 and get rid of the f4I am pretty sure there are more people who would prefer the perfectly useful wider aperture at the wide end, than there are people wanting to pay extra to get rid of it.
I think it comes down to conflation, from a practical standpoint. At least as far as Canon lenses, constant aperture typically means relatively fast, and variable aperture typically means relatively slow.I never quite understood why anyone think it is so great to have constant aperture in these days of automatic cameras?
It only comes at the expense of a more favorable f-number at the wide end!
So i.e. a 9-18 mm f/4.0 constant aperture might as well have been 9-18 mm f/2.8-4.0.
That behavior can be easily controlled with the custom function settings.Because when you shoot manual with wide open aperture you don't want the exposure changing while zooming in (getting darker) and back out (getting brighter again).
Which one? Never heard of that! (I believe you; I just never ever heard, or found, a related C-Fn on my cameras)That behavior can be easily controlled with the custom function settings.