Helping people with computers... one answer at a time.

For the most part, if you're mostly interested in snapshots and easy-to-share, easy-to-send pictures, JPEG's fine. You'll never notice the difference.

Leo, I thought I understood your explanation regarding pixels and resolutions, etc. I was wrong. Perhaps you can help me unscramble the omelet (sorry about the metaphor) concerning different formats. I just bought a camera that allows me to take photographs in JPG or JPG plus RAW or just RAW!

If I take a picture in RAW, the resulting picture is about 24 MB. Then if I put it through the supplied software (Silkypix), I can then save it as a JPG, which becomes an 8 MB; or as TIF, which becomes about 45 MB. I asked myself what's the point in having a picture containing 24 MB of data if I can't use it? I can view the RAW picture using FastStone and even save it as a PNG format. I'm thinking here of preserving as much data as possible. Should I just use the JPG format initially and then, if need be, manipulate various aspects with programs such as FastStone or Photoshop? I can very quickly fill my hard drive with just a few different formats which all look (to the amateur) much of a 'muchness.' Please help! Preferably with less words than War and Peace.

In this excerpt from Answercast #69, I look at various file formats for images, how they compare, and how they are used.

Picture formats

Well, hopefully, this will be less than War and Peace!

First of all, the article that you are referencing on pixels and resolution is actually independent of file formats.

Pixels, resolution, height by width, color depth; that actually applies to pretty much all of the pictures. What we need to talk about here are some of the many differences in file formats.

RAW image file format

Let's start with RAW because I think a lot of people don't really understand what RAW is.

As its name implies, it's a "raw" format and that is going to be specific to the camera that you're using. In other words, the RAW format output (by say a Nikon camera) is going to be dramatically different inside than the RAW format output by say a Canon camera. It's "raw" because it's actually storing information that is optimized for and specific to that particular camera: that particular camera's hardware, that particular's camera's light sensors, the actual photo cells that they use to grab the picture.

That is probably the most accurate representation of the picture before any manipulation is done on it. In fact, in my case, it's what I save.

Now, as you point out, a RAW file is actually fairly useless for sharing. You can't post a RAW picture up on the web; you can't post a RAW picture in a photo-sharing site because it implies that everybody who would be able to view that picture would have a RAW decoder for every possible camera's RAW format. And of course, they don't.

So, then, we start looking at other formats.

Before I leave to other formats, the one thing I'll point out then with RAW is that the size of the file (in your case, say 24 MB) may or may not relate to the size of the image, the number of pixels in the image. The problem here is that RAW formats contain a lot of information (as I said) that is specific to the camera.

They may record a single pixel in any of several different obscure ways. They can actually use some form of compression if they wanted to.

File size

So, the file size is kind of interesting.

It's true that the RAW file format is typically larger than the file formats you'll eventually use. We'll talk about exactly why that is in a moment. So, let's move on to some of those other file formats.

JPEG image file format

The most common file format that you'll find on the internet for photographs is JPEG (or JPG). JPEG is a standard; it's supported by almost every image display program, every web browser, every everything... almost.

Now, the interesting thing about JPEG is that it is by definition a "lossy" file format. So what that means is that when you convert your original image (the .raw format) into a JPEG, some information will be lost.

This is why I actually save all of my pictures as RAW so that I have everything possible, should I then want to go in and manipulate the image some more. JPEG loses something.

As you point out, you may not notice. You may not notice that, gosh, the colors are ever so slightly different or the pixels are every so slightly miniscule-ly less sharp than they would have been had it been in the RAW format. That's kind of the point of JPEG. It actually takes advantage of human eyesight and things we do and don't see in order to compress the image, to make it smaller, to actually use less data to render out an image that is of acceptable quality... and even there, the acceptable quality can be adjusted.

RAW format contains every bit of information about every pixel. JPEG? You can adjust it. When you save a file as .jpeg in an image manipulation program, usually you can adjust the quality of the image.

You can say, "Use lots of data to save this image because I want it to be as sharp and as appropriate as possible." Or, you can go to the other extreme and the picture will be very unrecognizable because everything interesting has been compressed out.

So, in my case, like I said, I save as RAW. What that implies is: in order for me to do anything with a picture that I want to then use somewhere else - I must first edit it.

I happen to do it in Photoshop. I edit my images. I crop them. I adjust colors. I do various things to them and then the result of that work I save in JPEG format - usually at a fairly high quality level - because at that point, the size of the image isn't going to be as big. Because, usually I end up cropping them.

So, that's one approach.

What format to save?

Now, many cameras (mine included) have the option of saving one, the other, or both: JPEG, RAW or both.

My... I guess you would say "recommendation" would be that if you are (I don't know...) an advanced amateur or a pro, I'd be tempted to save in RAW format - knowing that in order to do anything to any picture, you're going to then have to manipulate it: to save it in JPEG to do whatever.

If on the other hand, all you're really interested in doing is having some snapshots that you can deal with quickly and easily and upload to the web, it may not be important. That level of detail may not be important to you. In which case, having your camera save JPEG is more than sufficient.

Would you ever save both? You know, I did for a while but there just wasn't a point. I keep all my originals in RAW format. As long as you keep all of your originals (all of your unmodified originals) in whatever format they come out of the camera, then you know that you can always go back to those to make changes, to crop new versions, to do whatever it is you want.

TIF & PNG file formats

You mentioned a TIF file format.

TIF, in particular, tends to be a bad file format for photo sharing: mostly because it either isn't compressed or isn't compressed well. That's why you see that your TIF file ended up becoming actually bigger than the original - because it had to normalize.

It's a standard format; most programs certainly understand it - but it had to normalize all of this information that was unique to your camera in the RAW file format into a format that then has the information in a very generic and as it turns out, uncompressed format.

PNG is, I suppose, a bit of a trade-off in that it is a "lossless" format. The conversion from RAW to anything, from RAW to PNG will still involve just a little of bit of loss; but the compression algorithm in PNG is a lossless one, which means you get what you put in.

Choosing a format

So, it is a complicated topic, like I said. That's why, for the most part, if what you're mostly interested in is simply doing snapshots and easy-to-share, easy-to-send pictures, JPEG's plenty. JPEG's fine. You'll never, ever notice the difference.

On other hand, if you start getting a little bit more serious, if you want to start playing with things like colors and contrast and light balance and a whole bunch of random things that programs like Photoshop make accessible to you, then my recommendation (or at least my experience) is that saving in RAW format is usually the way to go.

Then, producing JPEGs, the way you want the JPEGs to look, is the second step that's required for every picture you want to share with someone.

Article C6014 - November 10, 2012 « »

Share this article with your friends:

Share this article on Facebook Tweet this article Email a link to this article
Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?

6 Comments
Doug Brace
November 10, 2012 11:46 AM

My preference is to save files in PNG. As far as compatibility is concerned with most photo editing programs, they recognize this file format very and they can be shared without problems as email attachments. PNG files can also be used for uploading to the various web photo sharing services as well.

Esley
November 13, 2012 10:07 AM

Very good article Leo I picked up what knowledge of Photoshop by running the program.
My XP had about 5 different cameras on it. I had
read about "Raw". I always save my original and
do editing, printing, ect from a copy. I get many
B&W photos that people want enlarged. Your resize article is great . I have windows 7 Pro &
plenty of disk space. Thanks

Vanya Marin
November 13, 2012 3:58 PM

Can I try to put it in "pictoresque" words...
RAW is only FULL and UNCOMPRESSED format that captures the widest range of information to your camera, without touching a thing about photo during light entering the sensor - NO WHITE BALANCE and COLOUR DETAILS, no CONTRAST and stuff are applied... Just raw and whole information!
It is RAW material to which you later always can come back to, over and over again and prepare it as new look, new format, new size... You can tweak these things from scratch, every time...
JPEG is - as Leo nicely stated - compressed format of lossy quality (raw is losless)... So, if you alredy take pictures in JPEG - you've pre-determined lot of things - like contrast, brightness, white balance etc... It is already applied to your pic during taking it - work is done in-camera, during compression...
Of course, you can manipulate (or FIX) those JPEGs in programs like photoshop, but only to a certain degree - even that "certain degree" de-grades quality of your pic and artefacts are starting to appear - and once you saved your changes, there's NO WAY BACK (like in analogue times - 'quality generation loss' accures with every new manipulation)...
Of course, it mostly depends on stuff you are shooting; how important it is to you, 'cause of quantity of taken pictures nowdays, I, for example, decide up in front if forthcoming pictures are of enough importance to be shot in RAW - not because of storage, that really isn't such an issue any more - but because of time - 'cause each and every RAW pic needs editing...(post production it is in pro-world:)
Thanx to various options nowdays, you can choose to shoot just JPEG if these are photos that aren't gonna turn into art pieces, you can shoot both at the same time - it spares you of editing pictures you don't think deserve editing, or shoot full RAW if you are doing something important, cause if the pic is important, from that RAW file you can really pull out unbelivible results in every way and detail of picture... (for example; that what in JPEG file is lost detail in underexpossed part of the pic - in RAW suddenly comes up as fully usable, recognisible detail, with just a "drag" of a photoshop slider)
Just keep in mind another 'time factor' - shooting in jpeg+RAW and RAW formats means that it takes much longer time to write every pic down to your memory card in camera after you press the 'trigger' - so you can lose some action because of slower bursts and less fps....
For that reason, new cameras provide usualy 3 different raw formats - full resolution (let's say all 21MP of your sensor), semi-resolution raw and low-res RAW...
THEY ARE ALL OF SAME FULL QUALITY, JUST THE FILE ISN't that big - and unless you plan to develop jumbo posters prom those pics, it is very cool to grade down your RAWsize... Then you get part of that time factor back....
Hope this shines just a bit more light on the question!
Cheers!

James
November 13, 2012 7:02 PM

If RAW is native to the particular camera (or brand of cameras), does that mean that you need to have the driver/software for your camera so that you can manipulate the pictures? Or does photoshop know how to read the RAW format for every kind of camera on the market?

It's kinda "yes" to both - Photoshop (or whatever you use) needs to know how to read the RAW format for every camera that it supports. As it turns out the RAW driver in Photoshop is updated fairly regularly. Don't know about other photo editing programs.
Leo
16-Nov-2012

Vanya M.
November 14, 2012 6:43 PM

Photoshop has its plug-in, standard part of new Photoshop versions - called cameraRAW (as does every decent photo- editing program - as Lightroom, ACDSee etc) and they read most, if not all important camera model's RAW files...
Adobe PhotoShop itself will open your RAW FILE directly in CameraRAW plugin, where you will edit and manipulate it - and then, when done and saved in chosen format, file will re-open further in Photoshop classic interface...
HOWEVER it may happen that some times it can take a while when new camera model hits the market, for Adobe guys to make update for CAMERARAW to read that brand new RAW...
SO it was very recently when CANON 5D Mark 3 came out, for first month or two it was almost impossible to open that camera's RAW files, untill photoshop's camera raw update arrived...

Roger R
November 22, 2012 6:19 PM

Finally, an explanation of the basic formats that I can understand. Thanks you, Leo, and those who commented!

Comments on this entry are closed.

If you have a question, start by using the search box up at the top of the page - there's a very good chance that your question has already been answered on Ask Leo!.

If you don't find your answer, head out to http://askleo.com/ask to ask your question.