BetterPhoto Q&A
Category: Digital Files and Formats

Photography Question 

Todd Smith
 

Raw Versus JPEG


If I compose an image, on a tripod, and expose the image as a Fine JPEG, then take the same photo again, this time as Raw, the histograms are different. The Raw image is lighter on the LCD and in Bridge. I would think that the histogram on the camera for both photos would be the same. I'm shooting with a Nikon D100.


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March 18, 2007

 

John P. Sandstedt
  A JPEG (in camera or after downloading) shows the results of the camera's computer chip and its interpretation of the image. Hence, the histogram from the camera. The Raw image contains no interpretation and would, logically, be different.


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March 19, 2007

 

doug Nelson
  If you are shooting something like family events or covering a news story - i.e., a situation in which you need to get the results out quickly to interested persons - by all means use the JPEG shortcut. For fine art and serious work, shoot in Raw and tailor the image brightness, contrast and color balance to your own desires in Photoshop, in high-bit color. Archive these images as TIFFs. You might even save 'em as a PSD, preserving Adjustment Layers.


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March 19, 2007

 

John P. Sandstedt
  Todd,
If you save you converted Raw files as TIFF files, you'll also save all layers.


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March 19, 2007

 

Todd Smith
  Thanks for the response. When I'm outside on a sunny day, and shooting photos, it is difficult to see the LCD display due to the glare from the bright sun. So I judge exposure by looking at the histogram, to be sure I am getting the best exposure. But the RAW histogram isn't as accurate as if I were shooting JPEG. Do you agree? I realize that I can compensate later in post-processing, but want the best exposure when I trip the shutter. Thanks.


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March 20, 2007

 

dave S
  if you read your info on raw, the cam is thinking that you are going to edit, so more information will be stored onm the file.


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March 20, 2007

 

William Schuette
  Todd, I think it depends on what you mean by "accurate." Histograms can tell you whether you are in danger of underexposure (histogram clipped at the left), overexposure (histogram clipped at the right), lack of contrast (values are bunched and do not extend throughout the range of the histogram. But for subtle changes in exposure, it is probably impossible to look at two histograms and say which one is right. There are simply too many variables. To make sure you get the best possible image, check that the exposure is acceptable with the histogram, then bracket exposure over and under.

Bill


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March 28, 2007

 

W.
 
 
  Dynamic difference
Dynamic difference

W.

 
 

Hi Todd,

like William suggests, "there are simply too many variables" to give hard & fast rules. The differences vary per brand, model, and even per camera. So it pays to find out what works for YOU and YOUR camera by doing a few tests (the results of which apply to YOUR camera. Not neccesarily to that particular model, or even to the next camera, of the same model, off the production line).

E.g. if you test the image quality and dynamic range between a JPG 'straight out of camera' and a JPG from the RAW file, you may see amazing differences (see attachment; scaled for BP!).
Which can be VERY different again with the next camera!

I.o.w. it pays to get to know YOUR specific camera intimately – by actually testing – instead of relying on general reviews or others' opinions (which they derived from other cameras, not yours).

Have fun!


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March 29, 2007

 

Richard Lynch
  "the RAW histogram isn't as accurate as if I were shooting JPEG. Do you agree?"

Both of the histograms are accurate depictions of the images they represent. The reason for the difference is that RAW images have raw capture information stored exactly as the information was captured, and JPEG images are the RAW data converted, and optimized according to rules created by the camera manufacturer (and possibly dependent on settings you choose, such as white balance). In other words, in-camera processing changes the JPEG, and compensates for exposure, etc.

As far as what is 'more accurate', as a depiction of your original capture, the RAW image would be, as it is the data from the original capture. The JPEG might look nicer initially because there are several things that occur in camera to make the most of the image.

I shoot RAW and do all my post-processing in Photoshop, with minimal corrections in Camera RAW -- as that is not necessarily the best place to make adjustments. When opening images, retain the high-bit advantage of your RAW images by opening them with the Depth set to 16-bit rather than 8-bit. This will give you more latitude in editing the images.

Hope that helps!


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April 03, 2007

 
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