How do I expose for this situation

[Mayavi]

I was doing some night photography yesterday and most of my pictures turned out to be bad. Example, see the following image. The top portion is not lit while the bottom half has plenty of direct light. How do I meter for this shot and what would be the correct exposure? I do not remember what the settings are for this particular shot, so please look at the Exif. No PP done except for white balance and coversion from RAW to JPEG.

http://lh4.google.com/jyernagula/RzKk6adAJjI/AAAAAAAAAU0/0ZCfczfzdBY/IMG_2511.JPG?imgmax=912

PS: I know that the building is not in focus.

[Mayavi]

One more

http://lh4.google.com/jyernagula/RzKk8adAJlI/AAAAAAAAAVE/7YggDjVKDII/IMG_2516.JPG?imgmax=912

[tdodd]

Your EXIF data is 400 ISO, f/8, 5 seconds and 10 seconds respectively. The problems you have to deal with are (apart from the focus issues)....

1. The scene contains a wide range of light levels, from shadowy unlit rooms within the building and dark skies through to the bright lights on the walls of the building.

2. Uneven lighting on the building itself.

The sky also looks very noisey on the first image, which leads me to believe it was underexposed initially and you had to lighten it during your conversion to jpeg, although you don't mention adjusting exposure.

Looking at the histograms for each image the exposures actually look quite good, maybe a little dark, but not bad. The thing is, there is no "right" exposure. It is your judgement to decide which elements of the scene are most important to you and ensure that they are neither blown out, nor lost in the shadows.

The fact that the building itself has different lighting levels is perfectly OK. I do not see any reason to need to try to match them up. Within the camera it would be an impossible task. What you could do is, with the aid of a tripod, use exposure bracketing to shoot identical images at -1, 0 and +1 exposure compensation and then combine them using HDR software or just manually merging the three exposures as layers in Photoshop.

Regarding metering specifically, I think it is fine to use evaluative for this scene, to fire a test shot and then to review the histogram and blinkies to see whether you have blown anything and if so, how much, and whether that is a problem or not. Do not use the image itself, displayed on the LCD, to judge the exposure, except for the blinky indicators. Like I said, from the histogram your photos look just a little dark, but you have preserved a lot of detail where the lights are, rather than blowing them out. If that was your intention then good job:) If it were me, I would be happy to see just a little more blowing out where the wall lights are, and to bring up the exposures elsewhere in the picture, but that's really an artistic choice.

What does puzzle me is the noise in the sky in the first picture. I'd be interested to see the original raw files and try processing them myself. Is there any chance you can upload them somewhere?

[Mayavi]

Thanks for your reply tdodd, it is of immense help. What I failed to mention in the first post is that I took several pictures from the same spot and added exposure to some when converting from RAW. I am not sure if it is this particular one that I adjusted. I am posting from my work computer, so don't have access to the pictures.

I was using the image replay to check for exposure, but would start using histogram more often now.

If it were me, I would be happy to see just a little more blowing out where the wall lights are, and to bring up the exposures elsewhere in the picture, but that's really an artistic choice.
I was going for that but didn't want to blow out the well lit areas. I probably was trying to do something that is not possible with my camera/skill limitations.


One more image:

http://lh3.google.com/jyernagula/RzKkvKdAJaI/AAAAAAAAATo/l51oIfF9svU/IMG_2450.JPG?imgmax=912

[tdodd]

Glad to help :)

The problem with only using the image to judge exposure is that you have a brightness control for the LCD display, so depending on how that is set your picture might look brighter or darker than it actually is. Also, when reviewing the pictures at night they will all look quite bright because your eyes are adjusted for the low ambient lighting so it really is a complete waste of time.

The histogram will tell you the truth of your exposure, and blinkies on the displayed picture will show you if you have blown anything and if so, how much. The rest of the picture on the LCD is really only useful for judging composition and possibly timing (e.g. eyes closed) and focus, but not exposure.

[tdodd]

Mayavi, you do seem to have a very strong bias towards yellow in the white balance of all your photos. I have posted a resized copy of your original and my poor attempt to alter the white balance to a more neutral look. It's not working too well on your file but it creates a much more interesting colour to the sky, as well as whitening the boats somewhat. Maybe your photo is more accurate but I'd be surprised if a scene was that yellow - the same with the building, earlier. How are you adjusting WB in your raw files?

[Mayavi]

tdodd, what are blinkies on histogram? Is it the spike at the bright end of the histogram? I have a very basic knowledge of reading histograms.

I do have a bias towards 'warm' images. The scene I saw was somewhere between your take and my take. I chose 'Flourescent' setting for WB, but I usually use color temperature for WB in my pictures. Lot of lighting at Tempe Town lake where I took this picture is yellow, so everything looks a bit yellow.

[tdodd]

Blinkies, as I call them, are not on the histogram but are displayed on the image itself on the LCD screen on any parts of the image that are completely overexposed to pure white. The display will flash (blink) between white and black wherever there is severe overexposure - e.g. in white clouds in a daytime sky, or wherever there is a light source included in the picture. You may need to enable the display of "blinkies" in he camera settings or custom functions, assuming your camera has that feature. My 30D and 40D do, but I don't think they are enabled by default.

Have a look at this review page of the 40D - http://www.dpreview.com/reviews/canoneos40d/page9.asp - and you will see the alternating/blinking black/white on the railings in the third picture down on the left of the bike.

If you have this situation you should see a peak in the histogram graph on the extreme far right - it may only be one pixel wide, so hard to see, but it will be there. You then have to judge whether the amount of overexposure is a problem or not within your overall image. I think it's OK to have a little bit overexposed, so long as it doesn't ruin the whole picture and your subject is exposed properly. e.g. you absolutely should not overexpose a wedding dress, thus killing all the detail in the material, but to have a few whisps of cloud or the centre of a light bulb that is pure white is OK in my book.

Have a look here for a deeper explanation of histograms - http://www.luminous-landscape.com/tutorials/understanding-series/understanding-histograms.shtml.

As for white balance, when shooting raw, it can be quite useful to be able to use the colour sampler on a part of the photograph that should be pure white and set that to be "white" as part of your white balance adjustment. That may throw things out too far if there are exceptional lighting conditions but should get you a good start on the right path. In your river photo I imagine the back of the boat over on the right should be white, and also the rows of pedallos or whatever they are over on the left. Now you don't necessarily want to kill the mood of the scene and turn those things a completely clinical white, but I guess they should be whiteish, with a hint of yellow, rather than just plain yellow/orange.

Is your monitor calibrated? Brand new modern monitors can often have quite a blueish colour temperature and you may be compensating for that by having too much yellow in your pictures. Presets can be good but fluorescent lighting is usually greenish and the WB setting for fluorescent light normally adds in some magenta to compensate. These photos look more like the lighting is sodium or tungsten, not fluorescent. Try the colour dropper for white balance and see how the picture looks.