Starting to edit my first shoot done with the V1u in 24p mode. I noticed a purple outline on people standing in the background and next to the windows on the Boat. Also a purple outline around the window. Whats causing this is it my Iris setting?

I believe it's chromatic aberration. I also noticed in this scene shot in 30P on some of the pine trees (full wide focal length). It's a bit more subtle than your example, but there none the less.
http://leebergermedia.com/images/rxburn.jpg

But not in this telephoto shot
http://leebergermedia.com/images/rxburn6.jpg

Brian, if you can, ask your dealer for a replacement. The Canon A1 is said to suffer from CA/color fringing more than the V1, but I must say I never saw it that bad, even at the zoom/aperture limits. Not to mention that the V1 I had before (or HC1 for that matter) showed an almost unnoticeable CA.

It is a chromatic aberration but I don't think is what we generally term chromatic aberration. I have seen the purple fringe on bright light objects shot with the v1. I have also seen this in footage from the XH-A1 but is less so because there is CCD smear that covers over the problem.

With cameras and lenses at these prices there will be aberrations of several types and it is best not too get hung up on them. I doubt whether your customers will notice them as they'll be far more interested in the content.

If anyone asks just say it is a lens flare!! :)

TT

I notice that it appears more in wide shots, but not telephoto.

Both the A1 and the V1 have fair amounts fringing. The amount varies from unit to unit.

Like Tony says, it's best not to get too hung up about it. Unless you have 10,000 to spend on a lens, you're unlikely NOT to see CA.

Oh yes... to minimise CA, reduce the iris to mid levels, avoid the extreme ends of the lens, and avoid high contrast edges - especially with back lighting.

And then thank the Lord you don't have to contend with the JVC HD-100's standard lens.

Both the A1 and the V1 have fair amounts fringing. The amount varies from unit to unit.

Exactly, and this is why I advised Brian to try and replace his unit. Didn't want to upset you, Brian!

Exactly, and this is why I advised Brian to try and replace his unit. Didn't want to upset you, Brian!

Thanks for the quick response guys.
Could my UV FILTER have caused the chromatic aberration to be more noticeable?

I started work on a short film last week just down loaded some of the footage it has the chromatic aberration also. I will call my dealer Monday and ask for a replacement unit. I never notice this on my Z1,FX1 OR A1U.

Alex there was another cameraman at the shot using a JVC GY-HD100U I will try to get some footage and compare.

It's very unlikely (but not impossible) that a flat glass UV filter could cause fringing.

However, UV filters can cause ghosting, flare, and loss of contrast.

And strong lighting (such as the light coming in through the windows) can be a challenge for any video camera (even with CMOS).

Is it that we talked too much about oil paint effect - I can also see it apart from the color fringes.
On certain patterns of the clothings and in the kitchen in the sink. Anyone else see it?

I agree Zsolt. It's mild, but I can see it too!

It is a chromatic aberration but I don't think is what we generally term chromatic aberration.Much more accurate to say it is fringing but not what we generally term chromatic aberration. Not all fringing is chromatic abberation (which is only one of many causes of fringing). In this case, most likely it is the chroma subsampling effect (color bandwidth limitation), as previously described by A.J. deLange in our Canon XL H1 forum: see http://www.dvinfo.net/conf/showpost.php?p=516365&postcount=40 and the rest of that thread for more details.

Nevertheless, it is not what we generally term chromatic aberration.

This is a non issue for me as it's a common artifact of high contrast edges over an overexposed background with electronic sensors. I remember when this surfaced on the first DVX100 clips and people freaked out. A gamma setting without a knee or much knee will increase this happening - with a DVX Cinegamma or similar setting on another camera, you must avoid any overexposure at all costs otherwise you will get this issue or similar ones.

It does not appear to be lens based CA which generally you need motion clips instead of screenshots to properly diagnose as changing focus/zoom should alter the amount of lens CA.

In this lighting situation, you need to either drop the exposure way down or get lots of fill or use a gamma/knee setting with lots of rolloff into highlights.

This is a non issue for me as it's a common artifact of high contrast edges over an overexposed background with electronic sensors. I remember when this surfaced on the first DVX100 clips and people freaked out. A gamma setting without a knee or much knee will increase this happening - with a DVX Cinegamma or similar setting on another camera, you must avoid any overexposure at all costs otherwise you will get this issue or similar ones.

It does not appear to be lens based CA which generally you need motion clips instead of screenshots to properly diagnose as changing focus/zoom should alter the amount of lens CA.

In this lighting situation, you need to either drop the exposure way down or get lots of fill or use a gamma/knee setting with lots of rolloff into highlights.

I don't agree with you that this fringing problem is a non-issue, but it can be worked around quite successfully. I don't own a V1U, but I have owned a Canon XL-H1 for quite some time now. The red and green fringing issue to which many here refer to as CA, occurs most often in overexposed, high-contrast shots, especially where sharp edges are shot against a high contrast background such as trees against the sky, especially at the outer edges of the frame.

Most of the footage I have seen here exhibits this fringing problem too, but not to the same extent that my XL-H1 does. Also, most of the shots I have seen here, with the exception of Steve Mullens work, tend to be overexposed. I think new shooters, or those new to a camera like the V1U tend to rely on the auto mode which overexposes most scenes.

This fringing problem can be reduced to a minimun by avoiding the long and wide ends of the zoom range of your lens and avoiding overexposing your shots, especially very high-contrast scenes. Brian's stills at the top of this thread are perfect examples of overexposed, high-contrast material. Use of the ND filter, and reducing the exposure should minimize or eliminate the fringing in these shots.

The example 24p V1N footage shot by Jung Kyu is a great example of the use of the ND filter to minimize the problems of fringing associated with overexposure. These shots are great and exhibit very little fringing. This footage was well shot from an exposure point of view.

See this link to view Jung Kyu's clip: http://www.dvinfo.net/conf/showthread.php?t=84987

However, I don't agree with the statement that you "need motion clips instead of screenshots to properly diagnose... the amount of lens CA." In fact, it is very easy to analyze lens problems associated with CA in a still photo. CA problems are predominantly at the edges of the lens and not in the center. When you see stills with fringing at the outer edges of the frame only, the probablity that the fringing is CA is very high.

Problems with the chroma subsampling effect (color bandwidth limitation) of electronic sensors, can and will occur anywhere in the frame, while CA occurs at the edges of the frame, more so on the left and right of the frame than the top and bottom because the left and right sides of the frame are the extreme edges of the lens in a 16x9 frame. If this were a chroma subsampling problem, you could see the fringing anywhere within the frame.

If you take a look at the stills Brian provided, you will notice that they are all wide shots (bad area of the lens for CA). You will also notice that they are all very high-contrast, overexposed, and the fringing is on the left and right as well as top and bottom of the frame, but not in the center. This is not a chroma subsampling problem. It is CA. CA isn't a problem at the center of the lens, only at the lens's extremes.

This problem could be reduced to a minimum by turning Auto OFF, setting IRE to 70, using an ND filter and lowering the exposure level. Setting IRE to 70 allows you to see overexposure peaks before there is a problem and gives you plenty of headroom to work with when adjusting your exposure in high-contrast scenes.

There is also the possibility that Brian's camera does have a problem. I have looked at a lot of footage with fringing problems, since I have been on a mission to understand this fringing problem so as to erradicate from all of my shots, but this is probably the worst case I have seen. The problem is that the shots are so overexposed and blown out that it is difficult to determine whether it is definitely CA or a camera problem.

CA is usually both green and magenta on the left and right sides of sharp objects and these stills have mainly magenta fringes, although PDVD_009.jpg does show signs of green fringing on the door of the refrigerator. Magenta only fringing is not characteristic of CA. I would certainly have the camera looked at if you can't get decent shots, since the camera is under warranty. But I would first try to shoot a similar scene with the camera set to Manual mode with IRE set to 70, using the ND filter, and reducing the exposure level. If you get a fairly fringe-free shot, It is probably not a problem with the camera.

Canon has written quite a bit about CA and other lens issues. To read Canon's FAQ on chromatic aberration (CA), visit this link: http://www.canon.com/bctv/faq/chrab.html

Canon offers a great deal of information on this and other issues on their website, but this article is a good starting point.

Dave all shots were in manual mode and the bulit in ND FILTER on the V1 was in use mode 1 and mode 2.

Honestly, there are a ton of blocky artifacts throughout the entire frame. Almost like low quality DV25. I can't tell if this is the JPG compression you added when posting the image. See if you can post a PNG of the last two stills so we can take a better look.

Thanks for the quick response guys.
Could my UV FILTER have caused the chromatic aberration to be more noticeable?

I started work on a short film last week just down loaded some of the footage it has the chromatic aberration also. I will call my dealer Monday and ask for a replacement unit. I never notice this on my Z1,FX1 OR A1U.

Alex there was another cameraman at the shot using a JVC GY-HD100U I will try to get some footage and compare.

The purple fringing on these two shots is more like CCD overload. I can and have induced the same effect with my Sony F350 and the HSs18x5.5 lens. You need to either bring up the light levels in the room with daylight corrected lights, or go outside and ND or scrim the window to cut down the light coming in. The effect gets worse at the ends of the lens coupled with wide open aperture. The camera is not at fault on these two shots.

We have some purple fringing shots in high contrast areas from the HD100 grabs in the Texas HD Shootout.

-gb-

You don't tend to get CCD overload in a CMOS chip. :)

What ever the reason for the fringing it is also reproducible on CCDs and CMOS based cameras.

TT

Why are these still images so blocky? To me that was as much a distraction as the purple fringing.

Honestly, there are a ton of blocky artifacts throughout the entire frame. Almost like low quality DV25. I can't tell if this is the JPG compression you added when posting the image. See if you can post a PNG of the last two stills so we can take a better look.

I Changed the JGP compression to reduce the file size. I will post the video clips tonight. I aslo called BH to exchange the cam the Rep. advised me that it was over there 7 day return policy, So I am sending it to Sony so they can check out the cam. I am Very disappointed with BH.

Has anyone tried using the "Knee Point" on the V1? This would be the ideal situation for it. High contrast with a very overexposed background. Try using "auto" and see what you get. I'm interested to know the results!

SH

You don't tend to get CCD overload in a CMOS chip. :)

What ever the reason for the fringing it is also reproducible on CCDs and CMOS based cameras.

TT

Purple fringing has been a problem for still camera sensors also. So let's just say it's 'sensor' overload. The problem is really bad with a high key light. See this attachment from a Kodak still camera of my friend's Harley.

1976

Note the purple fringing where the front rim/tire meet as well as the handlebars with dark shadows. In short, a high contrast situation and a high key light (close to noon day sun..yuk). The aperture was f3.0 and shutter was at 1/750.

-gb-

Purple fringing has been a problem for still camera sensors also. So let's just say it's 'sensor' overload. The problem is really bad with a high key light. See this attachment from a Kodak still camera of my friend's Harley.

1976

Note the purple fringing where the front rim/tire meet as well as the handlebars with dark shadows. In short, a high contrast situation and a high key light (close to noon day sun..yuk). The aperture was f3.0 and shutter was at 1/750.

-gb-

That is exactly what I saw on my V1 and now on my XH-A1. To be completely honest I don't find these flares distracting.

Ironically these flares are the things we spend a long time in post trying to simulate to make 3d renders look more "real."

TT

To be completely honest I don't find these flares distracting.

That's where you and I come at it from different perspectives. Those purple fringing halos stick out like a sore thumb to me. I absolutely feel that they kill the artistic vibe in my stuff. But to each his own. I have learned what situations produce this phenomena and I try to avoid them at all costs.

The two pictures in the earlier post I referenced appeared to be a staged shoot. I feel like there is ample opportunity to get rid of that stuff in that scenario. OTOH, if you're doing live stuff, it can't always be avoided. I've seen the blue edge on network HD golf broadcasts where they are live and have to get the shot, regardless of conditions. And once again, the commonality there is that the sun is high in the sky during the broadcast and a white shirt or white hat against a green background will produce blue flare on the right side of the subject (ie, a high contrast area).

-gb-

well, i think you guys have put your finger on what I've been experiencing, re purple fringe...here -> http://www.geocities.com/ravens202/Image0.jpg

Bill,
At what focal length did you you shoot this this image?

Lee..

shot with a JVC HD110 at full zoom, ie 85mm f/2.4 (Fujinon 17x5BRMU) HDV 24p....and you're looking at > 100% crop. The original image showed the purple fringe completely around the periphery of the target, i.e., no opposing green fringe, so it's not CA.

I Changed the JGP compression to reduce the file size. I will post the video clips tonight. I aslo called BH to exchange the cam the Rep. advised me that it was over there 7 day return policy, So I am sending it to Sony so they can check out the cam. I am Very disappointed with BH.

Are you sure you didn't recompress to mpeg or something before you made the jpg's? At this filesize (around 200kb) jpeg's shouldn't look like this. It almost looks like upconverted dv25, as someone else also mentioned...

I used to think there was a fair amount of fringing due to CA on the Sony FX7/V1, but when I see the fringing in almost all shots from the Canon A1/G1, I don't feel so bad. There's a current thread in the A1/G1 section on reducing noise, and in that section there's some posted jpegs. There's some really bad CA (or what looks like CA) on the Canon cams. By comparison, the Sony has a very minimal issue in this area.

The purple fringing in the bike shot above seems different to me than the fringing I'm discussing. The bike fringing is horrific and would drive me nuts if I saw it. It almost looks like 'blooming' on a CRT that's been overdriven.

I used to think there was a fair amount of fringing due to CA on the Sony FX7/V1, but when I see the fringing in almost all shots from the Canon A1/G1, I don't feel so bad. There's a current thread in the A1/G1 section on reducing noise, and in that section there's some posted jpegs. There's some really bad CA (or what looks like CA) on the Canon cams. By comparison, the Sony has a very minimal issue in this area.

The purple fringing in the bike shot above seems different to me than the fringing I'm discussing. The bike fringing is horrific and would drive me nuts if I saw it. It almost looks like 'blooming' on a CRT that's been overdriven.


I don't have a V1U but plan to buy one. I have owned an XL-H1 for quite some time and the fringing is my number one complaint about the XL-H1. I have been wrestling with this problem ever since I bought the XL-H1. I tried Canon's new 6X lens but it still has some red and green fringing problems, although not as bad as the 20x lens. The Canon A1 and G1 share this problem with the XL-H1 so I would never consider purchasing either one.

This red and green fringing problem is a very big deal to me because we plan to do a film-out for our next project.

I have been evaluating V1U footage for quite some time. We have decided to purchase one V1U after NAB. And after we have completed our tests, if the fringing is indeed less than the XL-H1, and I think it will be, we plan to sell the XL-H1 and buy two more V1Us.

The V1U footage I have seen to date, has this red and green fringing problem too, but not nearly as much as my XL-H1. I believe the V1U is superior to the XL-H1 in this, and all other ways that are important to us for our upcoming film project, even though I love many things about the XL-H1.

What's keeping us from purchasing a V1U now is that I believe that Sony has a new 24p 1/3" 3 cmos model (a direct competitor to the XL-H1 and JVC HD100/110, with interchangable lenses) ready for NAB, and we can wait until later this year for cameras for our new film project. Afterall, we still have the XL-H1 and a Z1U to complete pickups for our current project.

Just my 2 cents worth.

Guys the fringing isn't just a HDV thing. I have a 2/3" DSR-500 camera which is DVCAM and I have noticed this for years when shooting against bright white backgrounds that are over exposed. This is just something we have to deal with. I have yet to see a HDV camera that doesn't do this. You need some pretty highend glass to get rid of this. Glass that will cost well into the tens of thousands of dollars.

There are however ways to reduce it by taking care on how you shoot certain subjects.

Starting to edit my first shoot done with the V1u in 24p mode. I noticed a purple outline on people standing in the background and next to the windows on the Boat. Also a purple outline around the window. Whats causing this is it my Iris setting?

CLIPS WMV FORMAT

http://www.dvdaction.net/index_007.htm

Hello? Anyone? Has anyone tried the "knee level"? It works well with the HDW-F900. Except there we use a "CCU" with a manual adjustment, and you can dial in the amount you want. It's helpful in situations like the previously posted clip that was shot on the boat. It also can help when shooting interiors with bright windows in the BG that get overexposed. This can reduce the color fringing and apparent CA effect sometimes by "clamping" down the top 1/3 of the IRE. It is easily noticeable on a waveform.

Someone want to give it a try with the VIU and post the results, with and without?

I reviewed the sample jpegs and saw the video.

I agree with most who say that the excessive CA was caused by overexposed video. Unfortunately, the V1 doesn't over a lot of ND, but had the ND been used, I feel the CA would not have been so pronounced. All the other wide shot samples I've seen, the CA is barely noticeable on the V1, unlike the canon A1, where it is present in every wide shot. Thus, I feel that these samples are not set up correctly and are poor examples of the capabilities of this camera. One thought, correct me if I'm wrong, would the backlight compensator along with the ND filter, not only reduce the highly overexposed background but also brighten up the foreground?

As far as CA is concerned, I agree with another comment on this thread that you are not going to virtually eliminate it without adding an expensive lens. Since an expensive lens will hinder the camera's low light capabilities, you need larger chips. Gee I guess that's why the V1 is under $5k and the XDCAM is over $20k.

Peace all

The only way to fix those original shots is to reduce the difference between the brightest (the light coming in the windows) and the darkest parts of the frame. There's two ways to do this. Gell the windows with ND gells or bump up the light on the talent and in the room.
Adding ND in front of the lens will just make everything darker, the Backlight setting in the camera will give you a shot around the same as what was posted.

John the built in ND filter on the V1U was in use. Also correct me if I am wrong the back light and spot light feature can not be used in manual mode on the V1U. This feature can be used on the Z1U and FX1 in manual or auto mode. I never notice fringing on shots taking with my Z1U if it was there it was not noticeable.

I read on article on the making of an HBO special were an XDCAM was used. The Cam or Lens also experienced Fringing.

http://digitalcontentproducer.com/cameras/revfeat/handson_xdcam_hd/index.html

“The new Canon 21X 5.7 IRSE 1/2in. optics lens performed well with the F350, with the exception of some blue and yellow fringing near the edges of the frame in some shots—especially high-detail wide-angle scenes.”


I love V1u but I guess its just knowing what to do and when to do it . The more you shot the more you learn. I plan to purchase a second V1U next month.

Brian,

You can use the backlight compensator or spotlight in manual mode with limitations on the V1. You can only manually adjust either the iris, gain or shutter with backlight compensator or spotlight on. If you manually adjust two or more of the above functions, you cannot use the backlight compensator or spotlight in manual mode. By the way, the backlight compensator and spotlight functions are menu items; you might want to assign them to one of the six or three assignable buttons.

As far as the CA comment, admittingly, the XDCAM was a bad example. My point was the better the lens, the less you see CA (in theory of course).

Peace
John

Brian,

You can use the backlight compensator or spotlight in manual mode with limitations on the V1. You can only manually adjust either the iris, gain or shutter with backlight compensator or spotlight on. If you manually adjust two or more of the above functions, you cannot use the backlight compensator or spotlight in manual mode. By the way, the backlight compensator and spotlight functions are menu items; you might want to assign them to one of the six or three assignable buttons.

As far as the CA comment, admittingly, the XDCAM was a bad example. My point was the better the lens, the less you see CA (in theory of course).

Peace
John


I read the same thing in the V1u manual when I first recieved my cam. I assigned a button to each function neither one worked in manual mode.
(see post)
http://www.dvinfo.net/conf/showthread.php?t=82539

I read the same thing in the V1u manual when I first recieved my cam. I assigned a button to each function neither one worked in manual mode.
(see post)
http://www.dvinfo.net/conf/showthread.php?t=82539
I did the same.

The limitation "You can only manually adjust either the iris, gain or shutter" IF you want to engage the backlight compensator or spotlight -- comes into play when you engage E1 or E2. Sony assumes you'll simply adjust exposure as needed.