The upcoming RF mount wide angle f/2.8L zoom will be wider than 16mm [CR2]

privatebydesign

Would you take advice from a cartoons stuffed toy?
Jan 29, 2011
7,379
374
119
Since the R mount has a registration distance of 20mm, anything wider than 20mm (more practically, around 24mm or so) would still need to use a retrofocus design.
Not necessarily, as there is no moving mirror there is nothing to stop the lens rear element protruding well behind the mount, as in the Leica designs. The shutter in the R is probably no more the a couple of mm forward of the sensor so potentially 15mm of recess is possible, this would mean even a 10mm focal length design could be made that wasn't a retrofocus. That is probably too much but I can see a focal length of 14mm non retro focal being very possible.
 

padam

EOS 7D MK II
Aug 26, 2015
530
184
Not necessarily, as there is no moving mirror there is nothing to stop the lens rear element protruding well behind the mount, as in the Leica designs. The shutter in the R is probably no more the a couple of mm forward of the sensor so potentially 15mm of recess is possible, this would mean even a 10mm focal length design could be made that wasn't a retrofocus. That is probably too much but I can see a focal length of 14mm non retro focal being very possible.
The lens still has to autofocus, and not will all the elements moving together (which also means that it can only be optimised to one distance).
While Zeiss kept the Biogon design for the 35mm Loxia they've changed to the Distagon with the 21mm Loxia, which implies that even for manual focus lenses it may not ultimately be the best choice for performance, which is what Canon is aiming for.
 

privatebydesign

Would you take advice from a cartoons stuffed toy?
Jan 29, 2011
7,379
374
119
The lens still has to autofocus, and not will all the elements moving together (which also means that it can only be optimised to one distance).
While Zeiss kept the Biogon design for the 35mm Loxia they've changed to the Distagon with the 21mm Loxia, which implies that even for manual focus lenses it may not ultimately be the best choice for performance, which is what Canon is aiming for.
None of which contradicts the fact that having a 20mm registration distance on a mirrorless camera means you can recess the rear element, meaning you are not limited to retro focus designs for focal lengths close to or even lower than 20mm.
 

koenkooi

EOS RP
Feb 25, 2015
241
106
None of which contradicts the fact that having a 20mm registration distance on a mirrorless camera means you can recess the rear element, meaning you are not limited to retro focus designs for focal lengths close to or even lower than 20mm.
I vaguely remember an interview with canon during launch where they said something like "Yes, we can recess the rear element a lot more, no, we're not gonna do that". I think RF lenses will all share the same lens cap, which limits the rear element.

They could do RF-S, where 'S' means the same as the S in EF-S, with new lens caps. But with a full image circle, people here are using 'RF-S' as shorthand for reduced-image circle instead of short backfocus, which confuses the hell out of me every time I see it used.
 

Michael Clark

Now we see through a glass, darkly...
Apr 5, 2016
482
183
Not necessarily, as there is no moving mirror there is nothing to stop the lens rear element protruding well behind the mount, as in the Leica designs. The shutter in the R is probably no more the a couple of mm forward of the sensor so potentially 15mm of recess is possible, this would mean even a 10mm focal length design could be made that wasn't a retrofocus. That is probably too much but I can see a focal length of 14mm non retro focal being very possible.

A 20mm lens must place the effective thins lens equivalent point in the lens 20mm from the imaging plane. This is usually well forward of the rear lens element in non-retrofocus lenses. In fact, it is often near the front element of compound lenses. So not only would the rear lens element need to be "countersunk" into the camera body for a non-retrofocus design wider than 20mm, pretty much the entire optical portion of the lens would need to be behind the flange. Of course this would create vignetting issues due to the mount flange blocking light from wider angles striking the front element of the lens.
 
Reactions: Antono Refa

Antono Refa

EOS 7D MK II
Mar 26, 2014
764
80
Canon has lenses which extend forward, usually to increase focal length. Couldn't Canon make lenses that extend into the camera to decrease focal length, then retract back into the barrel to fit in the standard cap?

I gather it would cause vignetting due to light hitting the sensor corners at an oblique angle.
 

Ian K

I'm New Here
Jul 20, 2016
15
0
Oh, to have an RF 11-24mm f/4L USM, even if it wasn't much smaller. I love that lens but it would be better without the extra bulk of the adapter. Make it a f2.8, even with the extra bulk would be interesting, especially if it had well controlled coma.
 

sid.safari

I'm New Here
Sep 5, 2018
20
18
I wonder if they will have a RF super telephoto primes like a RF 300mm f/2.8, RF 400 f/2.8, RF 500 f/4, RF 600 f/4.

Or will those be adapted from the EF family.
 

Rajinder Shukla

I'm New Here
Nov 26, 2018
14
1
82
As I recently read in Canon Rumers Forum that a RF 12-35 mm f2.8L USM and a RF 14 -20 mm f2.8L USM lenses are under development as new up coming RF lenses for EOS R system and may be RF 12-35 mm will have more recognition. As per your views above and my opinion EF 11-24 mm f4L USM lens is an exceptionally great ultra wide lens but with EOS R system a RF 12-35 mm f2.8L USM or still a RF 10-30 mm f2.8 L USM lens would be a hit lens and a 1st. Choice for real demanding professionals in the photo industry as EOS R Mirrorless camera is concerned. A RF 14-24 mm f4L could be a good choice for serious armatures and free lance photographers. A new real professional EOS R Mirrorless camera body with EOS 5 MK IV specifications plus Mirrorless added specifications is also seriously needed very soon.
R.Shukla.
 

YuengLinger

EOR R
Dec 20, 2012
2,243
272
Southeastern USA
I'd be happy with a rectilinear rf 12-24mm f/2.8L which had the least distortion (compared to other brands) at these focal lengths.
 
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Rajinder Shukla

I'm New Here
Nov 26, 2018
14
1
82
I'd be happy with a rectilinear rf 12-24mm f/2.8L which had the least distortion (compared to other brands) at these focal lengths.
As Nikon has already announced a great lens, f14-30 f4 with a slight curve on front element where you can use any threaded filter. Now is the right time for Canon.
In my opinion FR 12-35 mm f2.8L IS USM with the filter thread is the only appropriate lens which I have read in the beginning is already in the pipeline. I think RF14-35 mm doesn’t make much sense compared to Nikon,s 14-30 f4 lens.I am seriously wanting for the announcement of this lens along with a real Pro. EOS R camera body with upto 65 magapix resolution.
 

Rajinder Shukla

I'm New Here
Nov 26, 2018
14
1
82
I have held off on purchasing the EF 11-24 in anticipation of something like what is rumored: a 12-35mm f/2.8L that fits the R mount!?

Oh my.

Oh my.

Oh my.
I strongly appreciate and second your desire for a RF 12-35mm f2.8L IS USM Non Bulbous lens. Myself I am waiting for the day when Canon announces the release day of this exceptionally great product in Canon R System.
 

Rajinder Shukla

I'm New Here
Nov 26, 2018
14
1
82
I have held off on purchasing the EF 11-24 in anticipation of something like what is rumored: a 12-35mm f/2.8L that fits the R mount!?

Oh my.

Oh my.

Oh my.
I have held off on purchasing the EF 11-24 in anticipation of something like what is rumored: a 12-35mm f/2.8L that fits the R mount!?

Oh my.

Oh my.

Oh my.
i fully support your your patience.
 

Jack Douglas

CR for the Humour
Apr 10, 2013
5,952
746
Alberta, Canada
Waiting is a very subjective concept. Not so much if there is a "real" need. I'm certainly not sorry I didn't wait relative to the 11-24 and now with the purchase of the R I finally got my desired ND filter. Unfortunately, my daughter liked the R so much that she bought it after our Costa Rica trip so here I sit with two EF to R adapters and no R.;)

I suspected this would happen so now I await another R type camera. I was quite impressed with the R but it was actually not in my hands very much. The control ring adapter used with an EF lens gives a very handy way to shoot true manual with accuracy, having ISO on the ring, which gets controlled with a right hand finger, the result being evidenced in the viewfinder.

Once again, I'm inclined to think Canon has produced a Camera that will sell in spite of all the usual negative press. BTW I waited out the 6D2 after selling my 6D and certainly don't regret that.

Jack