The second part of this exercise asked us to photograph a number of subjects shooting each 5 times from -1 stop, through EV0 to +1 stop at half stop intervals in order to see which exposure level looked best and which gave unexpected but good results. My choice for the best exposure level is the larger example.
-1
-1/2
EV0
+1/2
+1
The doves are one of the few subjects that I shot which more or less work at all exposures from -1 to +1 stops. The -1/2 stop to EV0 work best as the background colour is nicely saturated and the details of the doves are at their best but they are acceptable even when slightly overexposed.
-1
-1/2
EV0
+1/2
+1
Like the doves, the drum kit also managed to look quite good all the way from -1 to +1 stop of EV range. I believe it is because that neither composition has any large extremes of light value. As we can see from the histograms below, both images show a fairly constant light level that can accommodate a small movement in exposure without becoming disastrously under or over exposed. We will see later on that when there are extremes of light values then a movement from the ideal exposure results in very poor results.
Dove histogram EV0
Drum histogram EV0
-1
-1/2
EV0
+1/2
+1
This gloomy drizzling day on the moor walking the dogs was a day where the camera was having difficulty in coping with the low levels of reflected light which meant that the cloud was just about the only source of relative brightness. As a consequence, everything below +1 stop was underexposed.
-1
-1/2
EV0
+1/2
+1
The Japanese snow lantern here is in an area of fairly constant tonal values so with no particular highlights or deep shadows EV0 is a very good exposure value. Because I prefer the greens to look a little more saturated I prefer the -1/2 stop value but there is little to tell between the exposures until we get to +1 stop which looks decidedly washed out.
-1
-1/2
EV0
+1/2
+1
The white barked tree here is shot against a pale sky just after sunrise but despite the low light levels the sky still completely dominates the tree and it can only really be seen properly at +1 stop. Any lower EV than this starts to turn the tree into a silhouette which, given the attractive detail, wouldn't be good. The histogram for this shot at EV0 shows the large hump representing the sky and the smaller hump which is the tree. Any lower EV and the graph moves left until the tree is completely black. Even at EV0 the tree is a long way left on the graph and to be exposed properly it needs to be moved closer to the centre by increasing the exposure value.
Tree histogram
-1
-1/2
EV0
+1/2
+1
Despite being a similar composition to the tree above, this clock tower occupies a larger area of the sensor so that the camera has tried to expose it as the main subject despite the brighter sky around it. The nature of the clock face, however, benefits from slight under exposure to highlight the rusty streaks that line it and to give it a more dingy feel. So a -1 stop exposure suits it much better than the +1 stop exposure that I chose for the earlier tree. Out of interest the histogram for the clock looks like this:
Clock histogram EV0
Clock histogram -1
