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

SteveC

R5
CR Pro
Sep 3, 2019
2,479
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The current RF lenses have brought something new to the table vs their EF counterparts. Either short/light or outstanding quality and autofocus speed for the L lenses. The RF24-105mm is not quite in this class though. An interesting review of the different ~100mm macros at:
Given the quality of the Laowa macro, a new RF100mm should have >1:1 magnification, IS and lens coatings and it will regain its lead in the current market.

Unfortunately I'm not in a position to watch the video, so could you clarify which of the two RF24-105 mm lenses you're talking about (there's an f/4 L and an f/4-7.1 [non L]).
 

Mt Spokane Photography

I post too Much on Here!!
CR Pro
Mar 25, 2011
16,716
1,689
can we see amount of focus breathing with a patent? or gotta wait for real life tests?
The location of the focus group usually determines focus breathing. Real life tests determine how much. Macro lenses tend to put focus groups close to the front so they don't change the angle of view. They are very aware that focus breathing for a macro lens is undesirable because of focus stacking. As focusing gets more complex and multiple lens groups move, it can be impossible for us to know. I hope there is essentially none.

The patent site is down now for maintenance, so I can't read the patent to see how its constructed and what they might say about focus breathing.
 

snappy604

EOS RP
CR Pro
Jan 25, 2017
591
490
I do not care if or how cynical you are. I already apologized for the silliness that debating it has brought, please consider that the end of that exchange on my part.
Your choice of camera system or your reason for chosing it is nothing I have any right or interest in judging anyway. To answer anyway, no I would not consider you a cynic for considering a switch to any system. Properly evaluating and questioning the benefits proposed by manufacturers and to a degree existing customers is perfectly reasonable.

As for your example, I can't judge what better means for you. The images will be extremely similar as the reach is virtually the same and both sensors and lenses are nothing to sneeze at in this comparison. For specific measurements, you may find one combination ahead of the other of course. There are many factors to the shooting experience that go beyond the result and would go into my personal judgement on whether or not a price difference is justified. I'm not interested in either combination, so I can't justify going through the pros and cons of each.

I'm not linking any reviews or charts since it is not my intend to convince you of anything here. You initially seemed to me to ask what's up with the rear element, and all I did want to do is provide my understanding and a quote of what that is based on for you to consider.

Anyway, even if a comparison of the EF lens on a 5Ds and the RF lens on the R5 that illustrates the RF combination beeing twice as sharp, I don't follow you how that would make a TC redundant. Assuming you are equating sharpness to resoultion here, without a higher resolution (or pixel density) body available you could still benefit from a TC in order to increase reach (when using fast enough lenses, of course).

well said, there are a lot of different needs and each person needs to evaluate if the system they invest in will or won't meet those.. having said that, there are times when the choices given by the manufacturer do appear frustrating ;-)

btw there were comments about higher resolution.. after going from 80D to R5 ... all I can say is don't underestimate the ability to crop.. I still get sharp and detailed images after sometimes fairly heavy crops. Like all good tools though, need to learn how to maximize it and that certainly takes time.
 

koenkooi

EOS 5D Mark IV
CR Pro
Feb 25, 2015
1,919
1,860
The location of the focus group usually determines focus breathing. Real life tests determine how much. Macro lenses tend to put focus groups close to the front so they don't change the angle of view. They are very aware that focus breathing for a macro lens is undesirable because of focus stacking. As focusing gets more complex and multiple lens groups move, it can be impossible for us to know. I hope there is essentially none.

The patent site is down now for maintenance, so I can't read the patent to see how its constructed and what they might say about focus breathing.

Both 100mm macro lenses from Canon have severe focus breathing, they go from 100-ish mm at infinity to 65-ish mm at MFD. And yes, I've been bitten by it when trying to do focus stacking without moving the lens.
 

LeBlobe

EOS RP
Nov 9, 2020
38
28
Montreal, Canada
The location of the focus group usually determines focus breathing. Real life tests determine how much. Macro lenses tend to put focus groups close to the front so they don't change the angle of view. They are very aware that focus breathing for a macro lens is undesirable because of focus stacking. As focusing gets more complex and multiple lens groups move, it can be impossible for us to know. I hope there is essentially none.

The patent site is down now for maintenance, so I can't read the patent to see how its constructed and what they might say about focus breathing.

yes site is still down . I didnt look into it before i thought it would be too technical for me hehe


Both 100mm macro lenses from Canon have severe focus breathing, they go from 100-ish mm at infinity to 65-ish mm at MFD. And yes, I've been bitten by it when trying to do focus stacking without moving the lens.

yes im curious what is average across popular macro lenses , i just use rf 35mm f/1.8 so far and hoped the new 100mm would be better.
 

Mt Spokane Photography

I post too Much on Here!!
CR Pro
Mar 25, 2011
16,716
1,689
I finally discovered that there is a error in the link to the patent site and then looked up the patent. The goal is high quality with higher magnification. Although they have examples with various magnifications from 0.5 to 2.0, I'd expect that 1.5 is their preferred magnification.

I think example 3 is interesting with a magnification of 1.0 - 2.0.

These will be expensive lenses if they were to be actually made.

Image surface infinity
Various data
Focal distance 99.75
F number 2.92
Half field angle (degree) 12.24
Whole-length-of-the-lens 168.47
BF 14.00


Magnification ∞ - 1.0 - 2. 0
 

melgross

EOS RP
Nov 2, 2016
772
525
An intelligent lens-design isn't about "the more lenses, the better".
One of the very best macro lenses, the Leica M Macro Elmar 90mm f4, has only 4(!) lenses, and doesn't miss a single one.
I often use it with macro rings on my EOS R, and it beats,without discussion,the EF 100 L IS.
Of course, it's an f4 lens, without AF.
And what should I say about the Apo Macro Elmarit 2,8/100mm, 8 lenses, so sharp at any setting and aperture that it almost hurts?
You mean, the more elements. And you’re wrong. They couldn’t do it in years past for a number of reasons. Calculation, even with lens design programs, was a real bear. Each extra element adds significantly to the problem. Then there was the mechanical integrity of the lens. Back when, Cooke was known for superb designs that never performed that well, because they couldn’t make them properly. The technology wasn’t up to it. Glasses are being developed every day, new coatings, etc. All of this allows designers to take more advantage of additional elements than they could use decades ago.

‘So yes, designers do look at more elements as being beneficial. It’s pretty obvious, because new lenses are all about more elements when performance, and speed, are the main thrust.

you mention a 90 f4, which I’ve used. It’s pretty good, but bested by a number of faster lenses these days. Now, try to make that Ken’s a more realistic f 2.8, as most macro’s are. Or an f 2, as we see more of them come out. How many elements do you think it would need?

and back in the days of film, what was considered as sharp would be though of today as being just ok.