Sigma 19mm f2.8 đánh giá

Sigma’s mirrorless lens lineup at the moment consists of a trinity of prime lenses, from wide-angle to short telephoto. We take a look at the widest of the current Sigma DN lenses for mirrorless lenses, the 19mm f/2.8 DN Art. The Sigma 19mm has been around for a little while, but, along with the 30mm f/2.8, received an overhaul in the past year when the lens was added to the ‘Art’ lineup. The lens is available for Sony E-Mount and Micro 4/3. I reviewed the Sigma 19mm f/2.8 for Micro 4/3 in January 2013, though it was obvious it was designed with the larger APS-C Sensor in mind. Sigma has made some updates with the Art version of this lens, so let’s see how this newer version fares. The Sigma 19mm retails for $199, and can be purchased at B&H Photo here.

Build Quality and Handling

Like the other two Sigma DN Art series lenses, the 19mm f/2.8 DN Art is a compact lens finished with a two-tone metal body. The lens comes in both silver and black, and the black version is reviewed here.

The Sigma 19mm is a well constructed lens built with high quality plastics, a metal mount and metal lens body. The rear ring of the lens is metal clad and finished with a matte black finish, while the front of the lens features the broad focus ring, which is a high gloss black metal. While the lens isn’t particularly dense, it still feels very nicely built, especially given the price. The only down side is that the focus group does rattle around in the lens body when the camera is powered down.

The lens is lightweight and relatively compact, allowing for easy handling and storage. A short bayonet mount lens hood is included, and is the same hood that comes with the Sigma 30mm and 60mm lenses.

The focus ring is prone to fingerprints, but the black finish fares better than the silver in this regard. The ring is well damped and easy to operate, but the smooth finish can be a bit slippery if you’re wearing wool gloves or the like. While it doesn’t offer great grip, the focus ring is still rather pleasant to use when manual focus is needed.

Autofocus Performance

The 19mm f/2.8 focuses quickly and surely. While there are faster focusing lenses around, there’s nothing to complain about with regards to speed. I found accuracy to be quite good. One down side is that it is not compatible with the phase-detect autofocus available in most of the modern Sony camera bodies, so tracking autofocus isn’t going to be particularly amazing.

Continue: Image Quality

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The Sigma 19mm f2.8 EX is probably one of the most exciting announcements in the Micro Four Thirds community based on the mere importance of it all. It is one of the first autofocus lenses made by a third party company for the system.

I’ve been testing the lens for around a month now, and its use has been one of the most interesting experiences I’ve had as a reviewer. To catch up to speed, check out our hands on review and our preview video.

Editor’s Update 10/28/2012: After using later versions of the lens, I have come to the conclusion that the units I was initially sent were slightly problematic. The lens elements only jiggle a bit because of the autofocus motor and during my review, the elements still jiggled around and the focusing was still a bit problematic after multiple autofocusing attempts. With firmware updates that came after the review was published, the latter problem was fixed. Additionally, the elements aren’t supposed to jiggle when electronic contact is made. After trying later versions of the lenses, this problem has indeed been fixed even after focusing confirmation. Additionally, you shouldn’t be shaking your lens around like a martini shaker to begin with.

Gear Used

Sigma 19mm f2.8

Olympus EP2

Olympus EPM1

Tech Specs

Performance Focal Length 19 mm Comparable Four Thirds and Micro 4/3 Focal Length: 38 mm Aperture Maximum: f/2.8 Minimum: f/22 Camera Mount Type Micro Four Thirds Format Compatibility Micro Four Thirds Angle of View 73.5° Minimum Focus Distance 7.87″ (20 cm) Maximum Reproduction Ratio 1:7.4 Groups/Elements 6/8 Diaphragm Blades 7 Features Image Stabilization No Autofocus Yes Tripod Collar No Physical Filter Thread Front: 46 mm Dimensions (DxL) Approx. 2.4 x 1.8″ (6.10 x 4.57 cm) Weight 4.9 oz (139 g)

Demo Video

Mind you, this video was shot a very long time ago when I started the review.

Ergonomics

The Sigma 19mm f2.8 looks and feels like a high end professional lens for the Micro Four Thirds system. Though it isn’t a pancake, it isn’t extremely large either. In fact, much of the extra size is characterized by the removable lens hood.

The lens feels well balanced on any Micro Four Thirds camera and is characterized by a large manual focusing ring. Because the lens is coupled, it will also work with a Micro Four Thirds camera’s ability to automatically magnify a said area when manually focusing.

Otherwise, it is great as purely just a grip.

It must be said though: this lens feels a bit naked and lacking without a lens hood. This goes double for users with larger hands. However, the lack of a hood makes the lens smaller and easier to pocket, even with the hood on reversed.

Nonetheless, this lens’s large size will still not make the package pocketable unless you’re sticking it in a large winter jacket. Otherwise, grab a neck strap for yourself.

Unlike other EX lenses, there is no AF/MF switch on the lens. That needs to be done via the camera’s menu system.

Focusing

Focusing for the most part is fairly snappy, but not as fast as Olympus’s MSC lenses. The 19mm f2.8 focuses very silently as well, which is perfect for when you’re at an event and don’t want to hear an autofocus motor.

To be very honest, this lens may be best paired with cameras like the EP3 and EM5 with their touch to focus/shoot functionality. That will give moms and dads with their brand new baby the best chance they have to capture their running toddler and be able to sharply and accurately get the little tike in focus.

Best of all, the focusing also works splendidly in low light situations even without the need of an AF assist lamp.

Color Rendition

Though the cameras has ultimately gotten over the entire algorithm of shifting everything toward the blue side of the spectrum in terms of color temperature, this lens still tends to render images more towards the warm to neutral size.

For the most part though, throughout my tests I often found the color rendition to look as good as well developed Kodak Portra; and these goes double for all the of the delicious skin tones that this lens gave me when photographing people: which is really my main subject in photography.

For the photographer that wants a lens that will give you a bit more reach than a 35mm focal length and wants to photograph people (like in street photography) the Sigma 19mm f2.8 EX is a very strong choice for you.

For the person just shooting photos of their family or that doesn’t necessarily want to do a lot of editing to their photos, this lens is also an excellent choice when combined with the fact that it is tack sharp all over. Note that this all depends on your own creative vision though: if you’re at a concert and want to neutralize a photo, then you’ll need to apply your knowledge of color theory to your editing.

As I’ve recommended before, it is a best practice to use the according focusing methods to ensure of this. That is, use tracking focus for moving subjects and single focus for stagnant. Though that seems like common sense, many people don’t do it.

In fact, in the photo in this section, I used single focus but still was able to get a sharp and wonderfully colored photo.

Image Quality

The overall image quality of this lens is terrific and phenomenal in the right hands. The lens takes a lot of careful use in order to create some of the best images that one can. To get the absolute best results in terms of sharpness, don’t focus and recompose because you’ll throw off the entire plane of focus. Only do that when you’re emphasis is more on capturing the scene.

Sigma often brands EX lenses as their top of the line and professional grade lenses. Indeed, the image quality from this lens exceeds those expectations.

The bokeh quality and lens flare control are also quite good (though flare control could be better) and there is no vignetting that I was able to notice. For the absolute best results, I recommend just shooting the lens wide open at f2.8 all day and night. It only becomes marginally sharper at F4 and f5.6.

Here are some other image samples from the lens.

Sharpness

This lens is tack sharp. It rivals even the Olympus 12mm f2 and 45mm f1.8. In all honesty, Sigma nailed it with this one as they have with all of their prime lenses.

Ease of Use

In fact, I believe that the lens was created for this specific purpose. Why?

– It’s super sharp

– It focuses very quickly

– It has the specific field of view

With all of these factors combined, it is hard to see how this lens cannot be such an excellent performer on your camera.

Even better is the fact that it focuses quickly on both newer micro four thirds cameras and older ones.

Conclusion

Sigma has a very big winner with the 19mm f2.8 EX. In fact, I found myself almost married to it during my review period. I much preferred this field of view vs the 60mm equivalent on the 30mm f2.8.

One major problem with this lens still stands though: during the camera start up period, the fact that this lens is attached will slow down the start up performance. Sometimes, it will take up to four seconds. And that…can be very annoying especially when trying to wake the camera up to catch a candid photo.

There is much to love about this lens: it is sharp, the color rendition is second to none, it focuses quickly, and it is also quite small. Despite the fact that this lens has so many strengths going for it though I have to admit why I didn’t purchase it. I firmly believe that f2.8 is too narrow an aperture for Micro Four thirds cameras. If you’re using an f2.8 lens, you should honestly be shooting with it wide open all day and all night because you’ll effectively always have more than you’ll ever need in focus. Indeed, I sometimes felt like using this lens wide open was like shooting with my 5D Mk II at f5.6. Granted, that is a significantly larger sensor.

If you don’t mind shooting at f2.8, then seriously spring for this lens as soon as you can due to the ultra affordable price. If you need a faster aperture, then be prepared to shell out the money for it.