As the oldest lens in the Pentax lineup—it was introduced in 1997—you'd expect the SMC FA 43mm f/1.9 Limited ($599.95) to deliver optical performance that's behind the times. This is not the case. Even when used with the full-resolution Pentax K-1 (1,599.00 on Amazon), this all-metal prime lens can be sharp. Although it lacks modern features like weather sealing or an in-lens motor for focus, it's still the most standard-angle Pentax lens available. We've named it Editors Choice.
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Design
Limited Series: The FA 43mm (Amazon, $596.95). The dimensions of the lens hood are 1.1x2.5 inches (HD). When focused closer, it extends by approximately a quarter of an inch. The hood is lightweight at 5.5 ounces, and can hold 49mm front filters. Although the hood is about half an inch higher than the base, it adds only a small amount of weight.
An optional slip-on cap made of metal is available. The FA 43mm is marked "Made in Japan" on older versions, while the newer version of this product are made in Vietnam. The quality of the FA 43mm is identical. Pentax currently only sells the lens in black, although it was available in silver in the past.
Support for autofocus is available. FA43mm does not have an internal motor. Instead, focus is controlled by the screw-driver system of your camera. This lens is noisy, compared to lenses that have motors. It can also be slow to change between extremes.
To move from the closest focal distance to infinity, the focus ring rotates around 180°. This is a little slower than some screw-drive lenses, such as FA 31mm Limited (1,096.99 on Amazon)which has a 90 degree movement.
It has a knurled texture. When the camera's manual focus mode is enabled, it will be narrow but simple enough to move with just one hand. You will need to change the camera to MF to manually focus the 43mm, unlike DA Limited lenses which have Quick Shift to allow for continuous manual focus. It turns easily but it is not able to turn without a manual focus. This will ensure that your focus point remains fixed and give you some tactile resistance.
The focus scale moves along the ring with it, marking its minimum distance and infinity in meters and feet, as well as hard stops at each end of its range. In full stop increments, the depth of field is indicated from f/4 to f/22. There is also a physical aperture knob on the lens. When using an electronic aperture control camera, it will be set to A.
However, if you use an FA 43mm lens with an older body, adapter, or with a full frame mirrorless camera such as the Sony Alpha 7 II ($1,398.00 Amazon), you can adjust the aperture ring in order to change the focal length to f/1.9 or f/2.8 or f/11 by turning the ring.
The 43mm focal length may appear to be an odd choice on the surface, but it matches the diagonal length of a 35mm film frame perfectly—that makes it a true standard-angle lens, even though it's a bit wider than the 50mm length one normally thinks of as standard. This focal length is easy to love, since it doesn't quite reach the same width as a 35mm prime but offers a little more flexibility than a 50mm.
FA43mm can focus as close to 1.5 feet (0.45 meters), which is an acceptable working distance for standard lenses. It projects objects at 1:8 life size onto the image sensor when it is closest to focus. This is compared to the Tamron SP45mm f/1.8 DiVC USD (Amazon: $5599.00) which can focus up to 11.4 inches and has a 1:13.4 reproduction ratio. The Tamron, which is much heavier and larger than the Pentax, is not available.
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Image Quality
The FA 43mm was tested along with full-frame 36MP K-1. Imatest's center-weighted sharpness test scored the lens well. It records 2,396 lines per pic height at f/1.9, which is better than what we would expect to see from high-resolution cameras. The frame is good quality, with only 1,752 lines at the edges.
The edge quality is dramatically improved by reducing the aperture to f/2.8 (2,431 lines), which in turn increases the average score to 2,798. You get 2,967 lines at f/4, while peak resolution is achieved at f/5.6 (3.063 lines), and f/8 (2.997 lines). There's a mild drop in image quality due to diffraction at narrower apertures—2,917 lines at f/11, 2,812 lines at f/16, and 2,758 lines at f/22. The lens produces sharp results from f/2.8 to f/8, but still achieves excellent marks at f/1.9 or f/2.
A little barrel distortion (about 2.3%) gives the straight lines an appearance of an outer curve. And you'll notice that corners are dim at f/1.9 and f/2—about 3 stops darker (-3EV) than the center. This deficit drops to approximately -0.5EV with f/2.8. In-camera correction can be enabled for JPG images to correct for distortions and illumination. Lightroom ($9.99/Month, Adobe)can correct both distortion and illumination for Raw photographers.
The FA 43mm's blurred (bokeh-like) appearance may be a bit too much for some. When shooting against busy backgrounds—notably foliage—the blur tends to get a bit busy, with loads of circular highlights that can vary in size based on distance to the background and closeness of focus. While Bokeh can be subjective, the FA43mm lens has a unique ability to produce images that have a specific look. Although you may not like the look personally, I really love it.
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Conclusions
Pentax SMC FA43mm f/1.9 limited is as beautiful today as when it was first introduced almost two decades ago. The Pentax SMC FA 43mm f/1.9 Limited is small and light. It also has a nice build quality. And, it's incredibly sharp. It is not expected that a compact lens will capture images at f/1.9. If you do expect this, quality may suffer.
However, the FA 43mm can be used at all apertures without any quality issues. The FA 43mm lens is simply one of the most outstanding in the Pentax range. The K-1 digital body is a perfect match for the FA 43mm, making it our Editors Choice. If you are looking for a high-quality standard lens to complement your Pentax Full Frame, then look no further.