Night Photography issue

[jeezopeezo]

All I went out on New Year's ever around 1:30am to get some shots of Teepee's at a Native American education facility. I had prior approval and my plans are to give them one of the prints but they did not come out the way I planned. No worries as I made this a trial run and marked some points down to improve on. Here are my questions...

How do reduce noise in night shots?
How do you reduce the rings of shades in the shots?

I can't remember the length of time on this shot but I will look when I get home.

Please take a look and let me know what you think.

[JohnB]

Rob,

I'm not sure what it is you don't like about that photo. Your composition is great as are the colors. I like the silhouettes of the Tepees. My only suggestion would be shoot a few in landscape for desktop wallpapers.

The rings of shade in the sky is called posterization. You might be able to reduce that by working at a higher bit depth. Though, I don't know what you can do about it when converting to JPEG as that format only supports 8 bits/channel. In Photoshop, you may be able to specify an algorithm when converting to a lower bit-depth image.

A google search for 'dealing with posterization' turned up some interesting results.

Steve has a tutorial on capturing night photos at the link below. He included a section on how he deals with noise.

http://paxtonprints.com/index.php?x=tut ... landscapes (http://paxtonprints.com/index.php?x=tutorial_night_landscapes)

[jeezopeezo]

John,

Thanks for the reply. I have read Steve's guide although it was a long time ago. Guess I need to refer back to it. As for the photo I like to composition and I have a ton more both portrait and landscape. I look at that photo and think it is a good starting point. I plan to head out when there is a full moon because they line up perfectly with the moon rise.

What do you mean shooting at a higher bit rate and posterization? I will Google it.

Can I reduce it by changing something in my settings?

[mirmilant]

Rob,

Not sure about your camera or its settings, but if you can you should shoot in RAW format rather than jpeg. That will help eliminate the banding (or posterization) in the sky that you see. Basically, with jpeg having just as an 8-bit depth it only has 256 levels in the tonal range between dark and light. In the RAW format, which is 12-bit, you get 4096 levels so you can get those rich and varied changes in colour and tone which are prevalent in sunset/sunrise and long exposure night shots.

Just a thought. In the end you'll probably convert to jpeg and you might run into these banding issues again, but at least you wont have them from right at the start of your workflow.

Cheers
Antonio

[JohnB]

I've never tried dealing with posterization in my photos before, so I can only make some assumptions on it as I know what it is and what causes it. What causes it is there are not enough shades to blend smoothly between the colors in your sky.

An image at 8-bits/channel has 256 reds, 256 blues and 256 greens. That's usually enough, but as you can see in your image, it's not always. If you're processing your images at 12 or 14 bits, you have 4,096 or 16,384 shades of each color giving you more room to blend colors. So, in your RAW conversion process, convert to 16-bit TIF images or 16-bit PSDs for processing.

This is the point where I become useless as I don't have experience with the Adobe suite of software. Hopefully this is enough information to help you figure out the rest or perhaps Steve or someone else will chime in and offer the details about dealing with this in Lightroom and/or Photoshop.

Ultimately, you will need to convert the image to 8-bit jpegs for the web, so you will see some sort of loss in the sky. It will either be posterization as you see in your images now or dithering (http://en.wikipedia.org/wiki/Dithering#Digital_photography_and_image_processing ).

As Antonio said, you'll need to work from RAW files rather than JPEGs.

[jeezopeezo]

My goal is to go for the print..in the end.

I did shoot this in RAW but if remember right the banding was present in the RAW photo as well. I will check tonight to make sure.

BTW....Thanks for the help. My next go around should be better. I am getting a million candle power spot light to help with focus points...that was a pain with a light that was slowly getting dim.

[JohnB]

Good idea about the spotlight for focusing. I have one that I rarely remember to bring with me when I'm out shooting at night. I also keep neglecting to put a small flashlight in my camera bag so I can see what's going on with my camera. I'd like to be able to see the focus ring on my lens at night.

[Steve Paxton]

Great composition Rob!

I am short on time at the moment, but I thought I would share just a couple ideas that might help. My experience has been that pronounced noise rears its head anytime you have longer than usual exposures. Dark images also suffer from noise. This makes nighttime photography especially challenging. Your image is beautiful - the composition is perfect; however I think it is slightly underexposed. The EXIF on the image shows 66 seconds at f3.8 and ISO 100.

You are right on track with the f-stop and ISO. I would be interested in seeing the image with the shutter speed bumped up two or three times (effectively adding 1-2 stops of light). My guess is that you would still have the beautiful silhouettes and the sky would have less banding and noise.

I try to bracket my images so that I have a variety of exposures to merge together. I am certainly not an expert on night photography; however I have had some success in merging the sky from one image with the foreground of another (of the same composition shot on a tripod). In cases like this, I liked the sky exposed one way (say 600+ seconds to get tons of star streaking action) and the foreground exposed another (exposed for much less time so that foreground elements are not blown out or overexposed).

I also routinely run the noise reduction filter two or three times on the image and use a layer mask so that it only affects the sky. Multiple passes with the noise reduction filter creates a very milky look that usually makes night skies look dreamy (however it kills details so you don’t want it to affect the foreground).

It is all about experimentation. You can create some amazing images if you are willing to stand outside in the cold and play around. One technique I haven’t had time to try is combining multiple images, exposed for a few seconds at a time, but shot in close succession. This allows you to keep the shutter speed down while getting the long exposure look (of the stars streaking). You have to shoot tons of images and it helps if your camera has an automatic shutter release feature (that you can set to shoot an image an regular intervals automatically). You bring all the images together in Photoshop as one singe shot.

There are tons of links on nighttime photography – The Noctures (http://www.thenocturnes.com/resources.html) is a site devoted specifically to this subject. Take a look!

Get out there and have fun! Post your images here so that we can see your progress!

PS - I never leave home on a night shoot without a flashlight. In fact, I turned the car around one night when I realized I left my light at home. A flashlight helps with focusing, seeing your camera (and changing settings) and keeping from walking into a dangerous area. I try to shoot in places that are nearly pitch dark so I couldn't even function without some kind of light. Grab yourself an inexpensive LED light that is bright enough to give you a quick focus point (10-20 feet away). There are a few lights out there that allow you to switch back and forth between a couple and multiple LEDs - this is helpful for keeping your night vision once you have everything setup.

[jeezopeezo]

Steve and everyone,

Thanks for the help with this. This weekend I might try to get out and shoot this again with this added knowledge. I will be sure to post my progress.


You are right on track with the f-stop and ISO. I would be interested in seeing the image with the shutter speed bumped up two or three times (effectively adding 1-2 stops of light). My guess is that you would still have the beautiful silhouettes and the sky would have less banding and noise.

I was shooting in BULB mode in this case so in your suggestion, I could just lessen the exposure time????

[Steve Paxton]

It is hard to say what your exposure should be based on that composition (since I was not there). In total darkeness my exposures run between 5 and 10 minutes. It really depends on what I am trying to achieve and the quality of light that is available. Your image would probably benefit from a longer exposure - double the exposure and it would be 132 seconds. Double it again and it would be 264 seconds.

It really comes down to experimenting with different exposure settings and bracketing your shots. You can take a pitch dark environment and turn it into day with a long enough exposure (which you may or may not want to do). Don't hesitate to adjust the ISO if you don't want to stand around waiting 10 minutes for each shot. You are probably safe dialing up to 400 ISO without adding too much additional noise (but again, experiment with this).

Overall it is a great image! I love the composition. I would love to see what else you come up with.

[Michael]

As everyone else said, shoot RAW. A few other things that you might want to try are playing around with your camera's advanced settings, things like long exposure and high ISO noise reduction should have noticeable effects on your noise levels (but will also effect your image), as will the Adobe RAW processing settings for noise and detail. Also, I would recommend taking a manual flash and playing around with it on low power(1/16 or 1/64), hitting the test button and using it to paint some detail into the teepee. It will allow you to separate the exposure of your foreground from the exposure of the sky. You can see the flap in your image, but it also suffers from posterization and this could help correct that. Finally, I would suggest being careful with pushing any of the sliders up too high in post processing, as this can cause posterization especially with levels, curves, and HSL controls. If you go again, post your new images and tell us what worked. Good luck!

[jeezopeezo]

Thanks everyone....I plan on going soon....just have to wait for the weather to clear up.