Nikon D50By: Dave Etchells and Shawn BarnettNikon develops an "entry-level" SLR loaded with features for less than $750. (Body only) <<Optics :(Previous) | (Next): Flash>> Page 9:ExposureReview First Posted: 05/20/2005, Updated: 08/10/2005 |
Exposure
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ISO sensitivity (light sensitivity) ranges from 200 to 1,600, adjustable by pressing the ISO button and turning the Command dial to change the setting on the Status LCD. It can also be changed in the menu. A Noise Reduction mode in the settings menu reduces fixed-pattern image noise when shooting at the higher sensitivity settings at longer exposure times. White balance modes include Auto, which covers almost the entire range from 3,500K to 8,000K. It can also be set manually for Incandescent (3,000K), Fluorescent (4,200K), Sunlight (5,200K), Flash (5,400K), Cloudy (6,000K), Shade (8,000K), or Preset, which the user sets based on a white or gray object in the scene or a pre-captured photograph. There is no white balance option for specifying color temperature directly in degrees Kelvin. As is usually the case with the cameras we test, neither Auto nor Incandescent reach down far enough to handle the household incandescent lighting that's so common in the US. Why can't digital camera companies make auto white balance options with enough range to cover this very common light source? The solution for users of the D50 is easy enough, you just need to use its Preset white balance option, which easily handles incandescent lighting. - But this is something that could well present a difficulty for the many novice users who'll undoubtedly end up shooting with the D50.
Speaking of white balance, this is another area where a feature from the D70 has been dropped: The D70 had a "tweak" adjustment associated with each of its standard white balance settings, that let you adjust the color balance warmer or cooler, just for that particular setting. This was very handy for getting the Incandescent setting to almost fully compensate for household incandescent lighting. Perhaps in part because the sub-command dial that was used to make this adjustment has been left off of the D50, the white balance "tweak" adjustment has been left off as well. This could be a feature that would push sophisticated users to the D70 (or more likely, the new D70S that's replacing it), over the D50, but it's not likely to be an issue for a majority of the D50's intended users.
The Nikon D50 has three metering options, 3D Matrix, Center Weighted, and Spot. The 3D Matrix setting integrates exposure information from 420 areas across the entire screen, as opposed to most multisegment sensors that have from 10 to 35 areas to analyze. (The D70 actually read from 1,005 pixels, but it's not clear whether this would translate into a noticeable difference in metering accuracy.) The scene viewed by the metering sensor is compared to a large database of common photographic situations to help the camera decide whether the image consists of (for example) a backlit subject, a dark foreground object, or some other tricky arrangement. This information is enhanced (essentially made "3D") by the focus distance information shared from the microchip inside Nikon's D- and G-series lenses.
As to the other metering options for the Nikon D50, center-weighted metering takes a light reading from the entire image area, but places the greatest emphasis on a circular area in the center. Spot metering in the D50 bases its reading from a 3.5mm circle centered on the active focus area (about 2.5% of the frame), excellent for quick measurements such as from a subject's face without having to move closer to the subject to get an accurate reading.
The Nikon D50's Exposure Compensation adjustment lightens or darkens the overall exposure anywhere from -5 to +5 EV units, in one-third step increments. It can also be adjusted to work in half step increments, but my own experience with digital cameras has been that half-step increments really aren't fine enough. Note though, that exposure compensation does not work in any of the camera's Digital Vari-Program modes. (Which I guess makes sense, since the whole point of those modes is to make photography automatic.)
An auto-bracketing feature takes three shots of the same subject with varying exposure values determined by either the photographer in manual mode or by the camera in all other modes. The exposure steps for bracketing can vary across a range of -2 to +2 EV (values are added to the already chosen exposure compensation value), in increments of either one-third or one-half. Through the Custom Settings menu, the Bracketing function can also be set to adjust white balance. (By default, both ambient and flash exposures are bracketed.)
I personally find automatic exposure bracketing a very useful feature on an SLR, although it does leave me with three times as many images to sort through on the computer later. As good as the D50's exposure system is, there's always a chance that I might prefer an exposure that's just a tad over or under the value the camera would choose on its own. Leaving my SLR (a D70, as it happens) set to continuous shooting mode, and the auto exposure bracketing turned on, I can very quickly grab three versions of each shot, so I'll be assured of having just the exposure I want when I get back home. The D70's auto bracketing options are a bit more sophisticated than those of the D50, in that it offers options to shoot either two or three frames in each bracket. I almost always use mine in 3-frame mode, and I suspect that 99.9% of the D50's users will never miss the 2-frame brackets of the D70.
The Nikon D50 also offers Sharpness, Tone Compensation (Contrast), and Hue adjustments, accessed through the "Optimize Image" option on the Shooting menu. For those familiar with the concept of the "color wheel", which arranges visible colors in a circle, Nikon's Hue adjustment will make sense: It offers a range of adjustment from -9 to +9 degrees around the color wheel. (A complete circuit of the wheel being 360 degrees.) If you don't carry a degree-calibrated color wheel in your head, I've provided the illustration of a color wheel at right. The dark bars show the total shift that the full 18 degree range of adjustment offered by the D50's hue control can produce. - As you can see, it's a fairly subtle adjustment. Note too, that the effect on any given color will depend on where that color is around the wheel. For red colors, a positive adjustment will shift the red toward orange, while a negative adjustment will shift it toward purple. For blues though, positive adjustments shift the color toward purple, while negative adjustments shift it toward cyan.
When reviewing images on the LCD monitor, you can call up a histogram and a blinking-highlight function to give you a complete readout on the exposure. These are both useful tools for examining your exposure in the camera instead of waiting to download images and then deciding to reshoot. The blinking highlights are the simplest to interpret - Just knock down the exposure a step or two if you see too many parts of your image blinking at you. The histogram is a bit more subtle, but once you've learned to read it, it's an excellent guide to knowing where you're at in terms of overall exposure.
Continuous Shooting Mode
Nikon claims that the D50's Continuous Shooting mode captures 2.5 frames per second, depending on the amount of image information and available SD space. Our own laboratory timing tests produced numbers that agreed very well with Nikon's 2.5 frame/second claim. (We measured 2.47 frames/second.) The number of shots you can capture continuously at this rate before having to wait for the memory card to catch up will vary with the file format you're saving to, the memory card speed, and even the subject content. (Shots of very plain objects with little detail compress better, so you can shoot more of them before the camera's internal memory buffer gets full.) With a deliberately hard-to-compress test target, we found that the D50 could shoot 4 RAW (NEF format) images, 16 large/fine JPEGs, or more than 100 small/basic JPEGs before its capture rate slowed. - A very good performance for a more or less "entry level" digital SLR.
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