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Old Sep 25, 2004, 11:55 PM   #1
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Hello,

I shoot with a canon digital rebel with a 512 sandisk ultra II compact flash Card. I have had this card for about 3 months and have shoot a little over 3000 pictures on it. I use a card reader to download all my pictures off the card. After transfering the pictures to my computer I format the card in the camera. Normally, this card will hold 154 pictures on maximum jpeg quality, but the other day, I noticed after formating the card, it would only hold 144 pictures. Also it seems that the camera will not write to the card as fast as it use to. Does anybody know what the problem is and how to fix it? Thanks
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Old Sep 29, 2004, 7:44 PM   #2
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Sorry I cannot help planters49, but I seem to be having a similar experience.



I just bought a new 512Mb Ultra II card from B&H for my Canon 10D. When it arrived I put it into the camera and the top displayestimated the card's capacity was 90 RAW images.



Now, this capacity estimate is always a bit optomistic with my 256Mb Ultra II cards, it always says they will hold 36 (always exactly 36 btw) when empty but they will only really hold around 28 images (I forget the exact number). So I wasn't surprized when, despite the 90 image estimate, I could only shoot 81 RAW images before I saw CF FULL...



But when I erased all the images in camera, using "Erase All" the estimate dropped to 80. And when I tried to fill the card, I could only take about 74 images. What happened?



Next I tried using the in-camera "Format", but when it was done, the estimate now said the card's capacity was only 73 images!?!?! And when I tired to fill it, I could ony take about 61 RAW images. What is going on?



I re-formatted again, and the capacity estimate stayed at 73, but this time I was able to take 78 images. Now I'm really confused...



By the way when the card is empty andI use a reader on my Mac it says it has 487.9 Mbavailable out of 487.9Mb capacity, which seems about right for a formatted 512Mb card, but why do I get all those different estimates and why was I able to take between81 RAW images one time and only 73 another, then 61, then 78 yetanother time?



All settings on the camera were identical at all times, this is not a case of turning on and off JPEG previews or something like that...



Any ideas? I guessI should send the card back.(but I bet a million dollars the new card does the same thing!!)



- ThomasH
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Old Sep 30, 2004, 12:18 PM   #3
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I bought my card from BHphotovideo.com also. Maybe they have a batch of bad cards that they don't know about or something???
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Old Sep 30, 2004, 12:45 PM   #4
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I just found the answer to my problem in a post over in the canon DSLR forum. Here is the link http://www.stevesforums.com/forums/v...mp;forum_id=37

Apperantly, when you increase the ISO, the file size increases. In my case I was shooting mostly with ISO 200, and when I discovered the "problem" i was asking about to begin with, my camera was set on ISO 400. When I changed the ISO back to 200, my card showed that I could take 154 pictures. I hope this helps anybody else that needs this question answered.
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Old Sep 30, 2004, 2:53 PM   #5
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Hey thanks for the update planters49! That may help explain my experience as well. I may have chaged ISO settings in the middle of all this, I'll go back and fool around with my camera and the card again. Maybe it's okay after all!

Thanks again!
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Old Sep 30, 2004, 3:23 PM   #6
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Uhhh.... but I just noticed that the folks talking about ISO changing thefile size are shooting JPEGs. Do you tink this also happens when you shoot in RAW format like I do?

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Old Sep 30, 2004, 4:22 PM   #7
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ThomasH wrote:
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Uhhh.... but I just noticed that the folks talking about ISO changing the file size are shooting JPEGs. Do you tink this also happens when you shoot in RAW format like I do?
YES... it changes in RAW too (RAW+jpeg). Try it the frame number goes down too in raw when you increase the ISO!
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Old Sep 30, 2004, 7:29 PM   #8
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Thanks Northern Hirtuse Laugher (or maybe they're just a hockey fan),

I'll do some experiments when I get a chance....

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Old Oct 1, 2004, 1:15 PM   #9
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All I had time for last night was a quick look at my folders full of RAW files, and sure enough they are all diferent sizes, from 5.1Mb to 6.3Mb. And those are the .CRW files themselves. When I first started with this camera I was taking the same kind of flower pictures at the same time of day and the .CRW files were always 5.2Mb, so I thought they would _always_ be 5.2Mb. I guess not.

So obviously the file sizes change even when shooting in RAW, which may explain the card capacity estimate differences I was seeing. I still want to do some experimenting to see if I can replicate the 90 to 81 to 73 sequence I've seen...

Thanks for all the help!

- ThomasH


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Old Oct 1, 2004, 3:32 PM   #10
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ThomasH wrote:
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All I had time for last night was a quick look at my folders full of RAW files, and sure enough they are all diferent sizes, from 5.1Mb to 6.3Mb. And those are the .CRW files themselves. When I first started with this camera I was taking the same kind of flower pictures at the same time of day and the .CRW files were always 5.2Mb, so I thought they would _always_ be 5.2Mb. I guess not.

So obviously the file sizes change even when shooting in RAW, which may explain the card capacity estimate differences I was seeing. I still want to do some experimenting to see if I can replicate the 90 to 81 to 73 sequence I've seen...
The reason that the RAW file sizes change, is because there is an embedded JPEG file inside of each .crw file.

Since JPEG file sizes will vary based on scene content from compression algorithms used, the RAW file sizes will vary, too. It is my understanding that Canon uses ISO speed for the estimates, since higher ISO speeds produce more noise and will usually produce larger JPEG files.

Keep in mind that it's only giving you estimates of shots remaining,since there is no way for the camera to knowin advance how well a given photo will compress (for the JPEG embedded within each .crw file).


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