#1. "RE: Active D lighting" In response to Reply # 0
My understanding is that active d-lighting is intended to provide more light in the shadows while preventing highlights from being blown.
My wife's D40 tends to blow highlights in high contrast scenes in matrix metering mode. Fortunately she shoots only jpeg, so I tuned the camera's picture taking settings to low contrast and a default of -0.3 EV.
In the D7K the active d-lighting mode possibly combines those two controls together to achieve the same result - to decrease contrast and prevent clipped highlights. I have not checked, but I would not be surprised if active d-lighting is not applied to raw captures unless one uses Nikon's editing software.
#3. "RE: Active D lighting" In response to Reply # 1
St Petersburg, RU
Although the camera has excellent dynamic range being able to capture very dark to very bright in a single frame, the dynamic range of many scenes is wider than any camera can capture in a single frame. Active D-Lighting does two things to increase the apparent dynamic range. In exposure in Matrix metering mode, it lowers the sensitivity of the camera a little to assure that bright highlights are not over exposed when the subject is is properly exposed. But doing that darkens the shadows so the exposure curves are modified to increase detail in shadows while maintaining good exposure on the main subject. Since it is automatic when turned on, the degree of modification is influenced by how much the scene's dynamic range exceeds the camera's capture range. When looking at JPGs that have been taken with this feature turned on, you can see the effect in bright contrasty scenes but unless you are using Nikon post processing software, the only effect seen in RAW files is less high tone clipping and a slightly less exposed image. Adobe and other products do not read the modified tone curve that is embedded with the frame in RAW so do not get the advantage of Active D-Lighting other than highlight protection when processing raw files. Even in JPG mode, you should not see any difference if the scene is not featuring a very wide range of tones, in the brightest highlights to the deepest shadows. A lot of people turn it off but they also usually think the camera overexposes a little and adds a negative EC(exposure compensation) but they are losing usable dynamic range. If you are processing with Nikon software and shooting RAW, using Active D-Lighting makes a positive difference in wide DR scenes. If you are shooting in JPG, it renders the image with the full effects of Active D-Lighting when turned on. In the summer with a lot of outdoor shooting it can help a lot. Stan St Petersburg Russia
#4. "RE: Active D lighting" In response to Reply # 3
Stan, I shoot Jpeg with the D7100, and am not a highly accomplished photographer. I shoot mainly landscapes, birds and grandchildren. Generally aperture priority, single,focus point. Would you suggest that I set Active D in the on position as the default? Thanks, Fred
#5. "RE: Active D lighting" In response to Reply # 2
Thanks Stan that's ananswer I can get my head around. I'm thinking that in the situation that parts are getting blown out I can easily adjust ev, or, which is likely for me, to drop to shooting 5 brackets and adjusting in photomatix
#6. "RE: Active D lighting" In response to Reply # 4
St Petersburg, RU
I use it on my D7000 unless I know the scene is one that I have control of lighting, or one that I know does not exceed the DR of the camera. A lot of people do not like it but usually they are using software for post processing that does not read the information regarding the altered tone curve embedded in the file. For casual shooting, where it is possible to run into scenes that exceed the highlight headroom it can't hurt, the only impact on the image if using non-Nikon software is the highlights are protected more than if Active D-Lighting is off. Stan St Petersburg Russia
#7. "RE: Active D lighting" In response to Reply # 0
As I understand it, Active D-lighting is setting that enables a combination of exposure metering changes and post-capture, in-camera processing to preserve highlights while pulling up shadows in high-contrast scenes. Under the hood, it works something like this:
Depending on the strength of active D-lighting selected, the camera underexposes to preserve highlight detail in the sensor. (Saturated pixels can NEVER be recovered by any kind of digital magic.)
During post-capture processing, a contrast curve is applied that "pulls up" shadows by something on the order of a few stops, depending on the strength of the setting.
The net effect is a reduction in the contrast of the scene to make it appear more like you might have perceived it by eyeball.
You can do much the same thing manually post-capture. That is, you meter on the highlights and add +2 or so exposure compensation to keep the highlights to the right side (but not off the edge) of the histogram. In your image editing program, you then apply a curve to "pull up" (lighten) the shadows to make them visible.
In either method, the shadows are seriously underexposed, so you are going to see more noise in the shadow areas than there would be if they were exposed properly. When you pull up the shadows, you are essentially retrieving information from an image that is encoded by only a fraction of the 14 bits of intensity data available to the sensor, so there will be coarser gradations between colors and more noise and possible color splotching. If the underexposure is not too severe, say 2-3 stops or so, these unsatisfactory side effects are not very noticeable.
The advantage of using active D-lighting is that you can do this all in camera at the time of capture. The disadvantage is that you cede all control of the procedure to the camera algorithm. Depends on what you want. Having said that, it works pretty darn good. Don't turn it on unless you need it, otherwise it just degrades your image slightly when it is not necessary.
#8. "RE: Active D lighting" In response to Reply # 7
>The disadvantage is that you cede all control of the procedure to the camera algorithm. >
You only cede control if you are shooting JPG. In RAW, using Nikon software to process, you can adjust the level of ADL or turn is off. There is some effect on the base exposure at all but the LOW in-camera setting. I leave my camera on low, except in controlled lighting situations. That way you can still adjust in post. If you don't have ADL on in-camera, the adjustment is not even available in CNX so you can't apply it retroactively.
Again, if shooting JPGs the effect is "baked in". If using other than Nikon software, don't bother with ADL at all.
#9. "RE: Active D lighting" In response to Reply # 0
Like Mick, I use ADL Low so there is no adjustment to exposure but I can adjust the curve later in Nikon software if desired.
I've done a good bit of testing related to ADL. The exposure adjustments are Low = 0, Med = -0.3, High = -0.7, and Very High = -1.0. So if you choose ADL Low there is no adjustment to exposure.
The other aspect of ADL is a curve applied to protect highlights and recover shadows. Part of this adjustment is to neutralize the exposure. This is a complex curve that I found very difficult to replicate in post processing. The amount of curve depends on the specific area of the image and makes selective edits rather than global edits.
You really want ADL for high contrast scenes where there are going to be blown highlights and you are struggling for some shadow detail. If you are shooting JPEG, or using Nikon and other programs that honor camera settings, ADL is useful. If you are shooting RAW and not using Nikon products for editing, the I would only use ADL Low or turn it off. The reason is the exposure adjustment would be applied, but not the curve unless you use Nikon software, so with all but ADL Low you just get an underexposed image.
The reason for using ADL Low is that it does no harm and preserves the ability to take advantage of ADL adjustments in the future as software permits.