more RAW vs JPEG (1 Viewer)

nigelblake · Feb 15, 2006

White balance is recoverable on Jpegs its just not as easy as on a RAW file and likely to add noise.

Having your monitor properly calibrated applies whatever file type you are processing.

Your camera processes an image to jpeg and discards other data that is not necessary to the image file according to the setting made on the camera, with RAW however all of that data is still in the image file, that is why you stand a better chance of correcting blown whites.

When there is a likelyhood of blowing whites I generally underexpose (- compensate) by 1/3rd or 2/3rds (sometimes more, Dippers being an example) of a stop and then dual process my image (make two conversions) to get best exposure on the highlights and shadows, these can then be combined using layers and some erasing or selected cutting to get the best 'across the image' appearance.

Neelly · Feb 15, 2006

paul goode said:
. Can anyone recommend a good supplier of cheap 1Gb CF cards?

Regards

Paul.

7DayShopper are selling 2GB Sandisk for £56.49 & 4GB for £114 OK they are not the Extreme but I have both the older ones and the Extreme and can't see any difference in writing speed
Neil

Leif · Feb 15, 2006

Neelly said:
7DayShopper are selling 2GB Sandisk for £56.49 & 4GB for £114 OK they are not the Extreme but I have both the older ones and the Extreme and can't see any difference in writing speed
Neil

Davoom seem okay. I paid £73 including P&P for a 2GB 100x card. Leif

SMC2002 · Feb 15, 2006

paul goode said:
Thanks for the replies. If the blown highlight problem is reduced then that is a good reason to investigate RAW further. I have never been bothered by the PP workflow of RAW because I am happy to use it in other aspects of photography and the workflow of post processing my crummy JPEGS is LONG!
For wildbird photography however the smaller buffer, reduced frame rate and no of images on a memory card concerned me. Can anyone recommend a good supplier of cheap 1Gb CF cards?

Regards

Paul.

Paul,
The blown highlight recovery and lost shadow detail recovery are the major benefits of using RAW. As mentioned, it is also easier to correct white balance issues using RAW. These are some of the advantages of working with a 12 bit per channel image versus an 8 bit per channel image (RAW vs JPG/TIF),

I have a little example posted, if you care to check it out. Here is a crop of a jpg right out of the camera. Here is the same cropped image after RAW conversion and adjustment.

Pretty remarkable recovery of blown highlights and the color correction was a breeze to do also.

Steve

paul goode · Feb 15, 2006

SMC2002 said:
Paul,
The blown highlight recovery and lost shadow detail recovery are the major benefits of using RAW. As mentioned, it is also easier to correct white balance issues using RAW. These are some of the advantages of working with a 12 bit per channel image versus an 8 bit per channel image (RAW vs JPG/TIF),

I have a little example posted, if you care to check it out. Here is a crop of a jpg right out of the camera. Here is the same cropped image after RAW conversion and adjustment.

Pretty remarkable recovery of blown highlights and the color correction was a breeze to do also.

Steve

Hi All,

Thanks for all the replies, guess I'll have to bite the bullet and stock up on memory because I feel that the main problem (well one of thousands) that I'm having is blown highlights particularly on birds such as willow and marsh tits. I've been underexposing by up to a stop and still getting problems

The 2 pictures you attached Steve certainly prove the point, notably the feather detail recovered in the birds cheek.

Nigel's technique also looks good, should keep me out of mischief for hours sorting that one!

Thanks for the help everyone, now all I need to do is to get my capture one software to recognise the 20d files.

Regards

Paul

nigelblake · Feb 15, 2006

paul goode said:
Hi All,

Thanks for all the replies, guess I'll have to bite the bullet and stock up on memory because I feel that the main problem (well one of thousands) that I'm having is blown highlights particularly on birds such as willow and marsh tits. I've been underexposing by up to a stop and still getting problems

The 2 pictures you attached Steve certainly prove the point, notably the feather detail recovered in the birds cheek.

Nigel's technique also looks good, should keep me out of mischief for hours sorting that one!

Thanks for the help everyone, now all I need to do is to get my capture one software to recognise the 20d files.

Regards

Paul

You could also set the in camera contrast to the lowest level, and restore contrast in post production, personally I always shoot at minimum contrast.

paul goode · Feb 15, 2006

nigelblake said:
You could also set the in camera contrast to the lowest level, and restore contrast in post production, personally I always shoot at minimum contrast.

Hi Nigel,

The camera is set to Parameter 2 so everything is set to zero. Is that what you mean or go to set 1 and wind contrast down to -2?

Regards

Paul

nigelblake · Feb 15, 2006

Yes Paul go to set 1 and crank the contrast down, you should find less blown white issues afterwards.

On my 20D I have the camera at set 1 with the contrast at -2 and sharpness at -2, saturation and colour tone at 0, while this looks flat and soft straight from the camera it will give you much more latitude when sharpening, particularly after resizing, as there are no sharpening artifacts being resized in the image.

Parameter I is the preset and has +1 on three settings (contrast, sharpness and saturation,)

parameter 2 is all at zero, however these are more like +2 with the -2 effectively being zero, because the 0 setting does include some processing.

I should add that if you are shooting RAW then you can make these adjustments with your RAW processing program, post exposure.

paul goode · Feb 15, 2006

nigelblake said:
Yes Paul go to set 1 and crank the contrast down, you should find less blown white issues afterwards.

On my 20D I have the camera at set 1 with the contrast at -2 and sharpness at -2, saturation and colour tone at 0, while this looks flat and soft straight from the camera it will give you much more latitude when sharpening, particularly after resizing, as there are no sharpening artifacts being resized in the image.

Parameter I is the preset and has +1 on three settings (contrast, sharpness and saturation,)

parameter 2 is all at zero, however these are more like +2 with the -2 effectively being zero, because the 0 setting does include some processing.

Hi Nigel,

Thanks for the quick reply. I've messed around between Parameter 1 & 2 and assumed 0 meant no processing. I'll now set your recommended settings and see what happens. Bring on the Weekend! Norfolk beckons this weekend so I think I'll stick with JPEG, can't afford any more memory cards just yet.

Thanks and regards

Paul

compa · Feb 15, 2006

SMC2002 said:
Paul,
These are some of the advantages of working with a 12 bit per channel image versus an 8 bit per channel image (RAW vs JPG/TIF),

Steve

Just a minor correction ... TIFF files can contain 8 or 16 bits per channel.

SeanKP · Feb 15, 2006

compa said:
Just a minor correction ... TIFF files can contain 8 or 16 bits per channel.

I'd always assumed (and I know how dangerous that can be!) that if you were starting with an 8bit JPEG which was subsequently converted to TIFF there wouldn't be any point in going to 16 bit TIFF as the data had already been 'lost'. Have I got it totally wrong again?

SMC2002 · Feb 15, 2006

SeanKP said:
I'd always assumed (and I know how dangerous that can be!) that if you were starting with an 8bit JPEG which was subsequently converted to TIFF there wouldn't be any point in going to 16 bit TIFF as the data had already been 'lost'. Have I got it totally wrong again?

Sean,
I think you have it right. The only way I know of to get a 16 bit TIF with more than 8 biits of data/channel is to save a 12 bit RAW conversion as a 16 bit TIF versus an 8 bit TIF or jpg. Don't ask me where they come up with the additional 4 bits per channel though?

A normal TIF right from the camera is an 8 bit file. At least it is/was on every digital I ever used. So your assumption should hold true. I also agree that there probably isn't any advantage to saving an 8 bit per channel file as a 16 bit file. As you point out, the data is already lost and even though you saved it as a 16 bit file, you really only have 8 bits/channel worth of data to work with.

Steve

compa · Feb 16, 2006

SeanKP said:
I'd always assumed (and I know how dangerous that can be!) that if you were starting with an 8bit JPEG which was subsequently converted to TIFF there wouldn't be any point in going to 16 bit TIFF as the data had already been 'lost'. Have I got it totally wrong again?

Not at all! You have it right in general. There can be a minor benefit when doing editing to have the extra headroom, but in general there is no reason to convert from 8 to 16 bits.

My point was that TIFF can faithfully represent a RAW file with no loss of detail.

robski · Feb 16, 2006

Personally I shoot 99% jpeg and save Raw for the nasty things in life like high contrast and colour balance. The fact that I don't have a lot of storage space and speed on my computer demotivates me from using the Raw route full time. I've only bought one PC in the past 20yrs, I kind of resent forking out money on PC parts when I can get by using pre-enjoyed bits and pieces for little or no cost.

I came across an interesting view point the other day. Whilst walking along a footpath with my camera I bumped into a guy walking his dog. he spotted the camera and announce that he was a Pro photographer. So we got chatting about equipment and his subject matter. He then asked if I sold my pictures and I said no it's mainly a hobby but if somebody was to thrust money in my direct it would come in useful to buy new equipment etc. After a while it became clear that for me there was no pressure to get a good shot and I would not be that upset if the whole days shots ended up in the trash can even if was down to my own stupid fault. For him he had to sell the picture if it was good or bad.

So if there is a market for your images it makes sense to shoot both if your camera supports it. Then you have the option to try and save the shot from the raw format. For me if the jpeg won't come right then it's trash, no big deal. I have found if you have a good jpeg it's a lot of hard work using the raw route to improve apon it.

Now we get to the point of my posting. I have noticed that some Raw converters have the option of linear or a gamma conversion. Also the results can be quiet different in each Raw converter dispite trying to use the same setting e.g if you compare the output from the Canon and PS CS utilities. There seems to be little discussion on the merits of each program and how to use their settings.

paul goode · Feb 16, 2006

robski said:
Now we get to the point of my posting. I have noticed that some Raw converters have the option of linear or a gamma conversion. Also the results can be quiet different in each Raw converter dispite trying to use the same setting e.g if you compare the output from the Canon and PS CS utilities. There seems to be little discussion on the merits of each program and how to use their settings.

Hi Robski,

I'm not sure if what I am about to describe is the same as your thread or different but it has confused me.

Last weekend I was asked to photograph a friends birthday party and shot everything in RAW so I could sort out any white balance problems.
Looking on the camera some images appeared quite dark but nothing that couldn't be sorted out.
I uploaded the images to the PC using PSE 4 and then noticed that the dark images had changed to being overexposed when viewed in PSE4's RAW converter.
I thought that was strange but shut down PSE4 and opened Capture One as thats the RAW editor I'm familiar with and lo and behold the dark images are dark again!

At no point have I altered these files so what is going on, is PSE4 processing the files, in which case how do I stop it, or is this the difference you were describing in which case its one heck of a difference.

Regards

Paul

SeanKP · Feb 16, 2006

Hi Paul

In the version of Adobe Camera Raw that I have (which came with CS2) the default behaviour is for the program to make a 'best guess' of the exposure, contrast, shadow and brightness settings when you open a RAW file. I presume that the same applies to version of ACR that came with your copy of Elements. You can obviously revert to the 'as shot' settings for each photo or you can change the settings so that it opens all RAW images 'as shot'

Sean

paul goode said:
Hi Robski,

I'm not sure if what I am about to describe is the same as your thread or different but it has confused me.

Last weekend I was asked to photograph a friends birthday party and shot everything in RAW so I could sort out any white balance problems.
Looking on the camera some images appeared quite dark but nothing that couldn't be sorted out.
I uploaded the images to the PC using PSE 4 and then noticed that the dark images had changed to being overexposed when viewed in PSE4's RAW converter.
I thought that was strange but shut down PSE4 and opened Capture One as thats the RAW editor I'm familiar with and lo and behold the dark images are dark again!

At no point have I altered these files so what is going on, is PSE4 processing the files, in which case how do I stop it, or is this the difference you were describing in which case its one heck of a difference.

Regards

Paul

paul goode · Feb 16, 2006

SeanKP said:
Hi Paul

In the version of Adobe Camera Raw that I have (which came with CS2) the default behaviour is for the program to make a 'best guess' of the exposure, contrast, shadow and brightness settings when you open a RAW file. I presume that the same applies to version of ACR that came with your copy of Elements. You can obviously revert to the 'as shot' settings for each photo or you can change the settings so that it opens all RAW images 'as shot'

Sean

Hi Sean,

Thanks for that info. It must be whats happening because the images that are correctly exposed in the first place haven't noticeably altered.
I'll delve into the settings and find how to switch it off because it's guess wasn't very educated!

Mind you it graphically demonstrated what can be recovered from the underexposed shadow areas of a RAW file!! :bounce:

Regards

Paul

Recurvirostra · Feb 16, 2006

paul goode said:
Now I am baffled. If the original exposure was messed up enough to blow the highlights how can post processing a RAW file recover them? I would have thought than when that detail has gone its gone. If RAW has this ability I'll order a raft of memory cards and switch over today.

Hi Paul,

As others have said, the RAW file is not recovering blown-out highlights - it hasn't lost them in the first place.

Because the JPEG file is an 8-bit file it can only hold 256 levels of brightness (2 raised to the power of 8). A 12-bit RAW file contains 4096 brightness levels (2 raised to the power of 12). So, at its very simplest the JPEG will have 16 times as many blown-out pixels as the RAW file (4096 ÷ 256) assuming the same exposure setting was used.

However, it's not quite as simple as that, and because of the way digital cameras record information, the extra complexity helps the RAW format again, more than the JPEG. Assuming a 5 stop dynamic range in a photo, the number of brightness levels available to the RAW file for the brightest f/stop is 2048 while for the JPEG it is only 69. We now have, in a more realistic situation, 1 blown-out RAW pixel for every 30 blown-out JPEG pixels. A significant difference, I'm sure you'll agree.

There is a very good article which explains all of this much better than I'm able to at the Luminous Landscape web-site.

compa · Feb 16, 2006

Recurvirostra said:
Hi Paul,

As others have said, the RAW file is not recovering blown-out highlights - it hasn't lost them in the first place.

Because the JPEG file is an 8-bit file it can only hold 256 levels of brightness (2 raised to the power of 8). A 12-bit RAW file contains 4096 brightness levels (2 raised to the power of 12). So, at its very simplest the JPEG will have 16 times as many blown-out pixels as the RAW file (4096 ÷ 256) assuming the same exposure setting was used.

However, it's not quite as simple as that, and because of the way digital cameras record information, the extra complexity helps the RAW format again, more than the JPEG. Assuming a 5 stop dynamic range in a photo, the number of brightness levels available to the RAW file for the brightest f/stop is 2048 while for the JPEG it is only 69. We now have, in a more realistic situation, 1 blown-out RAW pixel for every 30 blown-out JPEG pixels. A significant difference, I'm sure you'll agree.

There is a very good article which explains all of this much better than I'm able to at the Luminous Landscape web-site.

Voodoo math!

If %5 of a photo's area is blown out then 5% of the pixels will be blown out - that is true if it is JPEG - RAW - TIFF - PNG - or whatever format you want to use. If a pixel is just short of blown out then that is a different story. For 1 level in jpeg you would have the potential of 30 different levels in RAW. If the light level hitting a pixel is above the dynamic range of the sensor then the pixel is "blown" - there is no level above that value - any value below that point is not blown.

The brightness of an area of a photo may be above the dynamic range of your monitor and appear to be blown out. Adjusting the image in PhotoShop or whatever can often make detail appear in the area that appeared blown. If that is the case it was not "blown" in the first place!

Recurvirostra · Feb 17, 2006

compa said:
Voodoo math!

If %5 of a photo's area is blown out then 5% of the pixels will be blown out - that is true if it is JPEG - RAW - TIFF - PNG - or whatever format you want to use. If a pixel is just short of blown out then that is a different story. For 1 level in jpeg you would have the potential of 30 different levels in RAW.

Well I said I may not be able to explain it very well. And I was trying to keep it as simple as possible. But I think you are agreeing with what I was trying to say anyway.

If a theoretical photo is perfectly exposed so that the very brightest spot (say, a single pixel) is white and the very darkest spot is black, then the JPEG will have about 30 times more area that is white (or blown-out) than the RAW. If 5% of your theoretical JPEG is blown-out you will have far less blown-out pixels in the RAW because it has many more brightness levels below pure white in which to store the detail, before you reach the next level down in the JPEG file (one gradation below pure white).

In real life, even if the photo is not perfectly exposed, whatever area is blown-out in the JPEG will be much smaller in the RAW because the RAW file has a whole bunch of levels below pure white, but still brighter than the JPEGs second brightness level, in which to store detail.

Or to put it another way, if you had a brightly lit card printed with 30 different shades of very light grey and you photographed it just slightly overexposed using JPEG, the entire photo would be blown-out. Using the same exposure with RAW you would (or perhaps, could) have a photo with 29 shades of grey and 1 section of white.

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