Vignetting normal with the 20x Lense? and Bad frames... at DVinfo.net

Nathan Quattrini · January 18th, 2007, 03:22 PM

I have started playing around a tiny with the H1 at work, and the first thing I noticed was once imported, there was noticable vignetting occuring around the whole frame, more so on the corners. Is this because of low light? The hood? Its all new to me so help would be great. Also the first 2 frames of every clip were jarbled up, is this a camera problem? Or maybe a problem with the Firestpre FS4 pro? Thanks

Daniel Epstein · January 18th, 2007, 06:57 PM

Was this vignetting only at the wide end of the lens or did you see it through out. It certainly isn't normal on the standard 20 lens in average situations. It could be an exposure issue as well. The lens will have fall off from the center to the corners in low light. Do the corners go full black or do they just shade the image. The hood is a definite possibility if it isn't seated properly. Also did you put any screw on filters or adapters on the lens? As for the bad frames this sounds like a Firestore issue.

Nathan Quattrini · January 19th, 2007, 11:11 AM

here are the vignetting examples (ignore the focus, test only) Not sure why they are stretched either....grrr....

1. top corners most noticable, some may be the light issue, but 2 is zoomed in and you see the same exact pattern of darkness, even more noticable in motion

2.

3. Again top right corner and right edge

and here are the garbledfirst 2 frames from a few files

Steven Dempsey · January 19th, 2007, 02:53 PM

I experience vignetting similar to that in some situations. I haven't really had the inclination to figure out why because it's fairly rare.

The garbled two frames at the beginning of your file is normal when capturing raw m2t files.

Daniel Epstein · January 19th, 2007, 05:23 PM

Actually looking at the frames it looks like fairly normal lens fall off in low light. When you are shooting in low light and have a neutral surface you will see many lens issues which disappear in better light levels. Very common with zoom lenses. Many defects appear outside of TV Safe which used to make them a non issue.

January 18th, 2007, 03:22 PM	#1
Nathan Quattrini Major Player Join Date: Jan 2007 Location: Warwick, Rhode Island Posts: 740	Vignetting normal with the 20x Lense? and Bad frames... I have started playing around a tiny with the H1 at work, and the first thing I noticed was once imported, there was noticable vignetting occuring around the whole frame, more so on the corners. Is this because of low light? The hood? Its all new to me so help would be great. Also the first 2 frames of every clip were jarbled up, is this a camera problem? Or maybe a problem with the Firestpre FS4 pro? Thanks __________________ Cinematography Site

January 19th, 2007, 11:11 AM	#3
Nathan Quattrini Major Player Join Date: Jan 2007 Location: Warwick, Rhode Island Posts: 740	here are the vignetting examples (ignore the focus, test only) Not sure why they are stretched either....grrr.... 1. top corners most noticable, some may be the light issue, but 2 is zoomed in and you see the same exact pattern of darkness, even more noticable in motion 2. 3. Again top right corner and right edge and here are the garbledfirst 2 frames from a few files __________________ Cinematography Site Last edited by Nathan Quattrini; January 19th, 2007 at 11:15 AM. Reason: fixing image links

January 19th, 2007, 02:53 PM	#4
Steven Dempsey Disjecta Join Date: Apr 2004 Location: Seattle, Washington Posts: 937	I experience vignetting similar to that in some situations. I haven't really had the inclination to figure out why because it's fairly rare. The garbled two frames at the beginning of your file is normal when capturing raw m2t files. __________________ Try my Digital Therapy: http://www.pinelakefilms.com/digital_therapy.html Films on ExposureRoom: http://exposureroom.com/members/disjecta.aspx/videos/

January 18th, 2007, 06:57 PM	#2
Daniel Epstein Trustee Join Date: Jan 2006 Location: New York, NY Posts: 1,267	Was this vignetting only at the wide end of the lens or did you see it through out. It certainly isn't normal on the standard 20 lens in average situations. It could be an exposure issue as well. The lens will have fall off from the center to the corners in low light. Do the corners go full black or do they just shade the image. The hood is a definite possibility if it isn't seated properly. Also did you put any screw on filters or adapters on the lens? As for the bad frames this sounds like a Firestore issue.

January 19th, 2007, 05:23 PM	#5
Daniel Epstein Trustee Join Date: Jan 2006 Location: New York, NY Posts: 1,267	Actually looking at the frames it looks like fairly normal lens fall off in low light. When you are shooting in low light and have a neutral surface you will see many lens issues which disappear in better light levels. Very common with zoom lenses. Many defects appear outside of TV Safe which used to make them a non issue.