Higher and lower sensitivity

The idea here was to explore the differnce that altering the sensitivity can make to an image i.e. taking similar shots at both normal and high sensitivity. I chose to use the arrival of the Olympic Flame in Portsmouth's Guildhall Square as the subject which proved trickier than anticipated but allowed a degree of experimentation with the ISO setting...

P305: f5.6 @1/400  ISO 100 25mm cropped

Increasing the ISO for P306 below has lightened the image so that detail at the forefront is clearer but the background now appears slightly overexposed.




P306: f5.6 @ 1/3200 ISO 1600

P307: f5.6 @ 1/800  ISO 400   25mm cropped

P308: f5.6 @1/4000  ISO 1600  18mm

Interestingly, I think the lower ISO in P307 above works better for the people detail whereas I was expecting this to work better in P308 bearing in mind the changing cloud and sunshine.

P309: f14 @ 1/200  ISO 1600 55mm cropped

P310: f5.6 @ 1/125  ISO 100  50mm cropped

Here again the lower ISO in P310 above works better for the image desired.

 



P312: f5.6 @ 1/1000 ISO 400  28mm

Using a higher ISO in P312 produces more visible background detail which in some instances would be useful and contribute to the composition. Here though, I think that  these details draws the eye away from the main subjects of screen and audience which is not helpful.



P314: f5.6 @ 1/60  ISO 100 28mm



I enlarged the digital view of P314 above to see the what the low ISO of 100 would create in terms of noise and graininess re texture. There was little to see here as opposed to the enhanced view of P316 below where white speckles are obvious when looking at blocks of colour .The grainess of the whole image is very apparent as well. The overall impression here is that while both images at 25% digital view appear fine, the higher ISO will have a greater impact when it comes down to printing especially if the image contains large areas of plain colour and a large print image e.g.A4 is required. 

P316: f5.6 @ 1/250   ISO1600 27mm

P315: F5.6 @ 1/100   ISO800  27mm