SHARPNESS
Sharpness is the ability for a lens to resolve fine elements. It is typically measured in terms of black and white, line pairs per millimeter. Simply put, the finer the line pairs a lens can resolve, the sharper the lens.
Keep in mind that sharpness is only one characteristic of a lens and should not be the only thing considered when purchasing. Most of the time, sharpness is over emphasized. Nearly all Nikon lenses are sharp. The lenses reviewed here are all capable of achieving high levels of sharpness.
Each lens score was determined using a pair wise comparison, and on my experience, test and evaluation.
BOKEH
Bokeh is the quality of blur a lens can produce. It originates from a Japanese word that means confusion. Sometimes in photography, shallow depths of fields are desired, backgrounds are commonly blurred out to eliminate distractions from the subject. Bokeh is the quality of the blur a lens can render. The important word here is quality, not the amount a lens can blur.
Bokeh is a subjective matter. Typically a more Gaussian blur is preferred, where elements of the blur fade and transition smoothly. Contrary, an example of undesirable bokeh would be patternish blur with hard edges. This type of blur usually takes away from the subject.
BUILD QUALITY
The build quality describes a lens’ durability, reliability, and overall handling. Some of Nikon lenses are made in Japan, while others are made elsewhere in places like China and Thailand. Although Nikon’s level of quality is always a leader in the industry, regardless of where a lens is built, some lenses are built better than others.
Additionally, features such as vibration reduction and manual focus override (M/A) encompass the build score as well because the overall usability is enhanced. Newer lenses that provide these features along with robust designs usually score high in this category.
VALUE
When assessing value, price should be computed as an independent variable. Value encompasses all capabilities and performance of a lens and compares it to Nikon’s asking price. As of October 16, 2011, Nikon introduced a fixed point of sale pricing policy. Basically, online retailers cannot discount their lenses. Nikon will not ship if they see any discounting. This excludes open box items and of course the used market.
The value score for each lens is determined using a pair wise comparison of all the features and capabilities against each lens, and then divided by the price. This may be somewhat misleading and you should read the pricing section in my lens review before purchasing.
MEGA PIXEL COUNT
Most manufactures signify camera quality based on mega pixels. Although this is a method to draw consumer’s interests, mega pixels are not a good way to measure a camera’s overall optical quality. However, when strictly discussing high end DSLRs, mega pixels a more important factor. Nikon’s DSLR vary in megapixel and sensor size.
The number of mega pixels is commonly a tradeoff to the amount of noise tolerated for a given senor. The greater the mega pixel count, the more noise becomes limiting. Currently, Nikon’s DX sensors, at 16MP and greater, are pushing the limits, not just on noise, but on the ability for a lens to resolve each pixel. The larger FX sensors provide greater possibilities for growth.
ISO (SENSOR NOISE)
ISO is the level of sensitivity a camera’s sensor is to light. It is specified as a number based on the old film speeds. Although camera manufacturers continually push the levels of sensitivity with each new release, true ISO can be measured and defined for each model.
True ISO can be measured by analyzing the noise levels based on a signal to noise ratio (SNR). As ISO (more sensitivity to light) increases, SNR and dynamic range is reduced. By analyzing the RAW performance of a sensor at a specific SNR and dynamic range, ISO can be measured unbiased regardless of the stated specifications.
The ISO scores here reflect the camera’s raw sensor unbiased performance based on my testing and evaluation.
BUILD QUALITY
The scoring for a camera’s build quality is based on my experience using the camera, how it handles, its features, and its capabilities. Depending on the user base, Nikon produces a variety of cameras with different qualities of construction and features. The professional cameras are built to the highest level of durability, while the consumer cameras are built “good enough”. The nice part about the consumer cameras is weight and size is much less than the professional cameras, which make them more portable and inviting to bring along.
When considering the scores for build quality, the user base is taken into account. So the more inexpensive consumer models are not unjustly scored less.
VALUE
Assessing value is difficult when it comes to cameras. Photographers needs and market timing play a critical role in how a camera is valued. For example the D3X is overpriced. But this is possible because of market timing. The D800 provides a much better value and exceeds the performance of the D3X. But the D800 was not available for 3 years that the D3X was.
The value of a camera is measured on its performance, features and capability, while cost is treated as an independent variable. Value is independent of the class of camera, from pro to consumer level. The scoring for value encompasses all features, performance, and quality then divides it by cost.