EOS Rebel T5: why is the red light (lower R corner) continually blinking when I turn camera on?

[LDTeacher]

I have a two year old Canon EOS Rebel T5. It gives great pictures, altho I am not always happy with the focus for long-distance images.  I guess I need to study the manual more.  My question is about the little reddish light at the lower R. hand corner of the non-lens face of the camera.  Every time I turn the camera on, it starts blinking...I have no idea what its function is...can anyone help me?  I'm not very tech literate about my camera - I bought it so I could take rapid-fire images of nature and my husband racing.  Otherwise, I have not learned much about lenses, etc. 

[LDTeacher]

Thanks for your very thorough and helpful answer.  I have often told my learning disabled students that there are no dumb questions....so I take your comment to heart! 

I have reformatted the card (after downloading all the images to my computer).  I usually purchase the Sandisk cards, so I'm hopeful that it's still good.  I have not had an opportunity to start taking new images, so I'll look for the blinking red light again when I start using the camera again.  For the moment, I'm wrapped up in writing a book to help parents of kids with learning disabilities, so my picture taking moments are limited right now.  I just got so fed up with the blinking red light one day that I had to post the question!  Everyone on this site has been SO helpful!  Appreciate all the helpful ideas, and the next time I get out the camera, I'm going to be more mindful and attentive to the suggestions everyone has shared. 

[TCampbell]

Every new card should be formatted .... and more specifically, you should format the card using the camera.  (Do not format the card in your computer.)  

When you go into the format menu, you will see a checkbox to perform a "low level" format.  On most cameras that option is checked or unchecked by pressing the camera button with the trash-can icon on it.  Check the "low level" option for the first format.  

If a card has bad blocks on it, the "low level" option will detect them and map them out of the filesystem (so that the camera will never attempt to use the bad block).  If you do not enable the "low level" option then it will not necessarily notice these problem areas and could end up attempting to write an image to it (likely resulting in a corrupt image -- which we don't want.)

You generally only need to apply the "low level" format once ... but if it's been a long while since the card was formatted, it wouldn't hurt to do it again just in case any problems with the card have developed over time.

The process of "writing" to a card is technically physically destructive and causes wear on the card.  Reading, however, is not destructive... you can "read" from a card an infinite number of times without causing any wear.  Original flash memory technology wasn't nearly as good as current technology.  Those old cards didn't have anything to perform "wear leveling" so the blocks at the beginning of the drive tended to be used over and over and over... the blocks at the end of the drive never got used.  Also, they couldn't take as many "write" and erase cycles before the blocks would become unreliable.  Modern cards seem to do much better and can probably be written and re-written over 100k times (it's unlikely you'll ever actually wear one out.  Your camera's mechanical shutter mechanism will probably wear out before your memory card does.

[LDTeacher]

Thank you for the complete explanation re: formatting the card in the camera. I am not sure, however, whether doing that will delete all the pictures currently on the card!?  Can you help!?

[amfoto1]

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@LDTeacherwrote:

Thank you for the complete explanation re: formatting the card in the camera. I am not sure, however, whether doing that will delete all the pictures currently on the card!?  Can you help!?

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The quick form of formatting in-camera will "mark" all the existing images on the card as "okay to overwrite", so be sure you've copied off any you want to keep. It doesn't exactly erase them (which is why you may be able to recover them if you accidentally format a card with images you want, so long as you don't start overwrititng them with new images).

The "deeper" or "low level" form of formating, I think will erase everything on the card.  I'm not sure because I very rarely do that... only if a card has been giving problems. On the other hand, I do in-camera "quick" format of every card, every time, first thing after I insert in the camera. That insures the card is ready for use in that particular camera. (I use several different cameras, which may or may not all use the same file system, etc.)

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@richard2996wrote:

I have the same problem after continuous shooting, it stays there for a longer time than it did before, even that I have been using the same card that I used before. 

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 Please read the earlier responses. Chances are you either have a slow card or that you haven't been regularly formatting it. Depending upon the camera and the write speed of the memory card, if you fire off a burst of shots the camera may have to pause to clear it's "buffer" (memory). While it's doing that, the red LED should flash. That's to warn you not to turn the camera off or open the memory card door and remove the card, until it's completed saving all the files that have piled up in the buffer.

If you shoot JPEGs only, the files are smaller, the camera should be able to take more in a high speed, continuous burst and if it needs to pause, the buffer should clear faster. If you shoot RAW, the image files are bigger so it will be able to take fewer images before needing to pause and when it does, it will take longer to clear the memory. If you shoot RAW + JPEG, that's a lot more data to process so will be able to take even fewer shots in a burst and take even longer to clear the buffer.

Just how fast all that happens depends upon the quality and write speed of the memory card you're using. Some is pretty slow, which will slow down the camera's peformance. But if you use memory that's at least as fast as the camera can write, that will give you the quickest image saves and shortest possible pauses to clear the buffer. Even faster memory won't help, since all cameras have their limitations, too. 

But, again, format the memory card in the camera. It only takes a few seconds and may help.

***********

Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7DII (x2), 7D(x2) some other cameras, various lenses & accessories
FLICKR & EXPOSUREMANAGER 

[richard2996]

I have the same problem after continuous shooting, it stays there for a longer time than it did before, even that I have been using the same card that I used before. 

[guywthclss]

Yes this just happened to me with my 7D Mark II. However, I'd just finished with my memory chip in my computer and I had my photo resizer, resize all the pics on the card. I did no file location, name changing or format changing. Just the resizing. The camera flassed for about 30 seconds and then back to normal

[kvbarkley]

"I had my photo resizer, resize all the pics on the card."

You have a very strange workflow.

[Waddizzle]

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@guywthclss wrote:

Yes this just happened to me with my 7D Mark II. However, I'd just finished with my memory chip in my computer and I had my photo resizer, resize all the pics on the card. I did no file location, name changing or format changing. Just the resizing. The camera flassed for about 30 seconds and then back to normal

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Never edit the files on your card.  Your camera should be the only device that ever writes to your memory cards.  You are probably very lucky that the camera found the files, and did not begin ovewriting them.

If you think that you did not change the file location, et cetera, et cetera, then you do not understand how computer memory storage actually works.  Once you edited the files, you actually did all of the above that you claim you did not do.  

For example, a computer overwrites an existing file by creating a new copy, which means the copy is stored at a different physical location on the memory card.  It then deletes the original copy, and re-assigns the original logical location to the new file.

You overwrote something that goes by many names as storage technology has grown and evolved.  But, the function of this something remains pretty much unchanged.  I first known of this thing as a BAM, or Block Allocation Map.  Files are stored in "pigeon holes", which is a concept similar to the egg tray in a refrigerator. 

The BAM tells the operating system which pigeon hole is associated with which file.  When you resized your files, and wrote them back to the memory card, this caused the data to be stored in a different group of pigeon holes.  The real danger is that not every device recognizes, or uses, the same size pigeon hole.  This is how data gets wiped out.

[ebiggs1]

" I'd just finished with my memory chip in my computer and I had my photo resizer, resize all the pics on the card."

I would also recommend not doing this.  However, if you did it on a WIndows machine I don't see why it wouldn't work. Even though you may have overwritten files the FAT is updated which may confuse the camera for a bit but it should figure it out.

If you did it on a Mac, good luck.  It is probably a miracle the camera figured it out at all. Mac's are so screwy.

Bottom line and best practice don't edit on your computer and put the card back in your camera.  I see no good reason to even do that.

[Oregonstitch]

I don’t see the red like for more the a couple seconds using Canon lenses.  But it seem the Tamron 28-300 zoom lens flumuxes some of the features.  The light flashes for a couple minutes when using the Tamron.    Normal?