V
Vivek
Guest
Tim, i would like to know the filters used. i have all sorts of polarizers (among a cubic meter box of various filters), including IR and UV polarizers.
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I believe Amin is trying something similar. I'm off to the Adriatic next week, blue seas a plenty, and will (nervously) pack a polariser too...Thanks. I still have a D300 somewhere and i am positive that i can produce 14bit NEF files that would show similar effects. If i locate the Nikon gear, i will shoot some and make the NEFs available.
Well, water does reflect what we perceive as a 'white' reflection, so it will reflect through a variety of wavelengths. It's not a perfectly uniform reflector, but not too bad, actually.Perhaps I am being naive, but is it not the case that water reflections have only a limited palette to start with, the more so if they are polarised?
Erik, whilst I respect your opinions may I yet again draw attention to the very carefully written post that you quote but do not address in which I make it really very, extremely clear, that the raw file itself, to which I have access, as does Iliah, his colleague, and of course Lloyd himself, is posterised. Iliah says so, so does everyone who has seen it. Yes it's made worse by colour space mapping but Iliah is very very clear that a good JPEG could not be made from that file, whatever form of colour space mapping or other PP juju, was performed. In other words the posterisation is beyond redemption. It's not the end of the world, the sky is not falling in, the earth keeps turning and the camera will make millions of exceptionally fine images and I am certain that you will enjoy it very much. But that particular image was posterised, before Lloyd even opened the file, beyond any hope of redemption.
As for 'good science' and sharing the file, he has shared it with two of the best brains in the business. Scientists share with relevant peers first, not necessarily with a whole lot of people they don't know the credentials of. In any event, Lloyd, with whom I have no affiliation whatsoever other than as a subscriber, is not a scientist, he's a reviewer and he will live and die by the quality of his reviews.
So in the final analysis it really doesn't matter, at all, that colour space mapping makes it worse. A dead horse is dead.
:deadhorse::deadhorse::deadhorse:
Whilst I respect everyones opinion (at least those whose opinions I respect anyway) I do wish to offer an alternative to the 'posterised' diagnosis.Hi Tim,
I also respect your opinion.
Best regards
Erik
Thanks Iliah - Doing my own tests with a blue filter at the moment..Dear Tim,
You can use RPP (current version is http://www.raw-photo-processor.com/RPP/RPP64_1748Beta.zip), switch off the colour management (output to raw RGB tiff, the choice is to the left of the Save button), set it to gamma 2.2 curve Curve type, and use the low acutance AHDMF demosaicing. If the result is visibly posterized, it is from raw and from nothing else.
Edit: that is, visibly posterized in per-channel view, to eliminate monitor issues and colour management completely.
The Star trail compression artefacts (example image available for download in RAWDigger site) are quite visible in my calibrated 27" screen at 50% viewing and modest (and quite necessary) push on the file. The gradient on the background gets broken so the artefacts are quite visible.
The same photographer has posted a few more samples into our local forum that show artefacting on quite small magnifications. For example very very low res pic (1100 pixels on long edge) behind link below shows the artefacts if one zooms to 200% with browser. High quality A4/A3 print would be quaranteed to show the same thing; the photographer who took the pics has printed them on different sizes and confirms this.
http://digikamera.net/keskus/viewtopic.php?t=12734522&start=0&sid=ece7ec3c79ce2f3d70b8f48682ba6a87
1) We cannot be sure how good a result would a full 14-bit file without any gapping give us since we do not have one. But the logic is quite simple: too few values in the Sony file ==> posterization. Now if we get a bit over 2x values common sense should tell us there is at least less posterization, right?
2) LLoyd shoots with only CA correction on. Also, if one is using Adobe products the CA correction cannot be avoided. I shoot with all corrections "off" in camera. If I import a pic taken with Batis 85/1.8 into Lightroom CC the software automatically extracts a build in CA correction profile from the RAW File and applies it, even if I do not check "Enable profile corrections"
The other gaps (the few nearly completely nonpopulated values inside the Red chunk in histogram) on the file were quite strange; they were actually present in all color channels in exact same spot so if this is caused by any lens correction something is obviously broken with that.
Personally, I do not think A7R II has anything nearly what one would call a real "posterization issue". But this is one example where a full, 14-bit lossless compressed, RAW would a bit tiny bit more robust. Throwing away data during compression/processing just is not a free lunch.
Again, I think these discussions have been very positive: I've learned new things about exposure & color filtering during exposure and color management I can potentially use in the future. My E Mount cameras (currently own 3 and an RX100 MKIII) are no worse than they were before these discoveries.
The star trail example was there just to answer the question "will this show up in a reasonable sized print?". It is often falsely claimed (in that other forum where shooting the messenger is the number one pastime ) that you need huge print or 200% magnification to see the artefacts when they can in fact show up in a small web size photo. The good thing is that outside star trails and few few very specific cases (I have a few high-DR night photos, well lit bridge on near-black background that are somewhat PP-limited by the artefacts) it is very very hard for anything to surface. But still, lossless compression (and non-filtered 13/14-bit bulb) pleaseHi,
The star tracks artefacts are caused by the "delta compression", no questions about that. It has nothing to do with combing, gaps, tonal curve etc. You take out the delta compression and those artefacts go away.
Yes, Sony should remove the delta compression.