topic Re: SD card cannot be read in EOS Rebel T7 in EOS DSLR & Mirrorless Cameras

SD card cannot be read in EOS Rebel T7

PhotoJenic — Tue, 26 Sep 2023 12:40:56 GMT

I have a Canon Rebel T7, a 256mb SD card (full size not micro,) and a Mac.

When I use an adapter and plug the card in it says, “this disk inserted was not readable by this computer.” If I reformat it on my Mac then my camera says that it can’t read the card and I have to format the card on my camera. If I format the card on my camera then my Mac gives the same not readable message. I’ve done so much googling I can’t find an answer!

I’ve tried two different brands of 256mb SD cards. The only card that works on both my camera and Mac is an old 4mb card I’ve had for years.

Is the card size too big? Do new SD cards require a different card reader? (My reader is years and years old. I had been using a Mark II for 14 years and it just died and I’m unable to afford to upgrade.)

It’s been a giant headache as I photograph a service every Sunday and I now have to transfer my photos onto my mom’s PC to a flash drive to get them onto my Mac to edit. She’s only visiting so once she leaves I can’t access my photos. Please help me before I pull my hair out!

Re: SD card cannot be read

shadowsports — Tue, 26 Sep 2023 06:52:15 GMT

Greetings,

For your T7, I would suggest a full size SD card UHS-I, 32GB or smaller.

SanDisk, Lexar or similar. Your cards should be purchased from a reputable source. B&H photo, BestBuy, etc.

Avoid Amazon, sellers there frequently and sometimes unknowingly sell counterfeit cards.

This is a good card. About $12 😀

Re: SD card cannot be read

AtticusLake — Tue, 26 Sep 2023 07:46:42 GMT

@PhotoJenic wrote:
I have a Canon Rebel T7, a 256mb SD card (full size not micro,) and a Mac.

I think you mean a 256GB card. "mb" is millibits -- a thousandth of a bit, which is impossible. "MB" would be megabytes, but there are no 256MB cards on the market. This may seem nit-picky, but the size of the card really matters, so it would help if you could confirm what you really have.

If I reformat it on my Mac then my camera says that it can’t read the card and I have to format the card on my camera. If I format the card on my camera then my Mac gives the same not readable message.

When you "format" a card, what you're actually doing is creating a new, blank, filesystem on the card. So the question is, what kind of filesystem? I don't use Macs myself, but I would guess that a Mac might create some kind of Apple filesystem. If so, then it's no wonder your camera can't read it, because a camera won't support Apple filesystems.

If you format in the camera, then it will create an exFAT fileystem -- assuming that the card is actually 256GB. It may well be that your Mac can't read this, if it's an old one. Then again...

Do new SD cards require a different card reader?

I'm not sure about this; if your reader supports SDHC, then it might work for SDXC. But from what I'm seeing online, formatting the card may be an issue. To be safe, use a reader that specifically supports SDXC.

I’ve tried two different brands of 256mb SD cards. The only card that works on both my camera and Mac is an old 4mb card I’ve had for years.

I have to assume you mean 4GB (4 GigaBytes, not 4 millibits). In which case, this is no surprise; the camera will format it as FAT, if it's that small, and then the Mac should have no trouble reading it.

Bottom line:

Understand your card capacities, and the notations used to specify them
Understand the generations of SD (SDSC, SDHC, and SDXC) and the sizes of cards they support
Understand the different types of filesystem

There's plenty of info about these online. The "Comparison" section of the Wikipedia article has a helpful table: https://en.wikipedia.org/wiki/SD_card#Comparison

I made a video about memory cards that might help: https://moonblink.info/MudLake/tech#Cards

You might find the other videos on that page useful, too.

Re: SD card cannot be read

AtticusLake — Tue, 26 Sep 2023 07:51:11 GMT

The Canon page on the T7 says it supports SDXC: https://www.usa.canon.com/shop/p/eos-rebel-t7-ef-s-18-55mm-f-3-5-5-6-is-ii?color=Black&type=New

So 256GB should be OK... right? Or am I looking at the wrong version of the camera?

Ian

Re: SD card cannot be read

Waddizzle — Tue, 26 Sep 2023 10:00:47 GMT

The xxxxD models are listed to be compatible with SDXC cards, but they are not. Speaking from personal experience and numerous posts like this one, they do not.

My T5 would lock up, give formatting errors, and other bad things. If put the same cad into my 6D, no problem. Put a SDHC card in the T5, no problem.

Insert a different SDXC card into the T5 and cycle repeats. They don’t work.

Re: SD card cannot be read

AtticusLake — Tue, 26 Sep 2023 10:44:42 GMT

Oh, interesting! Then the 256GB card may be the problem.

But if true, then that's definitely a bug. The T7 claims SDXC compatibility, and a camera that new should have it in any case.

Re: SD card cannot be read

AtticusLake — Tue, 26 Sep 2023 10:57:30 GMT

I can't find anyone else having this problem with the T7.

This looks like a good guide to cards for the T7:

https://havecamerawilltravel.com/canon-eos-rebel-t7-sd-card/

He doesn't mention problems with SDXC; in fact, he says "I’ve used UHS-II SD cards in my Rebel T7, and they work just fine." All the UHS-II cards I can find are SDXC.

These articles recommend a bunch of SDXC cards for the T7:

Re: SD card cannot be read

Tintype_18 — Tue, 26 Sep 2023 12:35:39 GMT

Page 5 of theT7 manual states the SDXC will work along with two other cards.

Re: SD card cannot be read

kvbarkley — Tue, 26 Sep 2023 13:09:31 GMT

"I don't use Macs myself, but I would guess that a Mac might create some kind of Apple filesystem."

While the native Mac filesystem is HFS/APFS, they have the capability of formatting in FAT, which is what the camera requires.

Re: SD card cannot be read

Waddizzle — Tue, 26 Sep 2023 13:27:07 GMT

@Tintype_18 wrote:
Page 5 of theT7 manual states the SDXC will work along with two other cards.

Maybe they have corrected the SDXC compatibility issue with xxxxD bodies with the T7. I do not think they have because there have been several posts like this one in these forums.

Do 64GB SD cards work in your T7? I tried at (4) different cards and they all eventually failed, or failed to format in the camera. Formatting in a computer only led to the inevitable failure to read in the camera. They would work for a SHORT period of time and fail.

If I put the same cards in my 6D or any other midrange body, they would work flawlessly. Since you seem to be using a T7, then I strongly caution against SDXC cards. I know what the manuals say.

The problem does not appear in the xxxD bodies like a T5i, T6i, T7i, etc.

Re: SD card cannot be read

Waddizzle — Tue, 26 Sep 2023 13:58:28 GMT

Here is an example of the identical issue from a year ago.

https://community.usa.canon.com/t5/EOS-DSLR-Mirrorless-Cameras/EOS-Rebel-T7-SD-Card-quot-Cannot-Be-Accessed-quot-Message/m-p/390092

The entry level Rebel bodes, xxxxD, do not like SDXC cards.

The beginner level Rebel bodies, xxxD, do not seem to [have] the problem.

Re: SD card cannot be read

PhotoJenic — Tue, 26 Sep 2023 14:28:22 GMT

Sorry, I definitely meant 256GB. It was after 1am and I was tired and frustrated. After 14 years my Mark II died so this card issue has thrown me off.

I’m wondering if it’s a card reader issue. The card that works in both my camera and Mac is an old 4GB SDHC and I looked at my card reader (it’s 10+ years old) and it only says SD on it. My new cards are SDXC. I’m thinking maybe it can’t read the new cards. My mom’s PC can and my photos are there so it has to be an issue with the reader or Mac.

My Mac is a few years old. It’s running Mojave version 10.14.6. I tried reformatting the card on it to FAT and something else that had FAT in it but both times the camera says it can’t read the card even though I thought I read that it could do FAT.

I’m going to buy a new card reader that works with SDXC and hope it works. If it doesn’t then I guess I’ll try a smaller GB card. Really trying to avoid having to get a PC just for this because I can’t afford it right now.

Re: SD card cannot be read

rs-eos — Tue, 26 Sep 2023 14:45:41 GMT

If you're using SDXC cards with your camera, the format should be exFAT and not FAT. You may already know this, but you can use the built-in Disk Utility application on your Mac to format SD cards to exFAT.

It does sound like your older card reader is having issues with newer cards.

Re: SD card cannot be read

kvbarkley — Tue, 26 Sep 2023 14:45:42 GMT

Are you formatting in ExFAT?

https://support.apple.com/guide/disk-utility/format-a-disk-for-windows-computers-dskutl1010/mac

Re: SD card cannot be read in EOS Rebel T7

Anonymous — Tue, 26 Sep 2023 15:40:02 GMT

Just to summarize what is being said here, it appears that the OP's memory card is working fine in the camera, as his mom's computer can see the photos on it. So, it is not a matter of the camera being able to support the 256GB card. His mac computer cannot read the card is the issue. It would seem that his 10-year-old card reader cannot support the large memory card's format. He should buy a new card reader and just to be sure, a smaller memory card (32GB or smaller).

Re: SD card cannot be read

PhotoJenic — Tue, 26 Sep 2023 15:42:20 GMT

I tried formatting the card on the Mac for FAT and I think it was also exFAT but after I tried both the camera couldn’t read the card and I’d have to format it on the camera in order to use it again.

I’m hoping it might be a card reader issue as my card reader is 10+ years old and it only says SD on it. The 4GB SDHC works just fine in both the camera and card reader so I’m wondering if it can’t read the SDXC ones. I know the card works fine in the camera because I was able to get my photos off it via my mom’s PC.

Makes my head hurt. I’m used to CF cards hah.

Re: SD card cannot be read

AtticusLake — Wed, 27 Sep 2023 07:34:37 GMT

If the card is SDXC -- i.e if it's bigger than 32GB -- then it needs exFAT, not FAT. As I noted I'm not a Mac user, but I seem to recall they were late to the game with supporting exFAT.

Re: SD card cannot be read in EOS Rebel T7

Waddizzle — Wed, 27 Sep 2023 11:24:44 GMT

The title of the thread is confusing. He also says the card cannot be read by the camera. I dunno

Re: SD card cannot be read in EOS Rebel T7

Tintype_18 — Wed, 27 Sep 2023 11:40:42 GMT

Not going back to read all the replies but....noticed the card is formatted on the Mac. Format in the camera.

Re: SD card cannot be read

normadel — Wed, 27 Sep 2023 19:38:12 GMT

"mb" is MEGAbits, not millibits. No such thing as millibits (which would be 1/1000th of a bit if there was such a thing).