green goo in luma transitions

[Keith Rollinson]

Strange manifestation which you can see in the link to the jpg (for some reason it would not allow me to 'manage attachments' here, so it's on my ftp.) PLEASE notice the green goo in the upper left screen between the black pillar and the whitish ceiling. At 1st I thought this might be a manifestation of my lcd (Panasonic LH1700WS) monitor, but it's definitely there.

http://www.rocketscientism.com/XDCAM/

It's the only file in there.

What I'd 1st like to determine is if this is a camera or lens manifestation -- thanks in advance for your insights.

Shot on a F350 w/ Fujinon HSs18x55BRD pretty much full wide at 0dB gain / f2.8 / cine3 / black stretch 18 / sharpness -20. For kicks, I placed a Sony Z1U next to the F350 - and it's completely clean. It was pretty low lightish, but I also saw green edging on the the top of the floor lamp when it was NOT in focus

[Keith Rollinson]

Just had a few minutes to do a little more investigation. If completely zoomed in on a relatively horizontal subject w/ white-to-black transition (eg. as the black pillar intersects the whitish ceiling per the jpg in 1st post), there is quite a show as you focus; as focus moves from in front of subject to focus on subject, there is the green glow rim as evident in the jpg that disappears when completely focussed. As focus travels beyond subject, this glow rim starts again, in red.

Is this the dreaded chroma aberration manifesting its ugly red/green rimming? It's really quite bad, if indeed it's the lens! Appreciate your feedback on this.

Keith

[Alister Chapman]

looks like CA to me, although it dosn't look like it's in focus which won't be helping. Almost all lenses will show some CA, even top end $30k lenses will exhibit some CA. Changes in focus will make it more obvious as the light paths for the 3 CCDs are all slightly different lengths, this is normal.

[Keith Rollinson]

Thanks for the response, Alister. Sorry if the 2nd clarifying post was not clear -- when in focus, the red/green rimming dissappears. When subject is out of focus w/ focus closer to camera, there is a green rim, diminishing as focus sharpens. When out of focus further beyond intended subject, the rimming is red, increasing as focus moves further way from subject.

I would still greatly appreciate hearing from others to help determine if this is a lens or camera issue.

Keith

[Nate Weaver]

White shading the lens supposedly takes care of this, yes Greg?

[Greg Boston]

Originally Posted by Nate Weaver

White shading the lens supposedly takes care of this, yes Greg?

That's exactly right, Nate. I had the very same issue that Keith is describing when I got my replacement lens.

I had to do a thorough white shading adjustment and it's very clean now. Only certain lens setting/key light position conditions will bring out the nasty blue CA and even then only in the outer parts of the image. The center is razor sharp.

-gb-

[Keith Rollinson]

Cool, Greg - what does a thorough white shading adjustment entail? There is nothing about this in the Fujinon manual, or the XDCAM HD manual for that matter. Can I do that? Thanks again.

Keith

[Greg Boston]

Originally Posted by Keith Rollinson

Cool, Greg - what does a thorough white shading adjustment entail? There is nothing about this in the Fujinon manual, or the XDCAM HD manual for that matter. Can I do that? Thanks again.

Keith

It requires an advanced level of skill and that's why it's not covered in the owner's manuals. What lens do you have and have you done the camera firmware update?

We may be able to get it resolved without advanced procedures.

-gb-

[Keith Rollinson]

Thanks, Greg. The lens is the HSs18x5.5BRD (all the specs are listed in my initial posting above). And yes, I've done the upgrade -- after seeing this manifestation, w/ the wild hope it might've helped.

Keith

[Alister Chapman]

White shading won't get rid of this as it changes with focus. It is an effect caused by the way the the paths different wavelengths of light shift as the as the focal point changes. Shading compensates for variations in the amount of light at different frequencies thru the lens, not shifts in position.

[Keith Rollinson]

Still do not know what white shading is, but as you observed, Alister, it is completely dependent on focus. Just rec'd a call from Eddy Lee/Fujinon, who mentioned someone in TX (Greg?) who had the same problem. Mr. Lee thinks this is something caused by the camera, although he began by stating that this is normal for a 1/2" lens. Believe me, this is NOT normal. If the green/red luminance area was NOT the center of focus, but elsewhere, one would still clearly see this in frame, and it is totally unacceptable.

Appreciate your continued insights.

Keith

[Greg Boston]

Originally Posted by Alister Chapman

White shading won't get rid of this as it changes with focus. It is an effect caused by the way the the paths different wavelengths of light shift as the as the focal point changes. Shading compensates for variations in the amount of light at different frequencies thru the lens, not shifts in position.

The focal change is causing the condition to invert as focal length is changed. The fact that it manifests as magenta/green is indicative of white shading.

Before I did my correction mentioned above, I could focus on a metal trim strip on the bottom of my microwave oven door and depending on where I moved the focal point, the green was on top/magenta on bottom or just the opposite on the other side of the critical focus point. At critical focus, the effect was minimized but becomes readily apparent when aiming at a properly lit white target.

I promise you I saw the same thing as Keith, made my corrections in the service menu, and eliminated the effect. I did my correction at the middle of the zoom range because as you know, a zoom lens is all about compromise. If you make things too optimal at one end, they can be really whacked at the other end. This is the same approach I used when I would tune my ham radio antennas for a given band of frequencies. The antenna has a single resonant frequency based on it's physical properties. By resonating it in the center of the band, you accept that it will be less than optimal at the far ends, but not so far out as to be unusable.

-gb-

[Keith Rollinson]

You seem to recognize the problem, Greg, and from the sound of it, it's the camera? More importantly, how can I fix this?!? I'd gladly call you if that's a possibility -- you can contact me off-list if you wish at keith 'at' sector550'dot' com.

TIA,

Keith

[Keith Rollinson]

Geeez...no one can actually help me? I did a search for 'white shading', and found Greg's brief description from a couple of weeks ago, indicating calibrating the VMOD and R/G/B/ flare settings. Great! Or so I thought...my two waveform/vectorscopes are both TEK WFM300As, which allow for composite/component waveform display -- but only component analog SD vectorscope. I have no HD-SDI to YUV SD converter, so stuck again (unable to tweak here in house as per Greg's suggestions.)

If someone who has actually seen the problem (as described in the 1st two postings to this topic) could indicate of they approached SONY or FUJINON for help, this would at least help me take a course of action to get this fixed. As I wrote above, the Fujinon lens tech feels this is a Sony issue. Thanks again.

[Greg Boston]

Originally Posted by Keith Rollinson

Geeez...no one can actually help me? I did a search for 'white shading', and found Greg's brief description from a couple of weeks ago, indicating calibrating the VMOD and R/G/B/ flare settings. Great! Or so I thought...my two waveform/vectorscopes are both TEK WFM300As, which allow for composite/component waveform display -- but only component analog SD vectorscope. I have no HD-SDI to YUV SD converter, so stuck again (unable to tweak here in house as per Greg's suggestions.)

If someone who has actually seen the problem (as described in the 1st two postings to this topic) could indicate of they approached SONY or FUJINON for help, this would at least help me take a course of action to get this fixed. As I wrote above, the Fujinon lens tech feels this is a Sony issue. Thanks again.

Sorry Keith, I somehow missed your earlier post where you answered my question. Ok, make sure you enable the serial communcation on the lens as explained on another thread in this forum. Go into the Lens File menu and turn on Lens Auto Recall. When you power up the camera, the camera will recall the offsets that match that lens file id. I was informed that there are manufacturer supplied lens corrections for popular lenses implemented in the firmware. Try this first and see if the situation improves. Beyond that, there is a procedure that can be done but it's not a user level function.

-gb-