I just bought my first dslr (Nikon D5100) and I'm looking for an sd card to go with it. I would rather have just one card so I thought about 64GB SanDisk Extreme (45MB/s), however I don't know if I need to go that big. I know I will be using RAW+JPEG(fine) setting and the card should last for at least 2 weeks of taking photos say 60-100 a day and some full hd video.

So, the question boils down to whether 1400 RAW and 1400 JPEG images along with a maximum of 100 minutes of full hd video taken with a Nikon D5100 will fit on 32GB card or should I buy a 64GB one?

Thanks, Mike


2 Answers 2


38 GB is what is needed for the photos alone. This is based on the largest JPEG and NEF files I have from the Nikon D5100. Add video and you are over, so much so that I think you would be tight with 64GB and should go with the a 128 GB version. I have both a 400X and 133X version of the Lexar 128GB SDXC professional and they worked flawlessly until now. Sandisk also makes a 128GB Extreme but I do not have it. I do have some Sandisk 16GB cards in Extreme and Extreme Pro version which also worked without trouble so far.

Now I have never filled either one but there are reasons to have two. Personally, I do not by the you might lose because when you have only one card, it is hard to lose since it always stays in the camera except for downloading and goes right back. What I do buy is that some cards fail and I know they do. You may be one day the unlucky one in a million which has a flawed top-of-the-line card. If you buy a cheap card of course, your odds are much worse. The bigger your card, the more you stand to lose in one go. Also, if one break while you travel you will be sad about what you lost but you can still go on.

  • \$\begingroup\$ Thanks, it is a very good point. I did not have any SD card fail on me yet, but then they were never subjected to high write rates, so the potential to loose everything never crossed my mind. I would rather stay safe and on the basis of your advice I will go for one 32 and two 16 GB cards. Thanks @itai! \$\endgroup\$ Jul 1, 2012 at 9:06
  • \$\begingroup\$ That is very sensible. I have had hundreds of cards and did see a few handful die and simply stop being accessible. It is more bad luck than abuse with flash (unlike hard-disks), cheaper brands fail more but I even had a Sandisk Ultra IV fail, no Extreme or Extreme Pro yet and never any Lexar. On one occasion I had a defective card reader which fried both cards I put in it and then let out smoke! The $10 reader fried a $1000 card :( \$\endgroup\$
    – Itai
    Jul 1, 2012 at 14:36
  • \$\begingroup\$ That is a disappointing. In the end I ordered 4x 16GB Sandisk extreme (45Mb/s), a card reader and a 32GB Patriot Xt pendrive. I will be transfering photos onto my mobile and then onto a pendrive. \$\endgroup\$ Jul 2, 2012 at 22:03

You can calculate your approximate storage requirements by using manufactures published data. BUT you should never use a single storage card except in cases when you also have backup copies whose integrity is guaranteed. A minimum (but incomplete) requirement to guarantee (in normal terms) the integrity of a backup copy is to have 2 backup copies (in addition to the master copy).

All data storage devices fail.
If you reply on a single copy of data on any media you can consider not having lost it yet a matter of good luck.

Hard disks fail somewhere between 1 hour to 10 years from new, in most cases.
I've seen examples of both, and "a few years" is the somewhat safe limit to "trust" a hard disk for, as long as it is fully backed up very often.

SD cards MAY last decades without failure in some cases. But in most cases a card that is regularly used and never formated can be expected to run perhaps tens of load/download cycles without fault but would be exceptionally lucky to do so for hundreds of cycles.
If you format the card no less often than say every 5 load download cycles it MAY run for far longer without faulting. But, may not.

But, if the best quality USB memory card made by a top manufacturer corrupted a single file on any occasion that you used it, or lost much of the current data but was able to be reformated, or failed permanently, then nobody should be in any way surprised. While very low price and unknown brand is an indicator that you are more liable to have problems, and while high price and top brand indicate that you will probably not get worst case results, neither brand or price is an assurance that you will not lose some or all your data on any given day.

Never rely on one only card if a card failure would be catastrophic for you.
Always keep at least two and possible 3 copies of all files that you do not wish to ever lose.

If data loss matters to you swap out a card containing valuable files as soon as possible and replicate it as soon as possible. (When I am taking photos at events etc where file loss is completely unacceptable I rotate through several cards, download to a backup device (incrementally to an HP netbook usually in my case) during the current "session" and also retain the photos on the card at least until I have copied the files to a 3rd device (in my case a portable USB 2.5" hard drive).

  • \$\begingroup\$ Thanks Russell, yours is a good answer as well. I must have been replying (from mobile) to the first message when you posted yours. As I have said in a comment to the first answer, I will definitely not go for the 64GB one. \$\endgroup\$ Jul 1, 2012 at 9:48

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