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

[fish_shooter]

I have a 8" dome from my 16-35mm and 8-15mm and macro flat port for my 100mm macro. I am trying to understand your previous comment

"What I found interesting is potentially zero front lens element movement during focusing as this is implied in the posted pix unless there was an error as the SA ring appears to have moved. This is important for underwater photography since it is advantageous to have a fixed relationship between the front lens element and lens port (which is typically of the flat variety for a 100mm lens) as the lens port (part of the underwater housing) becomes part of the optical system. "

Why is it advantageous to have a fixed relationship between front element and lens port? The flat port won't become part of the optical system unless it is a lens or when a wet lens is added in front on the flat port.

The advantage is for wet lenses which are growing in number. Being able to add a wet lens increases the versatility of an underwater camera system. I have not tried a mismatch (not following a maker's recommendation) so see how far off one can be - an expensive experiment unless one already has the parts to work with as well as the time.

I was shooting with a dome port combined with a macro lens a couple days ago but it was one of my Nikon systems not not one of my Canons. I did a bunch of testing a few years ago to see how much port extension to use - one needs the right amount as you already know from experience with the 8-15 and 16-35.

 

[David - Sydney]

The advantage is for wet lenses which are growing in number. Being able to add a wet lens increases the versatility of an underwater camera system. I have not tried a mismatch (not following a maker's recommendation) so see how far off one can be - an expensive experiment unless one already has the parts to work with as well as the time.

I was shooting with a dome port combined with a macro lens a couple days ago but it was one of my Nikon systems not not one of my Canons. I did a bunch of testing a few years ago to see how much port extension to use - one needs the right amount as you already know from experience with the 8-15 and 16-35.

I'm not sure that you are clarifying your original point "This is important for underwater photography since it is advantageous to have a fixed relationship between the front lens element and lens port (which is typically of the flat variety for a 100mm lens) as the lens port (part of the underwater housing) becomes part of the optical system."
Domes are used to reduce vignetting in wide angle and return to a normal field of view and flat ports are used for magnification, minimum focus distance (especially for strobe use) and better sharpness. The use of an external wet lens is optional but only possible with a flat port vs a dome.
I can't see how the flat port is part of the "optical system" in the sense of this thread being about focus shift in the RF100mm

 

[JoeDavid]

I received this lens from Canon USA as soon as they started filling preorders and have been pretty impressed with its performance. It came with lens firmware v1.1.1. I’ll do a little more testing later but, with a quick test of f2.8-11, I didn’t see a focus shift occur. I was using a lens calibration tool with the target at 45 degrees to the lens. I’ll need to redo it at something like 30 degrees to get a more distinct view of the DOF at the smaller apertures. Anyway, the R5 was tripod mounted, IS off, electric shutter, remote release, and SA locked at zero.

 

[fish_shooter]

I'm not sure that you are clarifying your original point "This is important for underwater photography since it is advantageous to have a fixed relationship between the front lens element and lens port (which is typically of the flat variety for a 100mm lens) as the lens port (part of the underwater housing) becomes part of the optical system."
Domes are used to reduce vignetting in wide angle and return to a normal field of view and flat ports are used for magnification, minimum focus distance (especially for strobe use) and better sharpness. The use of an external wet lens is optional but only possible with a flat port vs a dome.
I can't see how the flat port is part of the "optical system" in the sense of this thread being about focus shift in the RF100mm

My comment on the focus shift issue has nothing to do with underwater photography but instead on the aperture that is being used to do the focusing.

I also noticed a lack of movement in the front element between infinity and 1.4x (scroll down a bit in the report to see the pix) but also noticed the CA ring had moved so maybe there is an error there. The lack of movement would be good since this would allow using wet lenses per above. There is already a discussion on Wetpixel about a potential extension of the lens when focusing of a few mm. I expect Nauticam will be testing the new lens and reporting back on compatibility...

 

[deleteme]

Not a

Not at all convinced. Focus shift, as LSXPhotog already wrote, is NOT acceptable for a macro lens.
What if the lens is used in manual focus mode? No firmware, in my opinion, could help since AF motors are switched of. I'm certain I'm not the only one using manual mode most of the time for macros...
And using depth of field button, provided existing (none on EOS R and RP), isn't very practical. What I'm hoping for is Canon mechanically-optically correcting this phenomenon!

I guess you will have to cast Canon into the lake of fire then.
I see it as very unlikely that they will do any hardware work on a released lens.
I think they count their base of customers as far more casual in their approach to focus and will default to AF in almost all cases.
The other thing they are banking on is that most people do not shoot macro wide open.
Yes, I get that even stopped down their will be a slight degradation. Canon is betting most will never see it.

 

[koenkooi]

I wonder how easy it is to knock the SA Control ring just slightly out of neutral. Or if during shipping it can be bounced around and "0" is no longer the actual neutral position. Focus shifting, after so many years of Canon macros not having the issue, is startling.

The SA ring has a lock switch on the bottom right:

 

[Del Paso]

For RF lenses the focus motor does all the focusing, even in manual mode.

That's right, but in manual mode, there will be no "firmware focus correction".
Yet, since all my macros are shot with MT 24 at f11 or f16, does it matter there's a bit of focus-shift? I'll give it a try (field-test) and then decide.

 

[David - Sydney]

My comment on the focus shift issue has nothing to do with underwater photography but instead on the aperture that is being used to do the focusing.

I also noticed a lack of movement in the front element between infinity and 1.4x (scroll down a bit in the report to see the pix) but also noticed the CA ring had moved so maybe there is an error there. The lack of movement would be good since this would allow using wet lenses per above. There is already a discussion on Wetpixel about a potential extension of the lens when focusing of a few mm. I expect Nauticam will be testing the new lens and reporting back on compatibility...

I think you mean the SA ring
Be interesting to see if Nauticam would include a focus and SA ring control on their port.
I am not following your point about lack of front element movement and wet lenses. It isn't a collapsing design. The EF16-35mm/4 has the front element moving with focal length within a fixed length external lens but doesn't have any issues with focusing as far as I know

 

[koenkooi]

That's right, but in manual mode, there will be no "firmware focus correction". [..]

Why wouldn't there be? Since you can configure direction, acceleration and sensitity of the focussing ring, there will always be a hefty chuck of software between the ring and focus motors.

 

[lnz]

Yes and no--mostly no.

If Canon never put out any other RF 600mm or 800mm than those f/11 primes, the statement might have some justification. As we don't know what they won't do...especially this early in the history of the mount...it's way too early to say this. (And I doubt it will pan out.)

f/7.1 zooms: If this is a reference to the 100-400, it's basically the same spec as the old 100-400, except that once you get to 400-f/5.6 you can then continue to extend it to 500 at f/7.1. So this is added capability, not less. The other 100-400 is a consumer level lens, just like those f/11 zooms, and can't rightfully be compared to the EF 100-400 L.

The 24-240, I'm a bit sympathetic to the complaint here, until I remember that this, too, is a consumer-level lens; they traded optical quality for 10x range, using software to compensate. Not a tradeoff I am interested in making, but still, a "new" niche filled.

If they never made any other lens to fill the 24-240 range (OK, this would require lenses in the plural, to be honest), or the 600 and 800mm, and stuck red stripes on the lenses, you would have a stronger argument.

As for the 100mm I'm going to wait to hear more.

on the 100-500 @400mm you are at f/6.4 so it's really a stepback. teleconverter work only @300mm plus another stepback

 

[Joules]

on the 100-500 @400mm you are at f/6.4 so it's really a stepback. teleconverter work only @300mm plus another stepback

The RF 100-500 @400 comment is muddy, because what you get displayed depends on whether you have set your aperture stops set to halves or thirds and it is hard to compare to the EF 100-400mm, as that is not exactly true 400 mm on the long end. In practical terms, they are very close.

As for the TC compatibility, that's a trade off. Keep in mind that the RF lens is much lighter than the EF counterpart. There's no free lunch, it is all a complicated set of compromises. That alone does by no means make it poor engineering.

 

[koenkooi]

The RF 100-500 @400 comment is muddy, because what you get displayed depends on whether you have set your aperture stops set to halves or thirds and it is hard to compare to the EF 100-400mm, as that is not exactly true 400 mm on the long end. In practical terms, they are very close.[..]

In my mind the physical aperture is the same in both the EF100-400II and the RF100-500. Which is not how I tend to think about those things, I'm too used to thinking in f-stops, which, as you say, are rounded differently when shown on the camera.

 

[jeanluc]

I have very little experience with macro shooting. Could someone more knowledgeable about it please explain exactly what focus shift is and how it works?

My (probably flawed) understanding is that the focus plane can shift when the aperture changes.

Is this when you deliberately change aperture after focusing? Or is it something the camera does by itself after autofocussing? I read something about focus shift not happening if you use autofocus. I know in the macro world MF is often used.

Just trying to understand. Thanks to any for a little more info.

 

[Del Paso]

Why wouldn't there be? Since you can configure direction, acceleration and sensitity of the focussing ring, there will always be a hefty chuck of software between the ring and focus motors.

I can't imagine it will work.
Example: what if I focus manually, using depth of field preview, would the firmware still (unnecessarily ) correct focus to compensate for a no longer troublesome focus shift ?
Just to say that this focus shift issue (if really exists !) still bothers me...

 

[koenkooi]

I have very little experience with macro shooting. Could someone more knowledgeable about it please explain exactly what focus shift is and how it works?

My (probably flawed) understanding is that the focus plane can shift when the aperture changes.

Is this when you deliberately change aperture after focusing? Or is it something the camera does by itself after autofocussing? I read something about focus shift not happening if you use autofocus. I know in the macro world MF is often used.

Just trying to understand. Thanks to any for a little more info.

With lenses that have an electronically controlled aperture, an R camera will always have the aperture wide open and only close it down when taking the actual photo or when the DoF preview button is being pressed.

So it doesn't matter if you're using AF or MF, you can only ever focus with the aperture wide open.

 

[koenkooi]

I can't imagine it will work.
Example: what if I focus manually, using depth of field preview, would the firmware still (unnecessarily ) correct focus to compensate for a no longer troublesome focus shift ?
Just to say that this focus shift issue (if really exists !) still bothers me...

That depends on Canon covering that use case when working on the firmware.

 

[mb66energy]

I am thinking that they will update it via FW.
The fact they did not get it on the initial deliveries of the product is about par for so many businesses today.

SHIP NOW! Fix later.

if memory serves well, Volker Pispers, a German comedian called it "Banana product, ripens at the customer."

 

[mb66energy]

I compared the RF version against the EF USM non-IS version
via the great TDP ( the-digital-picture.com ) web site and
I see better contrast and maybe better resolution on the RF (while
different sensors are some caveat for a good comparison).

But I think the vignetting is substantially lower with the old EF version
-- maybe some shift of priorities and the tendency to rely on post processing
which is easy in vignetting (if you have enough range).

Maybe the EF 100 is sufficient for my use with the EOS RP but will shine on
45 or 90 MPix!

 

[Fischer]

Really? Be honest. I can take it like a man. Is my photo of the sachem skipper highly disappointing? Does it show evidence of a focus problem? I need to know what is wrong with my photos if I am to improve.

I would also appreciate hearing about your personal experience with this lens.

I do not do macro normally - and focus shifting is only visible at certain f-stops, which I cannot see from your post. However, no modern HQ lens should have focus shift imho as it will potentially ruin some pictures, because the focus system gets fooled. Of course you can avoid this by avoiding the affected f-stops. Which is what some people tend to learn how to do.

But welcome to the club of EF 50mm L f/1.2 apologetics which now can add another group of lens owners (a lens I did use and dropped because of the focus shift). To me focus shift belongs to the graveyard of modern lens design. There are no excuses possible. YMMV.

The RF 50mm is a way better lens the old EF 50mm L lens for many reasons - the lack of focus shift is probably the most important.

 

[David_E]

…focus shifting is only visible at certain f-stops, which I cannot see from your post.

I’m not saying it isn’t a problem for some people with some lenses, only that I haven’t experienced the problem. There are, however, myriad things that can go wrong when photographing skittish arthropods in vivo and in situ.