I gotta say, you have an interesting mix of cards there!
Dude! You still have microdrives! Do those even still work?! (You realize that microdrives are actually tiny mechanical hard drives, not flash memory, right? Don't bang them around and don't go over 10,000 feet to use them.)
Sorry, I'm an IT guy and those things were SO COOL back in the day! I was showing one of those to my class way back when I used to teach IT in '97!! I had to do a Google search to realize that I guess they are actually still made and available! Really???
Here is a link to a great summary of their use in cameras.
OK, so I know this comment didn't answer your question. Sorry.
Sharing media between cameras will not hurt the media itself. It's just a memory device and will simple store the data written to it. The card itself doesn't care how its formatted or what kind of data it holds.
The problem arises in keeping track of the pictures themselves and the logistics of time date stamps, filenames/numbers, etc. Different cameras typically store their files in different folders but Canon cameras will usually all use a DCIM folder with a subfolder or many subfolders depending on how you set the camera. The folder name can be changed in the camera settings if you want to share media between cameras to make it a little easier. However, the camera will still look at the highest file number on the card in the appropriate folder and start numbering from there. Every time you change the card, the camera will start numbering the pictures based on the highest number it sees already on the card. This will cause problems later when you offload images to your computer if you are combining all the pictures from that event into a single folder and run across duplicate filenames. It will also cause them to be out of the sequence shot if you were sorting the files on the filename and not the time/date stamps.
Here is an explanation of what happens on CPS...
I'm not an expert on this but for me, the bigger challenge is keeping cards organized so no mistakes happen in the field and so I don't pull my hair out when I get home. If I am gone on a trip for several days and I arrive home with thousands of pictures from 3 cameras on multiple cards over several days on separate subjects, I am careful to organize the images on my computer when I offload them from the cards. Swapping the cards between cameras will complicate this, esp since their time/date stamps will be slightly off. And each camera will have different exposures, settings, lenses, etc so the post image work will be easier if I know ahead of time which camera took each image.
This is my system...
- Separate cards for each camera. (For my own OCD sanity, not because they wouldn't function correctly.)
- All cards are formatted in camera before leaving on the trip. All cards' image contents are double checked before formatting to ensure all pictures already on them are "OLD" and already exist in two places on my computer. I don't format cards right after I offload their contents to the computer because until I need the card again it serves as a redundant copy of the images for a few days/weeks in case something tragic happens to my computer.
- All of my CF cards have a small piece of green or blue painters' tape hanging slightly off their outside edge that I use to fold over the leading edge after it is full when I switch to another card in the field. This prevents me from re-using a full card. Re-using the card isn't a problem for the files already on the card but if I think it's a card that I forgot to format at home, I could lose a LOT of pictures in an instant. I did that years ago and started this system then. Re-using a card also wastes time since it will require more card switching when I realize it.
Protecting yourself from tragedy involves using some logic and common sense. When you are travelling, keep your full cards separated from your empty cards in separate places, luggage, etc. If sometone steals your camera bag, you'll lose your kit but you may still have a lot of your pictures if they weren't stored together with everything else. If you are on a long trip (more than a couple days), either take a computer or take a backup drive designed to save files off of you media cards. This way you can get a backup right away in case something bad happens. Anything can go wrong. Your images are extremely vulnerable to theft or loss when you are out of your home, office, etc. Photographers in groups will sometimes swap cards or drives to make sure their images are "offsite" in another place in case they are robbed, have a fire, whatever.When flying, obviously don't check your gear, carry it on the plane. Maybe take your media cards that are backed up on your computer or other device and mail them to yourself before the plane trip home. It all depends on how important those images are to you or your livelihood.
Thousand Thanks, Dear Mr. RustyTheGeek .
Wow, I have learn some thing new to day----Thanksssss for all great Recommends, Sir.
Yes, My OLd, OLD Tiny Machanical Hard Drives still working, But So slow---BUT JUST FOR THE SPARE CF. Only, When I run out of the spaces.
Yes, I will do as I did before, Just Keep Difference Files for Difference Cameras---BUT, I know Now, I can use Difference Format by Difference Canon Camera with out Hesitate= JUST IN AN EMERGENCY ONLY.
Have a great day , Sir.
PS, If I do not know some thing, and I do not want to ask the Experts/ Friends= Make me stupid all of my Life.