Raw to jpeg file sizes

technofan · 28-05-2005, 1:07 PM

Oki doki matey peeps,

Just a general question regarding file sizes. I have been snapping in jpeg (2.7mb) and raw (8mb) and converting the raw to jpeg (0.75mb). I would have thought that jpeg straight from the camera and jpeg processed on the PC from Raw would be similar in file size. Why is there an approximate 2mb difference? Anybody out there in the know?

Thanks,

Pete.

PS Have been playing with my new F4L 70-200mm lens this morning....coooool, it does pack a punch...the wife thinks I am trying to make up for something and that camera lenses are definately a 'male' thing

severnsource · 28-05-2005, 3:55 PM

Different compression algorithms. The amount of compression can be varied depending on the trade off you want between file size and loss of information; smaller file - more quality loss. Some designers algorithms seem to be more effective than others as well.

Bill

technofan · 28-05-2005, 3:57 PM

Thanks Bill

Pete.

dejongj · 28-05-2005, 4:48 PM

It also differs per photo...My RAW's are about 5mb, using ACR and saving at quality 10 Jpeg I end up between .7 - 1.8Mb...If I use quality 12 Jpeg they are at least 2Mb...

Try it at the maximum quality and then up the slider as maximum doesn't really mean maximum when saving as Jpeg...

mr jones · 28-05-2005, 5:34 PM

you've gotta remember that a raw converter can take much longer to convert a file than a camera, especially if you want the camera to take lots of photos in succession, therefore the raw converter can have a more indepth algorythm compressing the file more.

do you do alot of image manipulation after converting from raw? if so you may want to consider saving as a non lossy format such as PSD or .tif before finally converting to .jpg for distribution/developing. if you keep repeatedly saving .jpg file during manipulation you will loose image quality

RobertP · 28-05-2005, 5:49 PM

Using rawshooter my output jpegs on 'maximum' were 3 to 5 Mb in size from 8M raws. I now use 'higher' and get output files from 1.4 to 3M - more like the camera best jpg file sizes.

mr jones · 28-05-2005, 7:04 PM

rawshooter outputs to circa 25mb tiffs for me

technofan · 29-05-2005, 7:46 AM

Thanks Guys',

Informative stuff, I haven't done much work in RAW. The jpeg pictures I get are of such good quality that I've taken the easy way out....so far. However, when I eventually get out and about to take some 'serious' pictures I will work with 'lossless' formats. To that end what software is available that can recognise RAW files and provide excellent features (without breaking the bank)?

Ta

Pete Delaney.

EDIT: OK I found a free download of 'Rawshooter Essentials 2005' and I shall give it a whirl. I think from now on I shall stick to shooting in RAW format. Please feel free to tell me and everyone else what your favourite image processing software is (that supports uploading RAW images for processing). This is all good informative stuff

RobertP · 29-05-2005, 10:20 AM

I only use RAW when I want the best pictures I can get. It lets you make the changes you could have made on the camera settings - but after the shot is taken. If your settings were way off then all may be lost whatever you do in software but if your settings were only a bit wrong you can correct the exposure, white balance etc.

The reason for not using RAW all the time is that when you have taken a few hundred shots it can be a pain going through them all tweaking and processing. Rawshooter helps in that if you have a bunch of similar pictures you can copy the tweak settings from one to the rest of them. I shoot best jpg on the camera mostly and change to raw+small fine jpg if I think the situation warrants it. Having the camera jpg as well lets you see if your tweaks really did improve the image.

mr jones · 29-05-2005, 11:33 AM

Quote:

Originally Posted by RobertP

I only use RAW when I want the best pictures I can get.

surely you want the best pictures you can muster all the time though?

severnsource · 29-05-2005, 12:47 PM

Quote:

Originally Posted by mr jones

surely you want the best pictures you can muster all the time though?

A - not necessarily, you may only want low res pictures for web use for instance.

B - the best jpeg files aren't worse than RAW files in terms of quality. They will have been processed in certain ways that can be altered more easily from RAW files, but if you're generally happy with the cameras processing there is no real reason not to use jpeg files.

For another view on the issue try reading http://www.kenrockwell.com/tech/raw.htm

I've reverted to using RAW and jpeg because I've had a couple of lightly overexposed shots that could be corrected better from the RAW files, but most of the time I just use the jpegs.

RobertP · 29-05-2005, 2:39 PM

Quote:

Originally Posted by mr jones

surely you want the best pictures you can muster all the time though?

RAW files are great but need the time invested to make them worthwhile.

Yes I want pictures I can be proud of. All the RAW format does is make it easier to sort out a problem after the event.

For family occaisions or whatever it's the subject and relevance that are far more important that getting the technical details spot on. In those situations I'd rather have easy jpgs that need no or little editing effort.

HotblackDesiato · 29-05-2005, 8:47 PM

I use RAW all the time... just batch process the 6*4 snaps using defaults i've optimised for the camera. I only take any time with 4 or 5 shots in 100 and overall find i can get more from RAW than jpeg.

dejongj · 30-05-2005, 8:01 AM

I don't understand all this RAW takes more post processing time, surely if you took the picture correct the first time it takes the same amount; i.e. nil...And if you didn't take the picture correct RAW is a heck of a lot quicker as you can adapt the basics which you can't in JPEG...

severnsource · 30-05-2005, 8:31 AM

Quote:

Originally Posted by dejongj

I don't understand all this RAW takes more post processing time, surely if you took the picture correct the first time it takes the same amount; i.e. nil...

Well, it takes about 4 times as long to download the files onto your computer as you have about 4 times as much information to transfer. In order to get something useable from RAW you have to process it. You have to apply sharpening, exposure correction and colour balance, even if you do that as a batch process it will take time. Also you can't look at RAW files on a computer without extra software. JPEGs can be viewed on virtually any computer.

Quote:

Originally Posted by dejongj

And if you didn't take the picture correct RAW is a heck of a lot quicker as you can adapt the basics which you can't in JPEG...

That is not true either. The standard things like changing contrast, brightness, saturation and colour balance can all be done on jpeg files, as can sharpening and all the other image manipulation processes. If you start off with a high quality JPEG file and don't repeatedly save as jpeg any quality loss will be minimal.

What you can't do with JPEGs that you can with RAW is change the colour space, remove excess sharpening and you have less freedom to undo overexposure, but if you have got the settings right in the first place these are not significant limitations.

Bill

dejongj · 30-05-2005, 8:53 AM

Quote:

Originally Posted by severnsource

Well, it takes about 4 times as long to download the files onto your computer as you have about 4 times as much information to transfer. In order to get something useable from RAW you have to process it. You have to apply sharpening, exposure correction and colour balance, even if you do that as a batch process it will take time. Also you can't look at RAW files on a computer without extra software. JPEGs can be viewed on virtually any computer.

That is not true either. The standard things like changing contrast, brightness, saturation and colour balance can all be done on jpeg files, as can sharpening and all the other image manipulation processes. If you start off with a high quality JPEG file and don't repeatedly save as jpeg any quality loss will be minimal.

What you can't do with JPEGs that you can with RAW is change the colour space, remove excess sharpening and you have less freedom to undo overexposure, but if you have got the settings right in the first place these are not significant limitations.

Bill

1. 4x Longer download times: Well that depends on the RAW format of the camera, but common although potentially true it is hardly in the postprocess category of things....

2. Apply sharpening, exposure correction and whitebalance...That is not true! If you set it correctly in the camera in the first place, hence my point of taking the picture correctly....

3. Correct you can't look at RAW without extra software, so big deal. If you have so many pictures that you are worried about postprocessing times you should really be looking into additional software so you can catalog and manage the images you have shot. Great help and speeds up your whole process if you have different version of the same shot; i.e. keep the cropped and original versions together...and a B&W etc...

4. Well regarding editing posibilities...RAW editing is non-destructive and reverseable without having to 'worry' about inbetween safes...

Funny how you end it just with how I started it...If you have the settings right it doesn't matter....That's the same for points you stated in the first paragraph...So which is it ;-)

severnsource · 30-05-2005, 9:40 AM

Quote:

Originally Posted by dejongj

2. Apply sharpening, exposure correction and whitebalance...That is not true! If you set it correctly in the camera in the first place, hence my point of taking the picture correctly....

Sorry, you don't seem to understand what the RAW file is. It is the unprocessed output of the sensor, which is why it is called RAW. The only camera settings that affect it are the exposure settings. The RAW file will include the settings for sharpening, colour balance etc, but they will need to be applied to the file at a later stage, i.e. the file needs post processing to turn it into something that is useable.

Quote:

Originally Posted by dejongj

3. Correct you can't look at RAW without extra software, so big deal.

But it is actually an inconvenience. If I download JPEG files to my computer I can see the lot as thumbnails in their folder and look at them in Windows picture viewer or whatever viewing software I wish to use. RAW files are not viewable as thumbnails which means you are likely to have to load editing software; if that is Photoshop or its cut down versions it takes an annoyingly long time to load and is pretty useless as a viewer.

Quote:

Originally Posted by dejongj

If you have so many pictures that you are worried about postprocessing times you should really be looking into additional software so you can catalog and manage the images you have shot. Great help and speeds up your whole process if you have different version of the same shot; i.e. keep the cropped and original versions together...and a B&W etc...

I don't think that cataloguing software is going to have the slightest influence on processing times.

Quote:

Originally Posted by dejongj

Funny how you end it just with how I started it...If you have the settings right it doesn't matter....That's the same for points you stated in the first paragraph...So which is it ;-)

The point that I was trying to make was that the only processing that can be performed on RAW files that can't be performed on JPEGs is pretty unimportant.

Bill

dejongj · 30-05-2005, 12:00 PM

This is turning too much into an I know best session...Let's just say we are both right and put it in context...

On my Nikon D70 the customs curves can be set in the camera together with a number of other settings like sharpening etc...These in-camera settings are attached as meta-data to the RAW file; so the file doesn't get changed but the software that can understand it: NC, ACR are tested/confirmed by myself, pick it up as the default settings...With something like RAWHistory you can actually attach more than one settings file.....Without distorting the original picture.....So RAW is a lot more complex than you suggest...

Another thing that is incorrect, but lets say it is different yet again for the Nikon D70 (I don't believe that but it is the only proof I have got...)...Windows XP lets you easily browse those RAW .NEF files as thumbnails directly from the OS....So I am not certain what you are on about? Unless you use a non-current, non-mainstream OS, but that is not the majority of users...

I'm not even going to try and argue the point around catalog software as it contradicts everything you've said so far...

The last point, ah well as you didn't realise the ability to put multiple settings to a RAW file without destructing the original image I can understand the comment....

Finally don't get me wrong, I don't mind you preferring JPEG over RAW or anything else. I'm just correcting some myths...RAW does not equal more PostProcessing that JPEG by default....

severnsource · 30-05-2005, 12:28 PM

Quote:

Originally Posted by dejongj

I'm just correcting some myths...RAW does not equal more PostProcessing that JPEG by default....

I give in.

ASH1 · 30-05-2005, 1:13 PM

My view for what it's worth. I've used raw files for almost two years and only go back to jpegs if I'm using something like aperture priority. You can do more with a raw file over a jpeg and if you save your raw files as tiffs, you are left with a better image than a jpeg (more information).

As for them taking longer to download then certain factors come into play. For instants my 350D can download raw files quicker than my 300D could download large jpegs. And yes that is spitting hairs because the 350D has usb2 and the 300D only has usb1. You can also look at other thing like how fast your processor is and how much ram you have.

The point is does it matter if it takes a little longer to download if the end result is going to be better, and better it will be IMO. And as for raw taking longer to process that's not nessasaerlly true I have taken some pictures in raw that I don't need to alter and just convert them strait to tiffs. If you prefer using jpegs then use jpegs and the same goes for raw.

ASH1