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Understanding Active D-Lighting

Anthony Beach , Feb 25, 2008; 01:41 a.m.

Active D-Lighting (ADL) should not be confused with D-Lighting. ADL is essentially an image optimization setting that utilizes the Expeed image processor in the newest Nikon DSLRs; whereas D-Lighting is an editing tool in Nikon Capture and Nikon NX -- there is a difference between them and ADL appears to be superior to D-Lighting (although I will leave that to others to decide and analyze, and any contributions in this thread regarding that would be most welcome by me).

ADL can be turned off in NX and is ignored by Capture One (again, I will leave it to others to do their own tests to determine how other RAW converters handle ADL files, but please pay attention to the rest of my post before contributing your conclusions -- specifically as regards metering). Inexplicably to me, ADL cannot be turned on in NX; so it is a "use it or lose it" option. Turning off ADL in NX is tricky though, you need to go to the Active D-Lighting tab in NX (not to be confused with the D-Lighting tab) and select "Off" and leave that tab checked, if you uncheck that tab NX continues to use your ADL setting and disables contrast and brightness controls in the Picture Modes.

Something I really don't understand right now is why ADL cannot simply be turned on in NX. What confuses me is that ADL can be adjusted in NX and turned up or down, it can be turned off, but it cannot be turned on. This might suggest to some that ADL does something to the RAW data, but I have looked closely at the files and there is no difference between ADL and non-ADL captures.

Another peculiarity of ADL is the role it plays in metering. On my D300 ADL changes the behavior of Matrix metering and as ADL is turned up the camera decreases the exposure value (EV); Normal ADL decreased the EV by 1/3 of a stop and High ADL decreased the EV by 2/3 of a stop. This explains the widely reported increase in noise using ADL, as it is attempting to preserve highlights by essentially underexposing and correspondingly raising shadows. Using Center weighted metering EVs were constant at all ADL settings (Low, Normal, and High), so obviously the camera is using ADL and Matrix metering together to determine what Nikon thinks is the ideal EV.

My recommendation for using ADL then is to use it set to Low in conjunction with Center weighted metering (I set my D300 to "average" at b5 in the menu). This will allow you to use ADL in NX, to boost it or turn it off, and this will give you the most accurate histogram from the embedded JPEG. Of course, especially with high dynamic range (DR) scenes, it is best to shoot RAW as that affords about one extra stop of exposure latitude (that amounts to an extra stop of DR).

For better understanding how much exposure latitude the D300 gives you can check this out: http://photo.net/bboard/q-and-a-fetch-msg?msg_id=00OPW5 The D300 is practically immune from overexposing a RAW shot with no exposure compensation (EC) using Center weighted metering. For my own settings which give me the best information about how my D300 is exposing, you can find my settings here: http://photo.net/bboard/q-and-a-fetch-msg?msg_id=00OJid


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Walter Schroeder , Feb 25, 2008; 02:48 a.m.

Anthony good idea to start a serious discussion about this topic. If it is all done in software after the data were collected why should the in camera software do a better job than software running on a PC? I noticed that I can apply ADL in camera after the fact. A clear sign that data collection is not part of it. So perhaps at best a thing of convenience for in camera jpg or just marketing hype? (This last comment will give you 30+ comments to this thread^^)

I would not interpret anything into what NX can do or not - I gave up on this a long time ago. Considering the quality of the UI it could just relate to a bad lunch of the programmer^^.

peter Koralis , Feb 25, 2008; 03:08 a.m.

Juan Parménides , Feb 25, 2008; 04:17 a.m.

Thanks for the links. Very useful information to understand ADL.

Juan Parmenides

Elliot Bernstein , Feb 25, 2008; 06:48 a.m.

Anthony, the article Peter links to states "Its main reason (referring to active D-Lighting) for existence is to help combat dark shadows" which has been my understanding as well. While I have not noticed much difference using ADL (I have not really tested more than casually), I have found turning the contrast lower achieves the desired result. Can you explain the differences between the two approaches? Do you have any sample photos you can post?

And thanks for the settings link/tips!

Bruce Margolis , Feb 25, 2008; 07:21 a.m.

"Something I really don't understand right now is why ADL cannot simply be turned on in NX."

Here's my understanding from a Nikon rep last week.....

Active-D Lighting can't be 'turned on' in NX because only the newer Nikon cameras support it. In other words, you can't 'turn it on' for shots from a D70 or whatever.

The rep told me (as I have heard before) that NX is the only software that picks up all the data from the newer bodies because of their RAW conversion algorithms. I suspect this relates to ADL. I haven't tested this myself. Maybe it's true, maybe hype.

His suggestion was to use NX to -- at the very least -- convert RAW files to TIFFs, then use whatever processing software you like. Obviously he uses NX and says you don't need anything else, though he did have a Nik plug-in.

Again, I haven't tried this yet but it might be interesting to see if there really is a difference in preserving data using NX vs something else like PS.

Wayne Cornell , Feb 25, 2008; 10:26 a.m.

I have turned off Active-D (and sharpening) on the D300 after discovering they slow down NX processing considerably. I apply them after the image is loaded in NX. I Nikon's programmers ever get NX back to Ver. 1.2 speed I'll probably turn on Active-D on the camera.

Ellis Vener , Feb 25, 2008; 11:40 a.m.

Active D-Lighting samples. Shot with a D3 and NEFS processed in Lightroom v1.3.1

Robert Hooper , Feb 25, 2008; 12:15 p.m.

I did not see it mentioned above so I will add that there is still another D-Lighting which is available in at least the D80 body within the Retouch Menu.

From the D80 manual, page 110:

"D-lighting brightens shadows making it ideal for dark or back-lit photographs. Press the multi selector up or down to choose the amount of correction performed. The effect can be previewed in the edit display. Press OK to copy the photograph and return to the retouch menu or full frame play back."

The D80 makes an edited copy of the original image, of course leaving the original image unadulterated.

Sounds like something fun to play with on a long train trips or during extended airport layovers. ;<)

Anthony Beach , Feb 25, 2008; 02:17 p.m.

"I noticed that I can apply ADL in camera after the fact."

Hi Walter,

From what I can tell ADL can only be applied to JPEGs coming out of the camera after the fact, even when the original shot was RAW. On the other hand, if you shoot using ADL in RAW, then you can turn it off or adjust it in NX prior to conversion.

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