Minimum file size for photographs at DVinfo.net

Galen Rath · February 26th, 2006, 05:43 PM

What is the minimum file size for a photograph so that it translates okay when viewed on a SD television screen? What's the ideal size? Too big and it clogs up the NLE computing process I've heard, and at some point in the larger file sizes you probably won't get back a better picture on the TV screen--correct? I know really larger file sizes will allow you to zoom in as needed, but inn general for a wedding photo montage, what is the ideal camera setting?

Emre Safak · February 26th, 2006, 05:55 PM

That's right--there is only one size! For NTSC it's 720x480, for PAL it's 720x576.. and don't forget to account for the pixel aspect ration (e.g., SD is 4:3 while 720x480 is 3:2, so the pixel aspect ratio is 8:9).

What you could do, if you have a JPEG, is to ensure that the amount of compression is as low as possible.

Robert M Wright · February 26th, 2006, 07:02 PM

This is sort of a two fold question.

File size, per se, will have a direct correlation to both pixel count (resolution) AND compression method (if any). To be technically correct, both luminance and chroma resolutions factor in, in YUV color space, as being components of total resolution (but you probably don't want to worry about which color space the photo image is represented in).

For quality, it's best not to use any lossy compression method (like JPEG). TIFF or BMP, or a number of other file formats, using lossless or no compression, are best for quality. Lossy methods of compression can save you file space, but there is a tradeoff in quality for achieving smaller file sizes (JPEG compression does offer good performance if you need to get smaller file sizes than a lossless method can achieve).

As far as resolution, it depends on if (and how much) you will be panning and zooming. Ideally you would want to hit a frame resolution of 720x480 pixels (to create a DVD - ideally, YUV 4:2:0), at the proper aspect ratio, for the smallest part of the photo that will be used (and do the math to arrive at an ideal resolution for the entire photo, needed to accomplish that). Going over that ideal resolution can actually wind up making for a poorer quality end result (when the NLE downsizes it).

Patrick Moreau · February 26th, 2006, 07:07 PM

Quote:

Originally Posted by Emre Safak

That's right--there is only one size!

I don't think Emre read your whole question or he is misinformed. You will want a size larger than regular SD if you would like to zoom in. Generally, I would multiply the amount of zoom you prefer by the resolution of SD to get a good size for all photos. I use about 6MP images which is much more than you need but works very well in jpg format and gives you plenty of options. I would feel comfortable using half of that, or 3MP.

I wrote this as Rob was writing so the post may not be as useful now. Rob did a great job of going over all the details.

Bill Rankin · March 22nd, 2006, 07:49 PM

I am creating a montage that will group several pictures together with video immediately following to be played on a DVD player and displayed on a screen via a projector (DLP)

Should I use higher resolution for the pictures (300 v 72) since it will not be displayed on a television?

Since it is played on DVD player the max resolution can only be 72dpi ?

Please clarify...Thank you....

Emre Safak · March 23rd, 2006, 05:39 AM

It does not matter whether you view it on a TV or through a projector; it is the format (DVD) that matters, so the answer remains the same. At any moment, you can only show 720x480 (NTSC) or 720x576 (PAL) pixels.

February 26th, 2006, 05:43 PM	#1
Galen Rath Major Player Join Date: Nov 2005 Location: Illinois Posts: 323	Minimum file size for photographs What is the minimum file size for a photograph so that it translates okay when viewed on a SD television screen? What's the ideal size? Too big and it clogs up the NLE computing process I've heard, and at some point in the larger file sizes you probably won't get back a better picture on the TV screen--correct? I know really larger file sizes will allow you to zoom in as needed, but inn general for a wedding photo montage, what is the ideal camera setting?

March 22nd, 2006, 07:49 PM	#5
Bill Rankin Major Player Join Date: Jul 2005 Location: Houston, TX Posts: 433	What about photo resolution for display on projector? I am creating a montage that will group several pictures together with video immediately following to be played on a DVD player and displayed on a screen via a projector (DLP) Should I use higher resolution for the pictures (300 v 72) since it will not be displayed on a television? Since it is played on DVD player the max resolution can only be 72dpi ? Please clarify...Thank you.... __________________ Bill Rankin

February 26th, 2006, 05:55 PM	#2
Emre Safak Trustee Join Date: Feb 2004 Location: Brookline, MA Posts: 1,447	That's right--there is only one size! For NTSC it's 720x480, for PAL it's 720x576.. and don't forget to account for the pixel aspect ration (e.g., SD is 4:3 while 720x480 is 3:2, so the pixel aspect ratio is 8:9). What you could do, if you have a JPEG, is to ensure that the amount of compression is as low as possible.

February 26th, 2006, 07:02 PM	#3
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	This is sort of a two fold question. File size, per se, will have a direct correlation to both pixel count (resolution) AND compression method (if any). To be technically correct, both luminance and chroma resolutions factor in, in YUV color space, as being components of total resolution (but you probably don't want to worry about which color space the photo image is represented in). For quality, it's best not to use any lossy compression method (like JPEG). TIFF or BMP, or a number of other file formats, using lossless or no compression, are best for quality. Lossy methods of compression can save you file space, but there is a tradeoff in quality for achieving smaller file sizes (JPEG compression does offer good performance if you need to get smaller file sizes than a lossless method can achieve). As far as resolution, it depends on if (and how much) you will be panning and zooming. Ideally you would want to hit a frame resolution of 720x480 pixels (to create a DVD - ideally, YUV 4:2:0), at the proper aspect ratio, for the smallest part of the photo that will be used (and do the math to arrive at an ideal resolution for the entire photo, needed to accomplish that). Going over that ideal resolution can actually wind up making for a poorer quality end result (when the NLE downsizes it).

March 23rd, 2006, 05:39 AM	#6
Emre Safak Trustee Join Date: Feb 2004 Location: Brookline, MA Posts: 1,447	It does not matter whether you view it on a TV or through a projector; it is the format (DVD) that matters, so the answer remains the same. At any moment, you can only show 720x480 (NTSC) or 720x576 (PAL) pixels.