Cavision mattebox vignetting

P

planetearth

Well-known member
Hi there,

Bought a Cavision 3x3 mattebox. Obviously, their web site, the dealers, etc... support it's use with the dvx100. So, I checked it out and seemed fine at first glance. Then after 40+ hours of footage I start capturing and discover major vignetting when standard lens (no wide adapter) is zoomed out to its widest. Much of the vignetting (NOT ALL OF IT) will be cut off in tv, but we are in a webstreaming world where everything will need major cropping. Additionally, the concept of a rotating mattebox is hopeless in this case - as soon as I dial my 3x3 polarizer to a slight angle all the corners cut into the image. I contacted cavision and all I seemed to get was attitude. What happened to the concept of customer support, never mind a little courtesy. Additionally, there was much more vignetting on the left side of frame. Obviously the matte is not centered, it extends too far away from the lens and the design seems flawed (mind you, even if I take off the 72 to 85mm adapter and press the mattebox right up against the lens I still can't angle the polarizer). Anyone else experiencing this? Thanks for any info.
 
Re: Cavision mattebox vignetting

How long ago did you buy it? Cavision has a new adapter ring that is supposed to solve that problem. Now, the new adapter ring was to make it so that the trays would come out past the mic, maybe that made the vignetting worse? let me know.
 
Re: Cavision mattebox vignetting

I have not experienced this problem (although I purchased mine recently). You are shooting 4:3 or Letterbox?
 
Re: Cavision mattebox vignetting

Hi Jarred,

I bought it about 2 1/2 to 3 weeks ago, though they never informed the dealer in Toronto (DVshop - good people) of this change to the adapter either.

This is what I have found out. The old 72-85mm adapter for the DVX100 was the AR72 (or something like that). The new one is the AR82 (essencially it is the XL1 adapter). It is suggested that you also need to add a UV filter in front or back of it to give it enough distance from the lens to clear the on-board mic. The thing is, there is still vignetting when it is extended this far out. My suggestion - get the AR82 (XL1 adapter) if you get this mattebox (which is only about $19 Canadian for the AR82 as opposed to about $45 for the AR72), then either mount the mattebox upsidedown (which is silly and a pain) or keep the rear rotating filter tray rotated sideways. This way there is clearance for the onboard mic and you may be able to avoid vignetting when rotating your rear filter (but be very carefull with the seating and positioning).

Although Cavision doesn't seem to want to step up to the plate with me and I'm stuck finding solutions for them, I sure hope this information will help someone else out before they shoot a ton of footage.
 
Re: Cavision mattebox vignetting

Hi John,

I'm shooting 4:3 and intend to letterbox in post. How is your image on an underscan? Is it off center (more vignetting on the left side) or is my mattebox just faulty?
 
Re: Cavision mattebox vignetting

I have not experienced any problems (although I did go through the same hoops as you regarding adapters and step outs). I never shoot 4:3 so now i'm wondering if this is the case if I do!

Nevertheless, if I did shoot 4:3 I would crop in post anyway for 16:9 or 2:35.

If I have time today, I will look more closely into this and report tonight. I agree with you in that the CS has not been overwhelming and frustrating in the 'communication' department.
 
Re: Cavision mattebox vignetting

Good to hear about this.. before I make my impulse buy... I'll wait it out to see if this is really as shady as it sounds.  :-[

Jarred.. now we really need that review from you. HEHE
 
Re: Cavision mattebox vignetting

hmmm, interesting... correct me if i'm wrong but if you have a 72mm-55mm stepdown on your camera to fit on a 10x macro filter, you can't use cavision stuff?
 
Re: Cavision mattebox vignetting

Yes.. Sorry for the Delay in the review, but things like this keep popping up that I am working closely with Cavision to Solve.

I was actually the one that informed them of the Mic issue, and how they could fix it; It was odd to me that they missed that in Development but I dont know if thats something they looked for.  When I was testing it, its one of the last things I discovered after a good week of testing and never figured it out until I actually used it for production so I cant really blame them for slacking off, they pushed this product to market (I can take some of that blame, since I was doing some of the pushing)

The vignetting though I never experienced, and even tested for. Hopefully if you contact Jason at Cavision he will swap the 72 with the 82 for you, I would expect them to since it was sold to work for the DVX.

All in all its a great mattebox though, the 4x4 is pretty wicked as well, and very affordable.
 
Re: Cavision mattebox vignetting

Hmmm. I bought the 4X4 Mattebox with bellows from Cavision, and its great because I can control how far in or out the bellows extend, thus eliminating the vignetting problem. I can also use the rotating filters with no prob! I have the mattebox, follow focus, rods, pistol grips, french flag, varizoom, and LCD shade all on my little DVX.
I need to post some pics. It looks like its on steroids. Very cool!!!! 8)
 
Re: Cavision mattebox vignetting

Jarred is the person actually responsible for my 'set-up'. He advised me on what I would need and how to avoid any problems. He saved me an arseload of headache I'm sure.

Now that I think about it; I should send him a commission.
 
Re: Cavision mattebox vignetting

I will be contacting Jason Monday but I contacted him earlier in the week, received my 3X3 on Friday but he had said that he was sending me the new adapter because of the problem with the mic.  However, I shot about 15 minutes today and all was vignetted with the "new" adapter.  Of course, I will give him the benefit of an explanation...  I'll let you know what he has to say.

I like the mattbox and hope this can be easily resolved.  It's a comparatively good deal for what you receive if this issue can be resolved.
 
Re: Cavision mattebox vignetting

i'm not sure if you could ever convince me professional video accessories are a 'great deal for what you get' ;)
 
Re: Cavision mattebox vignetting

"Good to hear about this.. before I make my impulse buy... I'll wait it out to see if this is really as shady as it sounds.  
 
Jarred.. now we really need that review from you. HEHE"
 
Re: Cavision mattebox vignetting

Oup!! Wrong touch for last reply.

Same for me, I will wait to see if the problem is solve before buying the 3X3, but also thinking maybe the 4X4 with the ajustable bellow is better solution in the better world.
 
Re: Cavision mattebox vignetting

I will contact Jason today and figure out what the status is.
 
Re: Cavision mattebox vignetting

I spoke with Jason today. He believes the problem is due to using a UV filter. I indicated that I wanted to continue to use the UV filter. He is going to send me the other adaptor which with the UV filter should resolve the problem or i could take the UV filter off(which I don't want to do) and use the current adaptor. So, this could be the issue regarding vignetting. Dave
 
Re: Cavision mattebox vignetting

Why is this such a mystery? I assume they(cavision) have this camera over there also and a simple run down of the equipment used by users with problems ought to answer any variables in this equation. Fig out what filters/adapters the user has between the mattebox and the DVX lens and anyone should be able to reproduce what they're experiencing.
 
You must log in or register to reply here.
Back
Top