Exercise 7 - noise

It seems a long time since my last blog contribution - in fact its 4 weeks, a very long time. My principle issue being very grey, flat light and miserable weather; this weekend is the first time I've seen sun in I can't remember how long....

Weather: Nice blue sky and a low winter sun just hovering below the tree tops

Location: the study at my in-laws

It took a few attempts to compose the photograph and get the correct mixture of light and shadow. Plus, I didn't have my tripod with me so I had to create a makeshift platform using a stack of books secured to a stool with my belt.



Noise composition - ISO 200

Looking at the two extreme photographs (ISO 200 to 3200) it is difficult to distinguish much difference at normal print size, however, on closer inspection they are very different. Below are three areas at 200% magnification.  


Door at ISO 200

The door is white gloss, this close-up shows two blemishes:

a. A blue ink smear below the handle on the edge of the door

b. A dark paint chip in the bottom left hand corner.

Door at ISO3200

In this photograph it is still obvious that the door is white, however, the blue ink smear is significantly less defined because the noise has given the image a blue tinge - it almost looks as if the door is being viewed through wet glass. The paint chip is clearly visible as a chip rather than noise.

  

Stairwell at ISO200

The writing on the label in the guitar has clean edges and the strings are clearly defined. Similarly the architrave and the stitching on the quilt is crisp. In the deepest shadows the corner of the wall/ceiling can be easily seen.


Stairwell at ISO3200

The noise in this section of the image is easy to discern: the lettering on the guitar label is fuzzy; only part of the strings is defined; in addition the wood of the guitar is mottled. In the deepest shadows the vertical wall junction can be seen, but there is no definition at the ceiling. Overall the image is blotchy.



Pepper at ISO200

Again the stitching is clear and the rear 'edge' between Pepper and the quilt is easily observed. Whilst it is not possible to make out individual hairs, it is easy to see the ruffs in his fur around his chest.


Pepper at ISO3200

The stitching is obvious, but not crisp and the rear end of Pepper drifts into the quilt. The ruffs around his chest area cannot be seen, nor is it easy to make out his eyebrows (brown spots).


You will find it unsurprising that as the ISO is changed from 200 through to 3200 the noise gradually increases. Using this particular composition I found it very easy to discern the difference between noise and shadow, nonetheless, I do appreciate that on a subject less familiar it would not be at all easy.
I believe 'noise acceptability' would depend upon a number of things:

Ø        The knowledge of the audience in terms of the subject matter - most people have seen a dog, therefore a fuzzy dog is not a major problem. On the other hand, a fuzzy photograph of a rare animal would be unacceptable.

Ø        Professional versus family snaps - whilst everybody wants to shot sharp photographs there is a degree of tolerance when viewing your Uncles pictures of the last holiday. The same leeway would not be afforded to a professional whose services had been bought.

Ø        Available light levels - I believe it's much better to get a noisy image rather than no image.

Ø        Style and/or mood - noise/grain can be very effective when creating an atmosphere especially in portraiture and in certain urban settings.