Posted by David Senesac on August 27, 2008 at 2:55 PM
Do you have your computer display monitors horizontal versus height, X versus Y, display dimensions reasonably accurately adjusted? I'm tossing this out here because I know from experience, many users never bother adjusting their display dimensions beyond filling the usable screen dimensions. Just doing so is quite fine for general computer usage. However those for those more seriously processing images, a bit more accuracy allows a more true display that will be reflected in what others elsewhere see on their displays or what results on prints. And I'd expect not a few on this board will be surprised to see how square images are not displayed as square on their displays as they might have assumed. Well this is just a minor issue in any case and I don't expect anyone to admit they are not quite adjusted correctly. This input serves some utility for you out there that can use some tweaking. Although any monitor comes with directions for use, and there are loads of information from many sources on color and luminance monitor calibration, the above monitor issue usually is ignored. With MS Windows, there are a whole range of display settings with XGA at 1024x768 and SVGA at 1280x1024 most currently popular:
http://en.wikipedia.org/wiki/XVGA
Most of the commonly used Windows video modes are at a 4:3 ratio, however with the advent of LCD's and wide screen video, other modes are increasingly being used. Of note, one of the most popular video modes, SVGA aka XVGA at 1280x1024 is actually a 5:4 aspect. And note changing modes between different aspects may require XY adjustment to bring a square display back to square.
To calibrate one's monitor for more accurate X versus Y dimensions is trivial. One can merely display a square image at 100% pixels that fills most of their display. Then simply use a ruler to eyeball equal lengths and adjust their monitor horizontal width and vertical height controls. Be sure to take into account parallax. To avoid parallax error, use only one eye perpendicular to each of two measured points of a length. While running Windows, the result is likely to result in a less than the full horizontal width, leaving the edges dark. That also represents the XY display error per specific video mode.
Posted by Larry Fischer on September 3, 2008 at 10:54 AM
David, I think I understand what you are saying--but.
Seldom does one do anything important on a full screen, at least with the post-photo programs I have. The photos are within the fringed working space. Does that affect what you are trying to accomplish?
And, does FX or DX make the dimensions different? I think they would. Have you covered both in your presentation.
Thanks,
Larry
"He who knows not that he knows not, knows not. He who knows that he knows not, knows" Socrates, I think.
Posted by David Bostedo on September 3, 2008 at 12:55 PM
Larry - I don't think you do quite understand what David is saying. There are a couple of potential issues here, that would make an image of a perfect square or circle appear distorted on your screen. It has nothing to do with how large the image is displayed, what camera it was taken with, what format the image is in, etc. :
1) If you are using a wide screen display, but still have Windows set to a 4:3 ratio mode, you either have black bars on either side of the screen, or the image is stretched to fill the screen. In the second case, a perfect circle would appear flattened and too wide. I know several people at work who have been doing this (now that we're getting widescreen LCDs) and haven't noticed the difference until I pointed it out/griped about it. With an LCD, for best results, you should always set the OS/Video Card to use the native resolution of the monitor.
2) Even if you're using the correct aspect ratio for your monitor, you can still make fine adjustments (typically on a CRT, not so much on an LCD depending on make/model) to bring the image into a perfect aspect ratio; One that shows a circle as a perfect circle on the screen (i.e. not overly long or tall).
The mention of full screen was only for X-Y calibration so that you could be certain that images that should be square, really are on the screen.
I hope I've stated your points correctly here David. Please correct/elaborate if I haven't...
Posted by Robert Fisher on September 3, 2008 at 1:57 PM
I understand what David (S, not B) is saying but there are a couple things that make it less than necessary.
David points out that properly calibrating to the proper screen dimensions will help ensure I see the same thing as others do on their screens. That assumes that other people have their screens properly calibrated for both dimension and colour. That's an assumption I don't make and I think it's a pretty big stretch to make that assumption at all. I might expect other photographers to have their displays properly colour calibrated (even that isn't a lead pipe cinch). But for dimension? Not likely.
The other point David makes is that it will more accurately reflect what is seen in a print. In that regard I can agree but it's overkill. The differences are, in most cases, going to be so minor that they won't even be evident without very close examination. If I have to put a measuring tape on my screen to ensure that there isn't a millimeter or 1/16th or 1/32nd of an inch difference in the dimensions of a square or the diameter of a circle, it's not worth it.
I think this is taking the science of digital photography and putting it too far ahead of the art of digital photography.
Discussion
3 replieshttp://en.wikipedia.org/wiki/XVGA
Most of the commonly used Windows video modes are at a 4:3 ratio, however with the advent of LCD's and wide screen video, other modes are increasingly being used. Of note, one of the most popular video modes, SVGA aka XVGA at 1280x1024 is actually a 5:4 aspect. And note changing modes between different aspects may require XY adjustment to bring a square display back to square.
To calibrate one's monitor for more accurate X versus Y dimensions is trivial. One can merely display a square image at 100% pixels that fills most of their display. Then simply use a ruler to eyeball equal lengths and adjust their monitor horizontal width and vertical height controls. Be sure to take into account parallax. To avoid parallax error, use only one eye perpendicular to each of two measured points of a length. While running Windows, the result is likely to result in a less than the full horizontal width, leaving the edges dark. That also represents the XY display error per specific video mode.
Seldom does one do anything important on a full screen, at least with the post-photo programs I have. The photos are within the fringed working space. Does that affect what you are trying to accomplish?
And, does FX or DX make the dimensions different? I think they would. Have you covered both in your presentation.
Thanks,
Larry
"He who knows not that he knows not, knows not. He who knows that he knows not, knows" Socrates, I think.
1) If you are using a wide screen display, but still have Windows set to a 4:3 ratio mode, you either have black bars on either side of the screen, or the image is stretched to fill the screen. In the second case, a perfect circle would appear flattened and too wide. I know several people at work who have been doing this (now that we're getting widescreen LCDs) and haven't noticed the difference until I pointed it out/griped about it. With an LCD, for best results, you should always set the OS/Video Card to use the native resolution of the monitor.
2) Even if you're using the correct aspect ratio for your monitor, you can still make fine adjustments (typically on a CRT, not so much on an LCD depending on make/model) to bring the image into a perfect aspect ratio; One that shows a circle as a perfect circle on the screen (i.e. not overly long or tall).
The mention of full screen was only for X-Y calibration so that you could be certain that images that should be square, really are on the screen.
I hope I've stated your points correctly here David. Please correct/elaborate if I haven't...
David points out that properly calibrating to the proper screen dimensions will help ensure I see the same thing as others do on their screens. That assumes that other people have their screens properly calibrated for both dimension and colour. That's an assumption I don't make and I think it's a pretty big stretch to make that assumption at all. I might expect other photographers to have their displays properly colour calibrated (even that isn't a lead pipe cinch). But for dimension? Not likely.
The other point David makes is that it will more accurately reflect what is seen in a print. In that regard I can agree but it's overkill. The differences are, in most cases, going to be so minor that they won't even be evident without very close examination. If I have to put a measuring tape on my screen to ensure that there isn't a millimeter or 1/16th or 1/32nd of an inch difference in the dimensions of a square or the diameter of a circle, it's not worth it.
I think this is taking the science of digital photography and putting it too far ahead of the art of digital photography.