So sánh sony 135mm f1.8 gm va 70-200 f2.8 mg

Sau khi có thông tin rò rỉ về chếc DSLR mới dòng entry level Canon Rebel T8i / EOS 850D / EOS Kiss X10i thì ta cũng có thêm thông tin rò rỉ tiếp theo cũng của Canon về chiếc ống kính kit mới, giá rẻ hơn, nhỏ gọn hơn dành cho các máy không gương lật ngàm RF.

Chiếc ống kính mới này có tên Canon RF 24-105mm f/3.5-5.6 IS STM, hiện tại vẫn chưa có nhiều thông tin gì thêm về nó cũng như ngày ra mắt chính thức, nhưng trước mắt chúng ta đã có hình ảnh rỏ nét, chi tiết hơn về nó, nhất là ta cõ thể hình dung được một chiếc ống ngàm RF nhỏ gọn hơn, có giá thành dễ chịu hơn so với người đàn anh Canon RF 24-105MM F4 L IS USM.

Đây là hình ảnh của chiếc Canon RF 24-105mm f/3.5-5.6 IS STM, ta có thể thấy nó rất nhỏ gọn, nằm gọn trong lòng bàn tay, có cảm tưởng nó chỉ hơi lớn hơn chiếc ống kính kit 18-55 một tý mà thôi. Đây là hình ảnh chồng lớp để xem thử độ lớn của chiếc ống này so với người đàn anh Canon RF 24-105MM F4 L IS USM.

From the day Sony announced their 135mm f/1.8 GM lens I was wondering if it will be a better option for me to replace the 70-200mm f/2.8 GM. Being smaller, lighter and faster – that sounded like a good option. Plus, on my A7RIII or A7RIV, with just one click (switching to crop mode) it turns to a 200mm lens. For my casual shooting I wouldn’t even think about this. But for professional work – like weddings and other events, the versatility of the zoom lens is a king. However, the new 135mm has a faster Dual front and rear XD linear motors to achieve fast, precise, and quiet AF. It also have smaller minimum focus distance and aperture dial on the lens.

Size

The size difference is obvious. The 135mm is smaller and lighter than it’s bigger zoom-brother, but feel more dense. It is also lighter – 950g vs. 1480g.

135-vs-70-200 size comparison

I rented two copies of each lens and decided to do some tests. First, I wanted to compare the two copies of each lens for sample variations. Then, picking the sharper lens of each to compare the 135mm vs. 70-200mm. The sample variation test I will post in different article and add a link here, so please come back to check it. With the better copy of each lens, I tested them for sharpness, chromatic aberration (CA), or so called “color fringing”, bokeh, and AF speed. Also, call it my weakness, I love when the lenses can produce nice sunstars. So I decided to test that too.

Bokeh

The results from the bokeh test I think will be clear for everyone, so the winner – the 135mm was superior. It has softer and smoother bokeh.

Bokeh test – left: 135mm, right: 70-200mm

Bokeh test – left: 135mm, right: 70-200mm

The fact that it can focus closer (70cm/2.3’ vs. 96cm/3.15’) , makes it a dream for portraits and objects, when shooting near the minimum focusing distance.

Bokeh test @ min AF distance – left: 135mm, right: 70-200mm Bokeh test @ min AF distance – left: 135mm, right: 70-200mm

Close Focusing

When zoom to 100% you can clearly see the advantage of the 135mm. It is sharper, it focuses closer, and the bokeh is smoother. The DOF is so small, that focusing on the nose, you can see the eyes are already blurred.

Bokeh test @ min AF distance – left: 135mm, right: 70-200mm. 100% crop.

Chromatic Aberration (CA)

When I positioned the dinosaur figure so I can shoot against the sun, both lenses performed extremely well. As GM lenses they control well the chromatic aberration, although you can see it is visible on the 135mm when wide open at f/1.8. At f/2.8 I didn’t see any CA with both lenses.

CA 135mm f/1.8 setup image

Pictures below: left – 70-200mm at f/2.8, center – 135mm at f/1.8, right – 135mm at f/2.8.

Sunstars

Let’s see what sunstars both lenses can produce. I am very happy with the results from both lenses, but the 135mm has sharper edges, so it is my choice again.

Sunstars: 135mm (left) vs. 70-200mm (right)

Sharpness

In the first row of images of the book test I compared 135mm at f/1.8 vs. 70-200mm at f/2.8. I wanted to see how both lenses perform wide open. Then I compared them at f/2.8, f/4, f/5.6, f/8, and f/16. Wide open 135mm is on par with the zoom lens in the center and it is slightly softer in both corners. From f/2.8 I don’t really see any significant difference in sharpness between the two lenses. I know they both are extremely sharp and the differences will be in the slightest details. That’s why I made two other tests, shooting targets, to have more accurate results. But the book test shows how well both lenses perform in a real life situation.

The target test has the same settings like the previous one. You can see how 135mm is sharper and has better contrast than 70-200mm in all apertures. The 70-200mm is significantly softer in the top right corner.

In the last setup I used different target showing only two settings – in the extreme corners – with fully open apertures, and at f4. You can see the target shot zoomed out:

135 vs. 70-200 setup

The two settings at the extreme corners:

Conclusion

So, at the end you may ask – what did I decide – to get the 70-200mm or the 135mm? I think the 135mm f/1.8 GM will be my choice. The extra stop and a half more light, the size, weight, smaller focusing distance, better bokeh, slightly faster focusing (there will be separate YouTube video about that), and the extreme sharpness, even at f/1.8 make the choice easier. Meanwhile, even before the lens was in stock, Sony decided to increase the price with $100 to $2098.