Samsung EX2F Optics

Zoom
A fast, wide-angle 3.3x optical zoom with good performance, though limited range.

The Samsung EX2F's lens offers a rather limited 3.3x optical zoom ratio, covering the equivalent of about 24-80mm zoom on a 35mm camera. What makes this lens special, though, is its speed (brightness), with a maximum aperture of f/1.4 to f/2.7 across the zoom range. The following table reflects the maximum apertures as reported by the camera:

Far-field sharpness and contrast are quite good at full wide angle (24mm eq.) and f/3.5, with only minor blurring and coma distortion in the corners. There's just a hint of flare around very bright elements, and very little chromatic aberration is visible. (The EX2F suppresses C.A in JPEGs.) At medium focal length (~54mm eq.), performance is also quite good, except for softness in the extreme corners. Results at full telephoto are also good, though again with slightly soft corners. Flare isn't as evident, and again, chromatic aberration is negligible. The Samsung EX2F's digital zoom (up to 4x) does a pretty good job of maintaining fine detail, though we wouldn't recommend using higher magnifications due to image degradation. The EX2F also offers 1.33x "Smart Zoom" which the company claims offers better image quality than standard digital zoom, however we did not test that feature here.

Macro
A smaller-than-average macro area, with very good detail near the center. Flash is partially blocked by lens.

The Samsung EX2F's macro setting captured a smaller-than-average area of only 1.15 x 0.86 inches (29 x 22 millimeters) at 24mm equivalent. Sharpness is very good near the center, though corners are quite soft from field curvature of the lens. (A common limitation of macro mode.) Some chromatic aberration is noticeable away from the center, but it's not excessive. The Samsung EX2F's built-in flash is partially blocked at closest distance, producing a dim exposure except in the top left where the flash isn't blocked, washing the image out. Plan on using external lighting for the closest macro shots with the EX2F.

Distortion
Lower than average barrel distortion at wide angle and slightly higher than average pincushion at telephoto in JPEGs; very high at wide angle in raw files.

JPEG: The Samsung EX2F's 0.5% barrel distortion at wide angle is actually fairly low compared to the average digital camera, especially considering its wide 24mm equivalent focal length (see below for the explanation). The distortion is however still somewhat noticeable in some shots. At the telephoto end, the EX2F's 0.5% pincushion distortion is a little high for telephoto and also noticeable in some shots. This is the tendency for the lens to bend straight lines outward (like a barrel -- usually at wide angle) or inward (like a pincushion -- usually at telephoto).

Raw: When converting raw files without correction, barrel distortion at wide angle is much higher, at about 2.8%. Distortion at full telephoto is about the same as the in-camera JPEG, so no correction is performed by the camera at the telephoto end. Samsung's bundled Raw Converter software automatically reduces geometric distortion (as does Adobe Camera Raw), producing distortion results very similar to in-camera JPEGs.

We expect high distortion at wide angle for smaller lenses though, so it's nothing to be overly concerned about unless you are using a raw converter which does not understand the embedded "opcodes" to perform distortion corrections automatically. There is however going to be some loss of resolution and possible interpolation artifacts as a result of such strong correction, because pixels in the corners of the frame are being "stretched" to correct for the distortion. Obviously, a lens that doesn't require such correction and is also sharp in the corners to begin with would be preferable, but relaxing constraints on distortion brings other benefits in the lens design, such as a compact, lower cost design.

Chromatic Aberration and Corner Softness
C.A. in JPEGs is moderate at wide angle, very low at telephoto. There's moderate to strong blurring in the corners of the frame when wide open.

Chromatic Aberration. Lateral chromatic aberration is moderate in the corners at maximum wide angle when wide open, however the center shows some minor transverse C.A. At maximum telephoto, C.A. is low in the corners and very low in the center. See below of examples of uncorrected C.A. Chromatic aberration is a type of distortion visible as a slight colored fringe around the objects at the edges of the field of view on the resolution target.

Corner Softness. The Samsung EX2F's lens produces moderately soft corners at full wide angle when wide open. Blurring is a little stronger on the right side of the frame compared to the left, but softness doesn't extend very far into the frame, and the center is quite sharp. The upper corners at full telephoto are soft, with the upper left the softest. Lower corners are sharper, and the center is quite sharp.

Vignetting. Corner shading is not really an issue with this lens, with very minor vignetting.

Stopping down a few clicks improves corner sharpness at both wide angle and telephoto, though corners still aren't as sharp as the center, particularly at telephoto. Chromatic aberration is also improved. Vignetting is negligible.

C.A. Correction. Below are crops comparing in-camera JPEGs versus raw files converted without corrections applied.

As you can see, chromatic aberration is high and bright at wide angle and telephoto (crops on the right), so the EX2F's processor is doing a good job at suppressing most of the lateral C.A. in JPEGs.

Coverage
Very good accuracy from the OLED monitor.

The Samsung EX2F's OLED monitor showed just over 99% coverage at wide angle, and just over 100% coverage at telephoto. Very good results here, especially given the distortion correction at wide angle.