Tag Archives: long exposure

Red Streak Noise in Long Exposure Night Shots Solved

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Last Saturday, I was photographing along the California Hwy 1 coastline at night.  It was pretty dark requiring long exposures.  With that came a noise problem – a red streak in the image.  See below.

Long Exposure Night Shot of Sea Stack showing red streak noise

Long Exposure Night Shot of Sea Stack along California Hwy 1 Coast. See the two red streaks in the lower one-thirds of the image.

This was an eight minute exposure.  Shot at f22, ISO100.  Nikkor 70-200mm f2.8 lens and Nikon D4S body.  Fortunately, I had another two minute exposure of the same composition, made when there was a bit more light that would work for me as a keeper.  So, I had not lost the shot.  But, it was disconcerting to realize that I was limited to two minute exposures with this lens for night shots.

First, I wanted to ascertain that the red streak noise was repeatable.  I ran a series of tests on long night exposures yesterday, only to realize that with this lens, it was very repeatable as long as the scene was pretty dark and my exposure was greater than 2 minutes @ ISO100.  I also verified other ISOs and found that the red streak noise found during 4 minutes @ ISO100 and that found during 1 minute @ ISO400 were about the same.  There was no escaping this.  If I needed to shoot in very dark conditions – I will not be able to get away with shorter exposures, using ISO to compensate.  This was depressing …

Next, I attempted to see if “long exposure noise reduction” would compensate for this issue.  After all, the long exposure noise reduction works by making a dark exposure with identical parameters, with the shutter closed.  The idea is that the noise on the sensor would be same, which is later subtracted from the main image, thus reducing or eliminating to a great extent the noise resulting from long exposure.  The results of these tests were disappointing as well.  The noise was the same in the RAW files, but slightly reduced in the in-camera JPGs.  I shoot 100% RAW and would not be happy switching to JPG for the slight reduction in the red streak noise.  I needed to solve it fully.

As I drove around and lived my life today, it occurred to me that I should perhaps try to apply the long exposure noise reduction idea manually.  At the next opportunity I got, I put the lens cap on the same lens and made an eight minute exposure at f22 and ISO100.  The resulting dark exposure with red streak noise is shown below.

Dark exposure with lens cap on, recreating the red streak noise alone.

Dark exposure with lens cap on, recreating the red streak noise alone.

Now, I had to figure out a way to subtract the red streak noise seen in this image, from the original image.  Since I have been stacking images in Photoshop for years, this was easy for me to figure out.  Here is the procedure:

1. Load both images from LR into PS as layers.

2. Right-click the layers in PS and “Convert to Smart Object”.

3. Pull-down “Layer” > “Smart Objects” > “Stack Mode” > Range.

Stacking using “Range” makes sense, because it is essentially subtracting the maximum signal from the minimum signal and providing the difference.  Since the second image (containing only the red streak noise) has black in the rest of the image, only the red streak noise will get eliminated.

I tried this procedure and “bingo”, it worked.  The red streak noise was eliminated and there was no loss to the image quality.  All details of the underlying image came alive just as I had imagined.  The resulting red streak noise free image is shown below.

Red streak noise has now been eliminated in this image, using the procedure mentioned in this post.

Red streak noise has now been eliminated in this image, using the procedure mentioned in this post.

Conclusion – While I have not solved how to prevent the red streak noise in the first place, I have a pretty good procedure to deal with it in post.  Just take another image with the same exposure parameters as the real image, with the lens cap “on” this time.  This may be done several days later and in conditions different from the shoot.  Then, subtract the latter from the former using the PS procedure just outlined.

PS.  I have observed this red streak noise in my Nikkor 70-200mm f2.8 VR lens.  Others have reported it on the Nikkor 16-35mm f4 lens.  I checked my 16-35mm f4 lens and do not see this noise in that one.

If you have seen this type of red streak noise during long night exposures, please try this procedure and let me know if it worked for you.  I would appreciate it, if you could post your success story as a comment here.  Thank you for your attention.

Working a composition

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When I come across something interesting to photograph, I do not click one image of an obvious composition and walk away.  I start with the obvious compositions, but I keep refining and altering my position, until I have attempted a lot of variations.  Very often, when I review my work later in Lightroom, I find that my later refinements bring out the fine keepers.

I photographed a waterfall along Fern Creek in Muir Woods, CA, last week.  Let me illustrate how I worked the composition in that case.

The following image is the first image I made when I saw the waterfalls.

Waterfall, Fern Creek, Muir Woods, CA, USA

The first image made of the waterfalls

This first image has a number of branches coming in the way of the view of the falls.  Clearly, I don’t like it and try another shot by moving a bit.  The next image shown here removes a bunch of the blocks and the view is somewhat clear.  However, one fern leaf snuck into the lower end of the image.  It is important to understand that I was viewing through the viewfinder on my f2.8 lens, but I was shooting f22.  This causes this fern leaf to be almost invisible in the viewfinder, due to shallow depth of field, but it shows up in the f22 image.  Plus there is a brown twig in the lower left of the image.  I see all this in my LCD panel and decide to try again.

Waterfall, Fern Creek, Muir Woods, CA, USA

The next image made

I moved and made the following image, in an attempt to remove distracting blocks to the view of the falls.  The following image has problems though.  Some other brown dried leaf has now snuck in, plus the brown twig on the left is still there.

Waterfall, Fern Creek, Muir Woods, CA, USA

The next image made

After some more adjustments to my tripod position, I made the following image.  This composition is almost OK, but, during the 30 second long exposure, I got distracted talking to my kids in the nearby trail and accidentally touched/hit the tripod during the exposure.  Observing the top edge of the rock, just after the falls, I realize that it is not exactly sharp, due to the accidental hit to the tripod during the exposure.

The next image made

I try again, this time getting a sharp image, with minimum distractions.

Waterfall, Fern Creek, Muir Woods, CA, USA

The next image made

Taking one of the final frames during these series, as my base, I decided to use Lightroom to crop it and develop further.  FInally, I removed some branches and twigs to clean it up further.  The final result is as shown below.

Waterfall, Fern Creek, Muir Woods, CA, USA

My final finished image

Many beginners ask me what I mean, when I say “work the composition more”.  I decided to illustrate using this example.

Let me know if you have any feedback on this post.

Discovering unimaginably great photographic compositions

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Great photographs are often not imagined that way.  Many advanced amateur photographers I know, step out into location, take an image with the most obvious composition and then walk away with the idea that they are done.  I did this for many years, but I no longer treat my photography that way.  I start with the most obvious compositions and then I stay and I stay and I stay.  I try another composition and yet another composition and keep on going until either physical exhaustion or mental exhaustion or my next chore deadline hits me.  Often, I stay at a location and make hundreds of images.  My best compositions then turn out to be those that are closer to the frame 100 mark and almost never near the frame 1.  The creative juices start flowing after the most obvious compositions are out of the way.  Your brain starts thinking out of the box, after the “in-the-box” thinking is exhausted.  This is in fact, a great way to train your composition skills.  Lock yourself into your closet and force yourself into making 100 different compositions.  Freeman Patterson taught me this through one of his books.  Later, when I attended a seminar by John Shaw, he told us the same thing.  Ever since, I have tried it very often and every time, I come up with some cool images.

Let me illustrate using one example.  This happened two weeks ago.  I was travelling with a fellow photographer in his car.  Fortunately for me, he was driving and we had an hour to drive before our night photo shoot in San Francisco.  He happened to tell me about his new Fuji X100S camera in his glove compartment.  I found myself pulling it out and making hand-held shots.  I made 300 frames that night and will show you a sample of the progression from trash to good (atleast for my eyes).

I started with images like this one.

One of the first images I made in a series of 300. Nothing spectacular. No big deal. But, this is just a beginning.

The first images made in a series will not be necessarily spectacular.  But, it is important to get going.

After a few frames, this is yet another frame that was made.

This image was made shortly after the car started moving. Nothing spectacular here either. But, some ideas are developing. The streaks due to long exposure is triggering a thought …

I want to extend the idea of making light streaks with long exposures.  So, I try some more shots.

The streaks are more prominent in this shot. This is validating that some cool images are possible. Need to try variations, with the same idea.

OK, at this point, I am thinking, “what else I can do with this idea?”  And then, I make an image like this.

Extending the idea of brandishing my camera during a long exposure. Still not a killer keeper, but I want to keep going.

By this time, I want to keep going with the idea further.  Then, after a few frames, I made this image.

Continuing on the streaks during long exposure idea.

Now, the idea of creating an image with streaks during a long exposure, while brandishing my camera, is very encouraging.  This is still not a keeper image for me, but it is getting close.  I want to keep going.

This is getting a lot closer to a clear keeper. In fact, with a crop to remove the emptiness of the bottom most area and the dark top right area, this is indeed a keeper. Very encouraging.

With the right crop, this is a nice keeper.  Let me keep going.

Ooooh! My first keeper, for my eyes. Made by brandishing my camera in circular movement plus bottom left to top right.

By this time, I have completed shooting over 200 frames.  From now on, I went on shooting solid keepers.  Here are some examples.

One of the keeper images, from a series of 300 shot in a one hour car ride. Never imagined this composition, before I started the car ride.

One of the keepers from the series of 300 images made in a one-hour car ride. This composition could not have been imagined prior to the ride.

My favorite so far, from the whole series. To my eyes, this is a lovely composition.

To summarize, you should practice your photographic composition often.  How about 100 images a day?  If not, atleast do 500 images a week.  In any one practice session, include atleast 100 images of a simple subject.  Your composition skills will shoot through the roof, if practiced consistently.  This is more useful than reading tens of books on composition.

If you found this article useful, let me know.  Email me at info@pixgaga.com.  Feel free to forward it, comment on it, and above all please use it.

Good luck with your photographic composition.