ex1 skew question at DVinfo.net

Sam Alcoff · December 6th, 2008, 02:06 PM

I'm trying to wrap my head around the cmos and skew. Can you point the ex1 out a train/car/subway window at a 90 degree angle and shoot the vertical lines going by without skew if you have a fast enough shutter speed? Or will you still get skew? I really like the opening shot of the sour strawberries video on vimeo, shot on ccd, and I haven't found a lot of similar shots from the ex1. I'm beginning to lean to the ex1, but will the rolling shutter kill it?

Your replies are appreciated. It's clear that the ex1 is a great camera and if this is an issue, I don't see it as an achilles heel for everyone. That is, I'm not trying to reignite the cmos/ccd debate, I just want to know if speeding the shutter speed would keep the vertical lines vertical. If there are examples online, I'd love to see them. Thanks.

Bill Ravens · December 6th, 2008, 02:55 PM

Regardless of the shutter speed chosen, the CMOS sensor "scans" the focal plane very much like the raster scans on a CRT TV set. My understanding is that the scan rate is 60Hz. This means that it takes the scan function 1/60 of a sec or .01667 secs. If there is vertical motion in the frame, a moving object that has moved from the top of the image frame to the bottom of the image frame in less than .01667 secs, will appear to be displaced horizontally, or skewed. This is regardless of the shutter speed chosen.

Steven Thomas · December 6th, 2008, 08:29 PM

Sam,
You're asking EX owners if they are bothered withe CMOS artifacts. I'm sure we all agree they are there, but it did not stop us from buying the EX. The image quality is excellent.

If you're worried about skew, stay away from CMOS sensor cameras. The Panasonic HPX170 is a decent camera that uses CCD.
Also, the upcoming RED Scarlet is supposed to have improved on their CMOS sensor with a faster scan rate.

EX1 whip pan:
http://www.dvinfo.net/conf/attachmen...astshutter.mov

Steve Phillipps · December 7th, 2008, 05:42 AM

It's the one thing that put me off the EX cameras in my brief testing of an EX1. I shoot wildlife, lot of flying birds etc., and the quick tests I did showed the background looking very jittery. But I know lots of people say it's nonsense, so will be trying an EX3 shortly side by side with my PDW700 to see how they compare.
Also, even if I didn't need interchangeable lenses I'd buy an EX3 over and EX1 purely on the strength of the viewfinder, the one on the EX1 is atrocious, almost as if they expected all users just to use the LCD.
Steve

Matt Davis · December 7th, 2008, 07:16 AM

Quote:

Originally Posted by Steve Phillipps

the one on the EX1 is atrocious, almost as if they expected all users just to use the LCD.

What? The EX1 has a viewfinder?! I thought it was an exhaust.

There's always the Hood-Pro.

Paul Cronin · December 7th, 2008, 09:24 AM

Steve would be interesting if you could test the EX3 vs the PDW700 with the EX3 hooked up to the Convergent Design Flash XDR set at the same 50Mbp/s 422 as the PDW700. I have the XDR and EX it is a huge difference at that setting and even better at the 100Mbp/s setting.

Steven Thomas · December 7th, 2008, 09:31 AM

Paul,
Congrats on the XDR.

You probably already know this but the EX1 whip pan sample video (posted above) was captured to XDR 4:2:2 100mbps long-GOP.

Playing back this video frame by frame shows has how well this codec holds up.
I'd like to see a comparison XDCAM 35mbps vs 50mbps under fast motion.

This capture drive and codec throws the Sony EX cameras into a another level of quality...unreal.

Looking at this video you certainly can see skew, but due to the high motion it's not obvious and thanks to the excellent 100mbps codec, there's no
obvious image flaws due to compression artifacts.

Paul Cronin · December 7th, 2008, 09:47 AM

Thanks Steve it was time. That example plus talking with Dan and Mike made me realize it was the right move for my business. I am still waiting on an Anton Bauer gold mount to arrive tomorrow so I can start field-testing. So far I have a few days in my office with AC power testing and have been very impressed.

Now I am going to move from EX1 to EX3 so I can upgrade the optics with nice Canon and Fujinon lens. Also it will be nice when Apple adds 100Mbp/s to Final Cut.

I will be posting on a thread I started “New Flash XDR owner” (http://www.dvinfo.net/conf/convergen...xdr-owner.html) some examples. Very excited to have it dialed in and using it on my next Aerial job.

Steven Thomas · December 7th, 2008, 10:01 AM

Thanks Paul. Yes, I've been following that thread. I'm looking forward to your 50mbps and 100mpbs samples!

Bill Ravens · December 7th, 2008, 10:18 AM

hey steve...

thanx for all your work with the flash xdr.
I'm on the early adopter list for the nano-flash. wish the boys at C-D would hurry up. I keep reading your posts and wishing.

Steven Thomas · December 7th, 2008, 10:32 AM

Bill, I believe this sample was done by Jim Arthurs.
I'm also waiting to buy the Nano.

Bill Ravens · December 7th, 2008, 10:40 AM

Quote:

Originally Posted by Steven Thomas

Bill, I believe this sample was done by Jim Arthurs.
I'm also waiting to buy the Nano.

oops..no, paul cronin desrves the credit.

Paul Cronin · December 7th, 2008, 10:57 AM

You are welcome Bill I will try and keep the learning curve going and post my findings.

Sebastien Thomas · December 12th, 2008, 12:36 PM

Quote:

Originally Posted by Steven Thomas

Sam,
You're asking EX owners if they are bothered withe CMOS artifacts. I'm sure we all agree they are there, but it did not stop us from buying the EX. The image quality is excellent.

If you're worried about skew, stay away from CMOS sensor cameras. The Panasonic HPX170 is a decent camera that uses CCD.
Also, the upcoming RED Scarlet is supposed to have improved on their CMOS sensor with a faster scan rate.

EX1 whip pan:
http://www.dvinfo.net/conf/attachmen...astshutter.mov

I did a short movie, almost shot in a moving car.
I had no problem with exteriors even when the car was moving fast.
The only time I had the problem was with the EX1 attached to a beam outside on the top of the car. The camera was shaking really fast.
Inthat situation, the skew is multiplied showing a "wave" effect in the image. Whatever, the director used the shot anyway :)

If you're not doing spcial shots, go with the EX1, you will have a so good experience you will not regreat.

December 6th, 2008, 02:06 PM	#1
Sam Alcoff New Boot Join Date: Feb 2008 Location: Brooklyn, NY Posts: 11	ex1 skew question I'm trying to wrap my head around the cmos and skew. Can you point the ex1 out a train/car/subway window at a 90 degree angle and shoot the vertical lines going by without skew if you have a fast enough shutter speed? Or will you still get skew? I really like the opening shot of the sour strawberries video on vimeo, shot on ccd, and I haven't found a lot of similar shots from the ex1. I'm beginning to lean to the ex1, but will the rolling shutter kill it? Your replies are appreciated. It's clear that the ex1 is a great camera and if this is an issue, I don't see it as an achilles heel for everyone. That is, I'm not trying to reignite the cmos/ccd debate, I just want to know if speeding the shutter speed would keep the vertical lines vertical. If there are examples online, I'd love to see them. Thanks. __________________ dvx100, macs, fcp, documentaryisneverneutral.com

December 7th, 2008, 09:24 AM	#6
Paul Cronin Inner Circle Join Date: Dec 2005 Location: Rhode Island Posts: 4,048	Steve would be interesting if you could test the EX3 vs the PDW700 with the EX3 hooked up to the Convergent Design Flash XDR set at the same 50Mbp/s 422 as the PDW700. I have the XDR and EX it is a huge difference at that setting and even better at the 100Mbp/s setting. __________________ Paul Cronin www.paulcroninstudios.com

December 7th, 2008, 09:47 AM	#8
Paul Cronin Inner Circle Join Date: Dec 2005 Location: Rhode Island Posts: 4,048	Thanks Steve it was time. That example plus talking with Dan and Mike made me realize it was the right move for my business. I am still waiting on an Anton Bauer gold mount to arrive tomorrow so I can start field-testing. So far I have a few days in my office with AC power testing and have been very impressed. Now I am going to move from EX1 to EX3 so I can upgrade the optics with nice Canon and Fujinon lens. Also it will be nice when Apple adds 100Mbp/s to Final Cut. I will be posting on a thread I started “New Flash XDR owner” (http://www.dvinfo.net/conf/convergen...xdr-owner.html) some examples. Very excited to have it dialed in and using it on my next Aerial job. __________________ Paul Cronin www.paulcroninstudios.com

December 7th, 2008, 10:57 AM	#13
Paul Cronin Inner Circle Join Date: Dec 2005 Location: Rhode Island Posts: 4,048	You are welcome Bill I will try and keep the learning curve going and post my findings. __________________ Paul Cronin www.paulcroninstudios.com

December 6th, 2008, 02:55 PM	#2
Bill Ravens Join Date: Nov 2001 Location: santa fe, nm Posts: 3,264 Images: 10	Regardless of the shutter speed chosen, the CMOS sensor "scans" the focal plane very much like the raster scans on a CRT TV set. My understanding is that the scan rate is 60Hz. This means that it takes the scan function 1/60 of a sec or .01667 secs. If there is vertical motion in the frame, a moving object that has moved from the top of the image frame to the bottom of the image frame in less than .01667 secs, will appear to be displaced horizontally, or skewed. This is regardless of the shutter speed chosen.

December 6th, 2008, 08:29 PM	#3
Steven Thomas Trustee Join Date: Sep 2005 Location: Gilbert, AZ Posts: 1,896	Sam, You're asking EX owners if they are bothered withe CMOS artifacts. I'm sure we all agree they are there, but it did not stop us from buying the EX. The image quality is excellent. If you're worried about skew, stay away from CMOS sensor cameras. The Panasonic HPX170 is a decent camera that uses CCD. Also, the upcoming RED Scarlet is supposed to have improved on their CMOS sensor with a faster scan rate. EX1 whip pan: http://www.dvinfo.net/conf/attachmen...astshutter.mov

December 7th, 2008, 05:42 AM	#4
Steve Phillipps Inner Circle Join Date: Apr 2006 Location: Wales Posts: 2,130	It's the one thing that put me off the EX cameras in my brief testing of an EX1. I shoot wildlife, lot of flying birds etc., and the quick tests I did showed the background looking very jittery. But I know lots of people say it's nonsense, so will be trying an EX3 shortly side by side with my PDW700 to see how they compare. Also, even if I didn't need interchangeable lenses I'd buy an EX3 over and EX1 purely on the strength of the viewfinder, the one on the EX1 is atrocious, almost as if they expected all users just to use the LCD. Steve

December 7th, 2008, 09:31 AM	#7
Steven Thomas Trustee Join Date: Sep 2005 Location: Gilbert, AZ Posts: 1,896	Paul, Congrats on the XDR. You probably already know this but the EX1 whip pan sample video (posted above) was captured to XDR 4:2:2 100mbps long-GOP. Playing back this video frame by frame shows has how well this codec holds up. I'd like to see a comparison XDCAM 35mbps vs 50mbps under fast motion. This capture drive and codec throws the Sony EX cameras into a another level of quality...unreal. Looking at this video you certainly can see skew, but due to the high motion it's not obvious and thanks to the excellent 100mbps codec, there's no obvious image flaws due to compression artifacts.

December 7th, 2008, 10:01 AM	#9
Steven Thomas Trustee Join Date: Sep 2005 Location: Gilbert, AZ Posts: 1,896	Thanks Paul. Yes, I've been following that thread. I'm looking forward to your 50mbps and 100mpbs samples!

December 7th, 2008, 10:18 AM	#10
Bill Ravens Join Date: Nov 2001 Location: santa fe, nm Posts: 3,264 Images: 10	hey steve... thanx for all your work with the flash xdr. I'm on the early adopter list for the nano-flash. wish the boys at C-D would hurry up. I keep reading your posts and wishing.

December 7th, 2008, 10:32 AM	#11
Steven Thomas Trustee Join Date: Sep 2005 Location: Gilbert, AZ Posts: 1,896	Bill, I believe this sample was done by Jim Arthurs. I'm also waiting to buy the Nano.