Exercise – Tungsten & Fluorescent Lighting.

Exercise Tungsten & Fluorescent Lighting (First part 3 images; second part 4-6 images.)

First, find a room lit fairly brightly by tungsten lamps. If there are fluorescent lights, turn them off. Wait until just after sunset, when there is only a little daylight left. With the curtains open, stand close to the window and look out for about one minute, until your eyes become adjusted. Then turn and look at the room light. What colour does it seem to be in the first instant that you see it? As you adjust your eyes for a couple of minutes to the room lighting it will seem less coloured. Quickly, look out of the window once more. What colour does the daylight seem to be? It is important to do this little test when the daylight is weaker than the room lights. There is a considerable difference in colour between tungsten and daylight when you compare them directly like this. Your eyes’ great ability to adapt makes the difference seem less but the camera does not adapt in the same way and the true differences are faithfully preserved. Before doing a shooting test measure the light level in the room with your camera’s meter. Take several readings, in different parts of the room, including close to a reading lamp, and in the darkest corner. If you have the sensitivity set to ISO 100, or close to it, the shutter speeds that you would need are very slow. At full aperture, what shutter speed could you measure? Would this be enough for hand-held shooting?Not only is tungsten lighting much weaker than daylight but, in most rooms, it is very uneven. Again, your eyes may fool you because they can adjust rapidly between the lightest and darkest parts of the room. Not so the meter, and not so the camera’s sensor. Compose a photograph in which both the interior lit by tungsten lamps and the exterior at dusk are both visible. Wait until the light levels inside and outside are approximately equal, and take three photographs, as follows: with the white balance set to Auto, with the balance set to daylight, and with the balance set to tungsten. Compare the results. What differences do you note? For the second part of the project find two different interiors lit by fluorescent lamps. If at all possible, make one of these an interior lit by the small CFL lamps, which to many people at first glance look like domestic tungsten lamps. Take two or three photographs, identically composed, in each location. The first image should be with the white balance set to Auto, the second to fluorescent, and if there is a choice of different fluorescent settings, the third to the alternative fluorescent. Compare the results, and note the differences. One thing you should notice is that the overall colour quality in all of them looks in some way unsatisfactory. Fluorescent lamps do not emit a full colour spectrum.

Exercise.

For this exercise I photographed my living room in the evening. I measured the light at various places around the room and for F2.8 at 100 ISO I got the following readings.

Pointing towards the lamp 1/60 second.

Darkest corner of the room   1/6 second

Middle of the wall      1/13 second

Outside 1/13 second.

If you loo at tungsten lighting for a while and then glance outside , I found that the outside light appeared to have a blue cast as my eyes had adjusted for the tungsten lighting.

Image 1 Auto White Balance.

With the white balance set to auto the image was correct for inside the room but too blue outside. I assume that auto white balance will go for the majority reading as as the interior light had a larger proportion of the image it calculated for that.

 

Image 2 Daylight White Balance

With the white balance set to daylight, the only part of the image which was correct was outside, the inside lighting was far too yellow.

 

Image 3 Tungsten White Balance

With the white balance set to tungsten the interior was correct but the outside light was too blue (the same as auto).

Fluorescent Lighting.

Contact Sheet 1 Fluorescent Lighting

Image 1 white balance set to auto created a cream caste.

Image 2 white balance set to fluorescent setting number 4 “cool white” produced a slightly pinkish caste.

Image 3 white balance set to fluorescent number 3 “white fluorescent” produced a correct balance.

 

Contact Sheet 2 Fluorescent Lighting

Image 4 white balance set to auto created a cream caste.

Image 5 white balance set to fluorescent setting number 4 “cool white” produced a slightly pinkish caste.

Image 6 white balance set to fluorescent number 3 “white fluorescent” produced a correct balance.

Summary, my camera has 7 different fluorescent light white balance settings so it is obviously a difficult type of light to deal with. Unlike in daylight, the auto white balance setting did not produce very good results.