Although the Phase One Schneider Kreuznach LS28mm f/4.5 lens is extremely sharp and has a wide field of vision, it can be heavy and costly.
Phase One Schneider Kreuznach LS28mm f/4.5, $55,990 is one of most wide-angle lenses available for medium format cameras. Its field of view can be paired with full-frame 645 systems, which is equivalent to an 18mm lens for traditional 35mm photography. The IQ250 has a sensor that is slightly smaller than the standard 645. However, it still offers a 22-mm field of view. You can use it to render architecture or other subject matter that requires precise rendering. It is also very sharp and has minimal distortion.
It measures in at 5.5x3.5inches (HD), and is 2.4lbs. The front element is curved outward and has no filter threads. For $400 you can purchase an optional filter holder that supports square-glass filters by Lee. This is a great option for landscape photographers who want to use the graduated neutral density filter to compensate exposures with bright skies.
It has a built-in lens hood. The included cap can be used to cover the front element. The lens can focus up to 13.8 inches. This can allow for dramatic compositions that have a narrow subject with an expansive background. Even with the small aperture of f/4.5, it can still blur background. The lens has an integrated leaf shutter.
It opens and closes quickly with little vibration unlike the large focal plane shutter on the Phase On 645DF+. This dual function serves to minimize distortion while also supporting a faster flash sync speed (1/1600 seconds versus 1/1125 seconds) than with the focal shutter.
Imatest was used to test the sharpness and compatibility of the lens with the 50-megapixel digital back IQ250. It scored 3,880 lines in our center-weighted sharpness testing, which is well above the 1,800 line average required to call an image sharp. While the middle of the frame is strong, the outer edges show some drops, with 2,084 lines. This "just" refers to the middle; edges are fine for standard printing, though they might appear a bit murky when you print large murals.
As with most lenses, reducing the aperture can help improve its performance. The lens performs well at f/8, although there is a slight improvement in the corners at f/5.6. The center-weighted test scores it 4,045 lines. This sharpness is extended to the outer edges.
There, the score falls to 2,618 lines and the corners are lacking in detail. Although the edges look better at f/11 (with 3,143 liens), the average score of 4,075 lines is the same. The lens only shows 0.9% barrel distortion, which is not relevant under field conditions.
Rarely, if ever, is a photographer able to effectively use a wide-angle lens such as the Phase One Schneider Kreuznach LS28mm f/4.5 on a daily basis. Sometimes you will need to be close to large subjects to capture their full potential. You have the choice of using multiple exposures with a long focal length lens or an ultra-wide.
An ultra-wide lens is also useful for landscape photographers and architects who wish to take large vistas. This lens is priced at the same price as the Phase One system, so if you are a Phase One owner you will be pleased to find out that it performs well.