I love using the Big Stopper from Lee Filters to create long exposure pictures. The Big Stopper gives an approximate 10 stop reduction in light, giving turbulent waves a misty, cotton-candy like appearance and turns clouds into streaky shades of light.
But taking long exposures on digital cameras is not without problems, namely in the form of hot pixels. During long exposures, the camera’s sensor heats up creating hot pixels which show up as red, green, and white dots. These hot pixels are normal and they seem to change the location or the number of them from picture to picture depending on factors like the age of the camera and shooting conditions.
Most cameras have some form of noise reduction. The camera I use, the Nikon D800, has a long exposure noise reduction that can be turned on or off. I’ve used it a couple of times previously, but it takes a while to work. In fact, the time from pressing the shutter button until the image is recorded is double. So when taking an eight minute exposure, the camera is busy for 16 minutes. Eight minutes for the initial exposure and then an additional eight minutes during which time JOB NR is displayed in the control panel.
So what exactly happens in the camera during that time? The camera takes a “dark frame”, which is a photo with the shutter closed immediately, after the main image and then electronically subtracts the noise from the photography. According to Nikon Canada, the NR feature should only be employed when using exposures longer than 1/15th of a second.
Doubling the exposure time is not something I was interested in doing. Taking an eight minute exposure is time consuming enough and if there’s any hope of capturing other images during fading (or increasing) light, time, as the say, is of the essence.
Here’s a picture that I took recently of a sunrise on Lake Ontario without using Long Exposure NR. A pretty decent shot. And when viewed at the magnification you are viewing it, it looks fine.
It’s when you zoom in to 100%, however that are problems. Check out the 100% crops below of the portions in the red bounding box from the picture above.
See the problem? How can you miss it, right? Hot pixels like you wouldn’t believe. Both of these crops have about 350 hot pixels.
There are a variety of tools that you can use to get rid of this noise. One such is a a program called Pixel Fixer. This program requires you to map out your hot pixels by creating a dark frame. This is achieved by taking a picture with the lens cap on in a dark room with the same setting as the picture from which you want to remove the hot pixels. When the dark frame is imported into Pixel Fixer, the program analyses the image and maps out the hot pixels. You are able to change the sensitivity settings. You then apply the mapped hot spots to the picture you want to fix and presto, the hot pixels are removed. I tried using this method with the picture above, but the program has limitations. I found that this program did not work for me. I have a feeling that it’s really only effective if you take the dark frame at, or soon after, the shots you took so the sensor is subject to the same conditions.
So what did I do? As painful as it seems, I used Photoshop to remove the spots one by one using the spot healer tool, the clone stamp, and the patch tool. There were approximately 52,000 hot pixels and other noise in my image of varying degrees. That’s a lot of clicks…carpel tunnel anyone? And while it does sound like a lot, in the case of the Nikon D800, it is actually approximately 0.15% of the sensor’s pixels. It took over a week of editing here and there to fix up the image.
Here are the 100% crops fixed up.
So was it worth it? I felt that the picture was worth saving, and true enough, it now hangs printed on acrylic in my home, so yes. But a week of my time, even if here and there, was definitely not worth it.
So from now on, I’m using Nikon’s in-camera Long Exposure Noise Reduction to fix up my images. Sure it doubles my exposure time and limits the number of pictures you can take especially when timing is of the essence. But ever since I started getting into long exposures I find that I’m taking a lot less pictures anyway, because you just want to get it right the first time. A lot of setting up, composing, doing light measurements, and then taking out that book while the camera does its work. So from now on, Long Exposure Noise Reduction will be set to ON. Lesson learned.
Morning’s Promise
Heritage Park, Bath, Ontario, Canada
Nikon D800 w/ 16-35 f/4 @ 25mm, ISO 100, 360 sec at f/11
Lee Filters Big Stopper, 0.6 ND Hard Grad, B+W Polarizing Filter
Share this Post
Comments 26
I gotta favorite this internet site it seems handy
Hmm it seems like your website ate my first comment (it was extremely long) so I guess I’ll just sum it up what I had written and say, I’m thoroughly enjoying your blog. I as well am an aspiring blog writer but I’m still new to everything. Do you have any suggestions for beginner blog writers? I’d genuinely appreciate it.
Author
Hi Ben, keeping up a blog is definitely a lot of work. From a reflective perspective it’s rewarding. It also forces you to try some new things. But it is very time consuming. At any rate, I would be glad to help you out. Why don’t you send me an email and we’ll go from there.
I really like what you guys are usually up too. Such clever work and reporting! Keep up the good works guys I’ve included you guys to our blogroll.
Bookmarked!!, I really like your site!
Every weekend i used to pay a quick visit this website, simply for enjoyment, as this this web page contains in fact fastidious funny stuff too.
Author
Hi Beth, thanks for your comments, i’m glad that you enjoy the blog posts. And thanks also for leaving a word like “fastidious”, not everyone leaves an awesome word like that in a comment.
I will right away grab your rss as I can’t in finding your e-mail subscription link or newsletter service. Do you’ve any? Kindly allow me realize in order that I could subscribe. Thanks.
Author
Hi Dave, yes we finally have a subscription service up. You can find it on the bottom of every page in the website. Thanks for reading and subscribing!
Hi there, just became alert to your blog through Google, and found that it is really informative. I am going to watch out for brussels. I will be grateful if you continue this in future. A lot of people will be benefited from your writing. Cheers!
Author
Charlene, you’re too kind. I’m not sure that a lot of people will benefit from the content herein contained, but even if a few benefit, that’s good enough for me.
Hey there and thank you for your info. I definitely picked up something new from right here. Well I am adding this RSS to my email and could look out for much more of your respective intriguing content. Make sure you update this again soon..
Author
Hi Fran, thanks for your comments. I do my best to update the blog content on a weekly basis, usually Thursday morning. Keep coming back and I only hope that the content continues to intrigue you. Cheers!
Some truly quality content on this site, saved to fav.
Author
Warren, thanks for your comments. I’m glad you like the content and that you’ll keep coming back for more. It’s all I can ask. Cheers!
You made some nice points there. I did a search on the issue and found a good number of people agree with what you wrote.
Author
Hi Stan, I’m glad you found some of points helpful. Noise is a horrible thing. Digital cameras have improved noise issues by leaps and bounds, so maybe in a decade or two, noise will be a thing of the past.
Your method of telling everything in this piece of writing is nice, everyone is able to effortlessly be aware of it, Thanks a lot.
Author
Thanks and no problem Marcia, that’s the goal!
Yes! Finally someone writes about noise!
Author
Time to make some noise right?
Whats Going down? I am new to this, I stumbled upon this I’ve found It positively useful and it has helped me out loads. I am hoping it aids other users like its helped me. Great job.
Author
Glad it helped you out Jordan…good luck!
Hello, you used to write great, but the last several posts have been kinda boringî“‘ I miss your tremendous writings. Past several posts are just a little out of track! come on!
Author
Ha, thanks for the comments Lou…guess I’ve been off my game a bit…I promise to do better 🙂
I have been on vacation for some time and completely forgot about your blog. Now I remember why I enjoy it so much. Thanks, I will try and check back more frequently. How frequently do you update your web site?