เมื่อวันที่ 2 พฤศจิกายน 2022 Canon ได้เปิดตัว RF135mm f/1.8L IS USM ซึ่งเป็นเลนส์เทเลโฟโต้ระยะกลางสำหรับเมาท์ RF เลนส์ที่มีรูรับแสงกว้าง 135 มม. เป็นตัวเลือกซึ่งเป็นที่นิยมของช่างภาพพอร์ตเทรตมาโดยตลอด และเลนส์รุ่นใหม่ล่าสุดสำหรับเมาท์ RF นี้เป็นเลนส์รุ่นแรกที่มีระบบป้องกันภาพสั่นไหวแบบออพติคอล (IS แบบออพติคอล) ในตัวเพื่อเพิ่มโอกาสในการสร้างสรรค์ อ่านต่อเพื่อทราบข้อมูลเพิ่มเติมเกี่ยวกับสิ่งที่ทำให้เลนส์รุ่นนี้โดดเด่น
Mention the term “portrait lens” and most people will think of a large aperture (fast) 85mm lens. However, did you know that 135mm lenses are also popular for portraiture?
First of all, let’s look at why fast medium telephoto lenses are ideal for portraiture:
- A large maximum aperture creates beautiful shallow depth-of-field (background bokeh) effects.
- Medium telephoto focal lengths provide a natural perspective: shapes and dimensionality are the same as what your eyes see.
- They let you take headshots and chest-up shots from a comfortable distance away.
With its f/1.8 maximum aperture, the RF135mm f/1.8L IS USM is around one stop slower than an 85mm f/1.2 lens. However, a longer focal length also results in a shallower depth of field, which mitigates the narrower maximum aperture and results in no significant difference in bokeh. f/1.8 is also slightly faster than the EF lens lineup’s EF135mm f/2L USM, which is currently out of production.
Take a look at the creamy background bokeh in the following examples from the RF135mm f/1.8L IS USM—they speak for themselves.
EOS R5/ RF135mm f/1.8L IS USM / FL: 135mm/ Aperture-priority AE (f/1.8, 1/1600 sec, EV +0.3)/ ISO 400/ WB: Auto
Know this: How focal length affects perspective
When you use different focal lengths to shoot the same model in the same location with the same composition, the resulting images will look different due to the different perspective effects.
- 50mm provides a perspective that is quite close to what we see. However, it still retains slight wide-angle characteristics. In other words, perspective exaggeration may still be visible depending on the shooting angle.
- A medium telephoto focal length (85mm to 135mm) provides moderate perspective compression. Facial features look more natural to human perception even from shooting angles where a wider focal length would result in distortion. At the same time, backgrounds are pulled in so that they look closer and bigger.
- At longer telephoto focal lengths such as 200mm, the perspective compression effect will become more visible. Depending on the situation and intent, this might result in an unflattering “flattening” effect on facial features.
As we can see, medium telephoto focal lengths provide the most faithful perspective.
EOS R5/ RF135mm f/1.8L IS USM / FL: 135mm/ Aperture-priority AE (f/1.8, 1/2500 sec, EV +0.7)/ ISO 200/ W B: Auto
Why shoot at 135mm?
At 135mm, you get...
- A tighter crop due to the narrower angle of view—easier to simplify the image!
- Creamier bokeh because depth of field is shallower at a longer focal length.
- A background that looks bigger and closer because of the “pull-in” telephoto effect. (This also enhances the background bokeh.)
It can be challenging working handheld with a long focal length, especially with slower shutter speeds—any camera shake becomes magnified. To counteract this, the RF135mm f/1.8L IS USM is equipped with an in-lens image stabiliser (Optical IS), which corrects camera shake by up to 5.5 shutter speed stops’ equivalent*1. It is Canon’s first 135mm prime lens with this feature.
When combined with a camera with In-Body IS, up to 8 stops’*2 image stabilisation is possible through Coordinated Control IS.
EOS R5/ RF135mm f/1.8L IS USM / FL: 135mm/ Manual exposure (f/4, 1/4 sec)/ ISO 100/ WB: 4200
The RF135mm f/1.8L IS USM’s wide f/1.8 maximum aperture makes it possible to use a faster shutter speed without bumping up the ISO speed. But what if you want to use a slow shutter effect, or achieve a larger depth-of-field by narrowing the aperture?
Conventionally, going any slower than 1/(your focal length) seconds introduces camera shake when shooting handheld, and on a 135mm lens, that means keeping at 1/135 seconds or faster. But with image stabilisation, you can go as much as up to 5.5 stops (Optical IS only) or up to 8 stops (with an In-Body IS-equipped camera) slower, increasing creative possibilities.
Video and still photography require different AF drive dynamics. For video, AF drive needs to be smooth to ensure seamless focus transitions. Meanwhile, in still photography, AF needs to be quick and precise to lock swiftly on moving subjects and ensure accurate focus.
The two different styles may seem to be in opposition, but the AF on the RF135mm f/1.8L IS USM is driven by the Nano USM (Ultrasonic Motor), which is capable of both. This makes the RF135mm f/1.8L IS USM a versatile choice for both stills and video.
EOS R3/ RF135mm f/1.8L IS USM / FL: 135mm/ Manual exposure (f/1.8, 1/1600 sec)/ ISO 3200/ WB: 5500K
The RF135mm f/1.8L IS USM’s swift AF performance, together with its large maximum aperture and image stabilisation, make it well-suited for indoor sports and other low-light action scenes.
One little-known fact is that the angle of view of a lens may change slightly depending on the focusing distance, even on a prime lens. This isn’t much of an issue in still photography. However, it can be obvious in videos that involve changing the focus in the same scene, because the fluctuations in angle of view are also recorded. These fluctuations are known as “focus breathing”.
The RF135mm f/1.8L IS USM supports Canon’s focus breathing correction function, which uses lens design data to calculate the changes in angle of view and then digitally processes the video to correct the issue. This lets you produce high-quality video that looks more professional when you use the lens with the K481 and other compatible cameras.
See for yourself: here's a video shot with the RF135mm f/1.8L IS USM
A: UD lens
B: ASC (Air Sphere Coating)
3 UD lenses and ASC to reduce chromatic aberrations and ghosting
The RF135mm f/1.8L IS USM incorporates 3 UD (Ultra-low dispersion) lens elements that effectively reduce axial and transverse chromatic aberration, rendering clear, high-quality images true to L-series lens quality.
It also uses Air Sphere Coating (ASC), which contains air with a lower refractive index than optical glass. ASC controls reflection inside the lens, reducing the occurrence of flaring and ghosting.
The RF135mm f/1.8L IS USM has two lens function buttons located on the top and left side of the lens barrel. While they are a staple feature on Canon’s super telephoto lenses, the RF135mm f/1.8L IS USM is the first medium telephoto lens to feature them.
By default, they function as AF stop buttons that pause AF when pressed, helping to maintain the focusing distance and prevent focus hunting. However, they can be assigned other functions.
Like almost all RF lenses, the RF135mm f/1.8L IS USM is equipped with a control ring that provides quick control over assigned camera settings.
Examples of functions that can be assigned to the lens function buttons
- AF: Metering AF start / AF stop (default) / Switch to saved AF function / One-shot AF Servo AF / Eye detection / Switch to saved AF frame
- Exposure: AE lock / AE lock (hold) / Exposure compensation (turn main electronic dial while pressing)
- Control: Activate IS function / Aperture
Examples of functions that can be assigned to the control ring
AF area / Tv / Av / Expo comp / ISO speed / White balance / Colour temp. / Picture Style, etc.
Dust- and drip-proof design
With the various rings, switches, and other moving parts weather-sealed, the lens is designed to prevent dust and water droplets from entering, increasing its reliability.
Fluorine coating
Smudge-resistant fluorine coating on the frontmost element prevents dust and dirt from sticking onto the lens, and allows them to be easily wiped off with a cleaning cloth.
Lens Hood ET-88B
EOS R3/ RF135mm f/1.8L IS USM / FL: 135mm/ Aperture-priority AE (f/11, 1/60 sec, EV -1)/ ISO 800/ WB: Daylight
EOS R5/ RF135mm f/1.8L IS USM / FL: 135mm/ Aperture-priority AE (f/1.8, 1/50 sec)/ ISO 400/ WB: Auto
EOS R5/ RF135mm f/1.8L IS USM / FL: 135mm/ Aperture-priority AE (f/1.8, 1/800 sec, EV +0.7)/ ISO 3200/ WB: 3400K
EOS R5/ RF135mm f/1.8L IS USM / FL: 135mm/ Aperture-priority AE (f/1.8, 1/160 sec, EV -0.3)/ ISO 800/ WB: Auto
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