compression and image loss

[woodchip]

We are going to be travelling in Ecuador and the Galapagos Islands for 1 month and have several questions. Is time a factor in image loss at different compressions? ie, is there more image loss over the course of 1 month than in the more normal time frame of just a few days? What would be the best compromise for mp and compression levels for such a trip? I am using a Canon G9 and from what I've read I'm not sure about 'superfine' although I have seen no detectable artifacting using the superfine at 12 mp on a 5 x 7 close up of a spiders head (off white). I am taking 2 - 8 GB sdhc Extreme III cards but would like to be free to take as many shots as I would like without having to download them there.

I really enjoy the pop of a high quality image so I tend to use more mp's than I really need to.

Also is there more corruption of the card through 'garbage canning' in one compression level than another? How much erasing can a card take before corruption starts to show up? Should you be careful that you don't keep erasing images at the same storage point on the memory card, if you can do that?

Thanks for any enlightment you can give me on this topic. Woodchip

[David Metsky]

Time is a non-issue. Once files are written they don't degrade unless you bring them into an image manipulation program and then save them a second time. Files don't degrade once they are written to the card, so nothing you do by deleting other images has any effect on the images you leave behind. Image degradation only happens when you use an image editing program on your computer, not on a memory card.

I'd take images as full image size and highest quality (superfine). 8G high speed cards cost less then $30, buy another and don't worry about it at all.

[Visual Reality]

Like David said...in the digital world, there is no loss of quality with time, unlike in the analog days.

The only time data is affected in a negative way is malfunction, corruption, or destruction of the medium its stored on. Otherwise, data is stored forever.

As far as deletion goes, each time you transfer the load of images to your computer, do a format from the camera menu rather than deleting one by one. Flash memory does eventually fail as each sector has a limited number of write cycles, however they can be read an infinite number of times. Since our cards don't have wear-leveling algorithms like the new SSD's, they will eventually fail.

[SpecialK]

16 Gb will not last long - certainly not a month. I suggest getting a Wolverine or similar portable storage device to load your files onto, or buying a few more cards :-)

Shoot your best quality shots.

[Visual Reality]

You will get a couple thousand 12MP JPEG files, if I can get 1200-1500 RAW files on my 16GB CF card, at 12.3 megapixels.

For 1 month of shooting I agree with SpecialK, that won't be enough. Should have gotten a cheaper brand and another 8GB instead.

[Joe1956]

I really enjoy the pop of a high quality image so I tend to use more mp's than I really need to.Memory cards are relatively cheap.

There will come a day for that once in a lifetime shot, or perhaps a year or two later an image saved in a dusty folder will jump out at you like it never had before, so you'll be glad that you'd set the camera to it's best quality settings and never looked back.

[woodchip]

Thanks for your feedback and suggestions. I did send private reply messages but don't know if they 'went' because they never showed up in my e-mail file. Woodchip