The Sigma 18-50mm lens is one of Sigma Corporation’s best-selling products. The Sigma Corporation is a Japanese company specializing in manufacturing a range of photography equipment, such as cameras and flashes. However, they are best known for producing an excellent range of high-quality lenses that are compatible with DSLR’s of other brands, such as Nikon.
Sigma introduced the Sigma 18-50mm f/2.8 Macro Lens in 2009. This kind of lens is perfect for indoor shots or portrait photography. It performs exceptionally well in the outdoors as well. However, this lens’ range is wide enough to shoot subjects at a considerable distance.
This is specifically designed to fit with the APS-C sensor. It gives a perfect view of 27-75mm on the Nikon D3200. The lens comes with a petal-shaped hood; you can use 72mm filters with this product.
The Sigma 18-50mm has an excellent reputation among many Nikon photographers. This is a great general-purpose lens that is well-built and easy on the pocket. It is for these reasons that many photographers recommend this lens.
Sigma Lens 18-50mm Specifications
- Lens18/50mm F/2.8 Macro Zoom Lens
- Front and rear caps and petal-type hood.
- Soft-case and user manual.
- Optical configuration: 15 elements in 13 groups
- The angle of view: 76°-32° with a 1.5x crop sensor
- Aperture: 7 blades and circular
- Full frame, APS-C only, 35mm equivalent, 27-75mm.
- Focus distance scale
- 7.9″ (200mm) minimum focus with image plane to subject
- 1.0″ (25.4mm) minimum focus with the end of the lens barrel to subject
- Focus ring turns in AF
- Filter size 72mm
- 0.34x maximum magnification
- F/22 min. F/stop
- Changes length when zooming
- Dimensions: 3.1” x 3.4” 79mm x 86mm-around filter ring
- 4.4” (111mm) maximum extended length
- Weight: 16.9oz (479g) 17.8oz (506g) with caps
The Sigma 18-50mm has an excellent reputation among many Nikon photographers. This is a great general-purpose lens that is well-built and easy on the pocket. It is for these reasons that many photographers recommend this lens.
Performance And Functionality
The Sigma 18-50mm is quite sharp. While the sharpness is mostly consistent throughout the zoom range, you will notice a slight improvement in sharpness at the wide angles compared to when the lens is at maximum zoom (50mm).
At 18mm, the lens has very slight softness at the corner, with excellent results showing in the center. At this zoom length, the center has 1.5 blur units, while the edges have 3-4 blur units. At an aperture of f/4, you’ll notice an improvement, as the softness in the corners reduces down to 2.5 blur units. You can get the same results at apertures ranging from f/5.6 to f/11.
At 35mm, with an aperture of f/4, the softness at the corner automatically decreases to 1.5 blur units and becomes consistent with the centre. The optimal results for sharpness are achieved at a zoom of 35mm with an aperture of f/8. At these settings, you’ll have just 1 blur unit all across the frame.
There’s also a slight difference between the right side and left side sharpness, with the right-side sharpness being slightly better. All in all, this is a very sharp lens – especially from f/4 to f/11.
Chromatic Aberration
Chromatic aberration is controlled very well by this lens, thanks to its special low dispersion (SLD) glass element and the use of two aspherical lens elements. It shows slight colors (red-blue) in the corners and isn’t visible in the center of the frame. The more you decrease your aperture, the less the chromatic aberration.
A super multi-layer (SML) coating also helps reduce flare. This coating also works to give excellent color balance.
Vignetting
For this wide-angle lens, the vignetting isn’t anything to worry about. Vignetting is visible when the lens is at its lowest aperture. At that aperture, and a focal length of 18mm, the corners are a half-stop darker than the center. As you stop-down, the darkness reduces to a third-stop darker, and at the maximum aperture, vignetting pretty much disappears.
Distortion
There is some distortion in the Sigma 18-50mm, but this is standard in most lenses. When zoomed out (at approximately 18-35mm), there is slight barrel distortion, and when zoomed in, there is pincushion distortion.
+0.75% barrel distortion can be noted in the corners at the wide end, and in general, +0.4% distortion is noted. -0.3% pincushion distortion is noted at the tele-end in the corner, and +0.1% barrel distortion is seen in general.
Autofocus Operation
The Sigma 18-50mm f/2.8-4.5 uses an electrical motor, which means that focusing is quick and quiet. However, this lens doesn’t feature Sigma’s most recent focusing motor – the hypersonic motor (HSM). The only noticeable difference between the HSM and the electric motor is that the former is a bit quieter.
The lens has a short focus. Hence it’s able to focus quickly. The lens uses an internal focusing mechanism. This means that the lens does not change length when focusing. Thus, the front of the lens does not rotate.
This lens does not support full-time manual (FTM) focusing. The minimum focus distance of this lens is 11″ or 0.28m.
On a Nikon D3200, for the autofocus operation, set your camera to AF mode and ensure that the focus switch is set to AF. To enable manual focus on the Nikon D3200, set the focus switch on the lens to M and then use the focus ring to adjust focus.
In addition, some Nikon cameras have viewfinders that indicate focus status. You’ll be able to see symbols showing when the subject is in focus, when the subject is in front of the focus, and when the subject is behind the focus. When you’re using this lens with an AF Nikon camera, in manual mode, adjust the focus until you see the symbol for ‘subject in focus.’
Though the lens has a distance scale, Sigma recommends that you confirm focus in the viewfinder rather than relying on the scale. There may be a slight focus shift in extreme temperatures, because the lens may expand or contract. Hence, to ensure that you’re taking in-focus shots, use the viewfinder too!
Filters
You can use one filter at a time on this lens. If you use two or more filters on the Sigma 18-55mm, you may notice some vignetting. This is also the case with thick filters, such as a polarizing filter. If you do use a polarizing filter, use the circular type.
Macro
The macro performance of this lens is outstanding. It offers a magnification of 0.33x or 1:3. The minimum focusing distance is 20cm.
There are quite a few great independent reviews of the Sigma 18-50mm lens available on the net. These will help you gauge the performance of the lens and determine whether the lens suits your needs or not.
User Interface And Design
Zoom Lock
One thing to note about the design of the Sigma lens is that it comes with a zoom lock. There’s a zoom lock switch on the lens. This lock can ensure that your lens stays at a focal length of 18mm and does not move.
The lock switch eliminates any zoom creep that may occur when the lens is tilted down.
Focus Rings
The focus feature of the lens works well. The speed of the auto-focus is excellent and keeps the process of capturing photos comfortable and smooth.
As we discussed earlier, this lens doesn’t rotate on its own. However, the auto-focus ring can rotate on its own. Sigma recommends that you do not touch the focus when it’s rotating during autofocus mode. Otherwise you can risk damaging the autofocus mechanism.
The manual focus, the ring can rotate by 45 degrees only. Moreover, the maximum magnification factor that is possible to reach is 1:5.
On the D3200, the ring rotates in the opposite direction of NIKKOR’s focus rings. This also applies to the zoom rings. Both rings turn quickly and smoothly.
Build Quality And Design
Body Of The Lens
This lens has a black plastic body and a rubber coating, which is extremely good for traction. The lens is specifically made for digital cameras and has the ideal properties to fit into the Nikon D3200.
The lens has a distance scale but doesn’t have a depth-of-field scale. The lens mount is made of metal, and the 72mm filter threads are made of plastic. A switch on the lens is available to enable or disable autofocus.
The body of the lens is also easy to attach to the camera body. On the lens mount surface, ensure that you keep all glass and optical elements clean. To attach the lens, you’ll have to match the mark on the lens to the mark on your camera body.
The rear lens work as a ‘vacuum cleaner’ since it allows the lens to draw in or push out the air. The lens’ aperture has 7 that have been rounded weakly. This results in an irregular heptagon. The irregular heptagon is further covered with diaphragms.
Zoom Ring
The zoom ring is very large; it’s approximately 0.75 inches wide. It is also made of rubber ribs. Due to its ability to rotate beyond 45 degrees, it provides good resistance, which is neither too tight nor too loose.
Lens Hood
The detachable lens hood has a petal shape that further lengthens the size of the lens by 1.5 inches. The design of the lens helps hood prevent any flare on your images. It also reduces the possibility of ‘ghosted images,’ which may be caused by a bright light coming in from outside the frame.
You can detach the hood by turning it counterclockwise. Similarly, you can attach it by turning it clockwise.
If you’re taking photos with the built-in flash, we recommend that you remove the lens hood. When using the camera’s built-in flash with this hood, you may notice that some flash output is cut off, which will result in shadows appearing on your picture.
To store the lens, it’s good to remove the hood so that the lens can fit in more compact spaces.
However, one point to note is that the lens doesn’t come with any form of dust or moisture protection. Hence, in order to care for it, Sigma recommends:
- Avoid any exposure to extreme temperatures or humidity
- Store in a dry and cool place with good ventilation
- Do not use any thinning agents In order to clean the lens. If you wish to clean the device, use a soft, damp lens cloth.
- Keep the lens away from water as it is not waterproof. If the internal mechanism of the lens gets damaged, it is often impossible to repair.
- Sudden temperature changes can fog up the surface. Hence, if you’re entering a warm or cold room, keep the lens in the case until the lens temperature matches the room temperature.
Conclusion
The Sigma 18-50mm f/2.8 Macro Lens is a fantastic lens that provides the photographers with what they desire the most – quality. This lens allows you to take high definition images and is perfect for those looking for a good but not-so-expensive lens.
The Sigma 18-50mm lens is compatible with any camera with a built-in autofocus motor since the lens itself does not have an autofocus motor. The Nikon D3200 has such a motor, and hence this lens works great with it!
Do note that the lens doesn’t come with a good image stabilization option. Hence, it’s important to use a tripod or another camera image stabilizer with this lens. This lens is best suited for indoor low light conditions.
This lens is also incredibly small and lightweight, especially for an f/2.8 lens. When this lens is fitted onto a compact D3200 body, the combination is ideal for any photographer looking for a sharp lens that they can carry around with them. The lens comes with a handful of accessories, too, such as a protective pouch, which makes it easy to store the lens.
The quick autofocus of this lens is rare to find among other lenses compatible with the Nikon D3200. Even in lowlight conditions, this lens can easily pick up focus and take sharp pictures.
This lens has a stellar reputation in the industry. It’s used by many photographers, even avid Nikon and Canon fans. Its amazing compatibility with other camera bodies has made it a popular choice among many photographers.
