Dear Sir / Madam,

Thank you for reading my question. Your expert answers/advice will be greatly appreciated.

I have a Nikon Coolpix 950 digital camera. It works very well for microscopic photography. I have recommanded to quite a few colleagus and some of them also bought the camera. They all have come back to me with same question which I couldn't answer. The question is outlined below. The camera has ten different "quality" settings: High Fine, Fine, Normal, Basic, XGA fine, XGA Normal, XGA Basic, VGA Fine, VGA Normal and VGA Basic. A storage disk of given memory size can hold different numbers of pictures depending on the "quality" settings. However, different format (i.e. "quality" settings) do not seem to a matter of resolution. For example, a photo in XGA Normal takes more memory and shows a much larger picture on the screen than a photo in VGF Fine format. But a photo in XGA Basic takes LESS memory (about 80K), and yet shows a much LARGER picture (same as XGA Normal) than a photo in VGA Fine (about 140k). Both give very good pictures undistingiushable from each other on the screen. Question: 1) Why a photo in XGA Basic take less memory space but shows a much larger picture on the screen? 2) What format should I use if I want to keep good picture quality without stuff my hard drive too soon?

Thank you very much for your time.

sincerely Gregory Sieverding

-- Gregory Sieverding (GregorySB@rocketmail.com), May 13, 2000

Answers

basic,normal and fine refer to the amount of compression in the Jpeg file. Jpeg is is a file type that when compressed a lot, will start to show artifacts. Any time you compress an image some data will be lost. The setting of fine has the least amount of compression (about 4 to 1). The other settings refer to the resolution. Resolution is how many pixels of information there is. In most cases the more the better unless your are using the pictures for the web. High fine is a tiff file with no compression and maximum resolution. This is a big file that is slow to write to the CF card. Most of the time I use the fine setting to get only a small amount of compression and the largest resolution. I get 57 pictures on a 40 MB card.

-- Ralph (REObert@aol.com), May 14, 2000.

Gregory, To add just a bit more information to Ralph's fine post, the XGA standard is 1024 X 768 pixels. VGA is 640 X 480 pixels. That is why they display in different sizes. As Ralph stated, the terms Fine, Normal, and Basic refer to the amount of compression when the image is saved. Fine is the least compression, thus the largest file size (not image size). High produces the largest picture (assuming the same display resolution (PPI)). Now you're probably more confused than ever. :-)

-- Steve (MilwaukeeChrome@aol.com), May 14, 2000.

To continue this, now I AM cornfused. The nomenclature for Olympus is slightly different:

In SQ mode it agrees with the above, however in HQ and SHQ modes the rez is 1600X1200 with no mention of format. So, what format are THOSE?

-- MikeB (airlinestuff@yahoo.com), May 14, 2000.

Mike, I assume you are talking about XGA, VGA, etc.??? Those sizes you mentioned are not directly related to previous computer standards. Over many years, computer systems have increased their resolution. As new standards were introduced they were named such names as EGA, VGA, Super VGA, XGA, etc. Digital cameras are not required to have formats that are directly related to any of those previous standards. It simply is not necessary that they have the same resolution or aspect ratio to match a monitor. It pehaps makes scaling the image to fit a monitor easy if it starts as one of those standards, but is not important at all. Does that help?

-- Steve (MilwaukeeChrome@aol.com), May 14, 2000.

The difference between HQ and SHQ is the amount of JPEG compression, SHQ has less compression (better quality) than HQ, but the size (resolution) is the same.

-- Roger Chi (rchi@scythide.com), June 26, 2000.