{"id":10724,"date":"2026-07-28T09:54:57","date_gmt":"2026-07-28T16:54:57","guid":{"rendered":"https:\/\/zxi.mytechroad.com\/blog\/?p=10724"},"modified":"2026-07-28T09:55:50","modified_gmt":"2026-07-28T16:55:50","slug":"log-ettr-sdr-vs-hdr","status":"publish","type":"post","link":"https:\/\/zxi.mytechroad.com\/blog\/photography\/log-ettr-sdr-vs-hdr\/","title":{"rendered":"\u4e3a\u4ec0\u4e48 N-Log \u505a Rec.709 \u66f4\u9700\u8981 ETTR\uff0c\u800c\u505a HDR\/HLG \u53cd\u800c\u4e0d\u4e00\u5b9a"},"content":{"rendered":"\n
\"\"<\/a><\/figure>\n\n\n\n

\u73b0\u4ee3\u624b\u673a\u4e0a\u7684 SDR \u5df2\u7ecf\u4e0d\u662f\u4f20\u7edf\u610f\u4e49\u4e0a\u7684 100 nits SDR \u4e86\u3002\u5f88\u591a OLED \u624b\u673a\u3001\u5e73\u677f\u548c XDR \u5c4f\u5e55\u5728\u64ad\u653e\u666e\u901a SDR \u5185\u5bb9\u65f6\uff0c\u4e5f\u80fd\u628a\u767d\u573a\u6216\u9ad8\u4eae UI \u63a8\u5230\u51e0\u767e\u751a\u81f3 1000 nits\u3002\u4e5f\u5c31\u662f\u8bf4\uff0c\u4e00\u4e2a Rec.709 \u89c6\u9891\u867d\u7136\u6280\u672f\u4e0a\u4ecd\u662f SDR\uff0c\u4f46\u5b83\u5728\u771f\u5b9e\u89c2\u770b\u73af\u5883\u91cc\u7684\u4eae\u5ea6\uff0c\u65e9\u5c31\u548c\u201c100 nits \u53c2\u8003\u76d1\u89c6\u5668\u201d\u76f8\u5dee\u5f88\u8fdc\u3002\u8fd9\u4e2a\u53d8\u5316\u4f1a\u76f4\u63a5\u5f71\u54cd\u6211\u4eec\u600e\u4e48\u66dd\u5149 N-Log\u3002<\/p>\n\n\n\n

\u6211\u7528 Nikon \u5b98\u65b9 N-Log \u5230 Rec.709\/BT.1886 LUT \u505a\u4e86\u4e00\u7ec4\u8ba1\u7b97\uff0c\u5e76\u548c\u4e00\u4e2a\u4e0d\u7ecf\u8fc7 LUT \u7684 HLG \u6280\u672f\u8f6c\u6362\u6bd4\u8f83\u3002\u4e24\u8fb9\u90fd\u5047\u8bbe\u663e\u793a\u5668\u5cf0\u503c\u662f 1000 nits\uff1b\u62cd\u6444\u7aef\u5047\u8bbe\u4e2d\u7070\u66dd\u5149\u5230 35 IRE\uff0cHLG \u6f2b\u5c04\u767d\u951a\u5b9a\u5230 203 nits\u3002<\/p>\n\n\n\n

\u7ed3\u679c\u5f88\u8bf4\u660e\u95ee\u9898\u3002\u4e2d\u7070 0 stop \u65f6\uff0cN-Log \u7ecf\u8fc7 Rec.709 LUT \u540e\u662f 42.07 IRE\uff0c\u5728 1000 nits SDR \u663e\u793a\u6a21\u578b\u4e0b\u7ea6\u4e3a 125 nits\uff1b\u540c\u4e00\u4e2a\u8f93\u5165\u505a direct HLG \u53ea\u6709\u7ea6 29 nits\u3002\u4e5f\u5c31\u662f\u8bf4\uff0cRec.709 \u7248\u672c\u7684\u4e2d\u7070\u6bd4 HLG \u4eae\u5927\u7ea6 2.09 stops\u3002\u518d\u770b -2 stops \u7684\u6697\u90e8\uff0cRec.709 \u662f 15.4 nits\uff0cHLG \u662f 5.6 nits\uff0c\u524d\u8005\u4ecd\u7136\u4eae\u7ea6 1.47 stops\u3002<\/p>\n\n\n\n

Stops<\/th>N-Log IRE<\/th>Rec.709 SDR nits<\/th>Direct HLG nits<\/th>Rec.709 vs HLG<\/th><\/tr><\/thead>
-4<\/td>16.49<\/td>1.6<\/td>1.1<\/td>+0.61 stops<\/td><\/tr>
-2<\/td>23.00<\/td>15.4<\/td>5.6<\/td>+1.47 stops<\/td><\/tr>
0<\/td>35.00<\/td>125.2<\/td>29.4<\/td>+2.09 stops<\/td><\/tr>
+2.32<\/td>57.20<\/td>545.5<\/td>203.0<\/td>+1.43 stops<\/td><\/tr>
+4<\/td>74.26<\/td>786.7<\/td>819.7<\/td>-0.06 stops<\/td><\/tr>
+5<\/td>84.42<\/td>874.2<\/td>1000.0<\/td>-0.19 stops<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

\u8fd9\u5c31\u662f\u4e3a\u4ec0\u4e48 N-Log \u8fd8\u539f\u5230 709 \u540e\uff0c\u6697\u90e8\u566a\u70b9\u7ecf\u5e38\u663e\u5f97\u7279\u522b\u591a\u3002\u566a\u70b9\u4e0d\u662f LUT \u201c\u51ed\u7a7a\u5236\u9020\u201d\u7684\uff0c\u800c\u662f\u62cd\u6444\u65f6\u843d\u5728\u4f4e\u7801\u503c\u3001\u4f4e\u4fe1\u566a\u6bd4\u533a\u57df\u91cc\u7684\u6697\u90e8\u4fe1\u606f\uff0c\u88ab Rec.709 tone curve \u548c\u73b0\u4ee3\u9ad8\u4eae SDR \u5c4f\u5e55\u4e00\u8d77\u62ac\u5230\u4e86\u5f88\u5bb9\u6613\u770b\u89c1\u7684\u4f4d\u7f6e\u3002\u4ee5\u524d 100 nits SDR \u65f6\u4ee3\uff0c\u6697\u90e8\u53ef\u80fd\u85cf\u5728\u51e0 nit \u91cc\uff1b\u73b0\u5728\u5b83\u53ef\u80fd\u88ab\u663e\u793a\u5230\u5341\u51e0\u3001\u51e0\u5341 nit\uff0c\u89c2\u4f17\u81ea\u7136\u66f4\u5bb9\u6613\u770b\u5230\u810f\u3001\u6d6e\u3001\u5f69\u566a\u548c\u538b\u7f29\u75d5\u8ff9\u3002<\/p>\n\n\n\n

\u6240\u4ee5\u5982\u679c\u6700\u7ec8\u76ee\u6807\u662f Rec.709 SDR\uff0c\u5c24\u5176\u662f\u7ed9\u624b\u673a\u3001OLED \u7535\u89c6\u3001XDR \u5c4f\u5e55\u89c2\u770b\uff0cN-Log \u5f80\u5f80\u66f4\u9700\u8981 ETTR\u3002ETTR \u7684\u76ee\u7684\u4e0d\u662f\u8ba9\u6210\u7247\u66f4\u4eae\uff0c\u800c\u662f\u5728\u4e0d\u526a\u6389\u91cd\u8981\u9ad8\u5149\u7684\u524d\u63d0\u4e0b\uff0c\u628a\u4e3b\u4f53\u3001\u4e2d\u95f4\u8c03\u548c\u6697\u90e8\u5c3d\u91cf\u653e\u5230\u66f4\u9ad8\u3001\u66f4\u5e72\u51c0\u7684\u7f16\u7801\u533a\u57df\u3002\u540e\u671f\u518d\u7528 LUT \u6216\u8c03\u8272\u538b\u56de\u6b63\u5e38\u4eae\u5ea6\u65f6\uff0c\u566a\u58f0\u4e0d\u4f1a\u88ab\u653e\u5927\u5f97\u90a3\u4e48\u96be\u770b\u3002<\/p>\n\n\n\n

HDR\/HLG \u7684\u903b\u8f91\u4e0d\u4e00\u6837\u3002HLG \u6280\u672f\u8f6c\u6362\u4f1a\u628a\u4e2d\u7070\u653e\u5f97\u66f4\u4f4e\uff0c\u7ed9\u9ad8\u5149\u4fdd\u7559\u7a7a\u95f4\u3002\u8868\u683c\u91cc +2.32 stops \u7684\u6f2b\u5c04\u767d\u662f 203 nits\uff0c\u5230\u4e86 +4 stops\uff0cHLG \u5df2\u7ecf\u7ea6 820 nits\uff0c\u800c Rec.709 SDR \u7ea6 787 nits\uff1b+5 \u548c +6 stops \u65f6 HLG \u76f4\u63a5\u5230 1000 nits\uff0cRec.709 \u5219\u88ab\u538b\u5728 874 \u548c 927 nits \u9644\u8fd1\u3002HDR \u7684\u4ef7\u503c\u5c31\u5728\u8fd9\u91cc\uff1a\u4e0d\u662f\u628a\u6574\u5f20\u753b\u9762\u62ac\u4eae\uff0c\u800c\u662f\u4fdd\u7559\u771f\u5b9e\u5149\u6bd4\uff0c\u8ba9\u4eae\u7684\u4e1c\u897f\u771f\u7684\u4eae\u3002<\/p>\n\n\n\n

\u56e0\u6b64\uff0c\u505a HDR \u65f6\u76f2\u76ee ETTR \u53cd\u800c\u53ef\u80fd\u6709\u5bb3\u3002\u4f60\u628a N-Log \u6574\u4f53\u5f80\u53f3\u63a8\uff0c\u786e\u5b9e\u80fd\u8ba9\u6697\u90e8\u66f4\u5e72\u51c0\uff0c\u4f46\u4e5f\u66f4\u5bb9\u6613\u628a\u5929\u7a7a\u3001\u706f\u5149\u3001\u53cd\u5c04\u548c\u76ae\u80a4\u9ad8\u5149\u63a8\u5230 HLG \u9876\u90e8\uff0c\u5931\u53bb HDR \u6700\u73cd\u8d35\u7684\u9ad8\u5149\u5c42\u6b21\u3002HDR \u4ea4\u4ed8\u66f4\u5e94\u8be5\u4f18\u5148\u4fdd\u62a4\u9ad8\u5149\u3001\u4fdd\u6301\u81ea\u7136\u4e2d\u7070\uff0c\u800c\u4e0d\u662f\u5355\u7eaf\u8ffd\u6c42\u6ce2\u5f62\u56fe\u201c\u7528\u6ee1\u201d\u3002<\/p>\n\n\n\n

\u4e00\u53e5\u8bdd\u603b\u7ed3\uff1aRec.709 SDR \u5728\u73b0\u4ee3 1000 nits \u5c4f\u5e55\u4e0a\u4f1a\u628a N-Log \u7684\u6697\u90e8\u548c\u4e2d\u95f4\u8c03\u663e\u793a\u5f97\u5f88\u4eae\uff0c\u6240\u4ee5\u66f4\u9700\u8981 ETTR \u6765\u6362\u4fe1\u566a\u6bd4\uff1bHDR\/HLG \u5219\u628a\u4e2d\u7070\u653e\u4f4e\u3001\u628a\u7a7a\u95f4\u7559\u7ed9\u9ad8\u5149\uff0c\u6240\u4ee5\u4e0d\u4e00\u5b9a\u9700\u8981\u6fc0\u8fdb ETTR\uff0c\u9664\u975e\u573a\u666f\u672c\u8eab\u6ca1\u6709\u91cd\u8981\u9ad8\u5149\u53ef\u5931\u53bb\u3002<\/p>\n\n\n\n

Why N-Log Needs More ETTR for Rec.709, but Not Necessarily for HDR\/HLG<\/h1>\n\n\n\n

Modern phone SDR is no longer the old 100-nit SDR we used to imagine. Many OLED phones, tablets, and XDR displays can show ordinary SDR content at several hundred nits, sometimes close to 1000 nits. So even if a video is technically Rec.709 SDR, its real viewing brightness can be far beyond the traditional 100-nit reference. That changes how we should expose N-Log.<\/p>\n\n\n\n

I compared Nikon’s official N-Log to Rec.709\/BT.1886 LUT against a direct technical HLG conversion. Both are viewed on a 1000-nit display. The exposure assumption is middle gray at 35 IRE, with HLG diffuse white anchored at 203 nits.<\/p>\n\n\n\n

The numbers are revealing. At 0 stop middle gray, the Nikon Rec.709 LUT outputs 42.07 IRE, which becomes about 125 nits on a 1000-nit SDR display model. The direct HLG conversion for the same input is only about 29 nits. Rec.709 middle gray is therefore about 2.09 stops brighter than HLG. At -2 stops, Rec.709 is about 15.4 nits, while HLG is about 5.6 nits, still a 1.47-stop lift.<\/p>\n\n\n\n

This is why N-Log can look noisy after being restored to Rec.709. The LUT is not magically creating noise. It is taking shadow information that was recorded in low-code-value, low-SNR regions and lifting it into a much more visible display range. In the old 100-nit SDR world, those shadows might have stayed hidden at only a few nits. On a modern bright SDR screen, they may sit at tens of nits, where noise, chroma crawl, and compression artifacts become obvious.<\/p>\n\n\n\n

So for a Rec.709 SDR delivery, especially for phones, OLED TVs, and XDR displays, N-Log often benefits from ETTR. The goal is not to make the final image brighter. The goal is to record the subject, midtones, and shadows in cleaner code values without clipping important highlights. Then, when the image is brought back down in grading, the noise floor is not amplified as aggressively.<\/p>\n\n\n\n

HDR\/HLG works differently. A technical HLG conversion keeps middle gray lower and saves room for highlights. In the table, diffuse white at +2.32 stops is 203 nits. By +4 stops, HLG reaches about 820 nits while Rec.709 SDR is about 787 nits. At +5 and +6 stops, HLG hits 1000 nits, while Rec.709 is compressed around 874 and 927 nits. That is the point of HDR: not making everything bright, but preserving scene contrast so bright things can actually be bright.<\/p>\n\n\n\n

This is why aggressive ETTR can be counterproductive for HDR. It may clean up shadows, but it also pushes skies, lamps, reflections, and skin highlights closer to the top of the HLG range, where highlight separation can be lost. For HDR delivery, the priority is often highlight protection and natural midtone placement, not simply filling the waveform.<\/p>\n\n\n\n

In short: modern 1000-nit SDR makes Rec.709 N-Log shadows and midtones very visible, so ETTR is often valuable for noise control. HDR\/HLG keeps middle gray lower and reserves headroom for highlights, so it does not always need aggressive ETTR unless the scene has no important highlights to protect.<\/p>\n","protected":false},"excerpt":{"rendered":"

\u73b0\u4ee3\u624b\u673a\u4e0a\u7684 SDR \u5df2\u7ecf\u4e0d\u662f\u4f20\u7edf\u610f\u4e49\u4e0a\u7684 100 nits SDR \u4e86\u3002\u5f88\u591a OLED \u624b\u673a\u3001\u5e73\u677f\u548c XDR \u5c4f\u5e55\u5728\u64ad\u653e\u666e\u901a SDR \u5185\u5bb9\u65f6\uff0c\u4e5f\u80fd\u628a\u767d\u573a\u6216\u9ad8\u4eae UI \u63a8\u5230\u51e0\u767e\u751a\u81f3 1000 nits\u3002\u4e5f\u5c31\u662f\u8bf4\uff0c\u4e00\u4e2a Rec.709 \u89c6\u9891\u867d\u7136\u6280\u672f\u4e0a\u4ecd\u662f SDR\uff0c\u4f46\u5b83\u5728\u771f\u5b9e\u89c2\u770b\u73af\u5883\u91cc\u7684\u4eae\u5ea6\uff0c\u65e9\u5c31\u548c\u201c100 nits \u53c2\u8003\u76d1\u89c6\u5668\u201d\u76f8\u5dee\u5f88\u8fdc\u3002\u8fd9\u4e2a\u53d8\u5316\u4f1a\u76f4\u63a5\u5f71\u54cd\u6211\u4eec\u600e\u4e48\u66dd\u5149 N-Log\u3002 \u6211\u7528 Nikon…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[799],"tags":[1031,807,802,853,851,808],"class_list":["post-10724","post","type-post","status-publish","format-standard","hentry","category-photography","tag-ettr","tag-hdr","tag-hlg","tag-n-log","tag-rec-709","tag-sdr","entry","simple"],"_links":{"self":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/10724","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/comments?post=10724"}],"version-history":[{"count":1,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/10724\/revisions"}],"predecessor-version":[{"id":10726,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/10724\/revisions\/10726"}],"wp:attachment":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/media?parent=10724"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/categories?post=10724"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/tags?post=10724"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}