Archived posting to the Leica Users Group, 2003/07/31
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Johnny Brownlow pointed out: > >All digital cameras show the same characteristic. The solution is simply to >expose for highlights. There is a mass of detail in the shadows that can be >brought out very easily. > What I find is: 1) exposing for the highlights is harder than one might at first think. If the highlight is a textured surface (like a concrete wall) you have to guess what the luminosity spread of the texture is (unless you have a very narrow angle spot meter). A highlight on rough concrete, for instance, has about a 2 stop spread of luminosities. So to keep from clipping any of the texture, you have to place it 1 stop away from the highlight clipping point. Of course, if you have a static subject (architecture or landscape) you can simply take a shot and see if the levels histogram is clipped, and adjust the exposure accordingly. For really nasty super high contrast subjects you can take multiple exposures at different exposure settings and merge them in Photoshop. This would be a merely academic problem, but exactly the same highlight clipping problems occur when shooting faces with rim lighting. Negative film is really much easier to work with in contre jour lighting. 2) The amount of shadow detail that can be brought out depends on whether or not you shoot in 8 bit JPG or 12 bit RAW. Exactly how many stops of shadow information you can get before you hit objectionable noise depends also on the equivalent ISO setting, and the light levels when you took the shot. For sunny day shots I find you can actually pull out shadow detail 5 to 6 stops below the metered exposure with a 12 bit RAW file. This gives you around 7 to 8 stops of usable exposure range, which is better than slide film, but less than color negative film (in my experience.) With JPG files, the amount of shadow detail you can pull out is more restricted, because you often get ugly and visible posterization. This is really obnoxious if you are trying to shoot sports on a bright day, as the D100's dinky little buffer fills up so fast when you shoot RAW files (after about 4 shots) that you are pretty much forced to shoot JPG files. 3) the lack of a shoulder makes the exposure settings trickier than slide film. Slide film does not clip the highlights as abruptly as digital. Highlight textures are feathered off, rather than being brutally sanded flat. 4) in high contrast light the matrix metering on the D100 fails early, often, and repeatably. I set exposure compensation at -1 stops to make it fail less often, but this is not dependable. 5) very very bright specular highlights (like sun sparkles on water) end up overexposed (as they would on negative film). That would be okay, except that the images of these very bright highlights tend to spread out in a particularly ugly fashion (I've heard this referred to as "blooming", where overexcited sensor sites share their extra electrons with adjacent sites). This blooming infects pictures of water, ice fields and urban night scenes with ugly blobs. More subtly, it sometimes effects landscape photographs where there are very bright highlights on shiny leaves. The perceived resolution drops in the foliage due to the blobs, and the color goes off as the green channel is saturated. Having said all this, in flat light the D100 is capable of astonishingly beautiful images. Luckily Seattle gives us a great gray soft box in the sky most of the year, so in most seasons digital imaging is quite satisfactory. In Mr. Brownlow's words of some years ago, "this bee can fly". Unfortunately the bee flies better on some days than others, and not well enough all the time to render film obsolete. I'm not going to sell all my film gear yet, even if Leica stops selling spare parts to individuals. By the way, for a particularly beautiful example of the use of C-41 color negative material in high-contrast light, see if your library has the book "Himalayan Odyssey". All shot on Fuji rangefinders. It's lovely being able to see inside all the shadows in the far off mountains. Mark Davison _________________________________________________________________ Add photos to your messages with MSN 8. Get 2 months FREE*. http://join.msn.com/?page=features/featuredemail - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html