Converting between pixel aspect ratios at DVinfo.net

Bjørn Sørensen · April 3rd, 2008, 07:55 AM

I have some still images in Photoshop that I want to use in a video project (DV 16:9 PAL)

I have scaled the images down to apx. 2500 pixels to be able to scale them in the timeline.

When I import the pictures they look wider than normal in FCP, and I know that has something to do with Square Pixels vs. Non Squaer pixels.

Question: HOW can I convert my pictures in Photoshop so they will look normal when viewed in FCP ?

Bjorn

Robert Lane · April 3rd, 2008, 08:54 AM

When you pre-scaled your images did you use the "keep aspect ratio" option checked in PS, or did you manually enter values for both horiz and vert?

When pre-scaling photos it's best to not make them much larger than the actual frame size you're working with. If it's HDTV spec then the max width should be around 1500px. Unlike a freeze-frame grab from video, actual still photos scale up and down very well before they fall apart, so don't worry if you plan to zoom in on your stills in your sequences. The only time you'd want to use a max pixel size of more than 1500 is if you're going to zoom in more than 200%, then you'd want more resolution.

Bjørn Sørensen · April 3rd, 2008, 09:02 AM

Robert,

I had the "keep aspect button" checked.

Can I downscale the width of the images with the "keep aspect ratio" button unchecked? But how many percent ?

Bjorn

Robert Lane · April 3rd, 2008, 03:18 PM

Don't use percent, use actual pixel numbers. That way you know exactly how big they'll be - or not - in the FCP canvas.

Liam Hall · April 3rd, 2008, 05:30 PM

That's odd, photoshop should be able to manage the different pixel shape. You could try manually changing it within FCP. Double click one of your stills in the timeline. On the motion tab, enter 42.22 in the "aspect Ratio" dialog- I bet that sorts it.

Mike Flynn · April 4th, 2008, 11:44 PM

You also might try messing around with the pixel aspect ratio in Photoshop. Go to the "Image" menu and choose "Pixel Aspect Ratio." Then change it to Widescreen DV or whatever your project calls for. That usually fixes it for me.

April 3rd, 2008, 07:55 AM	#1
Bjørn Sørensen Regular Crew Join Date: Nov 2002 Location: Denmark Posts: 143	Converting between pixel aspect ratios I have some still images in Photoshop that I want to use in a video project (DV 16:9 PAL) I have scaled the images down to apx. 2500 pixels to be able to scale them in the timeline. When I import the pictures they look wider than normal in FCP, and I know that has something to do with Square Pixels vs. Non Squaer pixels. Question: HOW can I convert my pictures in Photoshop so they will look normal when viewed in FCP ? Bjorn __________________ x

April 3rd, 2008, 08:54 AM	#2
Robert Lane Go Go Godzilla Join Date: Nov 2004 Location: Scottsdale, AZ USA Posts: 2,825 Images: 15	When you pre-scaled your images did you use the "keep aspect ratio" option checked in PS, or did you manually enter values for both horiz and vert? When pre-scaling photos it's best to not make them much larger than the actual frame size you're working with. If it's HDTV spec then the max width should be around 1500px. Unlike a freeze-frame grab from video, actual still photos scale up and down very well before they fall apart, so don't worry if you plan to zoom in on your stills in your sequences. The only time you'd want to use a max pixel size of more than 1500 is if you're going to zoom in more than 200%, then you'd want more resolution. Last edited by Robert Lane; April 3rd, 2008 at 03:18 PM.

April 3rd, 2008, 09:02 AM	#3
Bjørn Sørensen Regular Crew Join Date: Nov 2002 Location: Denmark Posts: 143	Robert, I had the "keep aspect button" checked. Can I downscale the width of the images with the "keep aspect ratio" button unchecked? But how many percent ? Bjorn __________________ x

April 3rd, 2008, 05:30 PM	#5
Liam Hall Major Player Join Date: Sep 2006 Location: London, England Posts: 969	That's odd, photoshop should be able to manage the different pixel shape. You could try manually changing it within FCP. Double click one of your stills in the timeline. On the motion tab, enter 42.22 in the "aspect Ratio" dialog- I bet that sorts it. __________________ Writer-Director-DOP www.liamhall.net

April 3rd, 2008, 03:18 PM	#4
Robert Lane Go Go Godzilla Join Date: Nov 2004 Location: Scottsdale, AZ USA Posts: 2,825 Images: 15	Don't use percent, use actual pixel numbers. That way you know exactly how big they'll be - or not - in the FCP canvas.

April 4th, 2008, 11:44 PM	#6
Mike Flynn Regular Crew Join Date: Sep 2004 Location: Renton, WA Posts: 94	You also might try messing around with the pixel aspect ratio in Photoshop. Go to the "Image" menu and choose "Pixel Aspect Ratio." Then change it to Widescreen DV or whatever your project calls for. That usually fixes it for me.