Dual slot memory cards

[slat]

If you have a camera, eg Canon R5, with cfexpress in one slot and SD in the other and you set the camera up to do raw to the cf and jpeg to the SD can you use a slightly smaller SD card since the files are smaller? Any drawbacks anyone can think of?

 

[480sparky]

I use dual slots to record raw files on both. This way, if one is corrupted, I've got the other as backup.

 

[greybeard]

I can't think of any reason that this would cause a problem if both raw and jpeg is what you want. Calculating the exact size cards you need would be a question for someone with better math skills then me.

 

[MontanaDave]

If you have a camera, eg Canon R5, with cfexpress in one slot and SD in the other and you set the camera up to do raw to the cf and jpeg to the SD can you use a slightly smaller SD card since the files are smaller? Any drawbacks anyone can think of?

I have an SD card in my R5 just in case the cfxepress fails, but have never used it in the field.
If I want jpg, I edit the RAW file and save as a jpg.
One drawback could be increased write speed since writing to 2 devices.

 

[JoeW]

I mean no insult in this but: I think you're overthinking this. First, the larger issue isn't the size of the card, it's the speed, the ability to write to the card. If you have a slow SD card in the second slot, it isn't going to matter what the size of the card is, it will cause big delays in transferring data.

Second, part of the idea of a second slot is to have backup. So I'd get a bigger SD card. Partially because SD cards are cheaper than CF cards. But mostly so that if you end up with a problem with slot #1 (forget to put in your CF card, the card is corrupt in some way, the slot fails, or you just shoot a ton of stuff and need more space) than you've got room on the SD card.

 

[slat]

No insult taken Joe. The speed issue is kind of what I'm thinking about here. A 512 GB SD UHS ll V90 which writes at 300 MB/s is $500 at one place I looked. The same size cfexpress is $150. The 512 GB UHS ll V60 is the same $150 as the cfexpress but half the write speed. My concern here is if I am in a situation that I'm using continuous shooting that I'll bottleneck with the slower card.

 

[Golem]

I have an SD card in my R5 just in case the cfxepress fails, but have never used it in the field.
If I want jpg, I edit the RAW file and save as a jpg.
One drawback could be increased write speed since writing to 2 devices.

Increased write TIME.

DECREASED write speed.

You "cut and spliced" that well intentioned info in an unfortunate way :-(

 

[RacePhoto]

No insult taken Joe. The speed issue is kind of what I'm thinking about here. A 512 GB SD UHS ll V90 which writes at 300 MB/s is $500 at one place I looked. The same size cfexpress is $150. The 512 GB UHS ll V60 is the same $150 as the cfexpress but half the write speed. My concern here is if I am in a situation that I'm using continuous shooting that I'll bottleneck with the slower card.

Wow, what are you shooting that needs all that expensive speed? Video? Then I'd understand.

Photos, which is where I still concentrate, "A 512 GB SD UHS ll V90 which writes at 300 MB/s is $500" sounds expensive. Do you need 512GB? ($399 at B&H now)

I'm not doubting, I just want to understand, why such a large and fast card? If it's for video, I understand, it's out of my area. 128GB BLACK UHS-II SDXC Memory Card $139

I don't have a dual slot camera, yet, but if it's like anything else in electronics, the system is only as fast as the slowest link in the system chain. So a fast card in one slot and a slower in the other, would only be as fast as the weakest link. If shooting RAW+JPG that could be interesting and yes the size goes up a little faster than just RAW.

Someone needs to answer, what I'd wonder if I was doing this. How does the RAW+JPG change the capacity of the buffer, the speed and number of images. I shoot JPG only because of what I do, and I need the full speed and buffer, now and then. It's rare, but, I feel necessary, to not have the buffer full and to have the fastest burst rate, at normal. I don't use (H), way too many photos to review and edit.

But mostly, why A 512 GB SD UHS ll V90 which writes at 300 MB/s?

 

[slat]

The CFexpress came with the camera. I was only looking at the 512 GB V90 to get a closer performance card to match the cf card. I don't shoot video very often. I think from continued research that a V60 will be fine in this situation.