• 12-30-2004, 02:50 PM
    John USA
    How to process RAW images?
    My first post. If this is already answered somewhere else please tell me and disregard this message. Anyway, I took 2 images one in TIFF format and one in RAW format.
    I used my Minolta Dimage 7Hi with identical settings for both images: ISO100, f8, 15sec.
    Left is the TIFF, right the RAW. The TIFF image appears too dark, the grass and the palm tree leaves are invisible. And even after 'fixing' it in Photoshop using curves or levels, too much noise appears in the image. I guess there wasn't enough data in the source image to begin with.
    http://www.reflectionseternal.com/tmp/tiff_before.jpg.http://www.reflectionseternal.com/tmp/raw_before.jpg
    The colors appear way different too. In general (maybe not as much in this image) the RAW image looks flatter, less saturated.
    My question is: How do I set the settings in the RAW loader of Photoshop to give an accurate record of the light conditions? I can clearly see the benefits of RAW such as 16 bit data (although I think my Minolta only does 12bits) and the ability to allow more processing after the picture is taken. But before I start fiddling with the image I would like to get a more accurate starting point, not just changing the sliders until it 'looks good'. There has to be a more scientific approach.
  • 12-31-2004, 01:43 PM
    Photo-John
    Interesting Question
    John-
    Your question is a good one, but I'm not sure there's a straightforward answer. The bottom line, in my opinion, is that a good exposure is a subjective thing. Personally, I prefer to make my images "look good." I don't care about accuracy. For me, the benefits of using RAW files are that I have a lot more lattitude to work with and I'm not relying on the in-camera processing to make the right decisions for me. I get to decide what my images look like. My method is a combination of exposure, RAW conversion, and post-processing in Photoshop.

    But if accuracy is really what you want, the best method is to shoot a gray card before you shoot your actual picture. Then, with your RAW conversion software, you use the gray card image to get a perfect expousre and white balance. However, keep in mind that there is no "real" light and color. What you're probably trying to capture is what you're eyes saw. That's not an objective thing either. What you see is a combination of what your eyes see and the processing and filtration your brain does to that data. Your exposure could be for the foreground/shadows in this image, it could be for the background/highlights, or it could be a combination of both. But there isn't actually a correct, accurate exposure. In the end, you have to make the decision about what the correct exposure is. That will always be some sort of compromise.

    I think what you want is the gray card trick. That's the closest thing you can get to accurately recording the scene. Lighting the gray card the way you want is key. For more on RAW handling and workflow in general, take a look at the Digital SLR forum and visit the moderator, Uwe's, forum. He has an excellent PDF booklet on digital photography workflow.

    Hope that helps. Let us know if you have more questions.
  • 12-31-2004, 09:49 PM
    Trevor Ash
    Re: How to process RAW images?
    Quote:

    My question is: How do I set the settings in the RAW loader of Photoshop to give an accurate record of the light conditions?
    Hi, welcome to the forums. Photo-JKohn always gives well thought out and constructed posts so I wanted to quickly emphasize his suggestion of using grey cards for setting exposure of raw or jpeg images.

    To answer your question more directly; you really can't do anything with the RAW loader to get things perfectly accurate. As john says, it's best to get the exposure nailed during the shot. You should also make sure you're using am appropriate white balance setting for the shot as well. Grey cards also help in getting a correct white balance for digital.

    The thing about RAW converters is that they're trying to give you a "good" rendition of the photo not necessarily an "accurate" one. In my opinion, consistency is usually more important that accuracy. Grey cards, proper technique, and understanding of digital capture help with consistency. With consistency, you can setup workflows to compensate for any lack of accuracy.

    Try setting white balance using a grey card per the instructions of the camera manufacturer. For what it's worth, I usually shoot the grey side of a grey card instead of something white for teh WB reading. They both work though.

    It sounds like you have a good understanding of what's going on (that's a HUGE advantage) but you're just after accurate and repeatable results. Give Photo-Johns suggestion of grey cards for exposure and white balance a try and see what happens.

    One more thing; In case it's not immediately obvious, all RAW conversion software will give you different results.
  • 01-01-2005, 03:27 AM
    JCPhoto1
    Re: How to process RAW images?
    A lot of people would give the answer to your question that you should get the shot correct right out of the camera so you don't have to post process. This doesn't apply to the suggestions others who have posted here but on other lists I felt the advice to get it right in the camera first was a snobish way of saying "if you were good you would get it right first". To me that just shows a misunderstanding of of the raw format. I shoot with a Nikon D2h and from my experience trying to set up certain settings in camera aren't as effective as leaving many of the camera settings off or neutral and doing post processing in the raw program that comes with the specific camera you own. It might just be my experience and I don't know what raw program there is with the Dimage. It did cost me $100. to get the Nikon software to edit the raw files. That's a lot of money to spend on something that should have come with the camera but it seems that for me I get much better results with post processing rather than trying to get it perfect right out of the camera. That doesn't mean you don't set the white balance and exposure right as that has to be done in camera first. You'll have problems if you try to do those basics later. With the shots you presented your going to have trouble using a grey card or any method of getting a white balance in low light situations like that. At night like that try to evaluate the light and set that in camera then you can adjust the color temp in the raw program later (or photoshop if you use that). You might also try a higher ISO in low light situations like that too. Like John said, there is no set formula to get it right straight out of the camera. Digital doesn't have a very broad exposure latitude and you were shooting in pretty extreme conditions. To get good exposure of the darker or shadows area's night shooting is tough.......Jim C
  • 01-01-2005, 09:52 AM
    Trevor Ash
    Re: How to process RAW images?
    I think John is trying to understand why RAW images look different than a jpeg version of the same shot. Are you starting to get a feel for the reasons yet John? Is that what your question is all about?
  • 01-01-2005, 10:06 PM
    John USA
    Re: How to process RAW images?
    Yes, I guess I'm disappointed that when the camera is in jpg or tiff mode, so in case the camera does the processing, details get lost. The exact same exposure in raw preserves those same details.
    The grey card is a good idea as a reference for accuracy, I'll try that, but I'm not sure if it will work in low light night conditions.