C300: What is ISO should I be at?

iijohnkeatingii

iijohnkeatingii

Member
Hi guys, I keep hearing this term base ISO and such. I'm about to begin shooting with my c300 as my main camera and a 5d mkiii as my second camera. I have plenty of lights available and I could feasibly put them at their minimum settings. Should I. Can someone advise me as to what ISO I should be using for both cameras. I really appreciate it.
 
ISO850 is the lowest ISO that gives you the camera's maximum highlight protection at 800%.

You still get all 12 stops at all the ISOs, but the dynamic range shifts towards the shadows at lower ISOs. Depending on how you light and what your goal is, you are pretty free to choose you ISO.

ISO850 and above gives you the same about of stops of DR above 18% gray (5.3 stops), but 850 will be the cleanest. Lower ISOs will be cleaner still with better reach in the shadows. There is an image that shows this relationship clearly:

dynamic_range_chart__hero.jpg
 
850 ISO is the basic level for canon-log gamma only.

If you shot in 25p/30p FPS then wdr gamma has basic 640 ISO (0dB gain). At 25i/30i frame per second is wdr gamma more noisier, it is better to use cine1 or canon-log in this case.
 
iijohnkeatingii said:
Thank you so much. That explains it. Can anyone chime in on the ideal ISO for the 5d MK iii?
Click to expand...

This is a complicated answer, so here goes:

1. The best ISO for the 5D Mark III in .h264 video and jpeg is 160. Then 320, 640, and 1250. At 1600 and above, use the lowest ISO that makes a proper exposure. Some would argue this also applies to raw, see: http://home.comcast.net/~nikond70/Charts/PDR.htm#EOS 5D Mark III but most think that 100, 200, 400, 800, etc. is best for raw.

2. The picture style you use also effects the acutance, micro contrast, dynamic range, and noise. Some are better than others. When graded properly, Technicolor Cinestyle is one of the best, along with Marvels Cine 3.4 and Neutral Flat (Prolost).

I avoid Portrait (lower highlight dynamic range), Visioncolor, Cineplus, VisionPlus and their like (crazy color artifacts) and Flaat (just moves the dynamic range around, and loses detail in shadows)

In high dynamic range situations, and shooting .h264 or jpeg, Highlight Tone Priority works well. I have seen much more raw like highlight retention using HTP in appropriate situations. You really do gain highlight range at the expense of some extra noise in shadows. You make the call, but it may be worth the trade.
 
C-Log basically underexposes by using ISO850 on a camera that has a base ISO of 640 (so it assumes that it's more sensitive than it is, and captures more highlights as a result). All the marketing material states 850 but underlines that by mentioning that this relates to C-Log. The camera even puts a special [square bracket] around the 850 to show that it's 'special'.

If you use a different Custom Profile or switch them off, using the Gain set at 0dB rather than ISO setting, you'll find that it equates to around 640ISO.
 
Is Canon log underexposing by 1/2 stop? So in effect it is like 1/2 stop of HTP? How does it work?

This is opposed to HTP on the 5D3 which underexposes by a full stop. ie. 800 HTP is ISO 400 with a special tone curve to make the final result look like a normal ISO 800 exposure with one extra stop of highlight detail.
 
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