D7100 'streaking'

Started Apr 7, 2013 | Discussions thread
_sem_
Veteran MemberPosts: 4,207
Like?
Re: D7100 'streaking' - doesn't look like blooming or flare
In reply to krikman, Apr 9, 2013

krikman wrote:

_sem_ wrote:

krikman wrote:

My whole point was in-camera ADL work. I can strongly conclude from my D300s behaviour that in-camera ADL works selective. It not just compresses data range but lengthen exposition for darks and somehow restores lights. At levels that impossible for written RAW data. All this required some 'area recognition' for dark and light regions.

Don't let the impression fool you. ADL is a black-box magic packaged thing but is no black magic. Several raw converters and HDR tonemapping programs let you do similar rendering, although not exactly the same, mainly because ADL does not disclose which elementary operations (fill-light, brightness, contrast, local contrast...) it applies and to which degree - there seems to be a sort of a scene-recognition indeed that sets the values, and of course it is totally undocumented. But the main operation is certainly the "fill-light" (shadows protection slider in NX), which was once done via exposure mask (USM) in Photoshop before it got automated.

Notice LR4/ACR allow one to boost shadows much more than VNX2 with ADL.

In my tests on D300s ADL max makes 2x longer exposition with better highligths and potent to recover. I feel magic here...

I guess you were not careful enough. ADL typically exposes raw data up to about a stop lower than non-ADL (but this is not evident in the in-camera and CNX/VNX previews). This may indeed result in a stop less blown highlights if you'd blow them with the original setting. But this is assuming that you don't watch the histogram and adjust exposure as to not blow the highlights. If you do, you're likely to end up with captures made at about 2 stops less than what is recoverable from raw with highlights maxed to the right (in RawDigger raw histogram), which results in the lifted shadows being noisier than they'd need to be. With ADL, the image indeed looks brighter, despite the raw data being exposed lower, due to the processing applied instantly, and the same processing is also applied upon opening in VNX2/CNX2. Some 3rd-party converters may show the lower exposure - but some may normalize exposure (Picasa) or apply a complex rendering preset (Adobe).

Get the first the free VNX and Raw Therapee, then trials of CNX, LR4, DxO OP (well, you don't need all at once). Play with the sliders and watch the histograms, and eventually you'll get the impression what is going on. There is one interesting exercise: open images with/without ADL in CNX2/VNX2, drag the exposure slider and watch the histogram. Then repeat the exercise with ADL replaced by the fill-light. Mind you can only change the ADL level (the post-processing part of it) in CNX2 and only if it was on while shooting. VNX1.5 used to discard ADL if the Exposure Compensation or maybe some other sliders were moved; I hear this is no longer the case with VNX2.

Reply   Reply with quote   Complain
Post (hide subjects)Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark post MMy threads
Color scheme? Blue / Yellow