Introduction

Canon EF 24-105mm f/4L IS USM was first announced in August of 2005, targeting event/street photographers who require a lens with moderate wide to medium telephoto coveraget range. The so called 'standard zoom' category of lenses is choke full of lenses from both original equipment manufacturers as well as third party independent manufacturers like Sigma and Tamron. The category remains very popular not only among pros and semi-pros, but also among novice, first-timers, who typically choose a standard zoom as their first lens due to its versatility. Yet despite so many choices out there, Canon EF 24-105mm f/4L IS USM was eagerly anticipated by many simply because it was one of the first professional (or 'L' type in Canon jargon) grade stadard zooms with an image stabilization technology. Priced at ~US$1,050 (as of February 2007), the lens is not the cheapest among standard zooms, but still affordable for many who want a quality lens for daily use.

The optical construction of the lens consists of the lens consists of 16 elements in 12 groups - certainly not a trivial configuration, even for a zoom. This includes a single Super-UD and three aspherical lenses, designed to minimize various  forms of aberrations and reduce distortion at wider angles. The build quality of the lens is simply superb, typical of Canon's other L grade lenses, the barrel is made of hardened plastic with nice black finish, fully ruberrized zoom and focus rings, and full sealing against dust and moisture. The lens weighs 670g (23.6oz) and measures 83.5 x 107mm (3.3 x 4.2in), although the lens extends during zooming towards the long end of the supported range, adding extra 3 or 4cm. At this size and weight, EF 24-105mm f/4L IS USM is not the smallest or lightest standard zoom out there, so some users (especially those of you owning a Leica M) might cringe at the idea of using this lens for descrete street photography.

The lens incorporates a modern, USM type auto-focusing motor. Manual focusing is still possible, using a dedicated focusing ring - switch the lens into a fully manual mode using an AF/MF switch found on the side of the barrel, or simply nudge the focusing ring a little bit to correct minor auto-focusing errors. Like with all modern EF/EF-S lenses, Canon EF 24-105mm f/4L IS USM does not have a dedicated aperture ring and all aperture settings have to be controlled directly from the camera. The minimum supported aperture is f/22. As mentioned above, the lens incorporates an image stabilization technology that is marketed to help stabilize the lens up to extra 3 f-stops. This is obviously a nifty feature for hand-held photography. The IS however should be disabled when the lens is used on a tripod - if you don't turn it off, you risk damaging the mechanism, which will keep trying to engage even with the lens positioned completely stationary. And even if you avoid damaging the IS mechanism, you risk additional shake from the internal gyroscopes 'going wild', trying to detect movement. Just swith it off, using an IS ON/OFF switch on the side of the barrel. By the way, the IS does not offer 2nd mode (panning), so it is effective for static scenes only.The lens accepts 77mm screw-in type filters and focuses down to 45cm (1.5ft).

 

Image

 

Canon EF 24-105mm f/4L IS USM is designed for full frame cameras, so when used on APS-C type bodies with 1.6x crop sensor, the field of view of the lens will resemble that of a ~38-168mm zoom - the wide angle is pretty much gone here, but you get an extra kick on the longer end. The factory box includes Canon EF 24-105mm f/4L IS USM lens, front and rear caps, EW-83H lens hood, LP1219 lens case, manual and registration card. The lens is compatible with Gelatin Filter Holder IV at the expense of lens hood which cannot be used with the holder, as well as with Canon's extension tubes EF 12 II and EF 25 II.

Note that early versions of Canon EF 24-105mm f/4L IS USM had a flare problem and Canon issued a service notice (see here).

 

Summary
Lens Composition 16 elements in 13 groups
Angular Field 84-23 degrees
Minimum Focus 45cm/1.48ft
Focusing Action AF/MF, USM
f-stop Scale f/4-f/22, camera-controlled
Filter Size 77mm
Lens Hood EW-83H (included)
Weight 670g/23.6oz
Dimensions 83.5x107mm/3.3x4.2"
Lens Case LP1219 (included)


Field Tests

The lens performed quite well across all focal lengths. Canon EF 24-105mm f/4L IS USM produced sharpest images at 24mm, with progressive degradation towards 105mm. At 105mm, the lens still produced decent results, but nothing extraordinary. Chromatic aberration was well under control. At 24mm, the lens had some minor artifacts, which were still present at 50mm and completely gone towards the telephoto range. As always, stopping down to f/5.6 or f/8 helped achieve best results.

Image stabilizer is a fantastic bonus in this lens! It works and works pretty well - the improvements are especially noticeable at the telephoto end where IS helps you gain extra 3 f-stops. Should you use this lens as a telephoto lens? The answer is - probably no, since there are better telephoto lenses out there. However, some photographers will find the extra focal length on this lens quite handy.

 

Vignetting @ f/4 - full frame vs 1.6x crop (24mm)
Vignetting @ f/4 - full frame vs 1.6x crop (24mm)

 

Vignetting @ f/4 - full frame vs 1.6x crop (105mm)
Vignetting @ f/4 - full frame vs 1.6x crop (105mm)

 

On a full-frame body, the lens produced noticeable vignetting with a wide open aperture at 24mm, which becomes practically negligible by f/5.6. Vignetting is reduced towards the longer end of the focal length, and become less of a nuisance even with wide open apertures. On an APS-C body with 1.6x crop factor, vignetting is practically non-existent throughout the entire zoom range. Color fringing was quite minor around borders and non-existent in the center. The lens held up nicely against flare and did not exhibit any noticeable distortion.

 

ISO 100, 1/1000, f/4, 24mm
ISO 100, 1/1000, f/4, 24mm


Lab Tests

Please note that MTF50 results for APS-C and Full-Frame cameras are not cross-comparable despite the same normalized [0:1] range used to report results for both types of cameras.

Three lens samples were tested in the lab, producing variance of ~5% in the center and ~21% around borders, averaged across the tested zoom and aperture settings. The review includes results from the sample showcasing better overall performance.

 

Canon APS-C: The lens showed solid results in the lab. Performance was outstanding in the 24-50mm range, with excellent center and very solid border  quality. Unfortunately, image sharpness degrades towards telephoto range, especially around borders. In the 70-105mm range, image center remains pretty sharp throughout tested apertures, but border quality is rather mediocre at f/4 (quality does improve once stopped down). The lens has a sweet spot around f/5.6 where it shows the best overall performance across the tested zoom range. At its best (24mm-50mm focal lengths), the lens would produce excellent 19in and decent 24in prints, which is pretty admirable for a zoom lens (if only performance remained at the same level throughout the focal range). Conclusion? Canon EF 24-105mm f/4L IS USM is a more or less well-rounded lens excelling in the standard zoom range. If you intend to use it as a walk-around lens - by all means do so, but you will be able to find better alternatives for your telephoto needs.

 

MTF50 (Line Width/Inch on the Print) @ 24mm
MTF50 (Line Width/Inch on the Print) @ 24mm

 

Normalized raw MTF50 @ 24mm
Normalized raw MTF50 @ 24mm

 

MTF50 (Line Width/Inch on the Print) @ 50mm
MTF50 (Line Width/Inch on the Print) @ 50mm

 

Normalized raw MTF50 @ 50mm
Normalized raw MTF50 @ 50mm

 

MTF50 (Line Width/Inch on the Print) @ 70mm
MTF50 (Line Width/Inch on the Print) @ 70mm

 

Normalized raw MTF50 @ 70mm
Normalized raw MTF50 @ 70mm

 

MTF50 (Line Width/Inch on the Print) @ 105mm
MTF50 (Line Width/Inch on the Print) @ 105mm

 

Normalized raw MTF50 @ 105mm
Normalized raw MTF50 @ 105mm

 

Chromatic aberration was not a major issue with this lens. CA averaged ~0.6px in the center throughout the zoom range and across all aperture settings. CA creeps up a little bit around borders, especially at the wider aperture level. CA here averages ~1px. CA drops a little bit with stopped down aperture, but never goes below 0.7px across the zoom range. Still, this is not the worst one can see in a standard zoom lens.

 

Chromatic Aberration (APS-C, Center)
Chromatic Aberration (APS-C, Center)

 

Chromatic Aberration (APS-C, Borders)
Chromatic Aberration (APS-C, Borders)

 

Here are a couple of 100% crops comparing image borders takes at 24mm, 50mm, 70mm and 105mm focal lengths (f/2 vs f/8).

 

Image borders @ 24mm (100% crop): f/4 vs f/8
Image borders @ 24mm (100% crop): f/4 vs f/8

 

Image borders @ 50mm (100% crop): f/4 vs f/8
Image borders @ 50mm (100% crop): f/4 vs f/8

 

Image borders @ 70mm (100% crop): f/4 vs f/8
Image borders @ 70mm (100% crop): f/4 vs f/8

 

Image borders @ 105mm (100% crop): f/4 vs f/8
Image borders @ 105mm (100% crop): f/4 vs f/8

 

Canon FF: Canon EF 24-105mm f/4L IS USM continued to show very respectable results on a full frame camera. Center performance is very solid across the aperture range and throughout the zoom. Regretfully, border performance follows similar to the APS-C pattern - results are outstanding in the 24-50mm range with borders remaining sharp throughout the aperture range. However, border sharpness drops noticeably in the 70-105mm range, and that is especially noticeable at f/4, where the lens seems to struggle the most. Stopping down helps quite a bit and by f/8 border performance is quite decent even in this zoom range. Conclusion? The lens is a solid addition to Canon's standard zoom lineup, but is not without weaknesses. Still, results are very solid in the 24-50mm and are quite decent throughout the rest of the zoom.

 

Normalized raw MTF50 @ 24mm
Normalized raw MTF50 @ 24mm

 

Normalized raw MTF50 @ 50mm
Normalized raw MTF50 @ 50mm

 

Normalized raw MTF50 @ 70mm
Normalized raw MTF50 @ 70mm

 

Normalized raw MTF50 @ 105mm
Normalized raw MTF50 @ 105mm

 

The lens showed decent handling of chromatic aberration on a full frame body. CA in the center is well under control, hovering at ~0.5px throughout the zoom and all aperture levels. CA around borders averages ~1px at f/4 (pretty much throughout the zoom range) and drops to ~0.8px by f/5.6, remaining at about that level throughout the rest of the tested aperture range (again across the zoom range).

 

Chromatic Aberration (FF, Center)
Chromatic Aberration (FF, Center)

Image

 

And here are some more 100% crops taken on a full-frame Canon 5D comparing image borders at 24mm, 50mm, 70mm and 105mm.

 

Image borders @ 24mm (100% crop): f/4 vs f/8
Image borders @ 24mm (100% crop): f/4 vs f/8

 

Image borders @ 50mm (100% crop): f/4 vs f/8
Image borders @ 50mm (100% crop): f/4 vs f/8

 

Image borders @ 70mm (100% crop): f/4 vs f/8
Image borders @ 70mm (100% crop): f/4 vs f/8

 

Image borders @ 105mm (100% crop): f/4 vs f/8
Image borders @ 105mm (100% crop): f/4 vs f/8


Alternatives

There are quite a few alternatives to Canon's EF 24-105mm f/4L IS USM lens. This is not surprising, considering that standard zooms are typically the best selling lenses. If you are looking for a high quality lens within same price level, Canon EF 24-70mm f/2.8L USM (review) is a good choice. While this lens is brighter then EF 24-105mm, it does not have an IS. For solid performing lenses that will not bankrupt you, consider Canon EF 28-105mm f/3.5-4.5 USM (review) or Canon EF 24-85mm f/3.5-4.5 USM (review). Both of these lenses are moderately prices (less then US$300). You might also want to consider Sigma 28-135mm f/3.8-5.6 Aspherical IF Macro (review), which is also an affordable choice. Of course there is no such thing as free lunch, so you will be trading build quality and performance if you trade down to these less expensive alternatives.

 

Recommendation

Canon EF 24-105mm f/4L IS USM is a very solid lens. On APS-C cameras, the lens becomes an interesting medium telephoto zoom lens. For full-frame dSLRs this is however a fantastic standard zoom. The build quality is very solid.  Overall performance varies from exceptional at the wide focal length to average at telephoto length. The lens adds a solid 4.4x zoom, which some will find quite handy. Image stabilizer is an another bonus here, making the overall package quite attractive. If you need a faster lens, go for Canon EF 24-70mm f/2.8L USM, which is also a solid performer, otherwise look no further.