JPEGs and compression

this may be a dumb question but a jpg/jpeg is compressed correct?


so if you do a RED Eye fix and then save does it get compressed again?

what about rotation?

 

Everytime you open a JPG and change something it will be recompressed. That is the risk with using a JPG file - they can be degraded rather quickly.

 

even if the edit is within the camera?

 

More than likely yes. There are ways around this issue, but I very highly doubt that the camera is implementing them. The lower the compression you use (higher quality) the less this will affect it. A two fold increase in compression will be at least a two fold decrease in cycles before visible degradation, I think.

 

I think on my kodak camera when I took vertical shots it automatically kept it rotated but on my canon it keeps it horizontal no matter what

is this common?

 

Both my Canon and Nikon (point and shoot and DLSR) will auto rotate. The Nikon isn't recognized right by Windows, but lightroom handles everything perfectly.

 

what do you mean auto rotate?

 

If I shoot in a portrait vs. landscape orientation, the camera can sense that and will bring the picture into the computer in the proper way - so that I don't have to rotate the pictures my self.

 

The problem isn't just that it is compressed, the problem is that it is compressed with a loss of information. I prefer lossless compression like that found in png files.

 

does kodak and canon rotate differently?