Camera rear LCD display not looking like downloaded files

[anonymous]

Having read this website's tutorials, the following might however indicate a little knowledge is a dangerous thing in my case.

I have had a Nikon D70 for a little over a year now and have produced some reasonable shots, but I am still struggling to understand what information is stored in a RAW file and how it is interpreted by graphics programs like Photoshop. I actually use Phase One capture software to process my RAWs. The real trouble I have is occasionally the image on the back of the camera looks fine, but when I download it and view the RAW image it is up to 2 stops underexposed. The white balance is also a problem as viewed on the back of the camera compared with the image downloaded to Capture One. I have started using the histograms much more now, but even they differ between the camera and the software. It has opened up a few questions as to what the RAW file actually contains. For instance if the RAW data is just the information directly from the CCD:

1. Does this mean that any settings I change on the camera for sharpness, saturation and contrast etc are not actually applied to the RAW data and only used to do onboard processing if I was to save the image as a jpeg on the camera for example.

2. Are these settings actually stored separately in the RAW file and applied to the image by the post-processing software?

3. How is the image on the back of the camera presented. The camera must do some processing before it shows the thumbnail. Is it applying the settings I have specified for viewing on the back of the camera? Is this why sometimes what I see on the back of the camera can be quite different to what I download and view in Capture One? I know the histograms are not quite the same between the camera and Capture One. I thought this might be because the camera displays only the luminance and capture One the RGB histograms, but it also displays a grey histogram which I believe is the luminance because it matches the green channel quite well.

I would be much more confident if I knew the images I download would be quite close to the preview on the back of the camera. You cannot preview the effects of white balance any other way. At the moment I always have to do quite a bit of processing to try and get the levels correct and the white balance when it would be nice to see the settings the camera identified applied automatically to the RAW data as a first approximation (which in most cases would probably be satisfactory) in the software. There may be a means in Capture One to apply the white balance, contrast and saturation set on the camera to the downloaded file if this data is also stored in the RAW file, but don't know if it is.

A tutorial on how the image displayed on the camera relates to what you may download as a RAW or jpeg would be useful, together with some tips on what you should be looking for on the camera (like the histograms) to know you have captured a decent image.

[McQ]

1. Does this mean that any settings I change on the camera for sharpness, saturation and contrast etc are not actually applied to the RAW data and only used to do onboard processing if I was to save the image as a jpeg on the camera for example.

All settings mentioned do not matter for the RAW file and are only applied to the embedded JPEG image (if used). These are just for JPEGs.

2. Are these settings actually stored separately in the RAW file and applied to the image by the post-processing software?

Settings such as white balance are actually stored separately and then read by the post-processing software, however I believe this is the only information that is passed on (not sharpening or contrast settings, for example).

3. How is the image on the back of the camera presented. The camera must do some processing before it shows the thumbnail. Is it applying the settings I have specified for viewing on the back of the camera? Is this why sometimes what I see on the back of the camera can be quite different to what I download and view in Capture One? I know the histograms are not quite the same between the camera and Capture One. I thought this might be because the camera displays only the luminance and capture One the RGB histograms, but it also displays a grey histogram which I believe is the luminance because it matches the green channel quite well.

The image on the back of the camera is usually the embedded jpeg and not the actual raw data itself (for all cameras I know of). As a result the settings you apply in-camera such as sharpening, contrast, saturation, etc should appear with the in-camera preview but not in the actual raw file you later develop.

What I would recommend doing is using the embedded JPEG file as a reference when developing the RAW so you can get a better match. I am not familiar with how to do this on the D70, but there are a number of programs which can extract this jpeg (Breezebrowser is one of them I believe). The only way to achieve a perfect match is to develop the file using Nikon's own software so that the same tonal curves are applied (this is probably the biggest reason for a difference in how they look). Also note that the image on the back of the camera almost always looks brighter than the actual file (especially in low-light).

I would be much more confident if I knew the images I download would be quite close to the preview on the back of the camera. You cannot preview the effects of white balance any other way. At the moment I always have to do quite a bit of processing to try and get the levels correct and the white balance when it would be nice to see the settings the camera identified applied automatically to the RAW data as a first approximation (which in most cases would probably be satisfactory) in the software. There may be a means in Capture One to apply the white balance, contrast and saturation set on the camera to the downloaded file if this data is also stored in the RAW file, but don't know if it is.

To play it safe just try to expose such that the histogram extends as far right as possible without clipping any highlights; you can always underexpose later in RAW and if you do, the image will actually have less noise than a regular "correct" exposure. Hope this helps at least get you started...