I recently bought a D7000 for my wife. I noticed that large capacity SD cards when formatted show a surprisingly small number of photos available. For example, I have 16GB Sandisk class 10 cards. when formatted, the camera gives a number around 460. This is for RAW files only. A simple calculation gives an estimate closer to double that number. However, in my D300 and D3s, a formatted 16GB CF card shows about 770 when empty. This cannot be explained by different file sizes between the bodies. Does anyone have an explanation for this curiosity?
Yes, I should have mentioned this. I use lossless compression, and both bodies are set to 12-bit, always NEF alone, no jpg. I noticed after browsing the forum that another post in the D7000 section (on SD cards) mentioned having a 32GB version of my card, set to RAW+jpg-fine, and got a capacity of about 640. That also seems off. If that setting produced 2 files 16MB each, there should be 1000 shots available, right--1000-fold difference)? (give or take...). I wonder if I'm missing something important about card storage, or perhaps the camera's estimates are far different from actual capacity. Anyone out there replicate my findings? Thanks to all....
It has certainly been the case with Nikon DSLR's that the capacity figure when using Compressed NEF or JPG is an underestimate. The camera doesn't know how much compression will be possible for future images - it varies depending on the amount of detail in the subject - so it errs on the side of caution.
Of course, this doesn't explain why the figure appears to be inconsistent between the various cameras. Perhaps the firmware is configured differently, or maybe the amount of compression applied varies.
Sun 30-Jan-11 01:13 PM | edited Sun 30-Jan-11 01:14 PM by rasworth
Or maybe, as has been pointed out several times on these forums over the years, Nikon does a very poor job of estimating usage. Having gone thru this same issue on D70/D200/D300 and now D7000 it would seem that they might improve their algorithms, but it appears not.
Either on the D70 or D200, I forget which, the estimation was so bad that Nikon corrected it somewhat on one of the firmware releases. On my D7000 shooting 14 bit lossless compressed the .nef's are generally slightly over 20mb each, resulting in a capacity of 375 images or so on an 8gb card. The camera display shows 224 on an empty card, the usual gross underestimate. The only saving grace is the remaining capacity is recalculated as the card fills up, so that one has a reasonable idea when the end is near.
>Either on the D70 or D200, I forget which, the estimation was >so bad that Nikon corrected it somewhat on one of the firmware >releases.
That was the D70; it's not quite the same issue we are talking about here.
The D70 had an error whereby the space remaining calculation always assumed uncompressed for NEF images, even though the camera only offered compressed NEF (!). The firmware update corrected this, but the figure still assumed minimal compression - which is what all Nikon DSLR's still do. Most of us get used to it in the fullness of time
I have to disagree Brian, IMO the figure used assumes WORSE than minimal compression. 8gb (real, not computer) divided by 224 is 35.7mb or so. I went out and did everything I could to drive up the file size, took pictures of trees with small leaves, lots of colors, etc. Nothing I did took the file size past 25mb.
So yes, I also am "used to it", but let's not alibi for Nikon, they are simply stated wrong in their remaining images calculation.
I'm not apologising for Nikon, just pointing out the difference between the obvious error in the D70 firmware (which they changed) and the general tendency of Nikon DSLR's to underestimate capacity when shooting in one of the compressed formats. I'm not sure I like it either, but it is what it is and they aren't likely to change direction at this stage.
>8gb (real, not computer) divided by 224 is 35.7mb or so. >Nothing I did took the file size past 25mb. >
It would be nice if it were that simple to calculate how many images could fit on a card, but unfortunately it isn’t.
It’s been a while since I used a lot of this information so someone please correct me if I stray or err.
First thing is that an 8GB card does not allow 8GB of storage area. It depends on the card manufacture but the overhead after formatting leaves about 7.5GB. Also your method does not take into account or allow for memory loss due to sector size and file allocation.
Although it’s a memory chip, it still conforms to the FAT32 standard. As such the bytes are allocated in sectors (generally 512 bytes per sector but I think more advanced systems use 4096 bytes per sector) and once a file is assigned to a sector the whole block is used whether the file needed the whole space or not. So if we assume a file size of 25MB per NEF and overly the file allocation to available sector space it comes out to about 299 images per 8GB card.
So Nikons 223 estimate in the D7000 manual is rather low and a more worst case scenario then the 232 that my camera reports when the card is inserted, which is less then the 299 I calculated. But would appear to be not as bad as you might think it would be via your method.
I imagine Nikon would prefer a user be pleasantly surprised by getting more images on a card then they thought they would, rather then have them irate that they ran out of space before they thought they should.
Thanks for the added detail, Pete. However, the roughly 300 from your calculations on an 8GB card translates to 600 on a 16GB card, which is much larger than what I'm seeing in the D7000 estimate of a newly formatted card. I'm also wondering if the SD technology is more nuanced than that of the CF standard, eating more space for some reason. Further, my NEF files are a bit over 16MB, and no where near 25MB. I wonder if the estimates are erroneously presuming the addition of some form of jpg concurrently stored.
>Further, my NEF >files are a bit over 16MB, and no where near 25MB. I wonder if >the estimates are erroneously presuming the addition of some >form of jpg concurrently stored.
I believe it is Nikons stance at a worst case scenario.
I was thinking about Richards’s statement of doing everything he could think of to drive up the file size, which made me think of the article over at Imaging-Resource on how they developed a target for the timing specification tests. They developed a multi-colored random noise pattern that would bring the best JPEG compression algorithm to its knees to get a better idea of the buffer capacity and camera speed.
But more to the point is that it’s not about the average image file size. Checking some of my images shooting lossless 14-bit NEF the file sizes ranged from just over 14MB to just under 22MB. It really comes down to where Nikon decided to draw the line in the sand, and it appears they used a worst case scenario of little to no compression.
Thinking about this I decided to see what it would take to get the 232 images shown on the camera display onto the card that shows its capacity as 7.68GB when in the card reader on my computer. Turns out it would be about 32MB file size.
Raw data at 14-bit from a 16MP sensor would be about 28MB without compression. A basic/large JPEG is listed in the manual as being on average about 2MB in size. Being a worst case hard to compress image, it is not unreasonable to me to consider the embedded JPEG being about 3.5MB or so coupled with the 28MB of raw data and EXIF data the file size could easily reach 32MB. So it seems to me that Nikon’s in camera routine for image count approximation is based on uncompressed raw data and associated embedded JPEG and EXIF data.
At least it seems like a reasonable assumption, please feel free to tear it apart and point out where I may have gone wrong.
If so, then the calculation would be incorrect for other combinations, so IMO it still doesn't compute.
Interestingly (at least to me) on page 320 of the D7000 manual they list average file sizes for the various combinations and the number of images expected for an 8gb card. 14 bit lossless compressed raw comes in at 19.4mb, which squares with my experience, but gives the expected capacity as 223 images. And nowhere is there a statement as to very conservative or whatever.
It’s not about accounting for every combination but drawing a line in the sand. And Nikon drew the line at minimal to no compression. Whether you feel that is a correct decision or not is personal preference and does not necessarily make Nikons choice wrong.
The column with the 19.4 figure has a footnote “All figures are approximate. File size varies with scene recorded”. For an example take my highest and lowest file size of just over 14MB and just under 22MB. Granted 2 images is a small sample but it would average out to 18MB. If I went through a lot more of my images then averaged it out it would most likely come nearer to Nikons 19.4MB estimate.
The number of images column is marked with the same footnote. The 223 figure is most likely a bit more conservative in that Nikon cannot predict the format of the card which can tend to vary in available space depending on the formatting scheme. For instance I have two Promaster 8GB class 10 cards. One has a volume label of D7000 with a total capacity of 8,032,092,160 and available space of 7.48MB. The other card has a volume label of SD with a total capacity of 8,249,794,560 with available space of 7.68MB.
There are just too many variables to develop an accurate estimate when writing a manual. And be it right or wrong, it was Nikons choice to use a line in the sand of minimal to no compression of the raw data when calculating the in-camera estimate.
Could Nikon have instead used about 20MB as the line in the sand instead of about 32MB, well yes they could have. But they didn’t, and that is just the way it is.
I'm sorry, I give Nikon absolutely no credit in this matter. At least they could have done the arithmetic correctly on their manual page. And your phrase "223 figure is most likely a bit more conservative" is a bit of an understatement, since something around 400 is the correct number. Realistic numbers for both the camera and manual, with an alibi phrase explaining possible variability, would have been much more useful.
We can dink with binary gb vs. real gb, and actual card capacities vs. marketing numbers all day, and it still won't excuse Nikon for this ongoing error. All it does is confuse users and provide fodder for forums.
>I'm sorry, I give Nikon absolutely no credit in this matter. >At least they could have done the arithmetic correctly on >their manual page. And your phrase "223 figure is most >likely a bit more conservative" is a bit of an >understatement, since something around 400 is the correct >number.
It’s not an error but a choice. Unless Nikon restricts the file size to a single value, any figure can only be an approximate estimate due to the highly variable nature of the issue. Yes using the average file size of 20MB would give a more realistic real world estimate, but still would not be exact. And quite frankly you can estimate the total capacity for any average you desire with a bit of math and know in advance what size card you would need for a given shoot.
The hot debate in my opinion is due more to those who wish their desires over the reality of the situation. I’m not saying you’re wrong to do so, but as Brain Tilley points out it is a fruitless endeavor. Nikon has drawn their line in the sand for whatever reason and are sticking to it.
I personally don’t pay much attention to what the remaining capacity is until it gets under 10. Being just a hobbiest 223 images on a card is more then I would use at any one given shooting scenario. And the fact I could get closer to 350 per card is just icing on the cake.
For an example I sat outside for about two hours watching the recent Lunar Eclipse firing off about 184 frames in the process. The average file size was 15.5MB. Nikons camera estimate on the empty card shows 232 images. Using the average of 20MB would show an estimate of 383. But using the average file size of the shoot indicates I could fit 495 images on the card. Yeah 383 is closer to 495 then 232, but neither 232 nor 383 is hand grenade close and those who rue over this issue would most likely be irate and gain fodder either way.
I could however see how a Pro might wish to know exactly though, but as previously pointed out using the average file size of 19.4 as the line in the sand would give a number that might be a more realistic expectation, but it will still only be an approximation(and if the average file was closer to 22MB you would run out of card before you thought you would). I guess it comes down to you can please some of the people some of the time, but you cannot please everyone all of the time. Not trying to dismiss or diminish those whom feel this is an important issue, it’s just not that important to me. I did my best to explain the why and where for’s as best as I understand it, and I don’t believe I have anything further to add to advance this discussion any further at this point.
>Yes, I should have mentioned this. I use lossless >compression, and both bodies are set to 12-bit, always NEF >alone, no jpg. I noticed after browsing the forum that another >post in the D7000 section (on SD cards) mentioned having a >32GB version of my card, set to RAW+jpg-fine, and got a >capacity of about 640. That also seems off. If that setting >produced 2 files 16MB each, there should be 1000 shots >available, right--1000-fold difference)? (give or take...). I >wonder if I'm missing something important about card storage, >or perhaps the camera's estimates are far different from >actual capacity. Anyone out there replicate my findings? >Thanks to all.... >
Mine says 440 with a 16Gb Sandisk Class 10 with 14 bit.
Curious about your settings though, 12bit seems a bit conservative, why not go with 14-bit?
Thanks, Steve--that's at least quite close to my experience. I will use 14-bit for landscapes, but wonder (uncertain at this point) if for wildlife the maximum photo rate will decline for 14 as opposed to 12 bit. That is the case with most Nikon bodies, the D3 and D3s being exceptions (according to Thom Hogan's guidebook).
My 7000 says that it has room for 467 NEF files when set at 14-bit loseless NEF format, but in actual use gets about 780 for a 16 gigabyte card. I have used a couple different cards and the results are the same.
Wow, that's more like what I expected and calculated. Given comments above, it seems that Nikon has taken an extraordinarily conservative approach to the capacity estimate. Another option might have been something about SD cards that differ from CF ones on my other bodies. In any case, thanks for the real live experience, both for my relief and surely that of others with the same puzzlement. cheers to all.
Been off-line for a while but would like to add my half-penny's worth: a) Nikon badly underestimates card capacities but corrects itself as it goes along. Rather like using a GPS, where the initial travel time estimate bears little relationship to reality because traffic jams - like not-yet-taken pictures - cannot be estimated in advance. b) If Slot 2 is set as "back-up", and a smaller card is inserted there, then the number shown will be as per the limit of the smaller back-up card rather than the larger card in Slot 1. So my personal experience, which I assume others can vouch for also. Nathan
One other thing I've noticed: SD cards formatted in another Nikon body (D90 in my case) showed a lower number of images available. After reformatting in the D7000 the number was closer to expectation. And like many of our compatriots I've experienced that the number of images that can be taken well exceeds the number that the estimate displays.
Thanks for that tip, Steve. The other down side with larger files is that the buffer capacity is limited. When I use the 7000 for wildlife, I'm frustrated often by running out of gas along the way with moving targets such as birds in flight. I have been spoiled by my D3s. Still, the D7000 can't loose all that much in terms of space with the extra 2 bits--perhaps the buffer affords one less shot? Cheers Gary