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Expodisc White Balance Filter

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Hi Dan,

 

Fascinating thread - very good idea on your part.

 

Any news on a likely timeline for a waterproof version for use outisde the housing?

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Wagsy-

Any ideas on how to get it to work on the A1? I'm using an Amphibico housing and this sounds very interesting if it could be used.

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Yes..I'm also very interested..

 

Dive safe

 

DeanB

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I'm just as interested using a Gates housing for the A1-U-Steve B)

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I'm very anxious for others to try the Expodisc, as it definitely made a huge difference for me. When I first started shooting the FX1 underwater in early 2005 with an Aquavideo housing, I immediately noticed the FX1 didn't like to manually white balance below 50' very well. Been trying to figure out why, ever since then. I heard about the Expodisc on a still camera forum, and went to a local camera shop to try one out. In the dimly lit store I tried white balancing on various areas. When the camera would not balance, I tried the same area with the Expodisc, and got immediate white balance lock. Then I had a strong feeling this would really work well underwater at depth, where I've been having problems. It works unbelievably well underwater, in all situations, and very quickly. Now manual white balancing deep underwater is enjoyable. Excellent colors, no blown out reds, and never too much or too little of anything else. Plus no more endless blinking when it couldn't lock in. For me, this will always be in my housing. Ready to hear from other happy users. I did post this information to help others, as I knew I was not the only one having these difficulties. Happy shooting!

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Daniel, you the man...

 

Your info is very much appreciated.. If it works for me I will gladly by you a pint, or 5....

 

Dive safe

 

DeanB

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Mmmmmmm, cool delicious beeeer!!!! Always glad to help when I can, and this was certainly a discovery worth sharing.

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So there must be some other Expodisc users out there with some comments. I think we would all like to hear your experiences. I have read in other posts that some of you have bought them, and others have PM'd me. Must be someone who has shot with it by now. Anyhow, I went out this past weekend, and am still incredibly impressed with it's performance. It was another less than perfect diving day, but shot some really good video despite the conditions. The color balance and saturation acheived by white balancing through the Expodisc is stunning, besides the fact that it white balances down deep whithout hesitation.

 

As far as Expodisc making a waterproof external version, they would like to, but there are a few issues. Here are some of them. If anyone has some good suggestions, I'm sure they would like to hear from you, or post it here.

 

1. Waterproofing - can be done, not a real big issue.

 

2. Size - There are many lens sizes and shapes to work with, and the Expodisc needs to filter all of the light coming in to work properly. I'm pretty sure it needs to completely cover the lens with no light leakage. How many sizes would they have to make, and what would be the best sizes?

 

3. Stowage and Use - External waterproof Expodisc would need to be easily installed, removed, and stowed while shooting. As with all manual white balancing, you need to do it often. How to best attach it to the camera lens, and stow away easily?

 

For now, all I can say is if you can fit one in your housing on a flip arm, do it. You will be really impressed with the performance.

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Dan are you noticing a difference in result depending on which general direction you point the camera to white balance? I would guess that if you white balance pointing out into the blue you would get a warmer result than if you you point in the general direction of a coral reef, and if you want the most neutral result you would point towards the surface. I know the Expodisc averages the light but it can only get light from 180 degrees or less.

 

If I bought the same housing as you I would really not want to lose the flip macro arm for many dives because I like to get stuck into some macro even on dives where big stuff is the main goal, so I think I would want to run the Expodisc in 2 different ways:

 

1. Wide-only shoot (e.g. Pelagics): Replace the flip macro with the Expodic and keep the UR-Pro flip filter in (like you've done).

 

2. Mixed or macro shoot: Replace the UR-Pro flip filter with the Expodisc and keep the flip macro in, and add screw-on or gel filter to camera.

 

How does that sound? And did that screw-on UR-Pro filter that you bought fit behind the flip arms or not?

 

You think I'd need a spare pair of arms for the Bluefin to fit an Expodisc or would it be easy enough to just swap within the existing arm?

 

Nick

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I have not tried the option of replacing the red filter with the Expodisc mounted in a "macro" frame. If it fits, I will probably do that instead. I have the lights now so I also would rather want to keep the macro lens if possible. Has anyone tried this?

 

I have only tried the Expodisc on one dive so far, and it did not work well at all. It was a low light wreck dive to 140' and the camera did not want to lock in. I will try it again in a couple of weeks with the lights correctly rigged up, and hopefully it will work better then.

 

Anders

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Good to hear Dan...I got side tracked and forgot to order mine...will do tomorrow.

 

Problem is though I want the macro +2 option on the flip arm as it gives me a closer zoom in range + macro when needed. I take it if I get a 67 mm one it should pop straight into the flip arm once I take it out of the ring.

 

Dan how thick is it again?

 

Maybe get it on a thin second custom flip arm or modify the second arm to allow it to slide in there for a WB with the 94 degree lens on. Keep the URPRO filter always on the end of the camera.

 

2 arms will work with the Macro Dome Port on no problems.

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If the expo disc took the place of the ur filter in the housing, how would the WB be correct since the lights you are using would not be part of the WB procedure? Even if the disc fit over the port externally, once again, you would be WBing sans lights and therefore, the WB would be off. Can anyone explain this to me?

Steve B)

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Guys,

Very interesting thread...in my travels recently i missed it. Dan, as you know I have the L&M Bluefin HD housing as well. I was just in cocos and had trouble WB deeper than 60 feet (pacific murk). I wound up balancing at 30 feet to keep the reds from oversaturating deep down. I would be very intersted in the Expodisc as well. To save me some time, could you share some tips on shaping the disc and installing it in the flip arm? Is it as simple as maching the macro glass diminsions? What did you use to cut the material with?

shawn

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In reply to Nick, Anders, Wagsy, Steve, Shawn, and everybody else.

I have been white balancing on the light source (surface, sun) for WA, but I have also balanced directly on the subject for close-up. This gives great results. Since the Expodisc blends the incoming light, you can balance on just about anything you point it at. I did not want to give up my macro lens, but the benefits of great white balancing at depth outweighed my desire for macro. The 80°WA shoots pretty fair close-up without the macro lens. And soon the UWA will be out, and that will have much better macro ability than the 80°WA/Flip Macro combination. The 72mm screw in URPro CC filter definitely blocks the CC flip arm on the Bluefin. It does not hit the Macro flip arm, but does hit the screws, which could be replaced with flatheads to clear. The L&M UWA is supposed to extend further into the housing, but not past the CC flip arm. So I think to mount UWA, I will remove screw in URPro CC filter from filter mount, and install in camera with thin retainer. Then remove CC flip arm, and space Macro flip arm back as far as needed with Expodisc installed. The macro flip arm is much more robust and detented. For those keeping the 80°WA and Macro flip, I’m sure you could mount a modified Expodisc fairly easily to the CC flip arm, and mount a URPro filter same as I described above. For those who do not have Bluefin HD, I can’t help you much with mounting the Expodisc, but I’m sure someone will find a way. BTW, the Expodisc elements (3) combined are .235†(6mm) thick after removing from filter mount. I cut mine with a hacksaw and filed the edges smooth, after using the macro lens as a template. Then sanded the contours off of the macro flip arm retainer before screwing the macro flip arm back together. I have not used Expodisc at night yet, but I did use it late afternoon during a dark thunderstorm with HID lights. I had to aim the camera and lights at the sand from only a few feet away to get white balance, but it balanced very well. Did not balance on anything beyond the reach of the lights. As is normal procedure, shoot with CC filter during daylight, and without CC filter when using lights. The Expodisc white balance filter is only for white balancing, and must be flipped out of the way before shooting. If shooting with CC filter, you must white balance through both (CC 7 Expodisc) filters, with CC filter between camera and Expodisc. I have contacted Expoimaging about the possibility of making a thinner Expodisc, and am waiting for a reply. For us, space is at a premium, and the thinner they can make it, the better. Will keep you updated, and hope I answered most of your questions.

Dan

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Correction.

(CC 7 Expodisc)
Was supposed to be (CC & Expodisc).

For Bluefin HD 80°WA with Expodisc in place of Macro Lens close-up example, see the Arrowhead Crab picture (#1) in [Post#22] above.

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I still don't understand how this works so forgive me. The expodisc fits in place of the ur filter. You bring it down in front of the lens and white balance. Okay, I think I got that. However, if you're using lights, the lights would not be able to be a part of the wb procedure, so how do you deal with that? One thing I have found difficulty with is, if holding a card or slate, in front of the lens, it is hard to aim the lights to completely fill out the card since my arms aren't the length of Wilt Chamberlains. Thus, I am white balancing on a less than fully lit card.

Steve B)

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Why would the lights not be part of the WB procedure? At greater depths or limited visibility, they have to be since there often might be no other light available, and it is the WB with lights that will be on the footage. Am I missing something here?

 

Anders

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I'm not sure, maybe its me who is missing something. This expodisc fits into the internal ur filter holder taking the place of the regular ur filter. It comes down in front of the lens for wb purposes. But your lights are external and the lens is focusing on the internal expodisc; thus, how are the lights lighting up anything? They're not. You white balance on the disc and bring it up, see a subject and put on your lights....but the cam was not WBed to reflect the light being generated.

At least, this is my understanding of it all, but perhaps I am envisioning it all wrong.

Steve B)

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i think the disc is somewhat see thru?! i am not sure but i would think it has to be in order to get correct readings

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Well, at least I know I'm not crazy. I thought there was a problem with this. While the expodisc sounds wonderful, to have something internally that is as easy to use as a ur filter, unless you can WB with the lights you will be using, it would negate any benefit other than if shooting without lights

Steve B)

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Wags,

 

"take it if I get a 67 mm one it should pop straight into the flip arm once I take it out of the ring."

 

Not so easy. I thought the same way and bought the expodisc without checking the dimensions - big mistake. This thing is so wide (as Dan just said - 6mm), I don't think there is a chance in hell of it fitting in the Phenom - I guess it might work with the flat port, but we definitely need a custom made filter arm?

 

It does work like a champ topside in a dark room (simulating depth) - I was suprised. Couldn't get the camera to balance with a regular slate at all, but right away with the expodisc.

 

Really wish I could try this. Open to any suggestions if any Phenom users come up with something.....

 

Aloha

Bryce

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I'm not sure, maybe its me who is missing something.  This expodisc fits into the internal ur filter holder taking the place of the regular ur filter.  It comes down in front of the lens for wb purposes. But your lights are external and the lens is focusing on the internal expodisc; thus, how are the lights lighting up anything?  They're not.  You white balance on the disc and bring it up, see a subject and put on your lights....but the cam was not WBed to reflect the light being generated. 

At least, this is my understanding of it all, but perhaps I am envisioning it all wrong.

Steve B)

 

 

Steve,

 

I believe the Expodisc is somewhat translucent, and the facets on the front of the filter spreads the light evenly to the flat part on the back of the filter closest to the lens. In this way the lights you use to illuminate an object will be part of the white balance procedure, and that is why it works for different types of light sources.

 

This is an excerpt from Expodiscs homepage:

 

"Each ExpoDisc is constructed of carefully selected and matched optical grade materials, then hand-calibrated to strict tolerances of color neutrality and light transmission."

 

Sincerely

 

Anders

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Here's my first attempt at shooting through the Expodisc. Can anyone tell me what I'm doing wrong?

post-3234-1154152401_thumb.jpg

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Nice shot there Nick...love the colours.

 

Bryce 6 mm thick..be abit hard to get it on the flip arm.

Can you post a image of it up close bryce?

 

Trouble is I want to keep my +2.

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hahahahah Nick!

 

yer taking the piss

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