{"id":10133,"date":"2024-07-08T22:02:45","date_gmt":"2024-07-09T05:02:45","guid":{"rendered":"https:\/\/zxi.mytechroad.com\/blog\/?p=10133"},"modified":"2024-07-09T07:50:08","modified_gmt":"2024-07-09T14:50:08","slug":"nikon-z8-hlg-nlog-stops-vs-ire","status":"publish","type":"post","link":"https:\/\/zxi.mytechroad.com\/blog\/photography\/nikon-z8-hlg-nlog-stops-vs-ire\/","title":{"rendered":"Nikon Z8 HLG \/ N-Log Stops vs IRE"},"content":{"rendered":"\n<p>Recently I switched from N-RAW to H.265 \/ HLG for quicker HDR workflow in Final Cut Pro, basically just drop the clips in a HLG timeline and that&#8217;s it, just like the iPhone&#8217;s Dolby Vision (HLG HDR) footage.<\/p>\n\n\n\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe loading=\"lazy\" title=\"85mm \u624b\u52a8\u955c\u5934\u6253\u9e1f | \u9e3d\u5b50\u6c42\u5076 | \u52a0\u62ff\u5927\u9e45 | Nikon Z8 | 4K HDR\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/CAySu64so1g?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n<\/div><\/figure>\n\n\n\n<p>I did some test about IRE vs stops in HLG mode and compared that to the <a href=\"https:\/\/download.nikonimglib.com\/archive3\/hDCmK00m9JDI03RPruD74xpoU905\/N-Log_Specification_(En)01.pdf\">theoretical N-Log curve<\/a>.<\/p>\n\n\n\n<p>Setup: I expouse the 18% midgray to 36% IRE in HLG mode to match that with N-Log. Adjust the exposure time first then aperture, ISO to over and under expose the midgray for IRE readings.<\/p>\n\n\n\n<p>Note: Techincally, you should expose midgray to <strong>38% IRE<\/strong> in HLG mode (<a href=\"https:\/\/xtremestuff.net\/recording-editing-with-hybrid-log-gamma-part-1\/\">ref<\/a>), diffuse white will be around <strong>75% IRE<\/strong>, 75%+ is for specular highlights (0~3 stops over diffuse white).<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Stops vs IRE<\/h2>\n\n\n\n<figure class=\"wp-block-image size-large\"><a href=\"https:\/\/zxi.mytechroad.com\/blog\/wp-content\/uploads\/2024\/07\/Nikon-Z8-_-Stops-vs-IRE-huahua-1.png\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"681\" src=\"https:\/\/zxi.mytechroad.com\/blog\/wp-content\/uploads\/2024\/07\/Nikon-Z8-_-Stops-vs-IRE-huahua-1-1024x681.png\" alt=\"\" class=\"wp-image-10136\" srcset=\"https:\/\/zxi.mytechroad.com\/blog\/wp-content\/uploads\/2024\/07\/Nikon-Z8-_-Stops-vs-IRE-huahua-1-1024x681.png 1024w, https:\/\/zxi.mytechroad.com\/blog\/wp-content\/uploads\/2024\/07\/Nikon-Z8-_-Stops-vs-IRE-huahua-1-300x200.png 300w, https:\/\/zxi.mytechroad.com\/blog\/wp-content\/uploads\/2024\/07\/Nikon-Z8-_-Stops-vs-IRE-huahua-1-768x511.png 768w, https:\/\/zxi.mytechroad.com\/blog\/wp-content\/uploads\/2024\/07\/Nikon-Z8-_-Stops-vs-IRE-huahua-1.png 1212w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/a><\/figure>\n\n\n\n<p>First of all, we can see that HLG curve is more contrastive than N-Log. Highlights will be clipped after <strong>5 stops over midgray<\/strong> which I think is OK for a lot of scences. N-Log retains more infornation in the highlights (if not over-exposed) up to 6.3 stops at the cost of noiser shadows. HLG has more detials in the shadow area, <strong>noise floor is about 2%<\/strong> at ISO 400 (12.5% for N-Log).<\/p>\n\n\n\n<p>Another thing intresting is that the HLG curve is very steep from -1 to +3 stops but quickly saturated afterwards (non-linear anymore), highlights are compressed and will clipped around <strong>96% IRE<\/strong>, making sure to set the <strong>high zebra to 245<\/strong> when shooting HLG.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Base ISO for HLG and N-Log<\/h2>\n\n\n\n<p>Nikon Z8&#8217;s HLG has a &#8220;nominal&#8221; base ISO 400. Under the hood, the sensor is working at ISO 100, shadows will be boosted by <strong>2 stops<\/strong> while highlights will be intact, bascially you are shooting at ISO 100 with 2 stops under to protect highlights.<\/p>\n\n\n\n<p>N-Log has a &#8220;nominal&#8221; base ISO 800. Same as HLG, the sensor is working at ISO 100, shadows will be boosted by <strong>3 stops<\/strong> while highlights will be intact, bascially you are shooting at ISO 100 with 3 stops under to protect highlights. However, you will see a lot of noise in shadow area due to insufficient light and 1.3 ~ 1.7 stops &#8220;over-exposure&#8221; is usually needed to compensate that to get clean image. <\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Consolution<\/h2>\n\n\n\n<p>HLG has a pretty good balance between highlights and shadows, very user friendly for HDR workflow. Unlike N-Log, there is no need to over-expose (even 1 stop under looks good to me), no camera LUT needed for restoration, zero or minimum color grading needed. Another advantage of HLG over N-Log is monitoring, most of the time you can rely on the screen\/viewfinder (with zebra on) to adjust the exposure and only open the waveform if needed. <\/p>\n","protected":false},"excerpt":{"rendered":"<p>Recently I switched from N-RAW to H.265 \/ HLG for quicker HDR workflow in Final Cut Pro, basically just drop the clips in a HLG&#8230;<\/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":[803,802,805,801,806,804,800],"class_list":["post-10133","post","type-post","status-publish","format-standard","hentry","category-photography","tag-expousre","tag-hlg","tag-nikon","tag-nlog","tag-nraw","tag-photography","tag-z8","entry","simple"],"_links":{"self":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/10133","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=10133"}],"version-history":[{"count":10,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/10133\/revisions"}],"predecessor-version":[{"id":10155,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/10133\/revisions\/10155"}],"wp:attachment":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/media?parent=10133"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/categories?post=10133"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/tags?post=10133"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}