PHOTOGRAPHIC NOISE- EXERCISE

Noise is the result of the effect of the sensitivity of light on the camera's sensor

It is the same as the level of grain captured in film photography.

Exposure is a composite of shutter speed and aperture level, but ultimately it is the amount of light that
reaches the sensor or film surface. If lighting conditions are reduced there would be a requirement for
the shutter speed to be slower. Therefore the shutter is open for a longer period of time to allow more light onto the shutter surface. If the shutter speed is slower there would be a requirement for the camera not to be hand held or your likely to reduce sharpness and may experience blurred images.

The alternative would be to shoot at a wide f stop or to increase the shutter speed but again sharpness
is compromised.  If the photographer wants to  As film photography you can achieve this by increasing the camera ISO level which increases the camera's sensor to light.

The side effect is the increased noise captured in the image. Noise is represented as increased pixelation
on the image.


The below chart shows the relationship
between shutter speed /iso rating and aperture setting

at the top iso of 6400 there has been a considerable increase
in the f number ( improved sharpness) and a faster shutter speed

The compromise on this is the final quality of the pixel level
on the final image.

copyright Ken Storch.


EXERCISE

TOLERANCE TO NOISE

• Take a series of images in daylight 
• Use natural indoor light
• Use an object which has areas of both texture
• and plain detail
• With the use of tripods and take the same
• images from the lowest to the highest iso.

The series of images below show the variation of the grain/pixel detail on the same image
set at the same aperture setting


SET UP

natural light
f4.5
tripod
silver reflector

1600 iso
1/80 sec

1600 pixel detail

1200 iso
1/60 sec

1200 detail

800 iso
1/50 sec

iso 800 detail

iso 400
1/15 sec

iso 400 detail

iso 200
1/5 sec

iso 200 detail


this exercise clearly shows that there a variance in the
clarity on the image based on the iso level setting

CONCLUSION

Iso setting influences the clarity of  the final image as
increasing the iso setting increasing the pixels and
adds grain the to final image.

ISO rating is vital when light is limited as it
allows the photographer to shot in
reduced lighting conditions.

The relationship between iso and exposure is
that the increased iso allows the photographer
to increase the shutter speed and not widen
the aperture and reduce the focus.

My priority would to use a tripod and reduce
shutter speed where it is appropriate to use
a tripod. This means I could use the slowest
ISO as possible