Loss of detail in high key areas?

Question

Lately I took a few pictures from quite bright things with a Nikon D700. Even though I did not overexpose them by at least 2/3rds of a stop, the pictures lacked a lot of details in high key.

Later on I saw comparison pictures between a Hasselblad H4D and a Nikon D700, and noticed: the H4D pictures had lot better distinction in high key, where the D700 just mashed stuff together.

Funny thing: For me this loss in detail was only visible in bright areas, not in midtones. So I wonder if this is a software problem of the D700 (and other DSLR), and how this could be avoided?

I heard the rumour Hasselblad is using a straight curve in cam, while DSLR always enhance highlights and darktones, and therefore loose separation in bright and dark areas - can something confirm this?
And can something be done about this?

[Update] The picture was shot in RAW, of course, and no whites had been clipped. You can see a picture with comparison between D80, D700 and H4D in this forum: http://www.fotografienonstop.de/showpost.php?p=30647&postcount=16 Look at the highlight details in the blue cloth.

Answer 1

DSLRs are generally regarded to be very unforgiving of clipped whites. With digital people generally recommend that you aim to underexpose with digital a little.

If you do shoot in RAW you will have a better chance of getting some detail back in the whites. Various RAW converters support highlight recovery which can work very well. The idea is that the data might be there in RAW but not showing up with the gammat of your monitor. Also on that topic, are you sure it isn't that your monitor doesn't have the contrast set to high? This would cause a loss of detail in highlights and shadows.

I have also gone so far as to create detail with burning and other techniques in photoshop if an area had lost all detail and I couldn't recover it from the RAW data.

It might help you to look at the histogram of your images to see if they are being over exposed. If the histogram is cut off on the right you are loosing highlight detail. Some cameras also have an option where when they display the photo back in the LCD they will flash RED over highlights that were clipped.

I recommend you go and over expose a bunch of images and under expose them in manual mode on purpose to get a good feel for this if you haven't already. If you meter from dark areas in the final image you will end up overexposing.

One last activity I did one was to shoot a bunch of pictures of a lamp with a textured shade on it. In order to reveal the texture of the shade I had to make the walls behind it totally black. In order to see the texture of the walls the lamp was just a big white spot. So in the end with a high contrast scene you have to decide where you want the detail to be. This is actually where subtle uses of HDR can be be nice.

Contrast is texture is detail.

Answer 2

Even though I did not overexpose them by at least 2/3rds of a stop, the pictures lacked a lot of details in high key

Can you clairfy that? Particularly the first part.

Yes, a MF camera will capture more total dynamic range than a FF, but light is light. If you underexpose and pull the shadows, you should get more detail than you're describing. The MF will have better color sensitivity but it doesn't appear to be what you are describing. It sounds like microcontrast, which can be affected greatly by lens and PP. Perhaps sensor could have something to do with it, but I cannot see why, especially at low pixel densities (as opposed to P&S which are quite diffraction limited). Do you have a link to the comparison and your own pictures?

Your camera likely has some sort of highlight compensation by default, especially in JPEG. Look at tone curves in DPR reviews, many cameras compress the highlights to capture more overall detail and simulate film. This is why most camera's ISO ratings are optimistic (ie it says 1600 but is more like 1100). I'm not sure if you can completely disable it on D700 and turn it off for JPEG, I know I can on K-x (often criticized for the linear highlights without highlight compensation).

If you are using RAW, you should have complete control. The Hasselblad user could have applied a better tone curve, but it should be within reach as long you capture the extremes of the dynamic range in the high key area you are talking about. After all, you are mapping 4096+ luminosity levels to 256 when you are viewing it on a computer. You may need to post process in some local-contrast.