FDR AX700 vs.FDR AX100 etc.

Paul Anderegg · November 17th, 2017, 01:14 PM

Cliff, I understand S-log compresses highlights, and my understanding is that it does this by doing away with a certain amount of shadow data. I don't want to make my highlights brighter, I want to make my shadows brighter without shoving my REC709 highlights into 150% IRE.

Below is a typical example of a bright thing that I exposed for, which results in everything else being a black hole, as well as a quick levels adjustment I made for air...basically just dropped highlights to 100IRE and pulled the mids up a bit. On my A7sII, it would look well balanced. :-)

Cliff Totten · November 17th, 2017, 02:05 PM

Well?....Slog doesnt really "do away" with anything. Its just a curve. Its a signal compressor. You should expose Slog to the right a stop or two. If you are not clipping your highlights, you can keep going and could get you deep into your shadows. When I say "keep going" I mean open your iris more and more or slow your shutter speed down to let more and more light hit your sensor. Just watch clipping like a hawk.

If you can use Slog in "low light" without needing gain/ISO and your highlights are bright but not clipped, than you did a good job and are prolly recording everything your sensor is able to see. I say "low light" because everybody has a different idea of what that term means.

Dont forget the Hell that Slog places on 8bit CODECS. Be ready to pay a "possible" nasty banding penalty in 8bit.

Also, MPEG, when stressesd will sacrifice bandwidth in the shadows FIRST. Your blacks and shadows will get blocky if the scene is too complex. If you are shooting tons of shadow, h.264 will dump that area of your video quick when it hits its bandwidth cap. ProRes HQ wont sacrifice shadows like this and "stretches" to rec709 better then a highly compressed h.264 long GOP does. 10bit Slog is basically bulletproof but 8bit Slog is a 50/50 hit and miss

When you normalize 8bit Slog, if you have allot of shadows, not only is Slog going to stress that 8bit normalization, but h.264 artifacts could be strong too..

Lou Bruno · November 18th, 2017, 07:53 PM

Thanks to all. I just received my AX-700. I have been in the video field since 1982. I still enjoy being enlightened by new technology in cameras. With that said, I have lots to learn about S-log. I am sticking with 709 for now. Lots to study and will be following this thread as well.

November 17th, 2017, 01:14 PM	#16
Paul Anderegg Trustee Join Date: Jan 2013 Location: San Diego, Califonia Posts: 1,559	Re: FDR AX700 vs.FDR AX100 etc. Cliff, I understand S-log compresses highlights, and my understanding is that it does this by doing away with a certain amount of shadow data. I don't want to make my highlights brighter, I want to make my shadows brighter without shoving my REC709 highlights into 150% IRE. Below is a typical example of a bright thing that I exposed for, which results in everything else being a black hole, as well as a quick levels adjustment I made for air...basically just dropped highlights to 100IRE and pulled the mids up a bit. On my A7sII, it would look well balanced. :-) Attached Thumbnails

November 17th, 2017, 02:05 PM	#17
Cliff Totten Trustee Join Date: Aug 2010 Location: Florida Posts: 1,197	Re: FDR AX700 vs.FDR AX100 etc. Well?....Slog doesnt really "do away" with anything. Its just a curve. Its a signal compressor. You should expose Slog to the right a stop or two. If you are not clipping your highlights, you can keep going and could get you deep into your shadows. When I say "keep going" I mean open your iris more and more or slow your shutter speed down to let more and more light hit your sensor. Just watch clipping like a hawk. If you can use Slog in "low light" without needing gain/ISO and your highlights are bright but not clipped, than you did a good job and are prolly recording everything your sensor is able to see. I say "low light" because everybody has a different idea of what that term means. Dont forget the Hell that Slog places on 8bit CODECS. Be ready to pay a "possible" nasty banding penalty in 8bit. Also, MPEG, when stressesd will sacrifice bandwidth in the shadows FIRST. Your blacks and shadows will get blocky if the scene is too complex. If you are shooting tons of shadow, h.264 will dump that area of your video quick when it hits its bandwidth cap. ProRes HQ wont sacrifice shadows like this and "stretches" to rec709 better then a highly compressed h.264 long GOP does. 10bit Slog is basically bulletproof but 8bit Slog is a 50/50 hit and miss When you normalize 8bit Slog, if you have allot of shadows, not only is Slog going to stress that 8bit normalization, but h.264 artifacts could be strong too..

November 18th, 2017, 07:53 PM	#18
Lou Bruno Go Cycle Join Date: Dec 2001 Location: Huntington, NY Posts: 815	Re: FDR AX700 vs.FDR AX100 etc. Thanks to all. I just received my AX-700. I have been in the video field since 1982. I still enjoy being enlightened by new technology in cameras. With that said, I have lots to learn about S-log. I am sticking with 709 for now. Lots to study and will be following this thread as well. __________________ Lou Bruno