Is this math correct?

Hi,

 

I'm getting ready to switch to digital from film and am looking at the Mac Pro,

which comes with a 250g hard drive. Have I done the computation correctly when I

compute that the Canon 1Ds III produces 21m files, so the 250g hard drive will

store about 11,900 images?

 

The images will be processed in Lightroom and CS3, and will be taken in RAW.

 

If my math is correct than I do not have to buy much more storage as it will

take me a while to accumulate that many images that I want to save. I will add a

second 250g drive for backup.

 

Thanks.

 

MarkF

Hi Mark, Files from your (or any) digital camera will vary in size depending on many things.

 

For example, RAW, sRAW and jpeg will all give you different file sizes. Since Canon I believe implements a little compression even on their RAW files, it's unlikely you'll ever get a single, 21M file from one photograph. (Once you open the file and save it as a PSD or TIF, it'll likely be *much* bigger than 21M, though)

 

In addition, file-size is affected by the subject matter. If you take a well-exposed shot of a flat, gray sky the file-size will be much smaller than a well-exposed shot of something with a lot of tones and details. Typically if you under-expose a shot, or if the shot is at all blurry, it'll be smaller in size.

 

So it'll be very, very difficult to "do the math" so to speak because there are so many variables - least of all, it's tough to guess how many shots you'll take per day/week/month, etc.

 

I can tell you I have that camera's "litle brother", the 1Ds Mark II and it eats up disk space like a pit bull. I'm constantly buying more storage to hold the files. Thankfully, storage is getting cheap because you also need to have a backup of everything, so you're looking at accomodating *two* copies of everything - at a minimum.

 

Then, as you open files, work on them in PS, perhaps save them with layers - as PSD and/or TIF files, not to mention jpegs for email and web use - you'll burn through storage quick. I guess Canon figures if you can afford $8 grand for a camera you can afford a few hundred bucks for extra storage at very regular intervals.

Hi Beau,

 

Thanks for the reply - I see that there are a lot of variables. I would still at least like to try to get a handle on this. If the 1Ds II theoretically generated 16m files, what would a typical file wind up being? Of course, some would be larger and others smaller, but is there a range that a typical file would be? And purely from a theoretcal point of view, is my math correct assuming files were actually 21m?

 

Mark F.

Good practice dictates you keep the hard drive clean and back up to two locations before you erase the cards.

 

As above, never modify the original files. Open, save as .psd, make your JPEGS from that master each time you need a new size.

 

I would have a master folder for each wedding, with sub folders for originals, .psd, and final JPEGS.

 

 

Bring each wedding to the hard drive, work on it, put it back in storage. After two years, contact the clients and tell them the files will be purged and they have one final chance to purchase prints.

 

Maybe burn a DVD of each for yourself if you want a record of your work.

Huh? I think you dialed the wrong number :-)

Well, I just took a quick peak at a portrait session I did not long ago - mostly head shots. The RAW files range from from about 15.1 Mbs down to 12.3 Mbs, which is a not-inconsiderable 3Mb variation. Predictably, the smaller file sizes were a bit under-exposed. (This is why they say "expose to the right" on your camera's histogram; there's more data in a "brighter" image)

 

But, in that particular session I told my camera to record RAW + Small Jpeg. I could've just recorded Jpegs (much smaller, but compressed, less-flexible files) or I had a bunch of choices like RAW + Large Jpeg, RAW + Med Large, RAW + Medium, medium small, etc.

 

And I believe the 1DsIII supports Canon's sRAW (compressed RAW) format, giving you even greater file-size choices. So you'd have to already know which of those options you'll want to use and speaking for myself, my needs change in that regard.

 

For instance, I don't shoot RAW if I'm taking pictures of my cats sitting around the house. I shoot Jpegs to save space. If it's something important - wedding, portrait, etc., I almost always shoot RAW. If I anticipate needing jpegs I'll set the camera to RAW + Jpeg, which gives me 2 files every time I pull the trigger. And as I mentioned, I can specify varying degrees of compression on the jpeg file - and thus its size - that goes along with the RAW file.

 

So there's really no "typical" at all, I'm afraid. And again, the portrait session I just looked at had the model against either a solid white or black backdrop. If she'd been standing in the woods on a sunny day and I exposed everything pretty "bright", the average file sizes would likely all change and be much larger because of the details in the background.

 

I guess if you *had* to pick an average, I'd go for a few megs less than the 21 megapixels... but if you shoot jpegs they'll be *much* smaller than that; if you shoot sRAW they'll probably be a bit smaller and if you choose RAW, that'll be the largest.

 

And no matter what you pick you'll use it up in no time. ;-) Good luck!

Hard drives are cheap relative to the camera you're getting, so if you can afford it, a pair of 500GB's might be a better starting point, although I suppose it all depends on how many shots you will take annually.

 

With digital, you'll probably take, oh, say ten times as many shots as you would with film :-) You don't have to keep them all, but they do tend to creep up on you.

D'oh! That last sentence should read "And no matter what size drive you pick, you'll use it up in no time".

 

One other aside... Even if I had the money to upgrade to the 1DsIII (I don't at the moment) I'm not sure I would *because* of the file-space issue. It's a huge PITA for me to keep up with the files I've got.

 

It takes forever (or it seems like it!) to copy them, burn everything to DVD - twice, etc. - so I usually buy external, USB drives. Lots of them. They're running around $250 for 500 gigs (You can probably find cheaper - that's an average) But because I need to keep *two* drives in case one fails... well, it adds up fast!

 

I figured that maybe 2 percent of my photos ever get blown up to prints in sizes that really need that much resolution. Often, I'm just printing 8X10s that an 8 or 10 mps camera would've worked just fine for.

 

So for me anyway, shoveling around, keeping track of, and storing the originals-plus-duplicates of all those huge files would weigh heavily on my personal decision to go for even more megapixels because I'm drowning in 'em now.

 

Don't get me wrong, they're great to have when you need 'em, but 98% of the time, I just don't. I'm thinking my next camera might be the successor to the 5D for that very reason. It'll be (I hope!) a FF camera with (I hope!) great image quality without these gargantuan file sizes to deal with.

 

If I could just afford an assistant... ;-)

Mark--

 

Your arithmetic is correct, but as others have pointed out, your disk won't have only image files shot with that camera on it.

 

Anyway, it's a lot of space, and if you're just starting out, it will take a while to fill it. Check the space, and when it gets about 75% full start adding firewire external drives.

 

There's no rush.

I ask why do you need to store so many files unless you are working commercially? And even if you are saving files for clients, do you need to save everything?

 

Don't you edit down to the really really good stuff?

 

I shoot probably 100 rolls of 120 film a year and some of 35mm. But I save less than 100 photos per year. Now I shoot mostly black and white so my gray scale files are smaller. But each keeper shot has a 120 Mb TIF from the original scan and then a 200-300 Mb unflattened PS file, plus a JPG. But my total disk usage for all these files is 149 Gb. I'm sure I could delete 1/3 of that.

 

I seldom shoot digital but when I do, I still delete 98-99% of the files.

 

Everyone needs to do what works for them but saving 10,000 photos is not what works for me.

<I>In addition, file-size is affected by the subject matter.</I><P>Subject matter has no

effect what so ever on file size. One can't gain or lose pixels because of subject matter.

William--

 

True, one can't gain or lose pixels because of subject matter, but some subject matter can be compressed more that others. The simplest encoding used, run-length encoding (RLE), widely used in PSD files, reduces the size if there are runs of identical pixels.

 

However, this is a minor effect that would never enter into coarse estimates of disk-space requirements, which is what this thread is about.

 

Bob--

 

Many photographers do delete digital files, but if you work out the costs, the work of doing so pays off at something like $2 per hour. It also runs the risk of deleting something that later will turn out to be important. Not to mention the possibility of a mistake that results in deleting the wrong file.

"Since Canon I believe implements a little compression even on their RAW files"

 

It's more than just "a little", but it's lossless, so no harm done.

 

A 10MP 1D3 produces files around 12MB - without compression they'd all be exactly the same size - around 20MB (with 14 bit (or even 12 bit) A/D resolution, it takes 2 bytes to describe 1 pixel. 2 Bytes x 10MP = 20MB :) (uncompressed).

A 21 MP camera produces 63 MB files, uncompressed, 24bit,

<I>Subject matter has no effect what so ever on file size. One can't gain or lose pixels because of subject matter.</i><P>

 

Sigh... Don't believe me? Try it. Shoot a gray, overcast sky with no detail. Or a shot of a white wall. Now take a shot of just about anything else that has lots of details. Now compare the file sizes and you'll see. RAW or Jpeg - it doesn't matter.<P>

 

Also... Look at a folder full of any shots you've taken. Are they all the same size? No. In fact, if you sort that folder by file-size you'll typically find that the largest files are your sharpest. Blurry images don't take up as much room as sharp ones either.<P>

 

So not only can your subject-matter determine file-size but your technique can affect it as well.

 

Oh - you're not "gaining or losing pixels" because of subject-matter; I didn't say that. There's not a one-to-one correlation between megapixels and file-size. Again, just look at your own digital camera images. It's easy to see they're not all the same size. Now ask yourself "Why is that?"

With some Hockey shots shooting raw + jpeg with the digital Epson RD-1S; the raw files are from 9890k to 9837k; and the Jpegs are 3286k to 2949k. Raw files tend to vary less in sizing the jpegs. With a P&S digital such as my 6 Mp Nikon L6 or the old Olympus 1.3Mp D360L; the Jpegs vary alot more in sizing with subject matter; since compression levels are more. AS Beau mentioned; a simple subject makes a smaller file size; a complex subject makes a bigger one.<BR><BR>With the 35megapixel 4x5 Phase One scan back; the TIFF files are all about the same size; 105megs each, since there is no compression.<BR><BR>The confusion is that information in a file thats redundant can be compressed in a lossless way; and the number of pixels stays the same. The opened files will all be the same size; the raw and jpegs vary in sizing due to the complexity of the image.

In scanning engineering drawings as bitmaps a 30x42" drawing at 400dpi is an uncompressed 24 meg image. With a clean drawing with little background/dirt the resulting lossless Group 4 Tiff files are typically 150 to 1000k; depending on the busyness of the drawing; ie how much lettering; lines etc. With a dirty old faded blueline with alot of backround; the file ballons larger in size say 3 megs sometimes. In each case the file captures all the pixels ie 12000 by 16800. The lossless group 4 tiff compression compresses these drawings over 100 times; with no losses; clean white areas compress well.

Lossless compression is like placing rolls of film in ones extra shoes that are in a suitcase while traveling. It doesnt mean the film or shoes are crushed; or not there. It just uses wasted unused space.

Thanks to all.

 

I guess this was not as straight forward as I thought. But I think I'm more like Bob Michaels. Since I switched from medium format B&W to slides about 25 years ago I've accumulated about 2,500 slides that I really like. For me, that means that I would be happy to make a large print to display. That's about 100/year, not counting family snaps for the album. So it sounds like the double 250 meg will do to start, and with the Mac Pro I'm told that it's now no big deal to add more space.

 

Mark F

Lot's of great answers, here are a couple of further thoughts:

you need HD space for the OS and installed Programs

the HD is less quick once it's over 50% full

Programs and files on the same HD slow you down a bit

a separate (and quick) HD for PS's use as a scratch disk is great

and best of all, back up your files, HD crash, get at least a second external HD maybe even

a 3rd or look at online storage (i.e. photoshelter)

Happy New Year

Mark

"A 21 MP camera produces 63 MB files, uncompressed, 24bit,"

 

Why would you want to have 24 bit resolution on a image who's A/D converter resolution maxes out at 12 or 14 bit?

 

Don't forget, RAW images consist of 3 greyscale images - each pixel of which can be described in 2 bytes (16 bits, 12 to 14 used).

<b>Colin Southern</b>: <i>Don't forget, RAW images consist of 3 greyscale images - each pixel of which can be described in 2 bytes (16 bits, 12 to 14 used)</i><p>

Actually, most* RAW images are a single grayscale image, with each 'pixel' having been filtered R, G, or B. Even without compression, that's how a 12-14-16-bit RAW file is smaller than the resulting RGB file.<p>

* The exception being Foveon-style raw files.

"Actually, most* RAW images are a single grayscale image, with each 'pixel' having been filtered R, G, or B."

 

At the end of the day you end up with a bunch of luminance values representing red filtered pixels, a bunch of luminance values representing green pixels, and a bunch of luminance values that represent blue pixels - ie 3 bunches of luminance values (or "grey scale images" for want of a better word). Filtering is what the BFA does - Pixels sorted into groups of R, G, and B pixels ( ie "monochromatic images" to be more technically precise) is the result of that filtering.

 

RAW files - are smaller than linear RGB files (like uncompressed TIFF) because they haven't been demosaiced yet (ie they're missing 2/3 of their information that the RAW converter extrapolates from surrounding pixels).