Sensitivity is a Photoshoot™ function whose settings allow the “pushing” of the “emulsion speed”. Since we don’t have an emulsion and we’re really altering the sensitivity of the sensor, we’ve understandably called the setting Sensitivity. Make the CCD chip more sensitive to light by choosing settings other than Normal. Pull down under the menu bar atop the monitor display, Setup>Sensitivity> to select any of the settings: Normal, +.50. +1.5, and +2.0.
Use these settings to modify the exposure index of the camera. Notice as you increase the sensitivity of the camera, the noise generation will slightly increase. Test each setting to judge the effect. You might want to test each setting along with each shutter speed (Setup>Exposure) with dark correct disabled. The result is not unlike pushed 2475 Recording film, but the pattern to the grain is more even.
Sensitivity also has another useful application. Use Sensitivity to modify the focus brightness. When you can’t quite get enough illumination on set for focusing, try pushing up the sensitivity, you’ll be pleasantly surprised at the gain in brightness. Do not forget to drop it back to normal for the actual capture.
Sensitivity has another important function, it reduces blooming in highlights. Do not expect to use Sensitivity to allow shoddy technique if you’re indiscriminately pounding gridspots on highly reflective surfaces like chromium plated cookware. If you have a high value that is blooming, try to tame the light source first. If that does not work, move the Sensitivity from Normal to +.50. Make the aperture correction and evaluate the area that is blooming. If the +.50 setting does not sufficiently tame the blooming area, try +1.0. If +1.0 does not work, you might be nowhere close to properly lit; go back to the beginning and see if there is another way to light the scene you’re trying to render.
Blooming is an interesting phenomenon in digital capture. It is a result of overexposing the chip. Each pixel well (a pixel well is like a bucket, it only holds so much and any more added to the bucket will overflow into the surrounding buckets. Most professional area array chips have blooming control, but the blooming control only works on one axis, left-to-right. That means the overspilling electrons from a saturated pixel well will spill to the top and bottom pixels wells. Blooming is visible as green colored pixels adjacent (above and below) to a highlight. The blooming artifacts in our T2 are green because in our current filtration scheme, the green filter has the least density of the tricolor set we use so it is the green color/channel that blooms first. If you overexpose the scene so brutally that all of the colors bloom you may get a very strange looking image, not unlike a meter capture gone berserk. We most often see these captures when new T2 shooters shoot black objects on white surfaces (destined for outlining). If the object isn’t lit right, the shooter will start opening up the aperture with the idea of “opening up” the black object, which will open up. The white surface opens up too, sometimes several stops past saturation of our heaviest filter, 47B.
To consider more loosely this blooming phenomenon, let’s go back to filmthink for a minute. If, for instance, you pull a Polaroid and the highlight is completely blown, what do you do? Lots of digiphiles and pseudo scientist types might jump up and down proclaiming inferior blooming control when it happens on a digital capture device and will suggest you have the wrong camera. Some will denigrate camera A and say camera B is the only one that’s worth buying. Does that remind you of people preaching the superior merits of such and such a film & developer as the only true combo? If that Polaroid has blown highlights, we trim the light or the aperture. Do the same with digital. While each of the professional level cameras has slightly different blooming control, all are workable and useable cameras if wielded by a competent professional photographer.