Using Coal Posts?

[Richard Lowther]

Does anyone know how the raw goal posts in the view finder works? I was shooting a extreme contrast shot at a water fall yesterday, where the talent was in thick shade from shade trees and the white water of the water fall was in the intense Hawaii sun. I was monitoring at 640 iso. The cameraman was freaking as he was getting warning from both sides of the goal posts. I tried to balance the picture the best I could with the limited HMI lighting I had. I put a 12kw on the black rocks in the background, this made little difference.
So I tryed to balance the shot using equal amounts of goal post on the white clip side and the black side.

When we brought the raw footage back we noticed the clipping in the white water of the water fall but couldn't see it on the black rocks.

The questions I have is does the goal post show a warning even if there is only a few pixels clipped? It seems that you can't use the goal post to balance the picture and its better to protect the white more is this correct?

Thanks
Richard Lowther

 

[Clint Lealos]

Yes, the goalposts will start to turn red when you start clipping anywhere in the frame. Sometimes there are hotspots in the frame that I don't mind... like reflections off a bumper or a lightbulb in the background. I ignore the goal posts in this case and use false color to make sure those are the only things in the frame that are clipping. Hope this helps. Sounds like you guys had some challenging shooting conditions.

 

[Jeff Kilgroe]

I think the goalposts as well as the traffic lights are triggered when 3% or more of your scene is out of bounds or starting to clip.

Based on the OP's description of the scene, there just may not be much that could have been done there without bringing in a lot more fill light or bounce for the dark areas. Or using various ND techniques beyond simple grads. Sounds like a good test case for HDRx if it were available.

If this was on an MX camera, I would have probably monitored at ISO 1000 or 1200 to help protect highlights. On the other hand, it seems the shadow details were important too, so if the scene's DR is beyond the camera's ability, then it becomes a compromise. If it was original mysterium, then 640 was probably a good choice.

 

[Clint Lealos]

Yeah, HDRx would have ideal I think

 

[Richard Lowther]

Thanks
for your input...yes we used MX cameras. Yes it was a challenge but still I was amazed at how nice it came out.
We had a still photographer using a Canon 5dm2 he gave up said the canon sensor couldn't handle this location. He showed me his stills, the background rocks were just black blobs and the waterfall looked like a white sheet. It is amazing how much detail we could pull out of the blacks with the MX sensor and how little the white water was clipped.
I am not sure monitoring at a higher ISO would have helped as we were looking at the sensor clipping.

I totally agree I need to invest in more filters. Is there other filters other than grad NDs that I could have used to bring just the white water down?

Has anyone used those contrast filters? Do they turn the whole picture milky or can you get a good contrast filter that just brings the blacks up and turns the high lights down?

Richard

 

[Jeff Kilgroe]

Glad it turned out alright. It's amazing what the MX sensor can do! I'm continuously surprised at what I can squeeze out of it.

As for the ISO monitoring, it's all metadata anyway. The MX sensor is natively about ISO 800. But in situations where I want to protect highlights more than shadows I like to bump the ISO up higher -- it's going the wrong way, but it causes the highlights to clip in the monitor just a bit quicker so I'm more aware that I might be over-exposing. Lot of people shooting RED approach it that way.

Most the time I stick to ISO 800 and I stick with RAW view and false color to see what's going on.

 

[Uli Plank]

I've never seen a contrast filter doing more than just diffusing some light, i.e. making the image milky. I believe it's physically impossible – why would RED investigate to make HDRx if it could be a simple filter?

Other than ND grads or tons of light or huge cranes with butterflies, there's only HDRx …

 

[Clint Lealos]

I think I remember reading here on RedUser that you can only gain a very modest 1/3 stop with using low contrast filters. The benefit is almost negligible. So, I agree with Uli... there's only HDRx

 

[ericyoung]

My understanding from the manual (page 61 of the 31.6.10 manual) is that the goalposts indicate the percentage of the pixels in the recorded area either falling into the noisefloor at the bottom or hitting digital sensor clip at the top.

So both goalposts showing halfway up would indicate half of the picture was clipping, and half was hitting minimum exposure. This would probably be the worse of both worlds. In this case, I think you'd have been better to expose for minimal white clipping, and try and bounce sun into the shadows if even your 12K wasn't giving enough fill under the trees.

Alternatively you could have locked off the shot, shot exposing for the foreground and then reshooting an empty background plate exposing for the waterfall in the background, and combining in post?

 

[Richard Lowther]

Thanks Thats helpful...... I guess I should read the manual.