D90 photos noisy at ISO 200?

[anm90]

I was taking some shots of the sunset this evening and they appear to be extremely noisy. Any ideas why? Here are the unedited photos.

1. Unedited straight out of camera

Camera Maker: NIKON CORPORATION
Camera Model: NIKON D90
Image Date: 2010:02:16 17:37:28
Focal Length: 30.0mm (35mm equivalent: 45mm)
Aperture: f/10.0
Exposure Time: 0.0013 s (1/800)
ISO equiv: 200
Exposure Bias: none
Metering Mode: Spot
Exposure: Manual
Exposure Mode: Manual
White Balance: Auto
Flash Fired: No
Color Space: sRGB

2. Here is a closer crop to show the noise better... again, unedited besides the crop.

3. Unedited out of camera

Camera Maker: NIKON CORPORATION
Camera Model: NIKON D90
Image Date: 2010:02:16 17:49:47
Focal Length: 18.0mm (35mm equivalent: 27mm)
Aperture: f/18.0
Exposure Time: 0.025 s (1/40)
ISO equiv: 200
Exposure Bias: none
Metering Mode: Spot
Exposure: Manual
Exposure Mode: Manual
White Balance: Auto
Flash Fired: No
Color Space: sRGB

4. Close crop

 

[matfoster]

less than ideal shutter-speeds at ISO 200 sensitivity for exposures taken at/after sunset...especially the first picture: f10, 800th sec at ISO200. i'd try a higher ISO/slower shutterspeed.

 

[Samanax]

Noise creeps in when the image is underexposed, even if you're using a fairly low ISO setting. For these shots you might want to try matrix metering instead of spot.

 

[BKMOOD]

Could be heat. In low light, one tends to use slower shutter speeds. As the chip/sensor takes longer to collect light (the image), it gets hotter. More heat, more noise. Bigger sensors can deal with this problem better than smaller sensors.

Could also be an issue with the signal to noise ratio (SNR). All pictures have a signal. All pictures have noise. However, in good light the signal is so strong the noise is minimized and often not even visible. In low light, when the picture signal is not as strong, noise fills in the gaps. Your camera is basically telling you, I can't see all of this picture so I'm going to fill in the gaps with stuff we call noise.

 

[anm90]

What sort of shutter speeds are more ideal for sunset shots? I was unaware that they made an impact on the quality of the image for something that is effectively not moving. I figured I should use an aperture that would lend itself to a large DOF and that the shutter speed wouldn't really matter (I was using a tripod).

Also, why would I use a higher ISO? Wouldn't that just increase the noise?

Here is another photo where I used matrix metering instead of spot and the noise is still quite prevalent.

1. Full size, unedited

2. Close crop

 

[tdiprincess]

This is all good to know since I'm going to be doing some indoor shots soon.
Good pictures BTW, even with a bit of noise.. in #4 I like the crisp lines in the sunset that you were able to catch!

 

[anm90]

Any other suggestions/explanations?

Thank you.

 

[KmH]

While heat can certainly play a role with longer exposures, it's not really an issue until the exposure ranges into several seconds long. I have made star trail images (with some noise) from exposures of up to 20 minutes so, 1/40 of a second is not an issue, noise from heat wise.

The main issue is underexposure, which is necessary because the Sun is in most of the images. You don't mention if the images were captured as RAW data files or as JPEG image files.

So, you should expose for the sky and let the Sun overexpose.

Have you read Bryan Peterson's inexpensive paperback book Understanding Exposure?

 

[robertwsimpson]

2 reasons:
1. I am assuming you took these in jpg mode
2. "Unedited straight out of camera"


to fix, switch to RAW, make sure you are properly exposing your photo, and then use noise reduction software.

problem solved.

 

[anm90]

I have read Understanding Exposure. That is why I was metering off of the sky just to the side of the sun. I did shoot these in jpg and have not experimented with RAW yet. Haven't had time to look at the software that came with the camera even. Perhaps I will try shooting RAW next time and see what I can come up with. What sort of noise reduction software would you recommend? I have Photoshop CS4 and Lightroom 3 (Beta) as well as the software that came with the camera.

Thank you for the input, it is highly appreciated.

 

[robertwsimpson]

if you're metering near the sun, you're still underexposing the photo. Since you're shooting in JPG, the camera is bringing the image up to normal exposure after you take the photo. That makes it noisy. When you shoot in RAW, and then look at the RAW file on the computer, you'll see the true exposure.

 

[anm90]

Ah, so should I be metering about where the orange glow turns to blue? Or should I be metering purely off of the blue in the sky?

 

[robertwsimpson]

I'd take probably 3 or more exposures with a stop inbetween each one just to make sure that I got the right exposure level that I wanted. Your camera does AEB. That's what I would use.

 

[KmH]

I have read Understanding Exposure. That is why I was metering off of the sky just to the side of the sun. I did shoot these in jpg and have not experimented with RAW yet. Haven't had time to look at the software that came with the camera even. Perhaps I will try shooting RAW next time and see what I can come up with. What sort of noise reduction software would you recommend? I have Photoshop CS4 and Lightroom 3 (Beta) as well as the software that came with the camera.

Thank you for the input, it is highly appreciated.

I do noise reduction as a multi-part task.

I start by capturing images in RAW and using the de-noise tools in ACR (Adobe Camera RAW - Detail tab - Luminance and Color sliders).

My main de-noise tool in Photoshop is Imagenomics - Noiseware Pro. I have several other de-noise plug-ins. My #2 de-noise plug-in is Topaz de-noise.

www.imagenomic.com www.topazlabs.com

 

[Samanax]

What sort of shutter speeds are more ideal for sunset shots? I was unaware that they made an impact on the quality of the image for something that is effectively not moving.

Shutter speed does effect exposure and a slower shutter speed would allow more light to reach the sensor and help keep the noise levels down.

I figured I should use an aperture that would lend itself to a large DOF and that the shutter speed wouldn't really matter (I was using a tripod).

But you don't want to use an aperture that is too small or you'll start to see the effects of diffraction. And for these shots you really don't have to worry about the DOF since there is nothing in the foreground to get sharp.

Also, why would I use a higher ISO? Wouldn't that just increase the noise?

Yes, higher ISO would introduce more noise into the images.

I have read Understanding Exposure. That is why I was metering off of the sky just to the side of the sun. I did shoot these in jpg and have not experimented with RAW yet. Haven't had time to look at the software that came with the camera even. Perhaps I will try shooting RAW next time and see what I can come up with. What sort of noise reduction software would you recommend? I have Photoshop CS4 and Lightroom 3 (Beta) as well as the software that came with the camera.

I use Noiseware Community Edition if I need to do any noise reduction on my images. This is the free standalone version of the software but there are plugins available for Photoshop.

I'm not into landscape photography and rarely ever do sunrise or sunset shots, but I did take this shot of a sunrise over the weekend...

I don't have the shot information because I stripped the exif out when converting to JPEG, but the shot was handheld. I used my Canon XTi and EF 50mm f/1.8 II lens. I was using manual mode and I'm pretty sure ISO was set to 100. I don't remember what the aperture was set to (was somewhere between f/1.8 and f/4.0) and shutter speed was somewhere between 1/60 and 1/125 (sorry I don't recall the shot info because I was mostly experimenting and took a lot of shots with different exposure settings). Shot in RAW and PP'd in Lightroom 2 and then CS3. No noise reduction.