Week 2: Camera Use: Self Directed Tasks "ISO Testing"

ISO TESTING

Day Testing ISO:

F5.6 1/10 ISO100 EF24-70mm@44mm

Night Testing ISO: under dimmed lighting

ISO settings: PIC 1-6 the grain in the image is not noticeable, noise is increased in PIC6-7.

Not enough light hitting the sensor and shutter speed to slow i.e. movement, on PIC1-2, dark and blurry.  Higher ISO increased grainy photos in PIC7-9.

PIC 10 F5.6 1/8 ISO102400 EF24-70mm@45mm

Why Photos Get Grainy

There are several reasons for grains in a photograph. The most commonly known and talked about reason for grains is ISO. In old days, when people used film, a general thumb rule was that grain in a photo increases as the ISO goes up. So, the higher the ISO, the grainier the photo would be. 

With digital technology, we understand that there are several other reasons for grainy photos. Here are some known reasons:

1. High ISO – As we briefly talked, higher the ISO, higher is the amount of grain.
2. Low light – Photos become grainy if enough light was not available when the photo was taken.
3. Too slow shutter speed – One school of thought believes if shutter speed is very low and light is low, photos may have lot of grain and noise.1
4. Camera – High-end DSLRs usually perform better in low light and handle high ISO with minimum noise. Same can not be said about low end DSLRs and point and shoot cameras. These type of camera have a small sensor, leading to high noise as effective light getting to sensor is lesser than if it were a high-end DSLR, which have a bigger and better responsive sensor. 
5. Excessive Post Processing – Another reason for grainy photos is over adjustment in post production. When sharpness of a photo is increased, grains/pixels in a photo become more prominent. If this adjustment is overdone, photo becomes grainy in no time.

Reference: http://www.learnfoodphotography.com/grainy-photos

It is just as correct to say the lowest possible level of noise is achieved when as much light as possible is hitting the sensor (without overexposing the image) and the ISO is as high as possible (without overexposing the image). In most cases the highest ISO possible will be 100.

Photo merge to HDR Photoshop. Images Pic3-10 merged in photoshop. The effect created from using different ISO in dimmed light at night. By Karen Cory Toussaint