Home Forums Gear Photography Mirror vs Mirrorless ?

Don:


With my Windows system: right click the image or the image file name, click the "properties" option, then "details." A ton of data comes up on the source of the image including pixel counts on the x and y axes as well as the "dpi" or pixels per inch.

One can alter the "dpi" count with photo processing software to change image size without revising any of the image data itself.

I'll bring in an example shortly.

Edited:

The box below this image is just a small portion of the metadata itself from an image file called BarkPileWeasel.





We downsize images for posting, so its dimensions are 1920 x 1200 pixels which still displays well on most monitors. If it was printed it would be processed at 350 pixels per inch generating an image that was about 5.48 x 3.42 inches. Good enough for a card, but not a 19 x 12 inch wall hanger

I won't put it up, but another image on this unit is 5472 x 3648 pixels. Printed at 250 pixels per inch, that would make a great 21.8 by 14.6 inch print. Quality would be slightly better at 300 pixel per inch, but most shops will let us get by at 250. If one wants super detail, some printers are capable of 600 dots per inch.

Bit depth (24) is the number of colors available. With a 24-bit image, the bits are divided into three groupings: 8 for red, 8 for green, and 8 for blue. Combinations of those bits are used to represent other colors. A 24-bit image offers 16.7 million colors.

If one scrolls up and down through that box he will find all the metadata for each image including things like camera make, model, exposure settings, dates, times, his/her name, and perhaps GPS coordinates if one has that activated on his camera.

Posting such images to the web can be risky as many are revealing far more data about themselves than they realize. Running one's images through some other software and resaving the file may or may not alter or eliminate that metadata. That data is still attached to Cookie's images that we serve up though Postimage.org. We have no business secrets that might be revealed and have the GPS systems turned off, so we don't really worry about it.

As an example, here's the meta data for Thirtythirty's DenaliAurora image in the Photo Association thread.

Don't think I'm revealing any secrets here, as we're just showing his camera settings, but we do put out more about ourselves than one thinks.

One might note too, that there is an option at the bottom of the Details box to remove portions of the meta data. This was a big deal a couple years back when folks were image posting nuts. Few realized they were putting names and the precise locations of their kid's cutsie images out for all to see or exploit.

That metadata is not available when images are displayed via the forum because most websites revise or downsize images for display or rapid transmission. Again, however, that data may be available if one downloads the file from the hosting site.

Probably clear as mud and more than one wants to know.

Have a good one,