Why so much noise at ISO200?

wildviper · October 1, 2006

Please help.

I am not sure what is going on with my pictures. Some come very sharp, while others "look" sharp, but are not.

here is an example of what I mean. This picture looks nice and sharp, but when I zoom in, I see a lot of noise and not sharp like other pictures I see online or even the ones I have taken with same lens.

Is this an element of:

1. Picture was not in focus originally?
2. Due to light quantity and quality, the digital produces noise even at ISO200?
3. The lens is bad
4. Sensor is dirty
5. Some other thing I can't think of.

This picture was taken with the 50/1.8 which is usually very sharp. So I am thinking, it is not the lens, but possibly the focus and/or light.

Can someone shed some light on this??

My camera and lenses are listed below. This was shot at ISO200 in semi-shade.

Thank you

wildviper · October 1, 2006

Here is the un-cropped picture.

Artur C. · October 1, 2006

Sharpness....a matter of speaking...
Is the photo noisy? Yes and no, several factors determine in camera noise, and honestly what I'm seeing doesn't so much look like chroma noise, or even luminence noise, but artifacting. The ambient temperature, ISO setting, and how you expose the scene will determine the amount of noise visible. Remember that shadows will display more noise then highlights, and at ISO 200 what you have is not uncommon. A digital sensor is more "data rich" to the right side of the histogram, so noise in the shadows are ok, the way to counter this is to expose for the highlights without blowing them out, then pushing the exposure back using camera raw, or if the difference is extreme, blend the exposures digitally.

colourbox · October 1, 2006

How was it exposed? With the example shown, there is a LOT of white in it. If auto exposure was used in this type of image (or a person on a snowy mountain) the sensor can be fooled into under-exposing because so much of it is unusually light. With digital, the danger of under-exposing is that an under-exposed image can show more noise for the reasons Artur C. mentioned, too much of the image shifted down into the noisy, data-poor shadows. That's just a guess. If you do auto-expose, then my other guess is that your images with more typical backgrounds, or backgrounds darker than the subject, don't look as noisy.

By the way there's nothing wrong with auto-exposure if you're watching the scene and apply exposure compensation that's appropriate.

Khaos · October 1, 2006

1. Where's the exif? You are shooting downward and it looks like you're using a rather shallow DOF.

2. Dynamic range in dslr isn't the best and shadowed areas will not pull in the greatest detail. The minute you bump up the exposure in RAW processing or increase the contrast and lightness in post processing, you are going to see noise in those areas.

3. coulorbox brings up a very good point about the exposure, so again, what's the exif? Did you manually set the AV and TV, set it at auto, and how did you set the camera for exposure, evaluative, center weighted?

Shay Stephens · October 1, 2006

Red is challenging
Dark red doesn't have much for the sensor to record. Half the sensor is green, 1/4 is blue, and one quarter is red sensitive. Now add to that, the red color is dark, and you are not giving the camera much to work with above the noise threshold.

Shooting red is always risky with our current crop of cameras. More light would help, but that is a balancing act too because red pegs out easy too.

wildviper · October 2, 2006

Thanx for the replies.

Not sure how to attach the EXIF...it is part of the non-crop JPEG, but guess it didn't come through.

Anyways, this was shot on Manual exposure with f/1.8, 1/30sec, Metering Mode was CenterWeight. And ISO was 200. No Exposure compensation and no other light, except daylight.

I appreciate the point of the red subjects. Will keep in mind. However, this happens to me even on non-red.

Just feel something I am doing is wrong. When I look at pictures of other people's, they look perfectly sharp.

ziggy53 · October 2, 2006

wildviper wrote:

Thanx for the replies.

Not sure how to attach the EXIF...it is part of the non-crop JPEG, but guess it didn't come through.

Anyways, this was shot on Manual exposure with f/1.8, 1/30sec, Metering Mode was CenterWeight. And ISO was 200. No Exposure compensation and no other light, except daylight.

I appreciate the point of the red subjects. Will keep in mind. However, this happens to me even on non-red.

Just feel something I am doing is wrong. When I look at pictures of other people's, they look perfectly sharp.

Here is your EXIF:

Make - NIKON CORPORATION
Model - NIKON D70s
Orientation - Top left
XResolution - 240.00
YResolution - 240.00
ResolutionUnit - Inch
Software - Adobe Photoshop CS2 Windows
DateTime - 2006:10:01 16:52:15
ExifOffset - 216
ExposureTime - 1/30 seconds
FNumber - 1.80
ExposureProgram - Manual control
ISOSpeedRatings - 200
ExifVersion - 0221
DateTimeOriginal - 2006:08:08 19:48:06
DateTimeDigitized - 2006:08:08 19:48:06
ShutterSpeedValue - 1/30 seconds
ApertureValue - F 1.80
ExposureBiasValue - 0.00
MaxApertureValue - F 1.74
MeteringMode - Center weighted average
LightSource - Auto
Flash - Not fired
FocalLength - 50.00 mm
UserComment - (C) Anand 2006
SubsecTime - 09
SubsecTimeOriginal - 09
SubsecTimeDigitized - 09
ColorSpace - Uncalibrated
ExifImageWidth - 466
ExifImageHeight - 700
SensingMethod - One-chip color area sensor
FileSource - DSC - Digital still camera
SceneType - A directly photographed image
CustomRendered - Normal process
ExposureMode - Manual
WhiteBalance - Auto
DigitalZoomRatio - 1 x
FocalLengthIn35mmFilm - 75 mm
SceneCaptureType - Landscape
GainControl - None
Contrast - Normal
Saturation - Normal
Sharpness - Hard
SubjectDistanceRange - Unknown

1/30th sec. could also have camera shake, in addition to the most excellent advice you have been given.

ziggy53

SpeshulEd · October 2, 2006

hey ziggy, what are you using to get that info. I know there are extensions and programs and whatnot to tell you the exif for pics on the net, I'd like to find a nice one, but don't really know whats out there.

henrytd · October 2, 2006

Getting EXIF from downloaded images

SpeshulEd wrote:

hey ziggy, what are you using to get that info. I know there are extensions and programs and whatnot to tell you the exif for pics on the net, I'd like to find a nice one, but don't really know whats out there.

Saving either of these pictures locally, and then viewing them using ACD See Photo Pro Manager shows the complete EXIF info. I use ACD See (and have for years) because it is a very fast photo management program. I especially appreciate that I can add Captions in ACD See very quickly (in the IPTC Caption field) and they will be picked up automatically as captions when uploaded to Smugmug.

Skip

Khaos · October 2, 2006

1.8 is very shallow, especially if you want the petals to be in focus from top to back.

1/30 is also too slow for that focal length handheld. You might think you're steady, but you're not going to get a sharp shot. Try taking a pic handheld at that shutter speed and the same pic but using a tripod and compare the two.

I've started becoming accustomed to using a tripod when I can. It makes a big difference. This shot would benefit from one. You can stop down for a larger DOF and do a longer exposure.

For flowers, you'll have to practice. Like Shay said, reds are a pain, as are bright yellows. After awhile you'll get the hang of how to expose properly to get the detail you desire.

SpeshulEd · October 2, 2006

henrytd wrote:

Saving either of these pictures locally, and then viewing them using ACD See Photo Pro Manager shows the complete EXIF info. I use ACD See (and have for years) because it is a very fast photo management program. I especially appreciate that I can add Captions in ACD See very quickly (in the IPTC Caption field) and they will be picked up automatically as captions when uploaded to Smugmug.

Skip

good to know, I'll have to look into that program. I used ACD See many many years ago, but haven't checked it out in a while. Sounds like I need to.

ziggy53 · October 2, 2006

henrytd wrote:

Saving either of these pictures locally, and then viewing them using ACD See Photo Pro Manager shows the complete EXIF info. I use ACD See (and have for years) because it is a very fast photo management program. I especially appreciate that I can add Captions in ACD See very quickly (in the IPTC Caption field) and they will be picked up automatically as captions when uploaded to Smugmug.

Skip

Like Skip says, except I used IrfanView. This freeware is a real Gem of software. Much of it is coded in machine language, and the entire software fits on a floppy. (When is the last time you saw anything valuable that fits on a floppy disk.)

The basic software includes both image viewer and image browser (thumbnails).

Like ACD See, you can also add both EXIF Comments and IPTC information.

http://www.IrfanView.com

ziggy53

dancorder · October 2, 2006

If you're using Firefox then this will save you having to download the picture and open it:

http://ted.mielczarek.org/code/mozilla/fxif/

SpeshulEd · October 2, 2006

thanks for all the help guys, I'll be checking out all of these programs when I get home from work today.

claudermilk · October 2, 2006

Khaos wrote:

1.8 is very shallow, especially if you want the petals to be in focus from top to back.

1/30 is also too slow for that focal length handheld. You might think you're steady, but you're not going to get a sharp shot. Try taking a pic handheld at that shutter speed and the same pic but using a tripod and compare the two.

I've started becoming accustomed to using a tripod when I can. It makes a big difference. This shot would benefit from one. You can stop down for a larger DOF and do a longer exposure.

For flowers, you'll have to practice. Like Shay said, reds are a pain, as are bright yellows. After awhile you'll get the hang of how to expose properly to get the detail you desire.

Beat me to it. Stop the lens down, put the camera on a tripod, and give the scene more light.

BTW, FxIF gives this:

Camera Make: NIKON CORPORATION
Camera Model: NIKON D70s
Image Date: 2006:08:08 19:48:06
Flash Used: No
Focal Length: 50.0mm (35mm equivalent: 75mm)
Exposure Time: 0.033 s (1/30)
Aperture: f/1.8
ISO equiv: 200
White Balance: Auto
Metering Mode: Center Weight
Exposure: Manual
Exposure Mode: Manual
Comment: (C) Anand 2006

wildviper · October 2, 2006

Ahhhhhhh....finally I know what to look-out for!!!! I am not as steady as a tripod.

So simple the idea, yet I never thought about it. THANK YOU!

I shall try this again and post the result here. Of course, it will be different flower.

Wow...Tripod!!!

claudermilk · October 3, 2006

Now before running out to buy a tripod, read this: http://www.bythom.com/support.htm

I have not yet upgraded my setup. Right now one mall store POS tripod Thom mentions in stage 3, and a shared setup my sister and I inherited consisting of some older Cullman gear. When I do buy it will be a Feisol 3301 and RRS BH-40LR; won't completely break the bank and will do the job; both parts have gotten glowing reviews every time I've seen them mentioned (some from very picky users).