SteadyShot -- Interesting if true

John Klein · September 24th, 2002, 06:45 PM

The halo around a light sounds to me like the digital edge artifact. But it could be a type of lens flare.

It's been an interesting read so far.

With my 150, I once shot a an orchestra that used ultra reflective drums where the reflected light (pretty hot) shone the effect of a star filter. Very mild (small enhancement), but the light point looked like a star. I thought it looked very nice. Then again if it were too blaring, it would begin to look tired but for now, everyone's gonna dig it!

Jeff Donald · September 24th, 2002, 09:02 PM

I'm working on some tests I've done concerning fireflies and the hallow effect i've obtained. Mike, what was the weather like when you shot your tests? Was it humid? We just had a little cold snap here, went into the lower 70's overnight and less humid the last two days. I reshot some tests with the halo (street lights). I think the halo is humidity related. Light refracting off moisture in the air. It is less noticeable in the footage I shot last night.

Jeff

Graham Baker · October 1st, 2002, 07:47 PM

The dancing firefly effect is not always apparent and I think it might be more to do with the 'type' of optical stabilisation.
The problem can be found in older Hi8 cams - my old TR2000 had this problem - I distinctly remember that by turning off the OIS the problem went away...
My knowledge of OIS systems is very limited but AFAIK, there are two types - one uses a moving or vibrating prism and the other uses a silicon lens that is moved or deformed to compensate for shake. IIRC, the silicon oil filled lens is perhaps the older type of OIS - my TR2000 had warnings in the manual about the possibilty of air bubbles showing on the lens after long, high altitude flights etc..

Mike Rehmus · October 1st, 2002, 10:21 PM

Jeff, it was a dry night but Vallejo has SF bay on 2 sides but plenty of wind. I'd say it wasn't very humid for California. Under 50% (just a guess).

Andre De Clercq · October 4th, 2002, 02:42 PM

The “mysteries” described in these posts are known and have been described and documented in the past and except halo, belong to the “lensflare” domain.
If we suppose “good “optics, halo or optical blooming (not to be confused with the CCD blooming effects) resulting from small and strong lightsources, is caused by diffraction.: The (intensity clipped) lightsource shows its “airy disks” just around the lightspot if the F-number is relatively low (large aperture). At higher F-numbers, the same diffraction phenoma generates the “star” (6 point stars when 6 blade diafragm is used).
Fireflies or pointsource ghostings are generated by surfaces (mostly) in the frontside of the optics path. Parallel flat sufaces are the best candidates for generation of fireflies. Hence fluid prism OIS is a problem candidate. Moving lens OIS concepts are more robust in this respect. Even perfectly coated surfaces (still reflecting .5% of the light) cannot resolve the problem. We should know that lightsouces often have a surface light intensity (nit) which can easely reach 10^5 times the (dark) scene intensity. If someone wants to verify the (dancing) fireflies, just keep the camera close (under about 45deg) to a white surface (in a dimmed room) and point a laserpointer under 45deg, into the cameralens and the wonderfull ghost are there.
Deeper reflections are possible too and depend on the conbined surface nonflatnesses of the internal optics . Shifting (internal) zoon parts have their influence too. Reflection raytracing (Zemax) can predict all this…
Besides the overalll flare effects, which tend to add extra (haze) on the whole scene, and thus reducing the contrast, the aperture form itself can occur in the picture as multiple color patches.(e.g. oblique shooting into the sun) This effect belongs to the internal reflection generated behind the aperture and close to the CCD (prism)

September 24th, 2002, 06:45 PM	#16
John Klein Regular Crew Join Date: Dec 2001 Location: Wisconsin, USA Posts: 182	The halo around a light sounds to me like the digital edge artifact. But it could be a type of lens flare. It's been an interesting read so far. With my 150, I once shot a an orchestra that used ultra reflective drums where the reflected light (pretty hot) shone the effect of a star filter. Very mild (small enhancement), but the light point looked like a star. I thought it looked very nice. Then again if it were too blaring, it would begin to look tired but for now, everyone's gonna dig it! __________________ < >< . . . . . < >< . . . . . < ><

October 1st, 2002, 10:21 PM	#19
Mike Rehmus Wrangler Join Date: May 2002 Location: Vallejo, California Posts: 4,049	Jeff, it was a dry night but Vallejo has SF bay on 2 sides but plenty of wind. I'd say it wasn't very humid for California. Under 50% (just a guess). __________________ Mike Rehmus Hey, I can see the carrot at the end of the tunnel!

September 24th, 2002, 09:02 PM	#17
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	I'm working on some tests I've done concerning fireflies and the hallow effect i've obtained. Mike, what was the weather like when you shot your tests? Was it humid? We just had a little cold snap here, went into the lower 70's overnight and less humid the last two days. I reshot some tests with the halo (street lights). I think the halo is humidity related. Light refracting off moisture in the air. It is less noticeable in the footage I shot last night. Jeff

October 1st, 2002, 07:47 PM	#18
Graham Baker Regular Crew Join Date: Sep 2002 Location: Melbourne Australia Posts: 43	The dancing firefly effect is not always apparent and I think it might be more to do with the 'type' of optical stabilisation. The problem can be found in older Hi8 cams - my old TR2000 had this problem - I distinctly remember that by turning off the OIS the problem went away... My knowledge of OIS systems is very limited but AFAIK, there are two types - one uses a moving or vibrating prism and the other uses a silicon lens that is moved or deformed to compensate for shake. IIRC, the silicon oil filled lens is perhaps the older type of OIS - my TR2000 had warnings in the manual about the possibilty of air bubbles showing on the lens after long, high altitude flights etc..

October 4th, 2002, 02:42 PM	#20
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	The “mysteries” described in these posts are known and have been described and documented in the past and except halo, belong to the “lensflare” domain. If we suppose “good “optics, halo or optical blooming (not to be confused with the CCD blooming effects) resulting from small and strong lightsources, is caused by diffraction.: The (intensity clipped) lightsource shows its “airy disks” just around the lightspot if the F-number is relatively low (large aperture). At higher F-numbers, the same diffraction phenoma generates the “star” (6 point stars when 6 blade diafragm is used). Fireflies or pointsource ghostings are generated by surfaces (mostly) in the frontside of the optics path. Parallel flat sufaces are the best candidates for generation of fireflies. Hence fluid prism OIS is a problem candidate. Moving lens OIS concepts are more robust in this respect. Even perfectly coated surfaces (still reflecting .5% of the light) cannot resolve the problem. We should know that lightsouces often have a surface light intensity (nit) which can easely reach 10^5 times the (dark) scene intensity. If someone wants to verify the (dancing) fireflies, just keep the camera close (under about 45deg) to a white surface (in a dimmed room) and point a laserpointer under 45deg, into the cameralens and the wonderfull ghost are there. Deeper reflections are possible too and depend on the conbined surface nonflatnesses of the internal optics . Shifting (internal) zoon parts have their influence too. Reflection raytracing (Zemax) can predict all this… Besides the overalll flare effects, which tend to add extra (haze) on the whole scene, and thus reducing the contrast, the aperture form itself can occur in the picture as multiple color patches.(e.g. oblique shooting into the sun) This effect belongs to the internal reflection generated behind the aperture and close to the CCD (prism)