The Truth about Contrast
Full Natural Contrast Range
Image Contrast in Zeiss Victory FL Binoculars and the Competition
Stephen Ingraham: Zeiss Birding and Naturalist Product Specialist
Critical observers sometimes comment on the difference in “contrast” between our Victory FLs and competitive models. Some users see the image in the Leica Ultravids and the Nikon HD binoculars, especially, as having higher contrast than our binoculars.
Some users will describe the difference not in terms of “contrast” but in terms of “brightness”. They may say the Leicas or the Nikons appear “brighter”. Close questioning and side-by-side comparisons almost always reveals that what they are seeing is a difference in apparent contrast, not in brightness.
Highly sophisticated observers also note that there seems to be a brightness difference between the Zeiss Victory FLs and the Ultravids and Nikons, with the FLs appearing slightly brighter in all situations, but having “lower contrast”, which is the same conclusion those who originally commented on “brightness” (as above) come to after a more careful, side-by-side comparison.
By “contrast”, in all cases, users are referring to the apparent difference between the light shades and the dark shades in the image, or how distinct the differences are. They are saying, in effect, that blacks are blacker and whites whiter through the competing binoculars: reds are redder, blues are bluer, greens are greener, etc.
In reality, the Zeiss Victory FL binoculars have a higher contrast range than the competition, while being brighter at the same time. We call our contrast range “full natural contrast.”
Think of working with an image in Photoshop or a similar image editing program. To increase apparent contrast, you could, if you were comfortable with the “levels dialog”, go to the levels control and pull the sliders in from both ends, reducing the number of different shades of dark and light by clipping off the ends, and then you would move the center slider slightly toward the light end of the spectrum (emphasizing dark shades at the expense of light shades). Visually it looks like this.
Full natural contrast range, with 256 levels of gray and of each color.
Clipping off the ends of the contrast range reduces the number of intermediate shades of gray and each color, but makes the steps between the adjacent shades “higher” and, to the unstudied eye, easier to see. You move the blackest blacks down into the dark grey area, the reddest reds down toward lighter reds, etc. and the whitest whites up into the light gray area, the lightest reds up into the pinks, etc. Then you slide the center to the left, emphasizing the darker shades, because our eyes interpret “darker” scenes as having higher contrast anyway.
Note, however that while the adjusted image of the bird looks more “contrasty” you have actually lost detail or information in both the lightest and darkest areas of the image, some of the subtle shades of color, and some brightness.
Sound familiar? Look for yourself. The difference in detail, color discrimination, and brightness is relatively easy to see in the images above.
What the Zeiss Victory FLs provide is, as near as is technically possible, a completely “natural” contrast range, wide open to both ends, the blackest blacks and the whitest whites, the reddest reds, the bluest blues, the greenest greens. We manage this without compromising the brightness of our image.
We could adjust our contrast range, by playing with our coatings and glass types, to produce the “high apparent contrast” image common in other optics…but why would we do that? Why would we sacrifice image detail in the dark and light areas of the image, color discrimination, and brightness overall, to achieve an increase in contrast that is only apparent?
In fact, over time, our users come to appreciate and expect the full natural contrast image that the Zeiss Victory FLs provide…so much so that other optics appear “clipped” and “dim” by comparison.
“Full Natural Contrast Range”: it is a Victory FL difference you can see.
Or at least that's the way I see it.