This report briefly reviews and compares the performance of the Canon EF 24-105mm f/4L IS lens against two other excellent performing Canon zoom lenses: 1) EF 24-70mm f/2.8L; and 2) EF 28-135mm f/3.5-5.6 IS. All three lenses performed remarkably well with only relatively small differences in performance being detected in the tests. All three lenses offer excellent sharpness and contrast across their aperture and focal length ranges and resistance to flare. Differences were noted in linear distortion, vignetting, out of focus highlights, resolution at f/8 and lateral chromatic aberration. The two expensive L-zoom lenses predictably outperformed the consumer quality EF 28-135mm lens on many tests. However, the differences in image quality that end up being visible in a print are surprisingly small. Lens Specifications Information on lenses used in test

Summary Conclusions/Opinions

EF 24-105mm f/4L IS
Strengths: This 4.4x constant aperture L-zoom lens provides close to the perfect focal length for event photography (e.g., weddings, receptions) as well as travel photography with a full frame camera. Sharpness and contrast are very good wide open at f/4, but improve if stopped down to f/5.6. Image stabilization is useful in low light, and superb L-quality build make it a lens that will survive heavy use under moist and dusty conditions. It is relatively light and compact (only being slightly larger and heavier than the 28-135 consumer lens.) It has the least amount of lateral chromatic aberration of the three lenses tested.
Weaknesses: The near perfect focal length range comes at the expense of greater linear distortion and vignetting (light drop off). At 24mm, there is moderate barrel distortion. At 100mm, there is moderate pincushion. The vignetting almost disappears by f/8. For most photographic applications, the vignetting and barrel distortion generally will not be noticeable.

EF 24-70mm f/2.8L
Strengths: This 2.9x constant aperture L-zoom lens produced high quality images that were most free of distortion and vignetting of the three lenses. Very sharp, high contrast images were produced over the widest aperture range. The 24-70 noticeably outperforms the 24-105 at 24mm. The f/2.8 aperture is very useful for low light shooting conditions when you want to stop motion and for background control with pleasing bokeh. Autofocus function under low ambient lighting conditions is noticeably faster with this f/2.8 lens than with narrower aperture lenses. This quality L-lens has been previously reviewed here.

Weaknesses (picking nits): If you are shooting an event/wedding with one lens, you will find times when you wish the 24-70 were a little longer (e.g., 85 or 90mm). If you are shooting events with two bodies and lenses or can move in closer, this isn't a problem. This lens has a little more lateral chromatic aberration than the 24-105. It is a large, heavy lens that may be objectionable to some if you have to carry it around for a day with other equipment.

EF 28-135mm f/3.5-5.6 IS
Strengths: If you can stop this lens down to f/8 or f/11, this 4.8x variable aperture consumer zoom lens provides excellent imaging quality at 1/3 the cost of the 24-105 L-lens. It is light and reasonably well constructed for light-duty use with very good image stabilization function. For many photographic applications, I can't differentiate image quality produced by it and expensive L-zooms. Even though the L-zooms give slightly higher resolution at f/8 than the 28-135, this slightly higher resolution is generally not noticeable in prints smaller than 8x10. This is a great travel lens with the EOS-5D, despite the introduction of the 24-105. I wrote an earlier review of this lens based mostly on film camera performance here using a different lens sample.

Weaknesses: The greater zoom range of the 28-135 is associated with linear distortion at the zoom ends as well as vignetting and mild chromatic aberration. Image quality doesn't hold up to large print enlargement if you shoot at apertures wider than f/8 or f/11 compared to the L-zooms. There are many times where you want to control background by opening up aperture, and your options with the 28-135 lens are limited. Good photographic skills can often overcome these limitations.
There is an obvious big difference between construction quality of this consumer zoom and that of the L-zooms. The consumer quality build of the 28-135 should hold up to careful use for many years. This lens is constructed of light-weight materials, is not sealed and is much more susceptible to moisture, dust and heavy-use structural wear than the L- zooms.
Other 28-135 users have posted reviews of poor performance and poor build quality for this lens, so there may be quality variability in the production of this consumer lens. I have owned two of them, and both have performed very well stopped down to f/8 or f/11 and have had good build quality.

50% MTF and Contrast Performance Data
The tests I ran indicated that there were smaller differences in 50% MTF and contrast performance among the three lenses than in any previous tests of multiple lenses I have run. All three lenses performed remarkably well.

Methods used to calculate 50% MTF and contrast from RAW images with an EOS-1Ds Mark II were comparable to these with the exception that differing working distances were used for each focal length. MTF/Contrast values should only be compared within a review and not between reviews since conditions varied between lens reviews for these test parameters.

28mm
50mm
85mm
100mm
135mm

I considered the possibility that RAW processing software was obscuring or compensating for differences in lens performance and repeated the analysis using in-camera large jpgs. Similar results from in-camera jpgs were obtained and are presented here.

Vignetting, Linear Distortion, Sharpness, Chromatic Aberration with an EOS-1Ds Mk II

Corner image sharpness, linear distortion, vignetting, and lateral chromatic aberration (CA) varied among the lenses tested.

In the following tables, sharpness and resolution summaries are provided. Corner image performance examples below are from the upper left corner of this chart. Resolution is quantitative and recorded from the images of the USAF 1951 pattern on the Edmund Scientific chart. The assessment of sharpness is qualitative. The field was recorded as mildly soft, sharp, or very sharp when it looked mildly soft, sharp or very sharp. Factors influencing sharpness included resolution, contrast, freedom from chromatic aberration, and field illumination. In the center of the field, there was generally good agreement between resolution values and the degree of sharpness. In the corners, there was less agreement since a lens might resolve line pairs at 44 lp/mm, but still give a soft appearing image because of lack of contrast, chromatic aberration and uneven illumination (vignetting or light drop off).

24mm

Vignetting and Linear Distortion - 24mm

Corner Sharpness and Chromatic Aberration (CA) - 24mm

Central Sharpness - 24mm

28mm

Vignetting and Linear Distortion - 28mm

Corner Sharpness and Chromatic Aberration (CA) - 28mm

Central Sharpness - 28mm

50mm

Vignetting and Linear Distortion - 50mm

Corner Sharpness and Chromatic Aberration (CA) - 50mm

Central Sharpness - 50mm

100mm

Vignetting and Linear Distortion - 100mm

Corner Sharpness and Chromatic Aberration -100mm

Central Sharpness - 100mm

Central image sharpness varied among the lenses tested. There was no central chromatic aberration. Examples below in the table are from the center of this chart.

Other Photographic Tests

Building / Landscape Test Target at 40mm and f/11 Slight differences in sharpness are more attributable to slight focus differences than intrinsic lens sharpness. All three lenses performed very well in this test.
Mannequin Test Target at 70mm You can see slight differences in sharpness (especially between the L-lenses and the 28-135mm lens at wide open apertures). Overall, all lenses produce images with excellent contrast and good to excellent sharpness for portrait application.
Resistance to Flare Monolight fired directly into lens. All three lenses are resistent to flare. All tests run at about 70mm. The EF 24-70 at f/2.8 shows relatively minor flaring with an internal reflection.
Out of Focus Light Patterns There are minimal differences in the patterns of out of focus background lights among the lenses. The 24-70 produces the smoothest out of focus backgrounds (bokeh). The 28-135 shows hexagonal aperture out of focus lighting pattern. All tests were run at about 70mm.

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© 2006, William L. Castleman
Initially posted 10 June, 2006, updated 15 June, 2006