Introduction

Canon EF 70-300mm f/4-5.6 IS USM replaces an earlier generation EF 75-300mm f/4-5.6 IS USM model that was discontinued in mid 1990s. The lens is one of about a dozen telephoto zooms in Canon's modern lineup, and is one of the only two consumer (read non L, non DO) telephoto zooms that implement an IS mechanism. Priced at ~US$550 (as of February 2008) it remains well within the reach of mainstream consumer looking for a long telephoto zoom, making the lens also quite popular among users.

The optical construction of the lens consists of 15 elements in 10 groups, including a single UD (Ultra low Dispersion) glass element. Build quality of the barrel is not really spectacular - it is similar to Canon's other consumer grade lenses, meaning that the shell is made of plastic and feels a bit flimsy. Both zoom and focus rings are pretty smooth and the zoom ring is quite broad and easy to grip. The lens cams wobble a bit inside. The lens sports a conventional USM type AF system as well as full time manual focusing, which can be controlled by an AF/MF switch on the side of the barrel (although the lens does not support FT-M in AF mode). When the lens is switched to AF mode, the focusing ring is locked and cannot be rotated, which is pretty convenient in the field. The lens has a lock button which would locks the zoom ring with cams fully collapsed, thus preventing the lens from extending accidentally during transportation. The lens also packs a second generation image stabilization technology, which offers two modes of operation: mode 1 tries to compensate for horizontal and vertical shake, while mode 2 compensates only for vertical shake (useful in action photography).

Canon EF 70-300mm f/4-5.6 IS USM is relatively (for a telephoto zoom) light and compact, weighing 630g (22.2oz) and measuring 76 x 142mm (3 x 5.6in), however, the lens extends when zooming towards 300mm, practically doubling its overall length. Unfortunately, the front element of the barrel rotates during zooming, which makes using circular polarizers not quite as easy as one would desire. The minimum aperture is f/45 (aperture is camera controlled, so there's no dedicated aperture ring and all settings have to be set from the camera), the minimum focusing distance is 1.5m (4.9ft), giving a maximum magnification of 1:4. The filter thread is 58mm.

 

Image

 

The lens carries EF designation, meaning that it is designed for full frame cameras and on an APS-C body with 1.6x crop sensor its field of view is similar to that of a 112-480mm zoom on a full frame body. The factory box include Canon EF 70-300mm f/4-5.6 IS USM lens, front and rear lens caps, manual and registration card. The lens is compatible with Canon's Gelatin Filter Holder Adapters III and IV and with optional ET-65B lens hood.

 

Summary
Lens Composition 15 elements in 10 groups
Angular Field ~84-23 degrees
Minimum Focus 1.5m/4.9ft
Focusing Action AF/MF, USM
f-stop Scale f/4-f/45, camera-controlled
Filter Size 58mm
Lens Hood ET-65B (optional)
Weight 630g/22.2oz
Dimensions 76x142mm/3x5.6"
Lens Case LP1222 (optional)

 

Field Tests

Canon EF 70-300mm f/4-5.6 IS USM demonstrated excellent results in the field. Image quality remained top notch in the 70-135mm range with both center and borders staying sharp straight from f/4. Quality seemed to deteriorate just a little bit in the longer zoom range, mostly around borders, but quality did not fall apart as with some other lenses.

For such a long zoom coverage, the lens is pretty light, which makes it easier to handle and shoot off hand. IS system is quite helpful although it is a bit noisy - every time it kicks in during focusing you can clearly hear the electromagnets spinning around, trying to compensate for the motion. AF system is reasonably fast but is not always accurate, especially at the longer end, where the lens hunts a little bit more then usual.

 

Vignetting @ f/4 - full frame vs 1.6x crop (70mm)
Vignetting @ f/4 - full frame vs 1.6x crop (70mm)

 

Vignetting @ f/5.6 - full frame vs 1.6x crop (300mm)
Vignetting @ f/5.6 - full frame vs 1.6x crop (300mm)

 

On a full frame body the lens shows mild vignetting at 70mm with wide open aperture. While vignetting by itself is not too severe, the fact that it is present at all on a telephoto zoom with such a slow maximum aperture is kind of disappointing. Vignetting is reduced somewhat towards the longer end of the zoom range, but it never completely goes away even at 300mm. An APS-C body is much more forgiving when it comes down to vignetting simply due to the smaller frame coverage of a cropped sensor, so the lens does not show any noticeable vignetting throughout the zoom at all aperture levels.

Color reproduction was quite accurate and in the shorter end of the zoom range carried sufficient amount of contrast to make images look vivid and real-life. Colors warm up a little bit and contrast level goes down as well. The lens did not show any noticeable distortion throughout the zoom range and held up nicely against flare at all aperture levels (not surprising for a telephoto zoom of such moderate speed).

 

ISO 100, 1/1250, f/4, 70mm (100% crop)
ISO 100, 1/1250, f/4, 70mm (100% crop)

 

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.

 

Canon APS-C: Canon EF 70-300mm f/4-5.6 IS USM showed surprisingly good performance on an APS-C camera. Image resolution in the center as well as around borders remained top notch in the shorter end of the zoom range (70mm to 135mm). Here the lens shows pretty balanced results across the frame and pretty much all aperture levels (well, dropping a little bit at f/11). As you start moving towards the longer end of the zoom range, image quality starts to degrade a little bit (mostly around borders though). At 200mm center performance is still pretty good across the aperture range, but you need to stop down to f/5.6 or f/8 to achieve best performance around borders. Image performance around borders degrades a little bit more further towards 300mm, while center quality still remains quite good. Here the lens shows best performance at f/5.6 where both center and border quality reach their peak. At 70mm, the lens produces results that would rival best prime lenses and is capable of delivering outstanding 19in and decent 24in prints, while the peak performance throughout the rest of the zoom range would give you excellent 16in and decent 19in prints. Conclusion? The lens delivers quite impressive overall performance throughout the zoom range. Image quality is simply superb with shorter focal lengths and remains quite solid in the long range.

 

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) @ 100mm
MTF50 (Line Width/Inch on the Print) @ 100mm

 

Normalized raw MTF50 @ 100mm
Normalized raw MTF50 @ 100mm

 

MTF50 (Line Width/Inch on the Print) @ 200mm
MTF50 (Line Width/Inch on the Print) @ 200mm

 

Normalized raw MTF50 @ 200mm
Normalized raw MTF50 @ 200mm

 

MTF50 (Line Width/Inch on the Print) @ 300mm
MTF50 (Line Width/Inch on the Print) @ 300mm

 

Normalized raw MTF50 @ 300mm
Normalized raw MTF50 @ 300mm

 

Chromatic aberration was not much of a problem on an APS-C camera. CA in the center was averaging ~0.5px across the zoom range and all aperture settings (although CA approached ~0.7px at f/5.6 @ 300mm). CA around borders, while somewhat higher compared to the center, is still quite manageable, averaging ~0.8px across the aperture and zoom range (again, CA at f/5.6 @ 300mm was higher, approaching ~0.9px, but even at that level CA can be considered low).

 

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

 

Chromatic Aberration (FF) - Borders
Chromatic Aberration (FF) - Borders

Here are 100% crops taken at 70mm, 100mm, 200mm and 300mm.

 

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

 

Image borders @ 100mm (100% crop): f/4.5 vs f/8
Image borders @ 100mm (100% crop): f/4.5 vs f/8

 

Image borders @ 200mm (100% crop): f/5 vs f/8
Image borders @ 200mm (100% crop): f/5 vs f/8

 

Image borders @ 300mm (100% crop): f/5.6 vs f/8
Image borders @ 300mm (100% crop): f/5.6 vs f/8

 

Canon FF: Canon EF 70-300mm f/4-5.6 IS USM continued to show very solid results on a full frame camera as well. Center performance remains top notch in the 70-200mm range, but even at 300mm center quality is still pretty decent. Border quality follows the suit and in the 70-135mm is simply outstanding, very good around 200mm and decent at the longest end. At 300mm stopping down the lens to f/8 would give the best results both in the center as well as around borders, but at wider apertures border quality is rather mediocre. This seems to be the only place where the lens gave up its ground on a full frame camera, which is of course a little bit disappointing. Conclusion? While performance around borders at 300mm is not necessarily the most impressive, overall quality you get through the rest of the zoom range is very respectable considering that the quality achieved is comparable to some of the best tele zooms available on the market.

 

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

 

Normalized raw MTF50 @ 100mm
Normalized raw MTF50 @ 100mm

 

Normalized raw MTF50 @ 200mm
Normalized raw MTF50 @ 200mm

 

Normalized raw MTF50 @ 300mm
Normalized raw MTF50 @ 300mm

 

CA on a full frame camera was as low as on an APS-C body, not exceeding ~0.5px in the center (across the supported zoom and tested aperture settings) and not exceeding ~0.9px around borders (with higher CA towards the longer end of the zoom range). Nothing to worry about here.

 

Chromatic Aberration (FF) - Center
Chromatic Aberration (FF) - Center

 

Chromatic Aberration (FF) - Borders
Chromatic Aberration (FF) - Borders

 

Here are comparison crops of image borders taken at 70mm, 100mm, 200mm and 300mm.

 

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

 

Image borders @ 100mm (100% crop): f/4.5 vs f/8
Image borders @ 100mm (100% crop): f/4.5 vs f/8

 

Image borders @ 200mm (100% crop): f/5 vs f/8
Image borders @ 200mm (100% crop): f/5 vs f/8

 

Image borders @ 300mm (100% crop): f/5.6 vs f/8
Image borders @ 300mm (100% crop): f/5.6 vs f/8

 

Alternativeso

Canon alone manufactures about a dozen telephoto zoom lenses in all shapes and focal ranges. However, the quad of Canon's 70-200mm L lenses are probably the ones you might want to look at first. If you insist on having an IS, then look at EF 70-200mm f/2.8L IS USM and EF 70-200mm f/4L IS USM, otherwise evaluate their non-IS versions, EF 70-200mm f/2.8L USM and EF 70-200mm f/4L USM. For a longer reach, consider EF 100-400mm f/4.5-5.6L IS USM, although this lens model seems to suffer from rather high variance in production quality. Canon is obviously not the only company manufacturing telephoto zoom lenses, so for a better price/performance ratio you might want to take a look at Sigma's 70-200mm f/2.8 EX DG HSM as well as Tamron's latest SP AF 70-200mm f/2.8 Di LD IF Macro.

 

Recommendation

For a consumer type zoom, Canon EF 70-300mm f/4-5.6 IS USM is a surprisingly solid lens. Image quality is quite good and in the shorter zoom range even rivaling that of the more expensive L grade lenses. Combine that with low level of artifacts such as CA, distortion, vignetting, as well as decent IS system and finally affordable price, and you got a winner on your hands. Or at least one of the best overall deals available on the market. But like many things in the real life, this lens has its own trade-offs as well. The build quality is one of them - it's a shame Canon decided to use such a flimsy looking/feeling shell for this lens. Relatively slow maximum aperture is another one. And kind of mediocre performance (especially around borders) at 300mm is yet another. Ultimately though, if you can live with these issues, you can get a really well performing workhouse, ghem, I mean lens.