exposure compensation in RAW?

Just a quick question about the Exposure Compensation process of RAW images to JPEGS.

I always thought you could, if you use RAW, alter the F-stop and exposure by one stop either way of what the image was taken at. Maybe I am wrong here?

If you can alter the exposure, is there an switch to do this, or do you do it via levels? Perhaps I need some special software?

I’m using a Canon G5 camera and Adobe Elements and the standard Canon File Utility programme

Thanks for any help…..Iain

With a proper raw convertor this is true. as a matter of fact you can adjust up to 3 stops in some casess. However, Elements, unless you have the ACR plugin, will not read raw files. I do not know the Canon program.

Photoshop CS has raw conversion tools, possibly the best around, built in. The new version of Elements, 3.0, soon to be released, will also have the raw tools built in, with just slightly less control than CS has now. There is always the possibility that you can find someone that had the ACR program for Elements/Photoshop 7 and upgraded to CS, that would be willing to give you/sell you their copy of ACR.

RAW gives you the ability to adjust white balance in the software, change exposure, contrast, sharpening, and a myriad of other settings after taking the shot. It is a remarkable tool, worth every bit the price of an upgrade to CS or even Elements 3.0

Agreed. There are also some free softwares out there that can convert RAW files - I think they are called irfranview, bibble (free?) and maybe one more.

Some cameras also come with RAW conversion software with more control, but I don't think the G5 has it.

Cheers

James

Thanks for your prompt reply. It looks as if I will have to shell out some clams for CS or wait until elements 3 is released.

I beleive the Canon RAW converter is very basic and only offers a few of the options available on its bigger more expensive cousins. You only can alter white balance, contrast, hue and phototype. Cheers.......Iain

Canon users are often fond of Capture One. I think what converter you like is dependent on your camera as well as the manner in which you work. For underwater, I think you work slowly and carefully on the conversion process and ACR is good for that (plus it supports a lot of cameras). For above water, people frequently take many images and the fast integrated browser in CaptureOne and Bibble might offer real advantages. I have never liked CaptureOne because of its odd interface but I plan to spend more time with it and hope to like it better. For underwater I expect I'll stay with ACR but that's just me.

Being able to adjust exposure by two stops or more in RAW conversion is not a good reason to be less careful with your shooting. Your best results will always be when you take care to get the image right every step along the way.

Actually, does anyone know what ACR stands for? Where does one obtain the ACR plug in?

As I mentioned I'm using a Canon G5 and Elements 1 at the moment. I'm using levels to improve my images, along with some of the other fuctions available within the programme.

To update to be able to utilise RAW conversion with all the benifits, etc - what programme do you suggest - Photoshop CS or wait until the release of Elements 3?

Many thanks.....Iain

Sorry!

ACR is Adobe Camera Raw.

The version used in Elements and Photoshop 7 was v.1

CS came with v2.0 and is now up to v.2.3.

Sorry to steal the thread but have a question on similar lines.

Have not really had a chance to play around with RAW on my D70 yet. I bought the new Nikon View and have Photoshop 7.

Will i be able to play around with all the RAW stuff (exposure compensation etc) in Nikon View? Does it convert something so that i can then move it on to PS7? Or does CS do something that Nikon View and PS7 cannot do?

Thanks

My understanding of the situation is that it has less to do with software than the camera type. The dynamic range of the DSLR's are much larger that the 8 bit file format of the jpegs, and the camera makers choose to clip some of it in the conversion process in the camera. So a raw converter can "reset the exposure" and bring it out. This is what I think my DRebel is doing. The amount of details that can be "recovered" does not depend much on the converter. It's only rendering what there is in the raw file. The detail tone and smoothness does.

For my Oly 5050, there isn't anywhere near as much "over exposure" that is recoverable. The dynamic range is not much more than the 8 bits in the format to start so just about all of it gets in the camera jpeg. I suspect the same is true of the G5 since it has a similar Sony chip.

Herb, Re"The amount of details that can be "recovered" does not depend much on the converter. It's only rendering what there is in the raw file."

According to Bruce Fraser's book, Camera Raw with Adobe Photoshop CS, pg. 32, CS uses special recovery algorithms to build color data when one or even two of the three channels are clipped on the high side i.e. overexposed.

Elsewhere in his book he mentions that he expects future versions of ACR to perform similar calculations for pictures with underexposed pictures.

Bottom line: Some converters are better than others at recovering lost detail. And when using the current ACR it's better to shoot to the high side as the ACR has better capabilities for coping with overexposed pictures than it does for underexposed pictures.

Still, I think Herb is exactly right. JPG's can only contain about 7 stops of range while RAW files contain much more. These days digital SLR's frequently provide 8-9 stops of usable range.

Adobe's converter does indeed provide a unique highlight recovery algorithm for overexposed channels but the penalty is hue shifts and banding. I measured this with my Kodak and reported it sometime ago. Eric has written an article on sunbursts and RAW converter anomolies which I suspect is related. My opinion is that RAW converters may have different properties when handling overexposure but you may not like any of them. Some time ago I wrote the author of Bibble regarding channel underexposure. He claims Bibble implements an automatic channel "blending" type concept when white balancing severely off-balance files (like we see underwater). This would be a form of underexposure recovery.

Ultimately, digital cameras are linear devices, so you want to expose them to their limits without clipping them. Since they have more range than 8 bits you want RAW to access the additional data and it's that additional data that provides exposure range. It's also the reason you always want to work in 16 bit until you are ready to output to the web or print.

...if you use RAW, alter the F-stop ...

You are not altering the f-stop per se, just altering the data to reflect a higher/lower exposure value.

Canon users are often fond of Capture One.

I looked over Eric and Alex's shoulder as they were using Capture One. I was quite impressed with it. It may be better than ACR, but I'm too lazy to use two separate programs.

Will i be able to play around with all the RAW stuff (exposure compensation etc) in Nikon View? Does it convert something so that i can then move it on to PS7? Or does CS do something that Nikon View and PS7 cannot do?

I use View as a transfer and browser program. You cannot play with the RAW file like you need to. You need Nikon Capture, PS7 (does a modest RAW conversion), Adobe CS with built-in ACR, Adobe Elements with ACR (currently an 8 bit conversion, 16 bit in v3), Capture One, Bibble, perhaps Qimage? or Phase One. There may be some other RAW converters, but these are the most common.

I recommend upgrading to CS. You could purchase Capture, but CS has some other nifty new features.

Will i be able to play around with all the RAW stuff (exposure compensation etc) in Nikon View?  Does it convert something so that i can then move it on to PS7?  Or does CS do something that Nikon View and PS7 cannot do?

Nikon's software offerings are rather fragmented and annoying.

Nkon View is basically just a browser and file transfer utility. It has the advantage of writing the files to your destination disk while retaining the "modified date" information. IE If I copy a file that was shot at 10:30 am on 10/17/04, the file shows as modified at 10:30 am, 10/17/04, rather than the time that I do the actual transfer.

Nikon's big-gun NEF converter is Nikon Capture, which is an extra $99 (:evil:).

ACR needs to be updated to the latest version to be able to open D70 nef files, remember that the file is different to the d100 NEF as it is compressed. If PS 7.0 is able to use the most recent ACR plugin you should be OK, but I have a bad feeling that the latest ACR only works with PS CS (:evil:)

Bibble has just been upgraded to version 4.0, and I have found it quite nice to work with. I'm probably not going to buy it though, as I find the ACR plugin perfectly adequate for my needs, and I usually work one file at a time. I also find the Capture 1 interface odd and counter-intuitive, but I did like the quality of the files it was producing. I think that Capture 1 is probably more suited to high throughput shooting in relatively consistent conditions, such as would be find in a studio environment. You can do batch processing in Bibble as well as Capture 1, and I find that Bibble's interpretation of the D70 NEFs at default settings to produce JPEGS produces quite a nice file out of the box. The JPEGS in my Enchanted Rock/Pedernales Falls gallery were batch processed at default settings by Bibble 4.0 (during my 30 day trial period...).

Ooops, Pseudoparkinsonian hypercaffienated post-posting quivers of the trigger finger :oops:

Adjusting the exposure up by one or two or three stops has almost the same effect as shooting at a higher ISO value - Noise and blotchiness. Many people recommend purposefully underexposing an image, then bringing it up in the RAW converter. I don't recommend this as it introduces un-necessary noise.

With my Kodak, I actually shoot to the right, overexposing as much as I can get away with. The overexposure is actually easier to correct on the Kodak - weird eh?

I use photoshop CS and I love it for the vignetting feature and the CA removal tool.

Cheers

James

And to answer Craig's question, No, the ACR in PS v7 will not open D70 NEC files. ACR 2.3, which supports the D70 and many other new cameras only exists in CS