AC90: Blacks more like rusty red on ac90

L

lockie86

Member
Hi,

still trying to get to grips with the AC90.

When shooting in sunlight with the white balance set to daylight, black clothes come out as a rusty red. Have got this result a few times now.

Is this because the generic daylight setting isn't great, and it needs to be properly white balanced?

Or because I'm using an ND filter to cut down the harsh sunlight?

Sorry if this is a stupid question, but I'm not that technical!

Any help greatly received!

Many thanks,
Mark
UK
 
Sounds like you are either running into infrared contamination, or you need to black balance. Try black balancing, it's the far easier fix. But I suspect you're encountering infrared pollution. If the black balance doesn't fix it, then look at getting an external ND filter with IR cut; it'll elminate the issue.
 
100% from Barry! My ac-130's did the same to me and I blamed the camera BUT it was the ND's .. time to toss out those ND's and get decent ones. Mine were pretty pricey too and the guy at the camera shop insisted they were top quality. Try the camera without your ND's and you will find the blacks will be black again and then get maybe something like the Genus Variable ND ..that worked for me and I had no more issues even with heavy ND dialled in.
 
Ah many thanks guys, yes I'm sure it's the ND. Do you have a link to the right one Chris? Just want to make sure I'm doing the right thing.

Many thanks again!

Mark
 
Try B+W filters or similar. It's a heftier price, but worth it.

FWIW, I've never had to screw an ND onto my AC130, not even on the brightest of sunny days. Just a UV filter for protection.
 
They available almost everywhere . just Google "Genus Variable ND" even on eBay. Mike? I used one to bridge the gap and avoid switching ND's when a cloud goes over the sun .. variable is seamless .. the internal ND's cause a flash on the footage when you switch .. wasn't good for weddings
 
Thanks guys. Does the AD90 have internal NDs that you can adjust manually then? I just thought it had an auto ND and you had no control over it?

Mike how are you managing with no ND filter at all, in bright sunlight? I've found that shooting stopped down in bright sun causes the image to be very soft, and Barry also backed this is a while back when he said:

So here's the thing -- you cannot cannot cannot cannot cannot cannot cannot cannot cannot cannot cannot cannot cannot cannot let an AC90 (or HMC40 or HMC80) stop the iris down any more closed than f6.8. That's the limit. Any more, and your picture will go soft and blurry, exactly as you are demonstrating. F/8 is tolerable, but still a loss of quality. F/11 is a disaster.

So how can I not use an ND on the lens on bright days? :-)

If I'm being real thick excuse me, I'm not v technical at all.

Many thanks,

Mark
UK
 
Mike has an AC-130 not a AC-90 The 130 has switchable ND's The ND's on the AC90 are auto just the same as my old HMC80's they come in automatically to keep the iris in the sweet spot. Yes, you can use no ND's on most days but just watch the iris setting ..if the day is really really bright the camera could "run out" of auto ND and with a small than F6.8 iris (like F8 or F11) your image quality could suffer. On my HMC80's I think I only needed ND's once at a wedding in 5 years so it has to be VERY bright to need an ND as the autoND's should do the job OK. I think just once my cam made it to F10 in bright sunlight in Summer!! Just carry maybe an ND2 of decent quality and use it when you have to....as Barry says you can get away with F8. The internal ND's in your 90 are integrated with the iris and work fully automatically ..you cannot adjust them so just trust them to do their job and happy filming!!
 
Even indoors under tungsten light, with no ND filtration (internal or external) the AC160 shows a lot more infrared contamination than the GH2. I expect the the AC90 is similar.
ComparisonSmall.jpg
 
Hy guys I'm still struggling to find the exact variable ND filter I need for the AC90.

I definitely need one for bright sunlight, as stopping down too far makes the image soft. But I need one that doesn't make blacks a rusty red.

Does anyone have a direct link they could paste please, or an exact name?

Chris said Genus Variable ND but I Googled that and loads came up, same for the B+H Mike suggested.

Any links would be brill. Sorry for being so thick but i don't want to spend loads on the wrong one!

I'm in the UK but once I know exactly what I need I can track one down here.

Many thanks!
 
I was advised that variable ND filters are fine for a still scene or a DSLR but not for video. This was from B&H Photo. I agree because as we pan, the contrast will almost always change. I sold my 90 because of the rust color. The solution is either a very light ND or none at all but be careful not to close the iris down too much to prevent a very soft picture.
 
Thanks Lou, can u suggest a very light (variable?) ND that would work OK (ish)? I definitely need an ND as stopping down too far causes softness as u say, but on a v bright day I def need one or it's too blown out.

To be honest I am tempted to sell this too, have had too many issues with it. What did you change to? I couldn't see much else decent around in this price range.

Thanks again and if you or anyone could recommend an actual filter or post a link that would be brill.
 
lockie86 said:
Thanks Lou, can u suggest a very light (variable?) ND that would work OK (ish)? I definitely need an ND as stopping down too far causes softness as u say, but on a v bright day I def need one or it's too blown out.

To be honest I am tempted to sell this too, have had too many issues with it. What did you change to? I couldn't see much else decent around in this price range.

Thanks again and if you or anyone could recommend an actual filter or post a link that would be brill.
Click to expand...

Personally I have some decent Hoya filters. I have a Hoya circular polarizer, a Hoya HMC NDx8, and a Hoya HMC NDx4. Those have allowed me to shoot in very bright conditions while I was out in Colorado. One time I stacked the ND8 and ND4 together for a very bright scene because I was shooting 24P in extremely bright conditions and wanted to keep my iris at a lower setting.

I use the Xume magnetic filter ring system which works very well for adding/removing external ND quickly. FYI, The main ring can stay on the camera and the lens cap still can be installed but once you add a filter to it there is no longer clearance for the lens cap. If you want to put the lens cap back on you need to remove the filter/filters first.

Link to the Hoya filters:

http://www.bhphotovideo.com/c/searc...N=4027134973+4294955270+4291413233+4242329411

And the Xume system:

http://www.bhphotovideo.com/bnh/con...J6YlaPW1MACFYk-Mgods2MAdA&is=REG&Q=&A=details
 
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Thanks R Hudson, are these filters variable and will they avoid the rusty looking blacks I've been experiencing? Many thanks for your advice!
 
Just go to the links, read about them, and decide if they will or will not work for you. They are not variable but using a variable on an AC90 is a pain with the lens hood on. I have not had any color shift problems with these filters.
 
The "rusty" blacks are most likely IR contamination, so you either need NDs and a IR filter, or NDs with IR filtration combined. Supposedly the new Hoya PRO ND filters have some degree of IR filtration, but I haven't read of anyone testing this feature yet.
 
Ive had great success with 4x4" Schneider Platinum IRND filters on my AC160, but those are eye-wateringly expensive.
 
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