A Brilliant Zoom Lens from a Third-Party Lens Maker

Almost every Saturday morning in Autumn, I often make time to visit this small lake in my town. The lake is elongated with shallow bed and only drops deep towards the middle; it's more of a swampland with cattail, Indian paintbrush, touch-me-not flowers and a few other plants and vegetation in the lake and along the shorelines. All kinds of bird species flock here to feed in the shallow water, herons in particular. Local fishermen are often spotted along the north side of the shore and under the bridge running over the lake's channel that joins with another larger lake where the water is deep. Local resident often float in their canoe in the afternoon just to enjoy the view. This place is particularly colorful in August.

Photography is all about lighting; it's the light that separates a boring image from an interesting one. Early at dawn this place is serene. I realize I did not have to go very far to find a good place for a potentially good photo opportunity. To the west of the lake, over to the trails and side walk, there is a grass hill filled with wildflowers. It was here that I have spent my Saturday mornings (August and September) during 2003-04 mastering my macro photography. To the east, the sun rises over the lake behind a row of trees in silhouette. With the right vantage point, the sun rise shot can be made with its reflection in the open shallow water. Sometimes, there would be thick layers of fog to accentuate the mood of the photograph that adds a sense of mystery and wonder.

Shortly after sun rise, all kinds of birds come out of their nest. Wild ducks are in the swamp eating duck weed, swimming around with their ducklings. Birds are everywhere glinging on cattail stalks, chirping. I have always wanted to photograph herons and birds, but my gear was never meant for bird photography. I pack light, easy for the hike; most of the time I bring two lenses (Nikon 70-180mm f/4.5-5.6 Micro-Nikkor and Nikon 17-35mm f/2.8) for landscape and closeup photography.

When I decided to haul my Tokina 300mm f/2.8 lens with a 1.4x teleconverter, hoping to get my chance on the birds, I encountered all sorts of problem. Sometimes they were so close; other times they were far away. Setting up the large 300mm f/2.8 to accommodate the sudden movement of the birds was just too much of a hassle, especially when I had to reposition the tripod in the mud and by then the birds were gone. Handholding the Tokina 300mm f/2.8 was just not possible. If I had a zoom lens in the 300mm range, perhaps it would increase a better chance of getting a snapshot of birds, if the lens were not large and heavy, like the Tokina 300mm f/2.8.

I never put serious thought about getting Sigma APO 100-300mm f/4 back then. Understandably, it was because the 100-300mm f/4 is neither long enough for wildlife nor fast enough for portraiture. Now that I can take advantage of a 1.5x increase in focal length on my Nikon D300 D-SLR with its 12 mega-pixel exceptional image quality, perhaps a lighter and smaller lens would offer a more convenient application.

Sigma APO 100-300mm f/4 EX HSM DG (IF)

The Sigma APO 100-300mm f/4 EX HSM DG (IF) is an amazing zoom lens that maintains a constant aperture f/4 in the entire focal range. It is the current generation of the original Sigma APO 100-300mm f/4 EX HSM (IF) first introduced in 2001 which has gone through various modification and improvement to benefit from the DG technology for digital imaging. According to Sigma, the DG designation means that the lens is built for full-frame or 35mm film format while at the same time still works on digital camera (APS-C, 23.6x15.8mm image sensor). However, on a DX-format Nikon body, the Sigma 100-300mm f/4 becomes 150-450mm f/4 through a 1.5x factor.

The rest of the designation--HSM, APO, EX--means that the lens has Hyper Sonic Motor (HSM), apochromatic corrected optical elements (APO) utilizing super-low dispersion optics and is the Pro series (EX) line. To sum up, Sigma 100-300mm f/4 features a well structured body, equipped with fast and quiet internal AF system and a set of optics that will produce high quality image resolution. The IF designation means that the lens features internal (inline) focus mechanism. Its front barrel does not rotate while at the same it still retains the same physical length during focus, there by, keeping the lens well balanced.

In the retail package the Sigma APO 100-300mm f/4 EX HSM DG (IF) comes with both caps, lens pouch, lens hood and a four-year warranty.

Mount/Availability

The Sigma APO 100-300mm f/4 EX HSM DG (IF) is available in Canon and Nikon-D. It is worth to mention that the non-HSM version is available in Sony, Minolta and Pentax. This is a standard full-frame 35mm film format lens and it will work on both 35mm file and digital cameras. On my Nikon F5 it produces the specified 100-300mm focal length. On my Nikon D300 DX format D-SLR the focal length increases by a 1.5x factor that translates to 150-420 f/4. For Canon D-SLR body with its 1.6x factor, the Sigma 100-300mm f/4 becomes 160-480mm f/4.

Field Test and Practical Usage

The Sigma APO 100-300mm f/4 EX HSM DG (IF) has a solid construction with rubberized focusing and zooming rings. The zoom ring seemed a bit stiff at first, but nonetheless smooth and well dampened. Focal lengths are marked in 100, 135, 200, 250 and 300mm on the zoom ring. In autofocus mode, AF action is swift and near silent, thanks to the HSM mechanism. I tested the lens on my Nikon D300 D-SLR and film camera F5; AF response was indistinguishable. On both cameras, the lens is pretty fast. Manual focus override is instant. Focus ring is wide; its action is well dampened and smooth in operation.

A special touch of the lens is its removable full rotation tripod collar. I like this feature tremendously. With the knob loosen, the collar can be rotated for a suitable handheld shot, which is my preferred habbit to prevent misplacing the collar. It can be removed completely from the lens if need to. The feel of the entire unit is nothing short of highest built quality and detail, even its well designed lens hood. With the hood on, the lens looks very impressive and huge. Its front barrel accepts 82mm filter size -- nothing to complain here (I've used Nikon 300mm f/4 ED-IF before that required the same filter size). Though, with the hood on, the filter or the lens cap cannot be removed or put on. The hood mounts on the front barrel (bayonet style), not screw-on thread.

The handling and mechanical operation of this lens are superb. The lens is huge, but much smaller compared to my Tokina 300mm f/2.8. Weighing at about 3 pounds, the Sigma APO 100-300mm f/4 EX HSM DG (IF) is light enough for a good handholdable shot. The use of a monopod works well with it; and I have used it on my Bogen 679 monopod with much success.

Optically, this lens is handsdown sharp. For evaluation, I tested it primarily on my Nikon F5 using Fujifilm Velvia slide. It is a lot easier to analyze its image quality on a light table using my 6x loupe. If it's proven sharp on Fujifilm Velvia, this lens will also be sharp on my Nikon D300 D-SLR. Amazingly, this lens is sharp at wide open, with a small hint of softness on the edges at 100mm. Sharpness decreases at 300mm wide open; but central sharpness is still very good. Between f-stops f/4 and f/11, this lens is at its best throughout its focal range, extremely sharp and contrasty with excellent color. I have a lot of old slides that I shut with Tamron 70-300mm, Sigma 70-300 and Nikon 70-300mm lenses; and I could not believe how I thought they were sharp when I compared images produced by the Sigma APO 100-300mm f/4 EX HSM DG (IF).

The Sigma APO 100-300mm f/4 EX HSM DG (IF) provides aperture from f/4 all the way to f/32, but I don't really see its application at f/22 or f/32. I tested at 100mm and 200mm at f/22 and f/32, the results were surpringly good. However, I expect to use this lens mostly a wide open or stop down to f/11. The good news here is that the lens produces superb picture definition at wide open almost throughout its focal range; well except at 300mm where its optimum performance seems to be around f/16. However, I am not afraid to shoot at 300mm at wide open; overall image resolution is still very good here.

Unlike short focal-length zooms, the Sigma APO 100-300mm f/4 EX HSM DG (IF) handles optical distortions very well; there is virtually no sign of barreling at 100mm or pincushioning at 300mm. On my full-frame 35mm film, light fall-off was seen at 100mm at f/4. It disappeared when stopped down to f/5.6. On Nikon D300, virtually no vignetting at all (of course, due to image crop here). Color infringing (shifting -- chromatic aberration) was seen at 300mm with constrasty subjects; otherwise, non-noticeable.       

With its nine blades, and long focal length, this lens produces excellent bokeh (out-of-focus background). This clearly shows that the lens is capable of producing excellent portraits, where isolation of the subject from the background is important. I have not used this lens on birds yet, but I have put it to the test at my son's (6th grader) Christmas concert. I stood towards the rear of the auditorium with my monopod with the lens attached to my Nikon D300. Its ability to zoom allowed me to crop the image; and I could frame the image easily. I loved it! Image results shot under stage lighting were very good too.

The lens provides focus distance windows, but without a distance limiter--a feature that should prove useful for a telephoto lens like this one. Its close focusing distance is 1.3 meters or 3.2 feet. I have used extension tubes to make the lens focus closer with great results. I can't wait to use this lens (in the summer) for closeup on those shy insects that I can't get close to them with my macro lens.

Conclusion

Simply put, Sigma APO 100-300mm f/4 EX HSM DG (IF) is a wonderful performer, extremely sharp and contrasty. It is a nearly perfect zoom lens, virtually no flaw at all. One small complaint is that its manual focus ring is too wide, basically covers the entire front section of the lens. Since manual focus is full-time, a slight "jerk" on the ring can throw the subject out of focus. Luckily, the focus ring is quite firm and well dampened (no focus creep).

For me, it was quite difficult to decide on this lens, because of its overlapping focal range with my Nikon 70-200mm f/2.8 zoom, a lens that I always lug with me for portraits and school sporting event. However, the Sigma 100-300mm f/4 covers the longer end that I need to fill, which will replace my Tokina 300mm f/2.8. It can be argued that with a 1.4x teleconverter, the Nikon 70-200mm f/2.8 would achieve similar focal range, but what about optical performance? Frankly, I have never used a teleconverter on the Nikon 70-200mm f/2.8 (because it will degrade optical quality, a sacrifice I'm not willing to trade). As a portrait lens, I often use it on my 35mm film camera. Optically, the Nikon 70-200mm f/2.8 is no doubt the world sharpest lens in this focal range, and I would fool myself to choose the Sigma over the Nikon for the 100-200mm focal lengths. On my DX format digital camera, the Sigma 100-300mm f/4 offers a better focal range and with optical performance close to the Nikon 70-200mm f/2.8. It's for this reason that I have decided to own both lenses, each for different application. Furthermore, the two lenses have the same physical size and weight; in fact, Nikon 70-200mm f/2.8 is a bit heavier.

Compared to Tokina 300mm f/2.8, the Sigma 100-300mm f/4 provides a better handheld shot and far more manageable, in terms of convenience. The loss of one f-stop does not really bother me much. To me, it is a fair trade between a fixed focal length and a flexible zoom, especially for my application.

The Sigma APO 100-300mm f/4 EX HSM DG (IF) has a fairly reasonable price for its handling and optical performance. If you require a focal length in this range, you can't go wrong with the Sigma 100-300mm f/4. Moreover, in Nikon mount, the lens still retains the traditional aperture ring which allows it to be compatible with any old Nikon SLR cameras. My Nikon 70-200mm f/2.8 is a G-type lens and is not compatible with my trusted Nikon F4 in my preferred Manual and Aperture mode for closeup and landscape photography, which I prefer to use over the bulky and power-hungry F5 body. For me, it is all the good reason to own both lenses.

In this focal range, the Sigma APO 100-300mm f/4 EX HSM (IF) virtually has no competitor. However, there are plenty of 70-300mm or 75-300mm zoom lenses in the consumer market, from prime camera makers to third-party lens makers. Sigma also offer such a lens: Sigma 70-300mm f/4-5.6 DG Macro; Nikon with their AF-D 70-300mm f/4-5.6 or AF-S 70-300mm f/4.5-5.6G ED VR. A much high zoom ratio is available with Nikkor AF 80-400mm f/4.5-5.6D ED VR. None of these provide a good constant aperture f/4 throughout the focal range, not to mention inferior image quality. If you have to choose a zoom lens in the 70-300mm or 100-300mm focal range and demand uncompromised image quality and admirable constant aperture f/4, the Sigma APO 100-300mm f/4 EX HSM DG (IF) is no doubt the only one; I highly recommend it!  

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Specifications: Sigma APO 100-300mm f/4 EX HSM DG (IF)

Lens Construction (Groups/Elements): 14/16
Angle of View: 24.4-8.2 deg.
Maximum Aperture: F/2.8-32
Minimum Focus: 180cm (70.9 inches)
Filter Diameter: 82mm
Weight: 1440g (51 oz)
Diameter x Length: 92.4x226.5mm (3.6x8.9 in)
Accessory: die-petal (tulip-shaped) lens hood
Mount: Canon, Nikon-D in HSM DG (new version); Sony/Minolta/Pentax in standard original version