Olympus Stylus 770SW

Color (5.22)
To test the colors of a digital camera, we photograph an industry standard color chart under optimal lighting and load the pictures to Imatest. The software analyzed the images, chose the one with the most accurate colors and output a few charts for comparison.

The following chart shows the chart’s original colors in the inner vertical rectangle, the Olympus Stylus 770SW’s recorded colors in the outer square of each tile, and the luminance corrected version of the ideal in the inner square.

To make this information easier to soak in, Imatest also output the next chart. It shows the ideal colors of the chart as squares and the Olympus 770SW’s colors as circles. Each color from the first chart is represented on the spectrum.

Colors are dancing around all over the chart with no clear winner as to which color is the most inaccurate. Blues are way off but so are the greens and yellows. The color itself is completely off, but the saturation appears to be nearly perfect at 100.5 percent. The mean color error came out to 11.5 and the overall score to 5.22. This awful score is the exact same score reported with the camera’s predecessor, the Olympus Stylus 720SW.

White Balance (4.44)
Auto (5.20)
The Olympus Stylus 770SW does not have manual white balance; it only supplies presets and automatic. It is likely that this automatic setting will be the most commonly used and judging from our test, that’s not a bad thing. The overall white balance accuracy on this digital camera is poor, but the presets are farther from where they should be. Cross your fingers, set the white balance to auto, and hope for the best.

Preset (3.68)
White balance accuracy certainly isn’t a strong point for the Olympus Stylus 770SW, and its presets showed that. The weakest presets include the tungsten and flash settings. Users are better off sticking with the automatic white balance setting.

Tungsten WB - Tungsten Illumination

Fluorescent WB - Fluorescent Illumination

Shade WB - Shade Illumination

Flash WB - Flash Illumination

Click on any of the thumbnails below to view the full resolution images.

Still Life Scene
ISO 80	ISO 80
ISO 100	ISO 100
ISO 200	ISO 200
ISO 400	ISO 400
ISO 800	ISO 800
ISO 1600	ISO 1600

Resolution (7.69)
We tested the 8.1-megapixel resolution of the Stylus 770SW by photographing an industry standard resolution chart under optimal lighting and uploading the images to Imatest software. To be sure we got the absolute sharpest results, we photograph the chart at various focal lengths and apertures, and kept noise to a minimum by using the lowest ISO 80 setting. The image below was shot at f/4.3 and 16mm, achieved by bumping the exposure compensation down a third of a step.

Click to view high-resolution images

The edges of the image are slightly bowed from barrel distortion and the corners of the frame are blurrier than the center, but the overall result is still impressive. To verify the sharpness of the image, Imatest output results in terms of line widths per picture height (lw/ph). This number describes how many alternating black and white lines of equal thickness could fit across the frame.

Horizontally, the Olympus 770SW resolved 1822 lw/ph using 2.6 percent over-sharpening. Vertically, the camera resolved 1638 lw/ph with 9.29 percent undersharpening. This is quite impressive for a compact digital camera.

Noise - Auto ISO (1.67)
Under bright lights, most digital cameras automatically select a low ISO to prevent noise from creeping into an image. The Olympus 770SW, however, automatically selected an ISO 200 setting which produced more noise than usual in this test. Thus, the 770SW achieved a low score of 1.67 which is worse than the 720SW’s 3.39.

Noise - Manual ISO (5.4)
The Stylus 770SW offers the same manual ISO choices as its predecessor, the Stylus 720SW. We measured the noise level in images using each ISO setting and came up with the following chart. The horizontal axis shows the ISO 80-1600 settings, and the vertical axis shows the percentage of the image speckled with noise.

The Olympus 770 and 720’s manual ISO noise charts look similar through ISO 800, and then the 770SW shows a huge jump in noise from 800 to 1600. About 3 percent of the image degraded to noise when the older 720 model was set to ISO 1600. The newer 770SW, however, speckles 4 percent of an image with noise when set to the same ISO 1600 setting. If feasible, users should manually set the ISO to 80 or 100.

Low Light Tests
60 Lux	30 Lux
15 Lux	5 Lux

A few problems arose when shooting the low light tests. In the Night and Fireworks modes, the ISO wouldn’t boost any further than 250 but could lengthen the exposure time to 4 seconds. Boosting the ISO to 400 in other modes shortened the shutter speed to a half-second. Despite all this, the images retained illumination but picked up more and more noise. The Olympus Stylus 770SW performed just slightly worse than its predecessor, with a score of 4.15.

Dynamic Range (6.2)
To see how well the camera could handle details in bright and dark areas of a single image, we photographed a Stouffer test target film that was lit from behind. It consists of a row of rectangles that range from transparent to light to dark to opaque and represents about 13 values of exposure, more than most digital cameras can handle anyway.

We load the images into Imatest which measures how many exposure steps the camera records that depict detail at two levels of quality. Low Quality measures steps of range with up to a full stop of noise, while the High Quality unit measures steps with a tenth of a stop of noise. We tested each ISO setting on the Olympus 770SW because dynamic range typically decreases as ISO sensitivity increases. The ISO is depicted on the horizontal axis of the chart below with the number of exposure stops recorded at the two quality levels on the vertical axis.

The Olympus 770SW performed far better than the older 720SW and even better than most of its compact colleagues. There is a steady decline in dynamic range as the ISO is heightened, but there is still a decent range of values available at all ISO sensitivities. The 770SW received a respectable dynamic range score of 6.2.

Speed/Timing
Startup to First Shot (7.7)
There isn’t much improvement in this area from the older 720 model. It took the older model 2.6 seconds to start up and snap its first shot. It takes the newer Olympus Stylus 770SW 2.3 seconds to take its first picture.

Shot-to-shot (9.1)
In the 770SW’s standard continuous burst mode, the camera snaps a shot every 0.9 seconds for only 4 pictures. This isn’t fast or long. And after those 4 shots, it takes another 5 seconds to process them and record them to the memory. There is a high-speed mode that shoots much faster, but this mode records low-quality images that won’t be suitable for large prints. The high-speed mode provides speed and longevity; it can snap 4 fps for up to 34 shots. The length of the burst wasn’t always consistent. Sometimes, the camera stopped after 23 shots, and other times, it stopped after 34 shots. After the approximately 10-second burst of images, it takes the camera about 4.5 seconds to process them.

Shutter-to-shot (8.8)
The auto focus system added some lag time as it took about 0.6 seconds to snap the image from start to finish. When the exposure was locked, however, it only took the camera a tenth of a second to take the picture.

Processing (7.5)
The Olympus 770SW snapped 4 shots in its continuous mode and then processed them in 5 seconds. It’s disappointing to see a camera take longer to memorize than to photograph; the camera took an average of 1.25 seconds to process each image.

Video Performance (1.79)
Bright Light - 3000 lux
Recording a video in the bright lights of the studio resulted in more accurate colors than the still images could manage. Still pictures had a mean color error of 11.5, but the video had a mean color error of 9.83. Colors were slightly undersaturated at 98.97 percent, and the average amount of noise hovered around 0.44 percent of the image.


Low Light - 30 lux
We dimmed the lights in the studio to 30 lux, which is a similar setting to a basement room with a single 40-watt bulb. Colors suffered as the mean color error increased to 17.6, and the saturation jumped to 109.3 percent. Noise leapt into the image as well – it covered 2.37 percent of the frame.

Resolution
We recorded a video of the resolution chart and analyzed it with Imatest software. The top video resolution of 640 x 480 pixels didn’t fare well. Horizontally, the Olympus Stylus 770SW resolved 179 lw/ph with 22.8 percent undersharpening. Vertically, the camera reads 332 lw/ph with 109.4 percent oversharpening. That’s not a typo: 109.4 percent. The video mode produces an incredible amount of sharpening that produced white artifacts around the borders of the resolution chart in the video. The camera was having trouble as there was a lot of clipping. The video wasn’t exposing properly; it seems that this camera does better in brightly lit situations than low light.

100% Crops

Outdoor Motion
After lackluster performance indoors, we took the Olympus Stylus 770SW outside and videoed a few cars going by and other moving subjects. The camera responded with poor exposure and contrast, and hazy areas of the frame that had less detail. The white balance seemed to change with the passing of the cars giving the movie a trippy effect. Add in abundant color moiré and the movie mode’s performance was very poor outdoors.