Using Faster Film/Higher Sensitivity

I haven't managed to experiment with film as of yet but I have been testing the ISO sensitivity settings of my DSLR. The Canon EOS 450D's ISO settings range between 100 and 1600 (100, 200, 400, 800 and 1600). To do this, I revisited Dunham Massey.

For my first three photographs I set my aperture to f/13 and then changed the ISO and shutter speed for each image. With a low ISO (eg 100) a slower shutter speed is required than at a high ISO setting (eg 1600). Each time the ISO is increased by one step it increases the exposer by one stop and therefore the shutter speed or aperture must be altered in order to obtain a correctly exposed photograph.

ISO 100, 1/25sec, f/13

In the low light and using the ISO setting of 100 I needed to use quite a slow shutter speed and therefore any camera shake or movement by the deer is visible.

ISO 400, 1/100sec, f/13

This shot is acceptable however it is slightly blurred, posobly due to camera shake.

ISO 1600, 1/400sec, f/13

My final shot at ISO 1600 is frozen solid and sharp!

High ISO settings are great in low light situations, they allow a photographer to use faster shutter speeds to freeze movement, however the images suffer from a slight grainy effect. In some situations this could be an apealing feature but in others it can be an undesirable factor.

The grainy effect isn't very noticable unless the photographs are blown up to full resolution. I have cropped small similar sections from each image to see how noticable the grain is.

Smooth area

100 400 1600

Detailed Area

100 400 1600

I feel that the grain is most noticable in dark areas. The darker fur in the first three crops show the distortion the most but the first two images are blurred and therefore I will compare two sharp images to see if the different is more or less noticable.

ISO 100, 1/320sec, f/8

To enable me to capture a sharp image at a low ISO setting I had to widen the aperture. This image has turned out quite dark, I must have underexposed it slightly.

ISO 1600, 1/1250sec, f/8

Keeping the aperture the same I increased the ISO to 1600, altered the shutter speed and took another shot.

Detailed view

100 1600

At ISO 100 the shutter speed is still a little slow and the image is slightly blurred, however, now that both photographs are sharp the grain of the high ISO image appears to be more obvious.


Next I set my camera on a tripod to see if the grain is more noticable between identical photographs.

Low and high settings
ISO 100 ISO 1600

Below are five shots I have taken (one at each setting).

Click to enlarge

(100 on left - 1600 on right)

The difference between each of these shots is barely if at all noticable so I have cropped a small section from each to further display the difference between low and high ISO settings.

100, 200, 400,
800, 1600

The difference between the lowest and highest setting is now more noticable. At the low end of the scale, the ISO 100 shot is crisp, clear and smooth whereas at 1600 the image is slightly grainy. The grain is much more noticable on dark areas. I feel that there is barely any difference between the shots and the effect would only be noticable if a photograph were to be scaled up to an A3 sized print. I need to experiment with film as I feel the grainy effect will be much more noticable. Having used ISO 400 film in the past I already know that to be quite grainy but I would like to see the difference between 100 and 800.