Canon RF 100mm f2.8 L Macro IS USM lens user review 28 October 2021

 

This flower ball was waving about in the wind in shade near the end of the day. I hand held the R5 with the RF 100mm L Macro using High+ drive and Servo AF at ISO 25600. Remarkably one can make decent photos this way.

Canon has a long history  of producing 100mm lenses for the “35mm” (24x36mm) format.

Trawling through the Lens Hall of the Canon Camera Museum we can see several 100mm Serenar types from 1946-1964, followed by two R versions of the 100mm theme from 1959-1963.

The first 100mm lens to have been specifically developed for close-up work appears to be the FLM 100mm f4 bellows model of 1969.

The FD series started in 1970 but I see no reference to a 100mm macro model until the New Macro FD 100mm f4 of 1979. This appears to have been the first 100mm lens suitable for close-ups without the need for a bellows. It had 5 elements and gave 0.5x lifesize images on the film.

The EF series starting in 1987 came with major changes including a completely new electronic mount and autofocus.

The EF 100mm f2.8 Macro arrived in 1990 with 10 elements and a maximum magnification on film of 1.0x.  I used one of these for several years in the 1990’s with mostly good results.

The EF 100mm f2.8 L Macro IS USM arrived in 2009 with several upgrades, including  weather sealing, L grade construction, optical stabiliser and ultrasonic focus motor.

This lens remains in the current catalogue and at the time of writing is still is available new. It can be used on EF mount DSLRs and also on mirrorless RF mount bodies with one of the EF-EOS R mount adapters.

This is an advanced design with 15 elements in 12 groups, a maximum magnification ratio of 1.0x and hybrid IS designed to work with close-ups. There are two focus groups ensuring good sharpness at infinity and close up. Length is 123mm and mass 625 grams.

The next big change for Canon was the introduction of the mirrorless RF mount towards the end of  2018. This was a case of better late than never as Sony switched their full frame  (24x36mm sensor) offerings to mirrorless in 2013 and set about taking customers from Canon and Nikon.

When Canon switched from FD to EF in 1987 none of the existing FD lenses could be used on cameras with the new EF mount. So Canon had to hurry up in 1987 and roll out lots of EF replacements for established FD standards.

This time around the new RF mount mirrorless bodies can accept any EF mount lens via one of the EF-EOS R Mount adapters.

This has freed up Canon’s lens developers to conjure up several new and innovative approaches  to design in the RF era.  One of the technologies which makes this possible is that Canon dual pixel AF works down to an aperture of f22 whereas DSLRs could not focus reliably below f5.6.

So for many of their RF lenses Canon has been able to include features and capabilities not seen in previous EF models.

Which brings us in somewhat roundabout fashion to the subject of this post which is the RF 100mm f2.8 L Macro IS USM.

In 2018 Canon could reasonably have assumed that photographers wanting to do macro work would already have an EF macro lens. These people can avail themselves of the considerable benefits of the new mirrorless bodies without having to buy a new lens. All they need to do is get the EF-EOSR adapter and they are in business.

So when Canon did decide to produce an RF mount 100mm macro lens the door was open for lens designers to come up with something not seen previously.

It appears they have embraced this opportunity with enthusiasm.

The result is an outstanding lens with several very appealing features and capabilities.

These include faster autofocus, more effective stabiliser on bodies with IBIS, 1.4x lifesize reproduction, overall improved image quality,  a lens control ring, and the mysterious new spherical aberration control ring.

 

This is the EF L macro

What is it for ?

In a previous era I think one could say that a macro lens is useful for close-ups and not a geat deal beyond that. But the RF 100mm L macro can do anything for which a 100mm lens is appropriate, including macro, portrait, documentary,  landscape, sport and action.

Description

RF 100mm L Macro on EOS R5

This is the largest 100mm lens I have seen. The length is 148mm and the mass 730 grams which is actually quite light for such a big lens containing a lot of glass.

To put this into perspective the EF 100mm L macro used on an R body with the adapter is the same length and mass.

There are 17 elements in 13 groups making for a complex optical formulation with concave front and rear elements and internal focussing from infinity to 1.4x lifesize.

Thisis the new RF L Macro 

You can see that the optical design of the RF version is quite different from the EF model.

The RF lens can only be mounted on a mirrorless R series body.

The lens comes with the ET-73C hood, front and rear caps and a soft pouch. Filter size is 67mm, the same as the EF version.  I mount a B+W F-Pro mrc uv filter permanently. All my tests are done with the filter in place. I often have the lens in the bush with bits of foliage, dirt, dust and pollen getting all over the camera gear. It is much easier and safer to clean this off the filter than the front element of the lens.

The exterior of the lens is understated in styling with a semi matt black finish.

There is a clicky ring at the front, just behind the red L ring. This can be configured to adjust any of several parameters selected from the menus. I disable it so as not so accidentally alter some setting.

Behind that we have the focus ring and behind that the mysterious SA (Spherical aberration) control ring. Fortunately there is a locking switch to make sure this is not accidentally moved. I have not experimented with the SA control so I really can’t comment about it.  I leave it locked at the default mid position.

Canon says it is “for smooth and easy control over the bokeh effect and soft outlines in images”.

I have to admit I am unaware of any upswell of demand for such a feature and it is not something for which I am currently able to find a purpose.

Behind the SA ring are three little slots in the surface of the lens barrel. These enable correct positioning of the Canon tripod mount ring and adapter specifically designed for the RF 100mm L macro lens.  This is not yet available at the time of writing.

Towards the rear of the lens barrel we have a focus limiter switch which could be useful when doing close-ups, to stop the lens racking out to infinity when it loses focus.  There is also an AF/MF switch and Stabiliser On/Off switch.

The lens is weather sealed with a rubber O ring around the outside edge of the mount.

Angophora costata

Focus Performance

Autofocus is very fast and quiet. Manual focus is easily managed using Canon’s “swinging arms” focus guide, which I find much easier to use and much more accurate than peaking.

An analogue focus scale pops up on the screen in manual focus. Press the Info. button if you don’t see it.

Autofocus is so fast that I can hand hold the camera, set Servo AF and High+ continuous drive on the R5 then track flowers which are waving about in the breeze. I get a usable number of sharp shots this way in conditions which would have made photography almost impossible with previous generation camera/lens combinations.

Yea BIF with a macro lens

AF is also fast enough to capture birds in flight provided they are close to the camera.

Is this the first ever macro lens which can do BIF ?

Note that when shooting small flowers in front of a busy background the AF system will often default to the background at which point it cannot see the flower at all as it is so far out of focus. The fix for this is to place one hand adjacent to the flower subject, focus on the hand then the AF system can see the flower and focus on it.

The focus shift issue

In his review on The Digital Picture Bryan Carnathan reported finding focus shift as the aperture is closed down at very close focus distances.  I was rather concerned about this as the depth of field at very close focus is only a few millimeters.

So I ran careful tests, focussing  at 5 meters then 1x magnification then 1.4x magnification. I made a tiny little focus accuracy target for the close-ups.

I found no evidence of focus shift at any distance or aperture. On the contrary I was impressed with the absence of any observable shift in the plane of best focus under any circumstance.

Focal length change with focussing

This is often referred to in reviews as “focus breathing”.

Canon says the lens has been designed to minimise focus breathing. And I was not aware of this phenomenon when using the lens at non-macro distances.

However in the close-up range the effective focal length does increase a bit as focus distance decreases.

Stabiliser

Canon  says  “The lens offers image stabilisation of 5 stops based on CIPA testing standard” and “8 stops of co-ordinated control when attached to an EOS R system with in camera IS”. 

The CIPA standard is DC-X011 available in Japanese and English and is a 46 page document describing in excruciating detail the protocol to be followed and exactly what types of image characteristics are measured. It is very much a laboratory operation.

My procedure for evaluating an image stabiliser is rather more basic and practical. I simply hand hold the camera and photograph a detailed subject at a distance of about 4 meters using a range of shutter speeds first with IS on then with IS off.

I note the average slowest shutter speed which gives a sharp image with IS on and with IS off then note the difference between the two expressed in EV steps.

This gives me on average a benefit from the stabiliser of about 3.5 EV steps with the RF 100mm L macro on the R5 body.

This is  nothing like 8 EV steps however the  stabiliser is nevertheless well worth having.

It steadies the viewfinder image which makes framing easier and gives the AF system a more stable platform on which to work and it does allow slower shutter speeds to be used provided subject movement is not an issue.

Canon also says that the stabiliser function switches to a hybrid mode when focussed close to improve stability with close-ups.  I have not yet attempted to test this however I find the stabiliser is very useful for close-ups. It allows me to use the lens without a tripod in many situations which in the past would have required a tripod.

Optical performance

MTF chart supplied by Canon 

The black lines represent contrast, the blue lines sharpness both at f2.8

The RF 100mm f2.8 L macro has some desirable optical characteristics which I have not seen to such a degree in any other lens.

It delivers a very high level of sharpness, resolution and contrast across the entire frame and into the corners from f2.8 to f16 inclusive.

Resolution declines a little at f22 and further at f32.

Most lenses, even really good ones improve when the aperture is closed down a stop or two from the widest available aperture then suffer from the effects of diffraction which on the 24x36mm format generally starts to become evident at around f11 if one is using a high pixel body.

For instance the RF 16mm f2.8 which I reviewed recently has soft corners until f5.6 or even f8 if one wants foliage in the corners to be sharp. But at f11 softness due to diffraction becomes evident. So the useful aperture range if one must have decently sharp center and  corners is f5.6 and f8.

The RF 100mm f2.8 L macro stretches that range right out from f2.8 to f16. When I review my test chart images I find it difficult to guess the aperture at which each image was made.

The situation with distortion is a bit weird. There is no significant distortion in uncorrected Raw files opened in Adobe Camera Raw. But when the lens correction profile is deployed a mild amount of barrel distortion appears.  What is that about ?

In most photos there is no detectable color fringing.  I can detect a small amount at 200% on some images with very high contrast edges but it is easily corrected.

The centering  on my copy appears to be perfect

The out of focus rendition (bokeh) deserves special mention.  This lens is very sharp in the in-focus zone and very soft and smooth in the out-of-focus zone. This of course is exactly what we want but few other lenses manage the transition so convincingly.

There are just two things which prevent me from rating this lens as perfect.

First, it is a bit prone to flare with the sun shining on the front element. I have to say this only became evident when I deliberately went looking for flare. In normal use with the hood mounted flare is not an issue.

Second, peripheral shading is evident at f2.8. This is easily corrected post capture.

 

This illustrates sharpness distribution at f5.6

Three dimensional sharpness distribution

Very few lens tests explore the distribution of sharpness in three dimensions produced by a lens as the aperture is changed. I now do this with every lens I own using the simple protocol outlined here.

This test is easy to do and can reveal considerable useful information. Many lenses especially wide angles and zooms produce a complex pattern of sharpness which can in some cases defeat attempts by the user to obtain image sharpness across the frame especially in landscape type scenarios.

The RF 100mm L Macro delivers  exemplary performance on this test.

Sharpness is very high along the line of focus right to the edges of the frame. As the aperture is closed the sharpness zone increases evenly and equally (equally on the image frame, that is) towards (down the frame) and away from (up the frame) the focus point.

This same exemplary performance continues in the close-up range with sharpness right to the edges of the frame and no distortion in the pattern of sharpness.

These Kunzea ambigua were waving about in the breeze. No problem getting sharp shots with the RF 100 L Macro

Alternatives

The obvious alternative is the EF 100mm f2.8L Macro which did not suddenly become any less capable because the RF macro came along.

In Australia at the time of posting  typical retail  prices GST paid are

* RF 100mm f2.8 L Macro, AUD2289

* EF 100mm f2.8 L Macro  plus the EF-RF adapter,  AUD1688

I note that one vendor is listing the EF version as “pre-order” which for a lens released 12 years ago is a bit comical. I assume they mean they are sold out and awaiting new supply which indicates the EF version is selling at least decently well.

I have also used the RF 85mm f2 Macro quite extensively. This is a very sharp lens which can deliver 0.5x lifesize images on the sensor. It is very suitable for many close-up subjects and is smaller and lighter than the 100L and half the price.

It feels a bit slow to focus compared to the RF 100mm L though, and that can sometimes get a bit frustrating.

I do not use third party lenses on my EOS R Canons because of many reports of unreliable autofocus and problems obtaining lens firmware upgrades to operate correctly with new bodies as they come along.

These Xyris juncea flowers sit atop a long thin stalk and are never still even when there appears to be no wind. In the past I would have clamped the stalk below the frame edge using a stake or tripod, had the camera on a second tripod and spent half an hour getting everything set up for the shot.  But with the RF 100mm L Macro on the R5 I just walked up and fired off a burst of frames several of which were tack sharp.

Conclusion…Much more than macro

I rate the RF 100mm f2.8 L Macro as one of the best lenses I have ever bought and used.

If this thing had a Leica badge the red dot afficionados would be raving about it while paying ten times as much for the privilege of ownership.

But it has a Canon badge so reviewers say OK, it’s really good, ho-hum, what’s for lunch ?

Even user forums have little to say about it.

I suspect the image problem for this lens might be that it could be perceived as a somewhat overpriced large macro when it is actually a fine lens with a wide spectrum of uses including sport, action, portraiture and really anything else for which the 85-100-135mm focal length range is appropriate.

Very highly recommended.