Patent: Canon continues development of EF supertelephoto lenses

degos

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Mar 20, 2015
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... the crop receives only 1/2.56 of the amount of light falling on the sensor and so the noise is greater.
Your statement is partially incorrect. The flux is lower but the irradiance is the same or higher due to being concentrated on the smaller sensor. Hence exposure is equivalent. Any additional noise artifacts are due to sensor design, not exposure.

Anyway we're talking about superteles, where people are putting the same x00mm f4 on a crop or FF so this discussion is irrelevant. The flux and irradiance is identical for both sensor sizes.
 

AlanF

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Your statement is partially incorrect. The flux is lower but the irradiance is the same or higher due to being concentrated on the smaller sensor. Hence exposure is equivalent. Any additional noise artifacts are due to sensor design, not exposure.

Anyway we're talking about superteles, where people are putting the same x00mm f4 on a crop or FF so this discussion is irrelevant. The flux and irradiance is identical for both sensor sizes.
The statement was correct. The photon noise of the image that is actually used is proportional to the square root of the flux and not the irradiance on the sensor. Circuits etc can of course produce additional noise but the poster was talking about shooting in low light where photon noise is dominant. What you have missed is that when you calculate signal to noise, dynamic range etc you do it for images that are enlarged to the same output size and the smaller sensor has to be enlarged more than a larger one. That is the reason why we get better IQ from a full frame sensor than a 2/3” although the irradiance on both sensors may have been equal. You have to enlarge a crop of the subject, say a bird, from a 500mm lens 1.2x1.2 times more than from a 600mm lens on the same sensor to give the same sized bird on screen or printed. That's equivalent to 0.5 stops advantage to the 600mm.

This is not airy fairy science, it is of practical importance and known by experience by practical photographers. If you use say a 600mm telephoto instead of a 300mm telephoto at the same f-number, after you have cropped the 300mm to the same size, not only do you have fewer pixels, the image is noisier. Also, my Sony RX10IV with its 1" sensor and 220mm f/4 lens puts the same irradiance and the same number of pixels on an image as a 600mm f/4 on a 1DX, but the Sony image becomes unusable at a relatively low iso because the image on the sensor has to be magnified 2.7x2.7 times to give the same size output as from the FF. So, don't worry about using a 1/3rd extra iso on a 600mm f/6.3 than a 500mm f/5.6 because the extra magnification takes care of the higher noise from the iso.
 
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GMCPhotographics

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I don't anticipate a great difference in the optical design between an EF and RF lens at these long focal lengths. The EF lenses have a pretty long distance between the back element and the sensor as it is. Simply redesigning the mount ought to be suitable.

Or, making an EF-RF adapter with a 1.4X teleconverter function built in. Best of both worlds!
I think the RF gains over EF mount with the big white teles has little to do with size, weight or optics. But every thing to do with mount communication....ie AF speed & accuracy and IS capability. The Rf mount will slightly loose to the Ef mount in size and length due to the extra mount distance to the file plane relative to the mount point. But with such large lenses, it's hardly an issue. However, the coms speed between the two mounts is vastly improved with the Rf mount. It's also possible that Canon start to mount other useful buttons and controls on the White Lens body shell because the data link between the camera and lens can cope with the expansion.
The weight reduction of the recent 600IIIL and 400IIIL have been due to moving the big elements further into the lens shell (which has also helped balance) and some lighter materials in the inner structure. These gains can be pushed only so far...so I doubt that we will see any more dramatic reductions in weight with a mk4 or Rf variant.
 
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tarjei99

EOS M50
Dec 27, 2013
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Since the most likely purchasers of EF x00 lenses are 1DX owners, I think it makes a lot of sense to make sure that they have the best lenses.

I'm also sure that many of the 5D owners also appreciate that their investment is being taken into account.

Those of us who owns 7Ds are also happy about this.
 
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AlanF

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I think the RF gains over EF mount with the big white teles has little to do with size, weight or optics. But every thing to do with mount communication....ie AF speed & accuracy and IS capability. The Rf mount will slightly loose to the Ef mount in size and length due to the extra mount distance to the file plane relative to the mount point. But with such large lenses, it's hardly an issue. However, the coms speed between the two mounts is vastly improved with the Rf mount. It's also possible that Canon start to mount other useful buttons and controls on the White Lens body shell because the data link between the camera and lens can cope with the expansion.
The weight reduction of the recent 600IIIL and 400IIIL have been due to moving the big elements further into the lens shell (which has also helped balance) and some lighter materials in the inner structure. These gains can be pushed only so far...so I doubt that we will see any more dramatic reductions in weight with a mk4 or Rf variant.
Canon does indeed claim the faster communications https://global.canon/en/imaging/l-lens/technology/rf_mount.html but I wonder if that will affect the speed and accuracy of the AF because the data being processed that appear to be rate limiting are from the image sensor and not much data has to be communicated to the drive motors in the lens.
 
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Daner

AE-1 Program
The total market for lenses in this price class is small enough that it makes sense to make these useful for EF, EF-S, EF-M (adapted) and RF (adapted) applications rather than segmenting them to RF only. Not that I expect too many M6 Mk. II users to be purchasing the 800mm, but now that I think about it, that combination could work well, even with 1.4 and/or 2.0 extenders.
 

Joe Subolefsky

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Sep 8, 2019
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Canon does indeed claim the faster communications https://global.canon/en/imaging/l-lens/technology/rf_mount.html but I wonder if that will affect the speed and accuracy of the AF because the data being processed that appear to be rate limiting are from the image sensor and not much data has to be communicated to the drive motors in the lens.
The new 400II and 600 III already have two extra communication contacts built in that are not used with current EF bodies that canon engineers said was to future proof the lens if you read the interviews. That's why I wrote a couple months ago like others wrote in this thread I kinda expect a EF-RF adapter with a built in 1.4 extender is coming. They have already made those lens light as possible and even if such an extender cost $800-1,000 they would sell the heck out of them.
 
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tron

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Wasn't there a rumor of a mount that would accept both RF and EF lenses without an adapter? If so, your theory above would make sense.
Let's think of this imaginary mount as ERF :D :D But seriously it would be very convenient except for the sensor movement so I do not believe it will happen. However a 1.4X EF to RF teleconverter for big white EF teles would be very interesting assuming the camera behind them is the so called Rs.

But: Why not Canon make an adapter that is either a 1X or a 1.4X just like the embedded in 200-400?

Of course, it will have to be a very small 1.4X to fit so I do not know if it is possible but maybe it is. Back in the early nineties I had bought a Sigma 1.4X for Canon which was very slim.
 

Del Paso

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The new 400II and 600 III already have two extra communication contacts built in that are not used with current EF bodies that canon engineers said was to future proof the lens if you read the interviews. That's why I wrote a couple months ago like others wrote in this thread I kinda expect a EF-RF adapter with a built in 1.4 extender is coming. They have already made those lens light as possible and even if such an extender cost $800-1,000 they would sell the heck out of them.
Can I place an order now?
 

AlanF

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The new 400II and 600 III already have two extra communication contacts built in that are not used with current EF bodies that canon engineers said was to future proof the lens if you read the interviews. That's why I wrote a couple months ago like others wrote in this thread I kinda expect a EF-RF adapter with a built in 1.4 extender is coming. They have already made those lens light as possible and even if such an extender cost $800-1,000 they would sell the heck out of them.
No, tell them they would sell a gazillion at $400-500. It's a neat idea to combine an adapter and TC. But, we would still need the straightforward adapter to use the EF lens at its native focal length.
 
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tron

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The 400mm and 600mm are a year old, so maybe they'll just release the 300, 500 and 800?
And 300 can't be improved. So 500 and 800 with 800 being the older. But it's time they introduced new DO lenses.
 

tron

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Canon showed a 400DO and a 600DO during the Canon expo a few years back, but went really silent about them soon after: https://www.canonrumors.com/canon-ef-600mm-f4-do-br-at-canon-expo/
Yes I remember this. But it weighted just like the new 600III so the only advantage would be the size. For me the size is equally important but maybe this will not happen now. The 400DOII is more than good enough (In fact it is very very good so there is no need for update).