artsy-fartsy or just weird?

[NewHampshire]

I found this interesting article on DSLR noise and thought I would share:

http://www.photoxels.com/tutorial_noise.html

Brian

 

[DougPaul]

There are some nice examples of noise at various ISOs in Night and Low Light Photography with Digital Cameras
http://www.clarkvision.com/photoinfo/night.and.low.light.photography/index.html

Several technical articles on digital camera image noise:
Does Pixel Size Matter gives a technical analysis of low light digital camera performance:
http://www.clarkvision.com/imagedetail/does.pixel.size.matter/index.html
Part 2 has a number of example pics:
http://www.clarkvision.com/imagedetail/does.pixel.size.matter2/index.html

There is an index to more technical articles on the topic at:
http://www.clarkvision.com/imagedetail/index.html#sensor_analysis


BTW, film is much noisier than a decent digital camera. Film also suffers from reciprocity failure (the effective ISO goes down at low light levels).

Doug

 

[darren]

forestgnome - you around? Can you post the exif of the original shot? How much did you crop, post processing, etc?

Thanks

- darren

 

[forestgnome]

been out of state for a funeral, now I'm off to work. Tonight, I'll post that exif data and the original image. I shot a few things at ISO1600 for experimentation as well.

Gorgeous image of the cardinal!

 

[David Metsky]

Not unpleasant, just different. Moving away from the monitor gives it a much different feel. Have you tried printing it out and viewing it from different distances?

 

[David Metsky]

Yes, and Darren's photos make we want to buy a dSLR as well.

 

[jwind]

"noise" is when your pixels come out a color they are not supposed to be. If you look at the rump of the moose you can see what I mean. Instead of being all brown/black you see some pixels are red and green. "grain" as we know, is just more pixles used to expose for a given spot, thus we get the splotchy, "chunky" look. (does that actually make sense!? )

Brian

Noise/grain has nothing to do with more or less pixels used. It has to do with EXAGGERATED imperfections in exposure. To get real technical, "grain" is specific to film, there is no grain in digital.

If you think of pixels as Buckets on the ground and rain drops as light photons i can make a very easy to understand analogy.

When it starts raining, AT FIRST one bucket my receive more drops (light) but after a little time, the differences between the buckets will be more or less the same.

When you shoot at a high ISO say 1600, you are taking a light sample from the first minute and the camera is pushing that to the correct exposure, thus exaggerating the inconsistencies in the buckets EVEN MORE. The rust is noise from poor aliasing and pixel feathering.

 

[jwind]

Also, while PROPER exposure is your best bet in keeping noise at bay, the shooting raw does help.

 

[forestgnome]

oops! It wasn't ISO1600; it was ISO800.

1/40" exposure
f/5.6
300mm
white balance - AWB
underexposed by 2/3 stop in AV mode
tripod

The cropping is heavy; about 60%?

 

[DougPaul]

ISO800.
1/40" exposure
f/5.6
300mm
white balance - AWB
underexposed by 2/3 stop in AV mode

Thanks.

Was there any postprocessing other than cropping?
Is this from the default JPEG or from raw?

For instance, if the image was brightened or sharpened in postprocessing, either would increase the apparent noise.

Doug

 

[forestgnome]

Yes, in PS I bumped up the contrast and saturation a bit. Then I hit the sharpener one time, but I honestly don't have a handle on that tool and i don't know what difference it made.

The file is a large/fine jpeg.

 

[Neil]

By moving the slider on my browser window down I "cropped" the rocks and water from the picture and I like it a lot better that way.

 

[DougPaul]

Yes, in PS I bumped up the contrast and saturation a bit. Then I hit the sharpener one time, but I honestly don't have a handle on that tool and i don't know what difference it made.

I would guess that each of these operations increased the noise and the total effect is visible in the pic. I think that explains the image.

Thanks.

Doug