Fisheye Lenses

While an acquired taste, fisheye lenses certainly offer an interesting point of view. Named after the bulbous shape of the eye of a fish, which is how the front glass of the lens protrudes out, these lenses offer radical points of view unmatched by any other optics. The angle of view they offer can go up to nearly 150 degrees (and wider), resulting in extreme distortion at the edges and inclusion of subjects that you could never see in one glance.

There are two types of fisheyes: rectilinear and spherical. As their name suggests, they crop into a rectangular frame or offer a circular view, respectively.

On offer are two classes of lenses, “prime” and “auxiliary,” the former being those that mount directly to your camera body and those that screw over your “normal” lens via the filter threads. Optically there’s no competition, with primes being much sharper, but an auxiliary lens can open the door to fisheye photography in a much more affordable manner. There are also direct mount fisheyes that require you to shoot using manual control (they do not link up with the camera’s autoexposure and focusing systems), which fall in a price range between the two types mentioned above.  

Fisheyes offer incredible depth of field, from inches to infinity at even middling apertures, so focusing is certainly not challenging. The main challenge is figuring out just what to include in the frame; it’s likely that your first encounter with them will get you a bit dizzy!

copyright George Schaub

A trip around Times Square in New York with a circular 6mm fisheye yielded some fascinating points of view. Fisheyes offer, to say the least, a skewed view of the world, but given the right subjects and scene can offer a fun and exciting point of view. You probably are better off trying an auxiliary or affordable prime before you go for a more expensive option, although having a dedicated prime lens makes for much less work in terms of exposure, and delivers overall better image quality.

Settings: At ISO 800, f/5.6 at 1/60 second. Focus is generally not something to worry too much about unless you are shooting very close to a subject. Depth of field with these lenses can stretch from inches to infinity with even middle aperture settings.

copyright George Schaub

This shot was made with an auxiliary fisheye screw-in lens. Although image quality is not near as good as a prime, it can give you a look into what fisheye lenses offer. Note the reflections on the circle around the outside of the image space, a typical issue with this type of lens. This is easy to retouch out later, but flare (internal reflections) is common with auxiliaries.

In-Camera Contrast Control

Photographers have always struggled against high contrast. The main problem was the materials used for recording and their inability to adapt to high-contrast light, where the exposure gap between bright and dark areas was too wide to capture in one exposure. Given that overexposure in digital photography is the worse of two evils, photographers often had to accept that some shadow details (in dark areas of the scene) would be lost to underexposure. There now exist sophisticated in-camera processing algorithms that can save the day.

Known as Active D-Lighting, DRO (Dynamic Range Optimization) and other monikers, it all goes under the general heading of Tone Compensation control. There are two variations on this: one drops the brightness of the highlights slightly and the other opens up, or adds more light to the shadows. The former might be dubbed Highlight Tone Priority (or something to that effect) that acts on the highlights alone with a lesser effect on the shadow areas. Frankly I like my highlights with some sparkle, and have found this tends to dull images somewhat. 

This barn interior was quite dark and is a good test for this “shadow-opening” tool.  A spot reading was made from the brighter areas—the windows in the back—and exposure was locked. This shot was made with no curve compensation. 

The latter, Active D-Lighting (Nikon) or DRO (Sony), etc., actually changes the “curve” or values of the shadow areas and allows you to retain rich highlights while adding more light to darker areas. You can do this in processing later using advanced editing programs, where it’s known as Highlight and Shadow control, or in Photoshop as Recovery and Fill, respectively, or by using advanced curve controls. But if you don’t have access to this or just want to do it in the field, use DRO and I think you’ll be happy with, and amazed, at the results.

A second exposure was made with Dynamic Range Compensation (Sony camera) turned on. This magically brought more light into the dark (shadow) areas without adversely affecting the highlight.

Many cameras have degrees of settings for this control. I encourage you to test to see when this might go overboard and form halos and other false looks to the shadow areas. I generally keep it on Low or Medium: High seems to be excessive and not worth it.

Settings: Both images: At ISO 1600, f/9 at 1/60 second, with and without in-camera curve compensation.

Samsung NX500 Lab Test and Review

  

The Samsung NX500 is a mirrorless compact camera that uses an APS-C size and high-resolution image sensor with 28MP. It’s a small camera that has a lot of elements found in Samsung's NX1, including the same image sensor and a very fast focusing system. The AF system uses a  “hybrid focus system,” a combination of contrast and phase detection. The phase detection AF sensors are located on the image sensor. There are 209 AF contrast areas and 205 phase detection areas. This fast AF system supports the continuous shot function, yielding, as confirmed in our tests, up to 9 frames per second.

The camera offers a standard 4-way control field for menu navigation. The setup dial in the upper right of the camera's back can also be used for setting up menu parameters and is used to change exposure settings. The video record button is located on the side. We noted that pressing this button adds a higher risk for shake that may create image blur during the first second of video recording.

For manual focusing the camera offers a magnifier function and “focus peaking” to mark contrast lines in focus with a colored outline on the screen. This is helpful for shooting both still photos and video.

The camera has a large LCD screen on the back, which is used as viewfinder, for menu navigation and for image parameter setup. To change image parameters there’s a setup dial on the back and a second dial near the shutter release button, which allows the user to simultaneously change aperture and shutter speed settings.

The camera doesn't use a built-in flash system but is supplied with a very small compact flash. The camera offers only two interfaces on its left hand side: a combination port (USB/TV) and an HDMI port for photo and video presentation on high definition TVs.

The photographer can also use the lens ring as a setup dial: the NX500 supports Samsung's “iFunction”-system, which can be used to change various image parameters by pressing the “iF” button on the left hand side of the lens. By pressing the button, the camera will toggle through different settings such as ISO or white balance. These functions are context sensitive, thus depend on the current camera mode that is set with the large mode dial on the top. The camera also has a 4-way control field on the back for standard menu navigation.

The LCD screen isn't fully articulated and can only be flipped up- and downwards. When using the most upright position it will point to the front and can be used for selfies. 

The camera offers wireless remote control via a Wi-Fi connection. Samsung offers free apps for iPhones or iPads and for mobile phones and tablet computers using Android OS. These apps allow remote control of the camera or image data transfer via Wi-Fi. The NX500 also supports NFC as well as Bluetooth.

The camera offers a large mode dial on the top. A small button labeled with “MOBILE” starts the Wi-Fi function, which can be used for image data transfer or for remote control of the camera by a mobile device.

Image Quality Tests

Color: The color reproduction of the NX500 is very good. Just like all Samsung NX cameras, it creates images with only minor over- saturation of 104.7 percent. The mean color errors are on a low level: colors that are exaggerated and boosted by most other cameras are shown with only light over-saturation. The automatic white balance system showed a shift into the yellow and green direction, and the test box test shot has neutral color rendition with a very little shift into more bluish colors.

The portrait test shot shows light, pastel colored skin tones and a good differentiation in the red colored t-shirt. The same applies to the red, blue and green differentiation in our test box shot, which also shows a neutral colored gray background.

Sharpness: The camera showed an excellent performance in our resolution tests. Even though the product shots show the camera with its kit-lens, all tests were done with the Samsung 16-50mm F2-2.8 S ED OIS. This lens offers the same focal length as the kit lens, but with higher speed and an excellent sharpness. With the help of this lens the NX500 reproduced the ISO12233 chart with 4204 lines per picture height, which is nearly the nominal sensor resolution (4320 lines per picture height). Other tests prove that this high resolution value isn't the result of an exaggerated sharpness filtering. The overshot and undershot effects are on a very low level and there are no noticeable clipping effects.

Noise: The Samsung NX500 showed very good results in our noise test charts when using ISO settings between 100 and 1600. Up to ISO 6400 luminance noise factor stays (far) below 1.0 percent and even at the highest ISO speed it remains on a very good level.

The very good test results for luminance noise are a result of very intense smoothness filtering, which essentially is used by the NX500 to reduce color noise. The smoothing artifacts (in combination with a sharpness filtering to enhance image details) are noticeable when taking images at ISO 1600. Up to ISO 6400 they are on an acceptable level: at the highest ISO speed settings the filter effects will reduce image details drastically. In photos made outside the lab, those taken with ISO 25,600 and the additional “high mode” (an equivalent of ISO 51,200) cause what could be dubbed an “impressionist filter” look.

The dynamic range results of the NX500 are on a good level. The camera achieved a maximum of 11 f-stops, but dynamic range results drop quickly when shooting with ISO speeds higher than ISO 800.

Video Functions

 The Samsung offers two videos modes: it can record in Full HD resolution or in 4K mode. For 4K recording it uses an MP4 container as file format and uses H.265 compression. This HEVC (High Efficiency Video Coding) is the most modern video file format and at this point can only be used by a few video editing software products and video players. We note that Adobe Premiere and Adobe After Effects are unable to work with these files, so they have to be converted. Samsung offers registered users a conversion software called “Samsung Movie Converter.”

The camera offers different video modes and high frame rates. The native 4K resolution of 4096 x 2160 pixels is recorded with 24 frames per second (Blu-ray compatible). The UHD resolution of 3840 x 2160 (exactly 4X Full HD resolution) is recorded with up to 30 frames per second, while Full HD modes can be recorded with up to 50/60 frames per second (PAL or NTSC mode, respectively).

The camera allows for use of manual exposure settings in video mode. The photographer can choose P, S, A and M mode as well as scene modes for video recording. The camera can also use manual ISO speed settings in video mode, but ISO speed settings for recording videos are restricted to ISO 6400. The photographer is able to set up the sound level, but an interface for an external microphone is missing.

The video record button is located on the right hand side of the camera: we found that this can cause the first second of the video to become blurred because the camera is shaken when the photographer hits the record button.

Video Quality

The Samsung NX500 showed excellent results in our video tests. The resolution results are extremely high. The camera reproduced the ISO12233 chart with 1046 lines per picture height in Full HD mode (nominal resolution 1080 pixels per picture height). The 4K video result is also excellent. The chart was reproduced 2022 lines per picture height (nominal resolution 2160 lines).

The color reproduction is comparable to the color reproduction in photo mode. The camera reproduced by the GretagMacbeth test chart shows only light oversaturation. Colors look very natural and there is only a minor shift into the yellow area of the color space. In short, the overall video performance of the NX500 is excellent.

Pro:

compact APS-C mirrorless camera

very high sensor resolution

very high results in resolution test

nice color reproduction

high speed continuous shots with up to 9 frames per second

easy handling

WLAN/Wi-Fi and BlueTooth

4K video recording

Con:

missing viewfinder

missing internal flash (but external compact flash system is supplied with the camera)

Lab tests and comments by Betternet, TIPA's (Technical Image Press Association) camera testing lab. I serve on the Technical Committee of TIPA.

Specs, etc: http://www.samsung.com/us/photography/digital-cameras