Lately I have been using HDR in a rather dark environment and I'm wondering if there is anything I can do about the noise.
The pictures were taken using a Nikon D200 with 18-200mm, ISO100 and f/8.
I have been told that it is the number of pixels that gives me all this noise and although I have noticed how well newer SLRs perform in low light I'm still wondering if buying a new body is the solution to get pictures like this one less noisier.
Noise in HDR photographs is usually caused by at least one of two factors:
1. A lot of noise in the original source photographs, for example if you are shooting at a very high ISO, and taking those files directly into your HDR software. Most HDR software does relatively poor noise reduction on source files.
2. Insufficient bracketing on the source photos for the amount of dynamic range you are trying to represent in the final image, requiring the HDR software to significantly pull up shadow detail from the depths of even the brightest bracketed shot.
In this case, I suspect that the second factor is the biggest issue causing noise in this particular shot. While the D200 does not have a remarkable sensor by today's standards, it still has very respectable noise performance at lower ISOs, and this was shot at ISO 100.
The original scene that you shot here looks to me to have had a great deal of dynamic range -- you have captured highlight detail out of the door, which appears to be of a bright sunny day, and yet the only light sources for the interior appear to be from the door and reflected light from a window we can't see upstairs. However, when processing the shot you are trying to reveal shadow and texture detail in areas like the staircase, which look to have very little direct light hitting them and would therefore be in extreme darkness compared to the sunlight visible through the door.
With such a wide dynamic range to capture, a bracketing of -1, 0 and +1 EV is really very minor, giving you only two stops more dynamic range than you'd get with a single raw file from your camera. While this is better than nothing, I suspect that this was not really sufficient to capture all of the range in the original scene. You can check this by looking at the brightest file (+1 EV) and seeing how much visible texture and detail you have in the shadow areas of the scene -- those areas should be fully brightly exposed, not deep in the shadows of the brightest file.
If those areas are still in shadow in the brightest file, then the HDR software is having to heavily boost the shadows from this file, which will always bring significant noise into the final shot, regardless of your camera. While newer cameras do also have more dynamic range, allowing more recovery from shadow areas without excessive noise, for the best results in HDR with any camera you need to make sure you have every aspect of the scene properly exposed in one of the files.
I suspect (and again, without being there or seeing the pre-HDR'd files I can't say absolutely) that the solution here would have been to either take more bracketed shots, or to bracket shots with a larger gap in exposure values, or ideally both. In a scene like this I would probably have taken a total of 7 shots, either at EV -3, -2, -1, 0, 1, 2, 3, or if necessary going one step further at -4, -2.6, -1.3, 0, 1.3, 2.6, 4. This would have given me either 6 or 8 stops of extra dynamic range over that of a single photograph for the HDR software to work with, allowing it to find a file with well-exposed, noiseless data even when it needed information from the darkest shadows of the scene.
Most older cameras only allow automatic bracketing of three shots, so if you want to do more shots, you need to control the camera manually. You can also do a bigger bracketing with the three shots you have, for example -2, 0, 2, which would give you 4 stops of extra dynamic range and given the HDR software a file with much brighter shadow detail to work with. Be careful though, if you make the gaps too big between the bracketed shots it can cause other quality issues -- I wouldn't personally go much above 2 stops between each shot, preferring to do more shots instead.
The final thing to be careful of is that your HDR bracketing is actually covering a useful area. For example, it's not much use doing 7 bracketed shots if your base exposure means that 6 of them are so dark that they can only be used for highlight information. When taking HDR bracketed shots of any kind, to get the most usable data it's best to look at the histogram for the darkest shot you have taken and make sure that it's just avoiding clipping the highlights in the brightest part of the image. ('Blinkies', or highlight alerts, can also be useful here) This means that you have a full range of highlight detail in the darkest shot, and your brighter shots will now give you more and more shadow detail in each one. If your darkest shot has even the highlights a long way from the right edge of the histogram, then your base exposure is underexposed.
Hopefully that makes sense, please do ask if you have questions. Unfortunately, like almost anything photographic, although HDR seems simple on the surface, getting the best results is a bit more tricky. However, I'd urge you not to simply throw money at the issue, as while a newer camera might help mask these problems, your D200 is almost certainly not the root cause of them.
In the meantime, if you are shooting the component shots in raw and have Photoshop, Lightroom or any other raw processing software, you can reduce the noise by doing the following steps:
1. Open the component bracketed raw files in your raw processing software.
2. Temporarily boost the exposure on all the shots by +3 using the exposure slider. (This will make them seem abnormally bright, but will show all of the shadow noise)
3. Use the raw processor's noise reduction tools as gently as possible to remove as much noise as possible from the darkest areas of each photo.
4. Reset the exposure slider to the default setting for all photos.
5. Export the files as 16-bit TIFF files, and use these as the source files in your HDR processing software.
Temporarily boosting the exposure shows all of the noise in the shadows of your files, and allows you to do as much removal of it prior to it going to the HDR software. If you've removed the noise well, the resultant HDR file should be considerably smoother.
@abirkill Thanks very much Alexis! This makes perfect sense. I have simply used the -1, 0, +1 without even considering the histogram, going for the light at the door. Also the technique for noise removal will help, I saved the results in ipeg which I could not use in Photomatix.
You have saved me money and time with this superb mini-course. Thanks for all your effort. Since I really like this urbex photography but cannot find abandoned places closeby, I'll practice what you have learned me in the office before people will turn up for work.
As Alexis @abirkill suggested, +1, 0, -1 EV three-bracket is really not worth the effort. Something like Photoshop ACR/Lightroom Process 2012 will do a significantly better job in the basic panel to recover shadows and boost highlights on either the 0 or -1 image than going through the machinations of HDR, even something dedicated like Photomatix, on such minimal EV ranges.
Yes, you have to shoot not blowing the highlights completely away, but with enough shadow detail lurking that can be recovered, and that can take some work especially with older, less sensitive technology. The newer Nikon cameras (undoubtedly other vendors just the same but I can't speak from experience there) do a much better job of this than the D200, in fact are designed specifically to do a better job of exactly this. The D750 and D810 specifically have introduced a "highlight weighted" metering mode, which in conjunction with the superb sensor technology can be made to shoot exactly this way practically automatically. Here's an example of a single frame, shot and processed exactly this way that even a few years ago would have required careful HDR bracketing and merging. http://365project.org/frankhymus/365/2014-10-29
Here's another (single frame) shot this way that has just too wide a lightness gamut, even with all the technology, and you see the "noise" being sucked into the shadows as they are raised. A big 7 bracket separated by maybe even 1 1/3 or 1 2/3 EV definitely needed, exactly as Alexis mentions too, with a super stable tripod. http://365project.org/frankhymus/365/2014-10-27
The lens, too, has a lot to do with the success of this strategy, or even a "wide" HDR. The Nikkor 18-200 is not really the sharpest puppy on the street. The first above was shot with the super sharp Tamron f/2.8 24-70 (the Nikkor 24-70 f/2.8 even better) paired to the D810, and the detail just popped out. Part of the failure of the second could also be attributed to the lens, the 10.5mm Nikkor fisheye, not the greatest performer in low light. Not designed to be of course, I really pushed it way too far. A DX lens on a full frame body to boot, losing 50% of the available pixels right there, I really should have mounted this up on my D7100 to start with, a really superb "shadow detail" performer too, by the way, for less than $1,000 right now.
I normally would not point to the camera body, but the D200 is 10 year old technology, and is rated at max ISO 1600, two stops below even the mid range current D5300, and three below (5 with "hi" boost) the D810/D750 bodies. I would suggest that Alexis' point number (1), the native ISO performance, might really be a contributing factor as well.
@danette@pamknowler@abirkill@frankhymus Thanks for all your advise. I know what to do now. I'll stick with the D200 and Nikkor 18-200mm untill I outgrow the hardware, which will take a long time I guess. In the meantime I'll practice HDR with the very useful tips provided. Thanks a lot!
@hjv Sorry for hijacking your thread @abirkill Wow Alexis, as always thanks for the amazing advice. I am just beginning to dip my toe into the world of HDR but as so many of my images have people and therefore movement in them I have only been able to do a single shot and even then the ISO has been around 800 which on a 7D is pants. Any advice on HDR and people in low light?
I had a D200 for ages. A great camera, actually, but it could be a bit noisy, although generally OK in good light at ISO100. Very noticeable in low light and in HDR, though. I upgraded to a later model and found it much improved, even though I was using the same lenses
@jo13 Unfortunately my advice for HDR with moving subjects is pretty much limited to 'don't do it'! :)
As you've seen, any kind of subject movement in between the component HDR shots results in ghosting which is pretty much impossible to remove without very intensive work in Photoshop.
Some HDR packages, such as Photomatix, do have automatic and/or manual deghosting modes. These detect, either automatically or by you drawing an area on the photo, areas of movement between the HDR shots, and force the software to use a single exposure to fill in these parts of the photo, but the results are seldom particularly impressive, with either a patch of heavy noise from a dark exposure being lightened and used in the corrected area, or overblown highlights and other weirdness from a light exposure being darkened and used in the corrected area.
I used Photomatix deghosting to fix the flag in this photo, which worked very well, but unfortunately this is one of a very few times where the output has been particularly usable for me.
As most of your people shots are posed portraits rather than street shots with people walking through them (correct me if I'm wrong), you do at least have a subject that's relatively still and listening to instructions. You can try and persuade your subject to hold extremely still, while doing a burst covering a reasonably wide range in a small number of shots (for example, -2, 0, 2 EV). The fast framerate of your 7D will rattle these off pretty quickly, so you may be able to get away without too much noticeable subject movement if the subject is advised to stay still throughout the burst, rather than moving after the first shot (or giggling at the paparazzi-like sound coming from your camera ;) )
You will still need to use a high ISO to make sure all the shots (particularly the most brightly-exposed shot) are taken quickly. However, HDR can actually reduce noise when done carefully. I am very reluctant to shoot single exposures on my camera at over ISO 400, but will happily do HDR shots at ISO 1600, because if you are doing a wide enough bracket, the HDR software will pick the best-exposed and least noisy sections from each photo.
Do experiment, but I fear that fundamentally you may struggle to get the results you're hoping with by HDRing shots of people or other moving objects. Unfortunately this is probably an area where more equipment, rather than HDR, may end up being the necessary approach for the results you are hoping for. I'd probably suggest that some combination of very fast (wide-aperture) lenses to allow you to use as low an ISO as possible, bringing your own fill light to the scene rather than relying solely on ambient light, or adding a camera with excellent high ISO performance like a 6D to your kit, may need to be considered to get you to where you want to be with these types of photo.
@abirkill As usual your knowledge amazes me and can't thank you enough for sharing. I have taken all your advice on board and will give what I can a go.
RE people in shots... if you have the option and there's only a few people, try waiting for them to move along, after all if you have to wait 5 minutes for a clean shot and you're NEVER coming back here... why not? Alternatively, politely ask them if they mind moving along for a couple of minutes while you grab the shot and then let them get back to their business
Last option, you could edit them out of the images before HDRing?
@abirkill Hi Alexis. I've just taken your advise to the extreme. Taking a sequence of pictures of my living room lit by a few bright spots. I have been using a Nikon Coolpix P7100, a camera I like very much, but that is even under good light conditions rather noisy. I've taken a sequence of 18 pictures, taking care of the histogram. Denoised all the pictures and then fed them into Photomatix. A little sharpening afterwards and that resulted in a great shot (technically) without noise! Thanks again!
@hjv That's great, if you can get results you're happy with from the P7100 (which I agree is quite noisy in a single shot) then with any luck you'll have no trouble with your D200. Glad I could help! :)
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1. A lot of noise in the original source photographs, for example if you are shooting at a very high ISO, and taking those files directly into your HDR software. Most HDR software does relatively poor noise reduction on source files.
2. Insufficient bracketing on the source photos for the amount of dynamic range you are trying to represent in the final image, requiring the HDR software to significantly pull up shadow detail from the depths of even the brightest bracketed shot.
In this case, I suspect that the second factor is the biggest issue causing noise in this particular shot. While the D200 does not have a remarkable sensor by today's standards, it still has very respectable noise performance at lower ISOs, and this was shot at ISO 100.
The original scene that you shot here looks to me to have had a great deal of dynamic range -- you have captured highlight detail out of the door, which appears to be of a bright sunny day, and yet the only light sources for the interior appear to be from the door and reflected light from a window we can't see upstairs. However, when processing the shot you are trying to reveal shadow and texture detail in areas like the staircase, which look to have very little direct light hitting them and would therefore be in extreme darkness compared to the sunlight visible through the door.
With such a wide dynamic range to capture, a bracketing of -1, 0 and +1 EV is really very minor, giving you only two stops more dynamic range than you'd get with a single raw file from your camera. While this is better than nothing, I suspect that this was not really sufficient to capture all of the range in the original scene. You can check this by looking at the brightest file (+1 EV) and seeing how much visible texture and detail you have in the shadow areas of the scene -- those areas should be fully brightly exposed, not deep in the shadows of the brightest file.
If those areas are still in shadow in the brightest file, then the HDR software is having to heavily boost the shadows from this file, which will always bring significant noise into the final shot, regardless of your camera. While newer cameras do also have more dynamic range, allowing more recovery from shadow areas without excessive noise, for the best results in HDR with any camera you need to make sure you have every aspect of the scene properly exposed in one of the files.
I suspect (and again, without being there or seeing the pre-HDR'd files I can't say absolutely) that the solution here would have been to either take more bracketed shots, or to bracket shots with a larger gap in exposure values, or ideally both. In a scene like this I would probably have taken a total of 7 shots, either at EV -3, -2, -1, 0, 1, 2, 3, or if necessary going one step further at -4, -2.6, -1.3, 0, 1.3, 2.6, 4. This would have given me either 6 or 8 stops of extra dynamic range over that of a single photograph for the HDR software to work with, allowing it to find a file with well-exposed, noiseless data even when it needed information from the darkest shadows of the scene.
Most older cameras only allow automatic bracketing of three shots, so if you want to do more shots, you need to control the camera manually. You can also do a bigger bracketing with the three shots you have, for example -2, 0, 2, which would give you 4 stops of extra dynamic range and given the HDR software a file with much brighter shadow detail to work with. Be careful though, if you make the gaps too big between the bracketed shots it can cause other quality issues -- I wouldn't personally go much above 2 stops between each shot, preferring to do more shots instead.
The final thing to be careful of is that your HDR bracketing is actually covering a useful area. For example, it's not much use doing 7 bracketed shots if your base exposure means that 6 of them are so dark that they can only be used for highlight information. When taking HDR bracketed shots of any kind, to get the most usable data it's best to look at the histogram for the darkest shot you have taken and make sure that it's just avoiding clipping the highlights in the brightest part of the image. ('Blinkies', or highlight alerts, can also be useful here) This means that you have a full range of highlight detail in the darkest shot, and your brighter shots will now give you more and more shadow detail in each one. If your darkest shot has even the highlights a long way from the right edge of the histogram, then your base exposure is underexposed.
Hopefully that makes sense, please do ask if you have questions. Unfortunately, like almost anything photographic, although HDR seems simple on the surface, getting the best results is a bit more tricky. However, I'd urge you not to simply throw money at the issue, as while a newer camera might help mask these problems, your D200 is almost certainly not the root cause of them.
In the meantime, if you are shooting the component shots in raw and have Photoshop, Lightroom or any other raw processing software, you can reduce the noise by doing the following steps:
1. Open the component bracketed raw files in your raw processing software.
2. Temporarily boost the exposure on all the shots by +3 using the exposure slider. (This will make them seem abnormally bright, but will show all of the shadow noise)
3. Use the raw processor's noise reduction tools as gently as possible to remove as much noise as possible from the darkest areas of each photo.
4. Reset the exposure slider to the default setting for all photos.
5. Export the files as 16-bit TIFF files, and use these as the source files in your HDR processing software.
Temporarily boosting the exposure shows all of the noise in the shadows of your files, and allows you to do as much removal of it prior to it going to the HDR software. If you've removed the noise well, the resultant HDR file should be considerably smoother.
You have saved me money and time with this superb mini-course. Thanks for all your effort. Since I really like this urbex photography but cannot find abandoned places closeby, I'll practice what you have learned me in the office before people will turn up for work.
Yes, you have to shoot not blowing the highlights completely away, but with enough shadow detail lurking that can be recovered, and that can take some work especially with older, less sensitive technology. The newer Nikon cameras (undoubtedly other vendors just the same but I can't speak from experience there) do a much better job of this than the D200, in fact are designed specifically to do a better job of exactly this. The D750 and D810 specifically have introduced a "highlight weighted" metering mode, which in conjunction with the superb sensor technology can be made to shoot exactly this way practically automatically. Here's an example of a single frame, shot and processed exactly this way that even a few years ago would have required careful HDR bracketing and merging. http://365project.org/frankhymus/365/2014-10-29
Here's another (single frame) shot this way that has just too wide a lightness gamut, even with all the technology, and you see the "noise" being sucked into the shadows as they are raised. A big 7 bracket separated by maybe even 1 1/3 or 1 2/3 EV definitely needed, exactly as Alexis mentions too, with a super stable tripod. http://365project.org/frankhymus/365/2014-10-27
The lens, too, has a lot to do with the success of this strategy, or even a "wide" HDR. The Nikkor 18-200 is not really the sharpest puppy on the street. The first above was shot with the super sharp Tamron f/2.8 24-70 (the Nikkor 24-70 f/2.8 even better) paired to the D810, and the detail just popped out. Part of the failure of the second could also be attributed to the lens, the 10.5mm Nikkor fisheye, not the greatest performer in low light. Not designed to be of course, I really pushed it way too far. A DX lens on a full frame body to boot, losing 50% of the available pixels right there, I really should have mounted this up on my D7100 to start with, a really superb "shadow detail" performer too, by the way, for less than $1,000 right now.
I normally would not point to the camera body, but the D200 is 10 year old technology, and is rated at max ISO 1600, two stops below even the mid range current D5300, and three below (5 with "hi" boost) the D810/D750 bodies. I would suggest that Alexis' point number (1), the native ISO performance, might really be a contributing factor as well.
As you've seen, any kind of subject movement in between the component HDR shots results in ghosting which is pretty much impossible to remove without very intensive work in Photoshop.
Some HDR packages, such as Photomatix, do have automatic and/or manual deghosting modes. These detect, either automatically or by you drawing an area on the photo, areas of movement between the HDR shots, and force the software to use a single exposure to fill in these parts of the photo, but the results are seldom particularly impressive, with either a patch of heavy noise from a dark exposure being lightened and used in the corrected area, or overblown highlights and other weirdness from a light exposure being darkened and used in the corrected area.
I used Photomatix deghosting to fix the flag in this photo, which worked very well, but unfortunately this is one of a very few times where the output has been particularly usable for me.
As most of your people shots are posed portraits rather than street shots with people walking through them (correct me if I'm wrong), you do at least have a subject that's relatively still and listening to instructions. You can try and persuade your subject to hold extremely still, while doing a burst covering a reasonably wide range in a small number of shots (for example, -2, 0, 2 EV). The fast framerate of your 7D will rattle these off pretty quickly, so you may be able to get away without too much noticeable subject movement if the subject is advised to stay still throughout the burst, rather than moving after the first shot (or giggling at the paparazzi-like sound coming from your camera ;) )
You will still need to use a high ISO to make sure all the shots (particularly the most brightly-exposed shot) are taken quickly. However, HDR can actually reduce noise when done carefully. I am very reluctant to shoot single exposures on my camera at over ISO 400, but will happily do HDR shots at ISO 1600, because if you are doing a wide enough bracket, the HDR software will pick the best-exposed and least noisy sections from each photo.
Do experiment, but I fear that fundamentally you may struggle to get the results you're hoping with by HDRing shots of people or other moving objects. Unfortunately this is probably an area where more equipment, rather than HDR, may end up being the necessary approach for the results you are hoping for. I'd probably suggest that some combination of very fast (wide-aperture) lenses to allow you to use as low an ISO as possible, bringing your own fill light to the scene rather than relying solely on ambient light, or adding a camera with excellent high ISO performance like a 6D to your kit, may need to be considered to get you to where you want to be with these types of photo.
Last option, you could edit them out of the images before HDRing?