sky overexposing: will French flag help?

[Stephen Armour]

Originally Posted by Marcus Marchesseault

"They will tell you to use a computer and programs and electronics tricks and tons of time, where a simple filter will solve all your problems for few dollars in seconds."

A graduated ND filter will work for some shots, but these are just test shots. Assuming that a subject might be placed in the real thing, a graduated ND might darken the top half of your subject. Also, graduated filters sometimes can be obvious in their use if they are not perfectly aligned with the bright part of the scene. With video cameras, the shot will often be dynamic so the ND filter would need to be re-oriented during a take which is not practical. I have gradual ND filters, but they are only part of the solution.

The only type of filter that may help without darkening your subject is a Contrast filter. There are Low Contrast, Soft Contrast, and Ultra Contrast filters that either darken the highlights, raise the blacks, or a combination of the two.

Controlling contrast involves many disciplines of photography:

-Observing your environment and selecting the best time to take advantage of natural lighting conditions

-Choosing the right exposure

-Using correct lighting, reflectors, and other lighting controls like scrims

-Using appropriate filters like Contrast and Neutral Density

-Selecting the best angle of your shot for the existing light

-Composing the shot so it will stay within the limits of your medium

These things are all done at the time of the shot irrespective of electronics. There are still more things that can be done now that we have sophisticated cameras and computers:

-Setting your camera for greatest contrast range compression by lowering knee and raising black levels

-Using color correction to bring highlight details down into the range of the display device and to bring underexposed areas back to a more natural appearance

-Using color correction to accentuate colors that may be made dull by exposing for greatest contrast range

-Replacing overexposed areas with substitute information using a luminance key (often "sky replacement")

There may even other things that people with more knowledge can elaborate upon, but these things are a good start. None of them will work alone and some of them take a great deal of effort. Combined, you can get amazing results but it will take time, expertise, and even money unless you are always able to shoot in perfect lighting conditions.

Now, if you can just figure out how we can get our little 1 chip A1 to color/exposure match our 3 chip V1...I'll be impressed.... :) ha! Only way I can figure to do that is buy another V1...

[Stephen Armour]

Originally Posted by Gareth Watkins

Hi there

Firstly a matte box would not be over kill for your camera, I use one all the time on my Z1... Check out models by TLS and Formatt...

A french flag while it will stop stray light from hitting the lens and flaring, it is a bit like wearing a baseball cap, it will shade the lens thus improving your picture, but won't have a massive effect on exposure.

To get the even exposure you are looking for you'll need to use an ND Grad filter... I've been using that and a polarizer a lot for the scenics I've been shooting recently. I find a 0.9 ND Grad gives me the best results...

regards
Gareth

Ditto on the polarizer too. We've found it helps some.

[Steve Mullen]

Originally Posted by Stephen Armour

Now, if you can just figure out how we can get our little 1 chip A1 to color/exposure match our 3 chip V1...I'll be impressed.... :) ha! Only way I can figure to do that is buy another V1...

Curious how you compare the video from your A1 verses the V1. Post some outdoor and indoor pix if you have time.

[Stephen Armour]

Originally Posted by Steve Mullen

Curious how you compare the video from your A1 verses the V1. Post some outdoor and indoor pix if you have time.

Steve, we were experimenting with trying to use our little Sony A1 as a "B" cam with our V1. Unfortunately I have already dumped the hours of testing we shot and compared under both artificial and natural lighting.

Due to the limited A1 controls, we mostly tried to see how close we could match the V1 to the A1, instead of the opposite.

The end results are not horrible, but definitely complicated. What suffered the most was the greens. Sometimes the 1-chip A1 colors (in natural light) were more "pleasing", but in general, the V1 color was clearly superior.

The most humbling thing, was discovering that after tweaking every possible combination of settings, we decided the "auto settings" already got us as close as we could possibly get with these two cams!

When we tried to adjust for contrast or brightness, color changed. When we tried to adjust our color more closely, contrast and brightness changed unacceptably. Everything was white balanced, both cams were side-by-side, tripod mounted. When we realized green seemed to be a prob in syncing these two cams, we shot a lot of shades of green foliage (both high and low contrast environments) behind our studio. We have a type of bamboo there, with both indirect and direct light, so the shadow and gradient levels ran the whole spectrum.

Using histograms did not really help, as the two cams apparently interpret their data in different manners.

Our final conclusion was exactly what I had suspected before we ever began testing: it is impossible to match these two cams closely. Though we can hide behind shot transitions and cam angles, for good production we need another V1. The A1 is a decent little cam and though quite limited, is inferior to the V1 in every aspect (except size). It's a great little cam to stuff in your backpack, but not real useful for production type work. We mostly fly it on our Merlin and it's nice for those tight spots where close color balance is not necessary or noticeable. But for a "B" cam, it's pretty limited with the V1.

Now if we can just sell off our old DV stuff (DVCPRO and JVC 3 chip) with all their controls and accessories, maybe we can get that other V1? We miss the manual controls of the Fujinon lenses, but love that V1 HD image.

BTW, we're using CF Prospect for ingest/editing.

[Steven Davis]

Originally Posted by Marcus Marchesseault

"They will tell you to use a computer and programs and electronics tricks and tons of time, where a simple filter will solve all your problems for few dollars in seconds."

A graduated ND filter will work for some shots, but these are just test shots. Assuming that a subject might be placed in the real thing, a graduated ND might darken the top half of your subject. Also, graduated filters sometimes can be obvious in their use if they are not perfectly aligned with the bright part of the scene. With video cameras, the shot will often be dynamic so the ND filter would need to be re-oriented during a take which is not practical. I have gradual ND filters, but they are only part of the solution.

The only type of filter that may help without darkening your subject is a Contrast filter. There are Low Contrast, Soft Contrast, and Ultra Contrast filters that either darken the highlights, raise the blacks, or a combination of the two.

Controlling contrast involves many disciplines of photography:

-Observing your environment and selecting the best time to take advantage of natural lighting conditions

-Choosing the right exposure

-Using correct lighting, reflectors, and other lighting controls like scrims

-Using appropriate filters like Contrast and Neutral Density

-Selecting the best angle of your shot for the existing light

-Composing the shot so it will stay within the limits of your medium

These things are all done at the time of the shot irrespective of electronics. There are still more things that can be done now that we have sophisticated cameras and computers:

-Setting your camera for greatest contrast range compression by lowering knee and raising black levels

-Using color correction to bring highlight details down into the range of the display device and to bring underexposed areas back to a more natural appearance

-Using color correction to accentuate colors that may be made dull by exposing for greatest contrast range

-Replacing overexposed areas with substitute information using a luminance key (often "sky replacement")

There may even other things that people with more knowledge can elaborate upon, but these things are a good start. None of them will work alone and some of them take a great deal of effort. Combined, you can get amazing results but it will take time, expertise, and even money unless you are always able to shoot in perfect lighting conditions.

I give you props for a very nice explaination Marcus. Very nice read.

[Marcus Marchesseault]

Mahalo (thanks) for the kind words. I'm really just putting together a bunch of stuff I learned here, and linked from around here, and backed up with my own testing. I did learn about filters and sunlight angles in my youth from my father. I'm going to be testing the last piece of the puzzle as soon as the Vog* clears. I just got an Ultra Contrast filter, so I'm going to try some high-contrast scenes with ND filters and the UltraCon to see how much latitude I get. I'm hoping that good filters, proper composition with respect to the lighting, and a single reflector on the subject might be all I need to get decent shots. If I can use filters to get my footage into the range where color correction has something to work with, I can get professional results without a 5-ton grip truck as long as I pick my battles.

*Volcanic fog/smog - I'm sure our cars are partly to blame, but winds from just the right direction and speed cause a nasty volcanic haze in Honolulu for several days once ever year or two. Kilauea is over a hundred miles away and we still get hit. You can't fight Madame Pele.

[Bob Grant]

Just a few tips about using filters with DV, a lot of filters, particularly the more expensive ones, are made for 35mm. The various differences in lenses can mean that their effect is dramatically different between when they're used on a DV camera and a 35mm camera.
For grad ND filters there are many variants, not just how dark the ND is but also how sharp the transition from ND to clear is. This is also affected by lens focal length and aperature. Being able to mount a grad filter in a rotating stage can enhance their usefullness too.

[Serena Steuart]

As Bob said, graded filters must be aligned with the brightness gradient of the subject, so you must be able to rotate the filter as well as slide it to correctly place the gradient. The filter (any filter) must be well out of focus, which is a trap when using short focal length lenses (particularly at high f/numbers). Filters that use particles for scattering (without checking, I think "black mist" is one) can cause unwanted artifacts in video, so it's always a good idea to test before you buy.

[Steve Mullen]

Originally Posted by Stephen Armour

Everything was white balanced, both cams were side-by-side, tripod mounted. When we realized green seemed to be a prob in syncing these two cams, we shot a lot of shades of green foliage (both high and low contrast environments) behind our studio. We have a type of bamboo there, with both indirect and direct light, so the shadow and gradient levels ran the whole spectrum.

What a great place to test for green. Which -- if this is the right question -- camera had more green?

According to many reports the A1 had a problem with saturated red being shifted toward magenta. There are also a few reports that Sony fixed this at some point in the run. Have you noticed this issue with your A1?

The A1 is showing-up on eBay and when you consider that you can remove the XLR and Mic and wind-up with a very tiny camcorder -- it looks interesting. I'm not worried about matching the V1 -- only whether the color is good.

Also, how about the A1's latitude in your bright sunlight?

[Simon Hunt]

This sounds like the perfect use for "Knee Level". Try Medium or High. If panning back and forth to a hot sky background you could even use the auto knee setting. I suggest some experimenting to see what you like and which setting is not to objectionable.

[Piotr Wozniacki]

Originally Posted by Simon Hunt

This sounds like the perfect use for "Knee Level". Try Medium or High. If panning back and forth to a hot sky background you could even use the auto knee setting. I suggest some experimenting to see what you like and which setting is not to objectionable.

Simon, if you mean High Knee setting for contrasty situation like the one described in my original post here, then I'm afraid you're wrong - the Knee should definitely be Low. And - IMHO - even in Low setting, the response curve is still not flat enough with the V1 (just compare it to Gamma 4 setting of the XDCAM, for instance).

Also, I'd recommend turning off the cinegamma (1 or definitely 2), as it tends to further increase contrast. My lesson taken with sceneries like in the grabs I posted made me re-arrange my custom buttons assignement; now I have a special button ready for High Contrast situations (cp with cinegamma off, knee low, black stretch).

[Bob Grant]

Probably what you'd ideally want is black stretch and / or the ability to adjust the master pedestal. However you don't seem to get that level of adjustment on prosummer cameras and perhaps for good reason. Bumping up the bottom end of the gamma curve is also going to bring up any noise from the sensors.

I recently did a piece shot on Digibetacam and the difference in latitude of those cameras compared to all the HDV cameras is quite significant, as it should be given the cost difference and the difference in size of the sensor elements. Even so though looking at what Piotr is trying to capture I'd imagine even film would be struggling to cope. The crew would be pulling out their monster lights and bounce boards to get some light into those deep shadows or else delaying the shoot to get the sun at a better angle.

[Piotr Wozniacki]

Originally Posted by Piotr Wozniacki

; now I have a special button ready for High Contrast situations (cp with cinegamma off, knee low, black stretch).

Ironically, I screwed important shooting yesterday - an indoor party, with sunshine behind the windows... I pushed my "magic button" twice by mistake, switching off the settings for High Contrast!

[Simon Hunt]

"Simon, if you mean High Knee setting for contrasty situation like the one described in my original post here, then I'm afraid you're wrong - the Knee should definitely be Low."

Sorry, not being a V1U owner I'm not sure which way this control works which is why I sugested some experimentation. I was going on my F-900 experience where you can dial in Knee level with the MSU. In which case the higher the value the higher the amount of "Knee compression".

How does "auto knee" work with the V1U?

[Piotr Wozniacki]

OK - so by "Knee Level" you mean the degree of flattening the curve, and not where the switching point is located on it. You are right - BTW, the "level" as you understand it is not low enough on the V1, IMHO - even with its strongest settings, which is "Knee Low"...