What’s Your Preference?

jennifer8 · #1 (**permalink**) 10-03-2010, 09:15 AM

Hi everyone
Stuck on module 2 of my online course. Just wondered if anyone would be kind enough to help with this ?

For the first part i had to shoot a scene with bright colours and shadows with a normal lens with my aperture set to f/8 and only change the iso. So i saw that the higher the iso the more noise was appearing on the images. So far so good.
Next i had to shoot a dark scene in low lighting same aperture and again just changing the iso. I used a tripod and shot at shutter speeds of between 1 and 30 seconds. I am now supposed to compare the image quality with the first exercise and incredibly they look to be better quality and the noise does not appear till at a much higher iso (1600).

Is that possible or am i seeing things again ?

Thank you so much everyone
Jennifer x x

Dirt_Bike_Ryda · #2 (**permalink**) 10-03-2010, 09:21 AM

are you saying that the photos you took at say ISO 800 were better then those of which were taken at ISO 200 ??

jennifer8 · #3 (**permalink**) 10-03-2010, 09:50 AM

Quote:

Originally Posted by Dirt_Bike_Ryda

are you saying that the photos you took at say ISO 800 were better then those of which were taken at ISO 200 ??

no they were of the same quality ! iso 800 were brighter but there was no noise like in the first exercise ! could my tripod have prevented the noise or the slow shutter speed did that improve quality compared to the first exercise ?

Dirt_Bike_Ryda · #4 (**permalink**) 10-03-2010, 10:15 AM

well. than in that case maybe you can't notice the extra noise then. which is good. what camera are you shooting with ??

your tripod will not prevent noise... not in the slightest. how-ever, slow shutter speed will increase noise.

noise is generated from your image sensor heating up, as you crank up the ISO more power is sent to the image sensor so it can "see" better whick creates more heat, the heat creates more noise, also, the longer the shutter speed, the more heat. as the sensor is left "looking" for extended periods, it heats up.

All that is a very, very, very vauge explanation and not to be taken word for word.

RichardTaylor · #5 (**permalink**) 10-03-2010, 10:21 AM

Were you shooting RAW or JPG?
If shooting jpg keep in mind the camera may be applying noise reduction at higher ISO

jennifer8 · #6 (**permalink**) 10-03-2010, 10:49 AM

Quote:

Originally Posted by Dirt_Bike_Ryda

well. than in that case maybe you can't notice the extra noise then. which is good. what camera are you shooting with ??

your tripod will not prevent noise... not in the slightest. how-ever, slow shutter speed will increase noise.

noise is generated from your image sensor heating up, as you crank up the ISO more power is sent to the image sensor so it can "see" better whick creates more heat, the heat creates more noise, also, the longer the shutter speed, the more heat. as the sensor is left "looking" for extended periods, it heats up.

All that is a very, very, very vauge explanation and not to be taken word for word.

I was shooting with my canon 550D ! really confused about what to write for my assignment. There must be more noise there but i just can't see it !!!

jennifer8 · #7 (**permalink**) 10-03-2010, 10:50 AM

Quote:

Originally Posted by RichardTaylor

Were you shooting RAW or JPG?
If shooting jpg keep in mind the camera may be applying noise reduction at higher ISO

Hi Richard i was shooting Jpg. Maybe if i shoot raw what i'm suppose to see will be more obvious going to try that now thank you x

jennifer8 · #8 (**permalink**) 10-03-2010, 11:39 AM

Shooting in raw was obviously the best option as the noise was very obvious ! wish my tutor had mentioned that and saved me hours of banging my head against the wall !! thank you everybody x

tuxcomputers · #9 (**permalink**) 10-03-2010, 11:42 AM

Quote:

Originally Posted by jennifer8

I am now supposed to compare the image quality with the first exercise and incredibly they look to be better quality and the noise does not appear till at a much higher iso (1600).

Is that possible or am i seeing things again ?

Thank you so much everyone
Jennifer x x

I don't think you are seeing things and my theory goes like this:

Your sensor has a "natural" ISO
Think of each pixel of the sensor as a bucket catching light
Each has a certain amount of levels that can be measured
Each pit is slightly different
When you crank up the ISO the camera amplifies the signal coming out of each pit
Amplifying the signal increases the difference between them and you get "noise"
When you are taking photos in the bright light the bucket is filled more at the same ISO than when it is dark
More difference between the pits appears to make the image have more noise

Look at the histograms, you will probably see in bright light it will be bunched to the right, in dark images it will be bunched to the left. Same ISO, more brightness = more noise.