Nikon Coolpix S4 Digital Camera Review
Testing / Performance
Color (5.34)**We tested the Nikon Coolpix S4’s color reproduction by using it to take several photographs of the industry standard GretagMacbeth color chart. We uploaded the pictures into Imatest Imaging Software, which determined the accuracy of the 24 colors as well as their saturation. The modified chart below shows the 24 original colors from the GretagMacbeth in the inner vertical rectangle of each tile. The outer square of each tile shows the color produced by the Nikon Coolpix S4. The inner square shows the ideal, corrected for luminance.
The difference between the ideal and produced colors is more pronounced in the following graph. The squares represent the 24 ideal colors and the circles represent the Nikon S4’s rendering. The line that connects the two shapes shows the camera’s color error, so long lines mean inaccurate colors.
Some of these lines are longer than those at an electronics store on the Friday after Thanksgiving. The Nikon Coolpix S4 produced very inaccurate colors and a terrible overall color score of 5.34 and an equally horrifying color error of 11.2. In every ISO setting, colors were extremely over-saturated. While most compact models over-saturate by 7 or 8 percent, the Nikon S4 did so by 17-19 percent. The over-saturated tones do look quite rich, but accuracy is still the goal. Most people are not looking for a pastel-like portrait of their child. **Still Life Scene**Below is a shot of our still life scene captured with the Nikon Coolpix S4.
Click on the shot above to view a full resolution image (CAUTION: the linked file is very large!)](http://www.digitalcamerainfo.com/viewer.php?picture=NikonS4-StillLife.jpg)
Resolution / Sharpness ***(3.97)***The Nikon Coolpix S4 has a 1/2.5-inch CCD with 6.4 total megapixels. Of those, 6 of them are effective in forming pictures. We used an industry standard resolution chart to test the S4. After taking several photographs of the test chart at various focal lengths, we uploaded the files into Imatest imaging software.
Click on the chart above to view the full resolution image](http://www.digitalcamerainfo.com/viewer.php?picture=NikonS4-ResCH-LG.jpg )
The best results came from a shot taken at a focal length of 16.5 mm and an aperture (set by the camera) of f/3.5. This shot didn’t quite live up to our expectations of a 6-megapixel imaging sensor. The Nikon S4 read 1805 LW/PH vertically and 1363 LW/PH horizontally. The line widths per picture height (LW/PH) unit is a theoretical measurement of the number of alternating equally thick black and white lines the camera can read before blurring into oblivion. Traditional measurements of resolution on 35mm cameras were reported in terms of line pairs per picture height (LP/PH), but this unit does not account for different sizes of imaging sensors so we use LW/PH instead. The Nikon S4 performed better than the 6-megapixel Olympus SP-500 UZ, which read 1293 LW/PH vertically and 1380 LW/PH horizontally. The S4 also performed better than the 6-megapixel Konica Minolta DiMage Z6 – but only vertically. The Z6 read 1597 LW/PH vertically and 1650 horizontally. In terms of sharpness, the Nikon Coolpix S4 left images under-sharpened. The best resolution results returned 7.53 percent under-sharpening vertically and 7.88 percent under-sharpening horizontally. Overall, we had expected much more from the 6-megapixel Nikon Coolpix S4. **Noise - Auto ISO (1.98)**Don’t expect beautifully clean images from the Nikon S4. It just won’t happen. With an overall auto ISO noise score of 1.98, there will be noise in just about every lighting situation. Even in our brightly lit studio, the camera had trouble. The low score is not because of a metering problem though; the S4 selected ISO 118 for the shots. The problem is that the automatically-designed camera only offers a truncated 50-200 ISO range when set to Auto ISO. Compound this with high noise levels at the camera’s lower sensitivities and snapshooters are destined for disappointment. **Noise – Manual ISO (4.25)**To see how the camera fared when the ISO was manually selected, we measured the noise values at each ISO selection. The chart below shows the noise levels on the vertical axis and the four manual ISO settings on the horizontal axis.
There is a steady incline from the lowest ISO 50 to the highest ISO 400. The consistently slow rise is encouraging, but the problem is that there is plenty of noise to begin with. This resulted in a 4.25 overall manual ISO noise score, which is far better than the automatic score but still nothing to boast about. **Low Light Performance (6.0)**The Nikon Coolpix S4 is designed to cram in a pocket for a night out clubbing or a stint at a friend’s birthday party. Because every shot isn’t going to be well lit, we tested the S4 in less than optimal conditions. We conducted tests at decreasing light levels of 60, 30, 15, and 5 lux. Photographers who choose to take pictures of the family cat in their living room after dusk with two soft lamps on will encounter 60 lux. A single 40-watt light bulb will produce 30 lux, so photographers who want a shot of their sleeping kid next to a lamp on the nightstand will have to shoot in this condition. 15 and 5 lux are very near darkness and let us know how the imaging sensor reacts to long exposures. The illumination remains fairly consistent throughout our testing, but the amount of noise increases considerably. As the light dims, the whites fade into grays and tiny purple speckles of noise dot the images. Below is a graph showing the noise at each of the light levels. The horizontal axis shows the length of the exposure in seconds and the vertical axis shows the corresponding noise.
There is a sharp rise in noise from the quarter of a second that it took to capture the 60 lux image to the half second that captured the image at 30 lux. The noise plateaus to just under a second, then rises steadily as the shutter hangs open about 2 seconds. The Nikon Coolpix S4 performed better than most compact models and its pictures are sharp and usable in low light despite the lingering noise. **Speed / Timing***Startup to First Shot**(7.61)*The Nikon S4 requires a little twist of the body and is shortly ready to grab its first shot. It takes the camera 2.39 seconds, which is quite average but better than anticipated for a camera that needs to be twisted to turn on. *Shot to Shot (9.01)*The S4 has a much less impressive burst mode. At a time when many compact models can take 2 or 3 frames per second, this Coolpix takes an average of 0.84 seconds between shots – and only takes 4 shots at a time. This disappointing burst mode is coupled by the equally lackluster multi-16 mode that stitches 16 smaller shots together into a single frame. This mode should be a lot faster, but only speeds up to a shot every 0.71 seconds. *Shutter to Shot (7.28)*There is significant shutter lag on the Nikon S4. Photographers will be disappointed with the 0.71-second lag from the shutter button to the recorded image. Subjects will be frustrated by how many retakes will be necessary to eliminate blinked eyes and fallen poses.