EX1, LED Stage Lighting, and WA adapter

[John Peterson]

For several years I have been using a B+W 77mm 486 Digital UV/IR Blocking Filter on my EX1 to shoot stage productions that involve LED lighting. It helps a little. But now one of my clients built a new theatre space that has an extremely wide stage with a short distance to the camera. So I bought a Sony VCL-EX0877 wide angle adapter. The problem with it is that you can't attach a filter to it.

Does anyone have any clever methods of rigging filters up to that WA lens?

Also,

The director loves to use a light violet in a lot of scenes which Sony cameras ALWAYS see as blue whether LED or Incandescent. Does anyone have a picture profile to compensate for it? Or does anyone have a magic PP that makes Sony cameras behave like the Canons do under the same LED lighting. They don't see blue when there is none.

[Dave Sperling]

No real suggestions on either front from me...
The integrated petal front to the W/A adapter (and the extreme convex shape of the front element) would make adding any kind of filter very difficult. You could try creating a spacer ring to mount a round filter slightly in front of the lens, though I'm not sure what size - and it would need to be very precise to avoid vignetting.
The front of the petal is about 4 1/2" round -- though attempting to place a 4 1/2" round filter in front of it would produce extreme vignetting in the corners because of the petal shape. My guess is that you might be able to rig a panavision size (4.565 x 6) or a square 6x6 on the front of the petal with little or no vignetting, but you'll need to create a reflection eliminating black rig around it -- which might actually work if you're in the back of a theatre and the house lights are down.

In terms of the blue, we never figured out a way to properly render purple tones on most of the Sonys. A couple of weeks ago we were shooting a Broadway show with 3 - F355's and decided to add my F3 as a wide master shot. (We had a whole monitoring setup with a quad split, scopes and 25" and 17" Sony monitors.) We also had the afternoon to try to get the cameras better matched since they were in previews and doing lighting adjustments during the day. Because the F3 differentiated the Purples much better than the 355's we ended up having to create an F3 profile that moved the purples further into blue - to better match the 355's. Not a solution to the purple becoming blue issue, but it did get the cameras to match so they could use the F3 wide shot...

[Boyd Ostroff]

Mattebox perhaps? I have the Century/Schneider wide adapter for my EX-1 and also their mattebox which clamps around the outside of the lens and has two filter slots.I also have their lens hood/filter holder that attaches the same way but was much cheaper than the mattebox. All of their EX-1 lenses had the same outer diameter to be compatible with these accessories. Don't know how that compares with the diameter of your Sony lens however.

Here it is with my journeyman camera operator. :-)

[Leslie Wand]

boyd got there first...

clamp on might not work, but matt box on rails will. unfortunatelly not a very cheap solution i'm afraid.

[Jan Klier]

Originally Posted by Dave Sperling

we never figured out a way to properly render purple tones on most of the Sonys.

It's an old problem. I have experimented with it a bit more in terms of lights and post rather than in-camera.

The core issue is that LED fixtures produce colors from three discrete and narrow spectrum LED sources that are independently driven. Since saturation is expressed as the distance between the the most dominant and next most dominant color, if the three color channels live in the extreme (e.g. 100/0/100 for purple) you get crazy gamut excursions that the codec pipeline can't handle and you lose all detail.

If you do have influence over the lighting design, the best solution (which I've tested) is to have the lighting designer mix in 20% green into their purples. It's not noticeable to the human eye, but is enough to dial back the saturation to avoid clipping. That is just counter to how most lights are programmed by default.

In the old tungsten fixtures which filtered a broad spectrum source, the filtering was never so strong that it would create this level of saturation.

[Pete Cofrancesco]

I’m currently editing a performance that has LED light issues. In certain scenes that are heavily saturated with color appear purple with all the details especially in the face washed out like if they were over exposed.

Op: I can’t imagine not being able to get wide enough to fit the entire stage if filming in the back of the theater.

As far as the filter. You could setup mat box on rails like in cinema but if the issue is LED lights then I would forget about it.

At a point there is only so much you can do and you just live with it.

[John Peterson]

Sorry I took so long to thank all of you. I do truly appreciate the help.

Went crazy looking into solutions. Came up with zero. Matte boxes would have to be 6 x 6 because the front of the Sony WA lens is 4.25" (108mm). And then finding filters that would work in that size were a dead end. There are no inexpensive gels I could mount in front of the camera tripod to shoot through either. And I wouldn't even know which ones.

I think I will try to talk the director into telling the lighting person to add a little green or yellow to her favorite violet haze LED lighting. We'll see.

But (a belated) thanks again.

John

[Boyd Ostroff]

Too bad you can't find anything. FWIW, this is the clamp-on sunshade/filter adapter from Century, it was pretty cheap IIRC. But it's 105 MM instead of 108 MM unfortunately. Probably not helpful for you, sorry.

https://www.bhphotovideo.com/c/product/376587-REG/Century_Precision_Optics_0VS_SS05_00_VS_SS05_00_4x4_Sunshade_Filter_Holder.html/BI/2855/KBID/3801

and this is the Century/Schneider .75x wide adapter that I am using. I use a Century/Schneider mattebox and rails now, but the clamp-on also works.

https://www.bhphotovideo.com/c/product/584259-REG/Century_Precision_Optics_0HD_75CV_EX3_0HD_75CV_EX3_0_75x_Wide_Angle.html/BI/2855/KBID/3801

Hope you find some solutions.

[John Peterson]

Thanks Boyd,

That takes 4 x 4 filters instead of 6 x 6 . Are those big enough as not to obstruct? If so, which filter would you use for cutting the LED color oversaturation?

I have seen that WA lens (used) for a reasonable price.

John

[Boyd Ostroff]

Sorry John, no idea what kind of filter you need for that application. The only filter I own is a ND grad, and it does not vignette when used in my mattebox if I line everything up just right. I actually got that clamp-on filter holder/sunshade in the post above for my Z1 many years ago. It fits the EX1 wide lens, but have never used it with that camera.

I got the mattebox when I purchased the EX1 back in 2010 (IIRC), it was a "kit" that included the rails, mount and a 105mm "funnel" that screws into the stock EX1 lens. I can't find that on the web anymore, but the part number on the faded B&H Photo receipt looks like CEDSXB44VEX and it was called a "DV Mattebox".

The mattebox itself is model MB-250 and apparently was made by Vocas for Century. This looks like it:

https://www.bhphotovideo.com/c/produ...2855/KBID/3801

Here it is on my EX1.

[Boyd Ostroff]

BTW, that lens was discussed at some length "back in the day" here at DVinfo. There were some problems initially with the lens vignetting on the EX1, and mine had this issue. After contacting Century, they exchanged it for another one. The one I have now is basically OK, but I see some very slight "dimming" in one of the corners. So, caveat emptor if you purchase one of these lenses, it may have some slight amount of vignetting.

There is also some barrel distortion, but I think that is to be expected. The built-in EX1 lens also has barrel distortion. I did a whole series of tests with/without the lens and IIRC posted them in a thread here long ago. Sharpness is generally very good though, and when I zoom in, I really can't tell much if any difference with or without the adapter.

[Paul R Johnson]

Looking back - you mentioned the lighting designer likes a light violet. Can you find out what gel this is - probably a Rosco colour or maybe Lee - once you find out what it is you can look it up and see what the transmission graph is like. I assume they mimic the colour with Led - so what? Full blue with a bit of red?

Filters don't work too well if the spectral response is very peaky, because all it can do is remove light, not fill in the holes!

[John Peterson]

Thanks for all the help. I plan to speak to the NEW lighting designer, but I have gotten nowhere in finding out which filters to consider trying. I assume they would be color correcting warming filters.

I wrote to Lee Filters and they told me that they have nothing.

I wrote to Rosco (twice) and they didn't answer.

The 4 x 4 and 4 x 6 glass filters are a fortune and to experiment by buying random filters is not worth the cost.

Would any of the gels work? Those are a lot less expensive. Are they clear enough to shoot through?

Thanks,

John