Help With Digital BlowOuts

seanmcleod

seanmcleod

Well-known member
I just got a Letus FE unit and was doing some initial tests with it. I have a fast Nikon 85mm f2.0 lens I was using with it as well as a FS-4 DTE. I noticed in the footage any overexposed or even slightly over exposed section of the video became extremely digitized and unacceptable to look at, with a little aberration to them as well.

Is this a problem known with 35mm adapter when the image is over exposed or is it possibly due to the DTE I was recording to? Does anyone use their adapter with a DTE or is it better to go to tape. I would imagine it makes no difference but I don't know for sure.

Also there was a decent amount of grain in the image even with the vibration running, is this going to happen regardless in the dark parts of the image or is it something I'm not doing properly?

Thanks to anyone who takes the time to clear these issues up for me!
 
Please post some high rez examples. I have figured a great technique to get blowouts to look acceptable using curve adjustment. Lemme have a tinker at your stuff.
 
Thanks Papa, but actually the weirdest thing has happened... when viewing on my Mac Book Pro Initially I saw some crazy digital artifacting and generally displeasing effects, but on my Mac Pro tower it doesn't show any of that. Still kind of grainy however...
 
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Sure!

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Hey Sean,

All I can tell you is that with my adapter (Letus 35) things seem softer and more filmic. My "blow outs" are much less than what they would be without the adapter.

But remember with all video cams, especially anything under EX1 level, you have to take precautions because video can only see so many "levels" (stops) of light. You can fix this problem with light modifiers. In your top picture, if you bought a 4x4 (or 6x6) Full Stop Scrim (net) over a frame and put it behind your actress. That blow out would go away, especially if you added more light to her to balance the difference. You have to keep your light levels in a 10 stop range or less (Lower end maybe even 9 stops). EX1/RED can take 11+, but it's probably good practice to keep the light levels at 10 stops for digital.

For the second pic, you'd probably just have to get maybe a soft 1K and bring her up a little so the background is there. The light behind her we can see some detail, so if she was a little brighter we could see into the light even more.

So bring up the dark areas and bring down the light areas.
 
Thanks jls4...

This was just me and my girlfriend testing the thing in daylight, no real goal. I know of the problems of light consumption 35mm adapters can pose, but was unsure of if the grain will always be present. Basically your advice is light properly and you won't have problems and I can't disagree with that!

Thanks for your help!

Anyone have any quick tips they learned along the way with these things that will save me a headache down the road? Any advice is welcome as I am a total noob when it comes to actually using the 35mm adapters in practice.
 
PaPa said:
Please post some high rez examples. I have figured a great technique to get blowouts to look acceptable using curve adjustment. Lemme have a tinker at your stuff.
Click to expand...

I, personally, am ALL EARS :)

I have a few blown shots in my film I would not mind doctoring a bit. When you film run and gun you don't a,ways have the luzury to set up elaborate scrims, flag and light set-ups.

So what's your trick? :)
 
Exposure tips for run and gun.

Here's a good one that never fails.

Set your zebras to 90. Then make sure your subject has no zebras on the important parts... ie skin/face. don't worry about the whole frame... Example: If your shooting a dark skinned person wearing a white shirt you'd expose for the face and maybe give yourself a 1/2 stop down. I think people beat themselves up on run and gun stuff too much.. You can only do what you can do.

This way if it's an quick interview you'll at least have the proper exposure on the important part of the footage... the face

I'm not saying this to be mean... really... but adapters are not magic... you'd have a blowout on your first shot no matter what.

In photo one your choices are to bring up your fill or move the subject turning the window light into the key. Then add fill as needed.

Also, remember the Letus you have performs best wide open to f4 for the least amount of noticeable grain.


In general for Letus Adapter use (Not Ultimate)

Try to keep the camera itself at f5.6... that will insure the sharpest picture of the GG

As I said before, Keep the lens on the Letus no higher than F4.. this will minimize the vibrating pattern on the GG.
 
all you can do with curves is bring down the intensity of the blow out and perhaps bring a bit more detail back into the image.

When i get home i'll show you an example of some stuff from this weekend, in fact you can see some of the effect if you look at my thread from our class project this weekend.
 
In a blow out in "some cases" you may have retained some data in one of either R, G or B. Which is why Papa's curve adjustments will / could bring some of your image back.
 
When you have blown out footage, usually it's the blueand green channels that peak first. Often times the red channel is not blown out and replacing the green or blue channel with the data from the red can save your shot.
 
PaPa said:
all you can do with curves is bring down the intensity of the blow out and perhaps bring a bit more detail back into the image.

When i get home i'll show you an example of some stuff from this weekend, in fact you can see some of the effect if you look at my thread from our class project this weekend.
Click to expand...

hi Papa, any chance of posting these shots and a link to the thread you mentioned above?

Here are a few shots I have exposure problems with. Sky is kinda blown. Not too bad, though... What do you guys think? Does it bother you when you look at it? Can it fly as is? Or should I worry about fixing it and if so how?

I did play with shot a bit by reducing contrast and brightness and it helped a bit, the original shot is more blown then this one.

I am unable to return to location to shoot again, turned to be private land :(. What is your advice in regards to the blow out:


SCREENGRABS%20Scene%202009%2028B%204.jpg



SCREENGRABS%20Scene%202009%2028B%208.jpg
 
The grabs looks fine, not distracting. There's really no detail left in those skies so you can't bring it back. If you really don't want blown-out sky then a sky replacement is the answer. Anyone with intermediate skill in a compositing program should be able to do it.
 
Very nice filmic grabs ! I dont think they are overexposed ,maybe second shot and sky should had more texture and cloud details there (if there were any clouds at that time).But sky is not white and thats important thing for human eye to accept it as non blown out footage.I would bring down highest whites but its not so overexposed here.
 
For shooting models outdoors (even run-and-gun) a reflector would help a lot. Use it to reflect/bounce some of the strong backlight onto the face of your model. You'll need an assistant to hold it, but it would help a lot with achieving the look you're going for.

http://www.adorama.com/JTFR36SW.html

There are lots of options when purchasing one of these. Do some searching on the internet to find one that best suits your needs.
 
Deuce,
What program are you posting in?
Final Cut Pro?

If so do you know how to do secondary color correction?
In both of those cases my guess is you could use the secondary color corrector to make a mask just of the over exposed area and then alter the color and exposure in that area. Could make the sky bluer or with some more play you could even probably give it some kind of a late afternoon grad. Depends what you want the mood to be.

That's just a guess without really playing with the footage. Generally though as that white sky is so separate from the rest of the shot it should be easy to isolate it and then go nuts. You will need to make sure the bright side of your face stays out of the sky correction, but that's not hard unless you walk across the shot and your overexposed face side merges with the sky. That would get tough.

Does that make sense? A decent colorist could do that work and you could learn to do it.

If you send me the shots full quality I'll take a stab at it as I'm trying to learn color correction.

PaPa - I'd like a little tutorial on that as well. I was talking to someone about the Red camera yesterday and he also said that if you only blow out one channel its not hard to bring it back with info from a different channel.



Lenny Levy
 
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