Photo Technical

Camera programs a good image, but you can perfect your shots – A56

Welcome aboard photo enthusiasts.  In the previous article introduced the new camera light meter of the digital age – the histogram.  As part of that initial presentation I used a photograph of a camera’s LCD display with a histogram of a photo I was in the process of taking.  Below is an image showing a photograph already taken in a display setting where I can review the histogram on my LCD.


The green arrow in the upper left corner indicates the review mode is active.  Grab your camera and put it into the review mode to see what symbol might appear and where it is located.

I’ve added in red lettering the word “histogram” and pointed to it with a red arrow.  Before focusing on the histogram, let me note the other symbols displayed from top to bottom:

–       10M – indicates the resolution that was set for the photograph taken.  It is the best or maximum resolution for this camera.

–       Next to it is the word “RAW”. This (is) always engages the maximum resolution, since is an unprocessed complete file.
–       To the right is the battery level, indicating it is full.
–       The next line down is the folder/file number followed w/box indicating this photo is on the memory card (otherwise indicate it is in camera memory).
–       80/82 lets us know the picture number/total # of pictures.
–       Followed by the histogram, to which the red arrow is pointing.
–       On down, far left, the red “P” let’s me know this shot was taken in Program Mode at an aperture of f/8 at 1/800 shutter speed.
–       At right, on the same line I see my ISO @ 800.
–       The circle with the broken arrow to the right means no flash was on or used, followed on the right with “2” between two triangles indicating the level of image stabilization (options are off, 1, and 2).

You can learn from some of this information, that I could have done a lot better taking this photograph.  It must have been early morning when I was not yet awake.  The setting ISO @ 800 might have been my best option for a late night photograph, but you can see it was taken in daylight, so I could have lowered the ISO to 200, even 100 for the best results.  Remember from previous articles that higher ISO settings produce more noise, that degrades image quality.

You can tell I had the leeway to make this ISO change by looking at the f/8 aperture and 1/800 shutter speed.  That f/8 is my camera’s smallest, and f/5.6 or f/4 would have been just fine for this shot along with a shutter speed of 1/500 or even 1/250 (or 1/125, although this yacht was moving slowly) .

Set at ISO 800 and in “P” or Program Mode (red letter on LCD display) means the camera automatically choose f/8 at 1/800 to make a good exposure.  If I had been awake and re-set my ISO in the morning to ISO 100, it would likely have set the aperture at f/4 and the shutter speed to 1/400.  [I used the word likely for “P” or “Auto” mode, because (as) only in Manual Mode will you know for sure, by having complete control that allows (allowing) you to decide and make the best settings for the particular situation.]

Go figure…going from ISO 800 to (400 to 200 to) 100 =’s a 3 stop decrease of light, while going from f/8 (to f/5.6) to f/4 and from 1/800 to 1/400 shutter speed increased light reaching the sensor by 3 stops of light, so the exposure, the amount of light hitting the picture capturing sensor, remains the same…perfect and the quality of the photo taken would have greatly improved.  O.K., so I screwed up by not changing to a better ISO (sensor sensitivity to light) !

Now, back to the light meter, that is the histogram.  Look at the photo included with this article… it is the dark rectangle with the white bar graph.  Overall, in analysis it looks good.  There is a broad range of tones.  The black/left side indicates there are no super blacks in the photo.  On the white/right side there seems to be some clipping (due to the 800 ISO).

You identify clipping on either side if a bar hugs either the right or left side.  With the clipping, in this case, only on the right side means some white areas have lost all detail…they are completely blown out.  It is likely the lost detail is in certain areas of the sky.  In this case, it may (Possibly) not be critical, nevertheless clipping on either end is better avoided (clipping on either end).

In conclusion, I mentioned the histogram (in the above photo) looked good (except for the highlight clipping) at ISO 800, f/8, 1/800.  Re-setting to the same exposure using ISO, f/4, 1/250, would have resulted in similar looking histogram, but even better, without the over-exposure clipping on the right, and the high signal to noise ratio that is a direct result of the high ISO.  At this juncture, I’ll take permission to come ashore.