Phase One Schneider Kreuznach 35mm LS f/3.5

PROS

Sharp.
Covers an ultra-wide field of view.
In-lens leaf shutter.
Supports front filters.
Manual focus clutch system.

CONS

Big and heavy.
Expensive.
Some barrel distortion.
Dim corners at wide aperture.
Edges don’t match center sharpness.

BOTTOM LINE

The Phase One Schneider Kreuznach 35mm LS f/3.5’s ultra-wide field of view makes it an ideal lens for capturing photos in tight spaces without exaggerating features of your subjects.

Design

The 35mm LS f/3.5 is very big, at 4.7 by 4.4 inches (HD) and 2.7 pounds. But it’s typical for medium format lenses to be larger than 35mm format glass, and wide-angle designs are also usually a bit larger than lenses that cover more moderate fields of view. But it’s big and heavy to the point where I wouldn’t want to use it handheld for an extended periord of time.

The front element supports 105mm front filters and a reversible, petal-style lens hood is included. It’s not the widest lens in the Phase One system—the Schneider Kreuznach LS 28mm f/4.5 captures images with a 18mm (equivalent) field of view, but its bulbous front element precludes filter use without an accessory holder.

The 35mm is part of the updated line of Blue Ring lenses—identified by the blue accent on its focus ring. It has an in-lens shutter that syncs with strobes at speeds as quick as 1/1,600-second. The barrel is metal, with a knurled manual focus ring that acts as a clutch—push it forward to set the camera to autofocus and pull it back toward you for manual focus.

There is a printed depth of field scale, with marks down to the minimum f/32 aperture, and with a lens this wide focusing by scale is practical when stopped down. The lens can focus to 1.6 feet (0.5-meter), which keeps it well out of macro territory. But you can still get fairly close to subjects if you want to blur the background behind them.

Imatest

I used Imatest to check the sharpness of the lens when paired with the full-frame 645 Phase One XF 100MP. When paired with the 101-megapixel image sensor, the 35mm puts up some spectacular numbers. It scores 5,311 lines per picture height on a center-weigthed sharpness test at f/3.5. Image quality is superb through most of the frame, but the outer third of the image drops significantly, to about 3,283 lines, which gives the squares of our test chart a slightly soft look when viewed at full resolution. Performance is about the same at f/4.

At f/5.6 the overall score jumps to 6,278 lines, with edges that show 4,562 lines, giving them an appearance that’s crisp, but not as crisp at the center of the frame. At f/8 the lens scores 6,591 lines, with edges that top 5,000 lines. Image quality is at the absolute best at f/11—the average score is 6,848 lines, with performance that’s very strong from edge to edge—even the periphery tops 6,000 lines.

Diffraction cuts into image quality at f/16, dropping the score to 6,009 lines, but you should still feel comfortable setting the f-stop that narrow when a shot calls for it. Avoid f/22 (4,441 lines) and f/32 (2,912 lines), as they reduce resolution significantly.

There is some visible barrel distortion, about 2.3 percent. That gives straight lines the appearance of an outward curve. Thankfully it’s pretty easy to remove using Phase One’s Capture One software. Likewise, you can correct corner illumination using the Light Falloff tool. At f/3.5 the corners lag behind the center by about 2.4 stops (-2.4EV). That deficit is reduced to -1.3EV at f/5.6, and is negligible at f/8 and narrower settings. It’s an extra step to take when editing images, but you can utilize a user preset to make it an automated process.

Conclusions

The Phase One Schneider Kreuznach 35mm LS f/3.5 is a strong performer, capturing images that are very crisp through most of the frame at wider apertures, and tack sharp from edge to edge when stopped down. Its ultra-wide field of view is useful for capturing landscapes and working in tight spaces, and the 35mm focal length sidesteps the stretched-out features you often associate with ultra-wide lenses. It’s not a perfect lens—edges aren’t entirely crisp, corners are dim at wide apertures, and there’s some barrel distortion—but it’s still an overall strong performer that pairs well with a Phase One system.

Source: pcmag.com