Patent: Canon RF 100mm f/2.8L IS USM Macro 1:1.4x

Canon Rumors Guy

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Canon News has uncovered a patent for a Canon RF 100mm f/2.8L IS USM Macro 1:1.4x. A macro for the RF system is already long overdue and I expect that we’ll see one announced some time this year.
The cool thing about this patent is that it has a 1:1.4x macro capability, unlike the current version which is 1:1.
Below are the two embodiments of the in Japan Patent Application 2021-047297. The second one is a bit confusing, as the aperture increases as the magnification increases, does this mean it’s an f/1.4 optical design? Time will tell.






Canon RF 100mm f/2.8L IS USM Macro 1:1.4x...

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H. Jones

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Perhaps Canon is designing this lens so that the aperture adjusts to maintain exposure as you get closer to a subject? The same way that a F/2.8 zoom lens artificially stops down the aperture at wider focal lengths to maintain your exposure? That would be quite an interesting and exciting innovation on a macro lens, though I'm sure some would enjoy it to remain at F/1.4 at all magnification.

I am also very excited to see Canon adding additional magnification to this lens. 1:1 is already great, but 1:1.4 is excellent, add in 1.6 crop mode and you get 1:2.24 magnification.
 

canonnews

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Perhaps Canon is designing this lens so that the aperture adjusts to maintain exposure as you get closer to a subject? The same way that a F/2.8 zoom lens artificially stops down the aperture at wider focal lengths to maintain your exposure? That would be quite an interesting and exciting innovation on a macro lens, though I'm sure some would enjoy it to remain at F/1.4 at all magnification.

I am also very excited to see Canon adding additional magnification to this lens. 1:1 is already great, but 1:1.4 is excellent, add in 1.6 crop mode and you get 1:2.24 magnification.
oh that's a good thought. when I wrote it up, the I puzzled a bit on that and why they would do it, but I like your explanation,
 

Nemorino

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This kind of focus breathing makes the lens unusable for focus stacking (without macro rail). I would like a higher mag like this, but I would also prefer a fixed focal length with less focal breathing.
 

stevelee

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This kind of focus breathing makes the lens unusable for focus stacking (without macro rail). I would like a higher mag like this, but I would also prefer a fixed focal length with less focal breathing.
If you are doing much stacking, you want a rail anyway, except of course for handheld. Changing focus changes magnification at close range.
 

Nemorino

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I 'm doing stacking in both ways. ;)
Sometimes I just put the camera on the floor and change the focus and it works very good. I often use this method with the Laowa 60mm but this lens has exactly this strange kind of focus breathing. At mfd you change the focal length from 2x to 1.5x mag without changing the focal plane. So I have to start at 1.5x mag. The different mag is not an issue.

Edit:
I wonder why this patent shows a shorter focal length at higher magnification. I would expect it the other way round.
 

koenkooi

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Edit:
I wonder why this patent shows a shorter focal length at higher magnification. I would expect it the other way round.
For higher magnification you need more and more space between the lens and the sensor, so to get 2x magnification while keeping the lens short you need to reduce the focal length.
I really like that my 100mm L doesn't change size when focussing, but it makes focus stacking using the focus ring a lot harder.
 

Stig Nygaard

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Actually 1:1.4 is < 1:1 so one will need a 1.4 TC to get to 1:1. At least 1:1.4 is better than 1:2 like the old manual focus macro lenses.

Yes, 1.4:1 would be cool. 1:1.4 is not that cool, and means it is not a "real" macro lens in traditional terms (Macro term usually used for lenses that can do at least 1:1).
 

Nemorino

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so to get 2x magnification while keeping the lens short you need to reduce the focal length.
But the distance between lens and subject decreases The RF35 has a mfd of 70mm (lens to subject) at 0,5x magnification. How short would it be at 1,4x?
 
Nov 19, 2020
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This kind of focus breathing makes the lens unusable for focus stacking (without macro rail). I would like a higher mag like this, but I would also prefer a fixed focal length with less focal breathing.
With a fixed focal length, you get breathing too, if by breathing you mean a change in angle of view. To have no change in AoV at all, the focal length needs to shorten at closer focus in exactly the right amount to compensate for the “natural” narrowing that would occur otherwise.

This is discussed here: https://doi.org/10.1117/1.OE.57.11.110801#sec8
 
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dcm

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Looking at the patent translation, it clearly describes the three sets of drawings at 1) infinity focus, 2) 0.5x magnification, and 3) 1.4x magnification. The element structure is very different from those in the EF 100 L macro. Another possible beneficiary of short back focus?

This could be interesting and easier to use than the super Zoom mode (1.2x) on the EF-M 28 macro lens.
 

juststeve

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Nov 29, 2018
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The 12mm is interesting in its relative compactness, barely over 3 inches long. And it appears it may be able to take a front end filter. Now, that may well have to be something like 95mm because of the extreme angle of view. Still, a front filter system might well be possible.

The other two lenses are not as compact, but appear as if they could take front filters. The front elements so bulb like as to limit filters and perhaps could take even 82 or even 77 filters.
 

Seeker

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May 17, 2020
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The macro notation of x:x is to be read like a fraction. So 1:2 is equal to 1/2 and 2:1 is equal to 2/1 or 2x.

True macro starts at 1:1 and the fancy 65mm Canon has allows 5:1 macro
 
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Seeker

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"add in 1.6 crop mode and you get 1:2.24 magnification."

That's not how magnification works. It is called CROP factor because the mag stays the same, you just block the edge of the image.

If a 1mm object is 1mm on the sensor, you have 1:1 magnification. It doesn't matter if he sensor is Full frame, Medium format, aps-c, mft, or a cell phone's 1/3 inch type.

For example, if you shoot a small object, say 12mm by 18mm, on full frame at 1:1, then crop the image to fill the screen, does that increase the magnification of the lens? Of course not, you just recomposed eh 1:1 image. Otherwise every lens is a macro lens if you crop the image small enough.

A 32MP camera with a 1:1 macro lens is not a 8x macro because someone crops down to 0.5 megapixels

And yes, even the online photo magazines get that wrong.
 

Nord0306

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Nov 11, 2018
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"add in 1.6 crop mode and you get 1:2.24 magnification."

That's not how magnification works. It is called CROP factor because the mag stays the same, you just block the edge of the image.

If a 1mm object is 1mm on the sensor, you have 1:1 magnification. It doesn't matter if he sensor is Full frame, Medium format, aps-c, mft, or a cell phone's 1/3 inch type.
I do agree with you completely, but for some pixel pitch makes a difference to the output. Back in the film days, the "resolution" of the film was pretty constant, so then magnification was a most important metric. It's not always true, but generally, smaller sensors have a smaller pixel pitch. When you then print or post your image, all that matters is the quality of the image (of which pixel density is not the only factor), not whether you used the whole lens light circle or not.
 

Bengt Nyman

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When using a macro lens the amplification of the object (and focus) is very sensitive to the distance between object and lens. It appears possible that Canon might be using this by mechanizing a Slider Assembly to alter the amplification (almost like a zoom) without having to change the distance between object and lens. This might be what gets them to 1.4:1 in one direction and possibly 1:1.4 in the other.
By the way, I am using their RF 35mm macro which has a nifty feature which greatly simplifies manual focus. It consists of two arrows which point apart when the chosen point is out of focus while moving towards coinciding, overlapping and turning green, when in focus. This tells you both which way to move and when you are in focus. I hope that Canon plans to give us both Slider Assembly Control (micro zoom) and arrow focus in their new RF 100mm f/2.8L IS USM Macro 1.4:1.
 
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