Has anyone published an explanation of how HWM really works? I have tried it several times but I am not comfortable using it - results are uncertain
Thanks
Thanks
Highlight Weighted Meter - what does it really do?
- Thread starter RichF
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SoCalRick
Well-known member
My understanding is that on the Z8/Z9 it tries to meter the brightest objects in the entire scene to near middle gray.
As I understand it, Nikon's Highlight Weighted Metering doesn't adjust such that the highlights are midtone (i.e. 18% reflectivity) but does identify the highlight areas and tries to keep them from being completely clipped. I haven't seen any published algorithms or numeric testing but based on my experience with it I'd guess it tries to limit the highlights to about a stop and a half to maybe two stops above midtone gray.
Here's a couple of articles about it with some examples and the recommendation that this works best when shooting raw and the potential need to then recover the shadow detail in post:
digital-photography-school.com
www.nikonusa.com
Personally I've used it a bit but only in fairly dynamic situations where things are changing fast enough and my subjects are moving around so much that it's tough to just dial in exposure compensation. IOW, things like a Bald Eagle or Osprey flying past changing backgrounds on a day where the light is also changing due to things like smaller clouds coming and going fairly quickly.
Those are tough shooting situations as the changing light discourages full manual mode with manually set ISO, the changing backgrounds and fast moving subjects makes exposure comp changes on the fly difficult and the subjects coming and going make it tough to take test shots and adjust based on the histogram or blinkies. In situations like that I'll still try to use exposure comp intelligently but can buy myself a bit of insurance on the brighter white feathers by switching to Highlight Weighted Metering. But when I do I expect to spend more time with each image in post as I'll likely have to pull up the shadow detail and possibly the overall exposure due to the biased metering.
Here's a couple of articles about it with some examples and the recommendation that this works best when shooting raw and the potential need to then recover the shadow detail in post:
How to Supercharge Your Photography with Highlight-Weighted Metering
If you shoot with a Nikon you may want to read this and try out Highlight-weighted metering mode if it's available on your camera.
digital-photography-school.com
Using the Highlight-Weighted Metering Mode
Learn when to use the Highlight-weighted metering mode that is featured in select Nikon DSLRs.
www.nikonusa.com
Personally I've used it a bit but only in fairly dynamic situations where things are changing fast enough and my subjects are moving around so much that it's tough to just dial in exposure compensation. IOW, things like a Bald Eagle or Osprey flying past changing backgrounds on a day where the light is also changing due to things like smaller clouds coming and going fairly quickly.
Those are tough shooting situations as the changing light discourages full manual mode with manually set ISO, the changing backgrounds and fast moving subjects makes exposure comp changes on the fly difficult and the subjects coming and going make it tough to take test shots and adjust based on the histogram or blinkies. In situations like that I'll still try to use exposure comp intelligently but can buy myself a bit of insurance on the brighter white feathers by switching to Highlight Weighted Metering. But when I do I expect to spend more time with each image in post as I'll likely have to pull up the shadow detail and possibly the overall exposure due to the biased metering.
This type of metering is primary intended for a spotlight artist on a stage where the artist is lit by spotlights to distinctly brighter than the background.
An matrix meter reading should to a reasonably extent bias exposure toward the darker areas of the stage - to some extent over exposing the artist from an ideal exposure level.
Slightly off topic spotlighting an artist is usually to encourage the audience to concentrate on the performer lit by the spotlights - a bit like deciding where to place highlights and shadows in a photograph.
This type of highlight metering biases a medium level exposure to that of the highlighted Artist rather than the average for the scene.
The best way IMO to find out when this type of metering is useful is to take test photos
Off topic and perhaps nit picking - even Kodak say 18% reflectance is brighter than a mid tone - whatever Zone System enthusiasts might proclaim.
At around 100 ISO most cameras have about 12 stops dynamic range.
18% reflectance is about 2.33 stops darker than pure white - about 9.5 on a dynamic range scale - and definitely not a mid tone when 12 stops dynamic range can be recorded.
When shooting at very high ISO's with dynamic range reduced to maybe 6 stops,18% might have some relevance - recognising Kodak when they published Professional Photoguide's allocated 15-30% reflectance to a medium light tone - in an era when 8 stops dynamic range was about right for black and white film in an average camera.
An matrix meter reading should to a reasonably extent bias exposure toward the darker areas of the stage - to some extent over exposing the artist from an ideal exposure level.
Slightly off topic spotlighting an artist is usually to encourage the audience to concentrate on the performer lit by the spotlights - a bit like deciding where to place highlights and shadows in a photograph.
This type of highlight metering biases a medium level exposure to that of the highlighted Artist rather than the average for the scene.
The best way IMO to find out when this type of metering is useful is to take test photos
Off topic and perhaps nit picking - even Kodak say 18% reflectance is brighter than a mid tone - whatever Zone System enthusiasts might proclaim.
At around 100 ISO most cameras have about 12 stops dynamic range.
18% reflectance is about 2.33 stops darker than pure white - about 9.5 on a dynamic range scale - and definitely not a mid tone when 12 stops dynamic range can be recorded.
When shooting at very high ISO's with dynamic range reduced to maybe 6 stops,18% might have some relevance - recognising Kodak when they published Professional Photoguide's allocated 15-30% reflectance to a medium light tone - in an era when 8 stops dynamic range was about right for black and white film in an average camera.
I use the HWM mode for airplanes in a direct sunlight as there is a lot of reflected light from small but significant areas along wing edges in such scenario.
The net effect seems to be similar to negative exposure compensation, with camera automatically applying it when there are clipped highlights in the frame. But it does not work perfectly for me. If there are very strong and very localized reflections present, they are still overblown without manual compensation applied.
The net effect seems to be similar to negative exposure compensation, with camera automatically applying it when there are clipped highlights in the frame. But it does not work perfectly for me. If there are very strong and very localized reflections present, they are still overblown without manual compensation applied.
I use HWM all the time - it's handy when you're in a situation where you want to stay in Autoexpsoure mode due to varying light levels (like some random combination of sun, shade, and clouds) and the background tonality and / or light is all over the place. (I'm thinking of terrestrial backgrounds since I don't often shoot against the sky - too boring).
Normally when you have varying backgrounds, just popping into full manual mode is the key, but in the scenario above the varying light levels make that less than practical. In some cases - like if the bird is going from sun to shade - you'd have to adjust exposure constantly as the bird was flying.
Of course, with varying light levels autoexposure is often a good way to go - but the varying backgrounds mean that it's likely to overexpose when the bird is on the darker backgrounds.
That's where HWM comes in handy.
When the bird is in the sun against a darker background, the camera wants to blow it out. HWM will prevent that.
When the bird is against a middle-tone background, HWM acts like matrix metering.
The trick is that HWM will sometimes underexpose a little more than we'd like, but with ISO invariant cameras it's easy enough to bump up exposure in post. The biggest trick is you don't want that bird against a sky in HWM - it's drop everything to middle tone gray. However, against terrestrial backgrounds it can work really well to keep highlights in check (and it doesn't have to be a white bird, I was just using it as an example).
Oh, and it also works well for strong backlight. I was in FL last month and had some strong backlight to deal with. The birds were flying in and out of shadow and the amount of backlight was all over the place and the intensity of the light varied constantly. HWM saved the day. Although some of the images were on the darker side, it was easy enough to bring them back in post. (As a side note, in strong backlight it's often a good idea to switch the camera to HWM and View Mode to "Ease Of Viewing" since it can make the viewfinder really dark. Just remember to switch it back to "Show Effects Of Settings" when you're done. Again, this is for strong backlight, not normal backlight.)
Normally when you have varying backgrounds, just popping into full manual mode is the key, but in the scenario above the varying light levels make that less than practical. In some cases - like if the bird is going from sun to shade - you'd have to adjust exposure constantly as the bird was flying.
Of course, with varying light levels autoexposure is often a good way to go - but the varying backgrounds mean that it's likely to overexpose when the bird is on the darker backgrounds.
That's where HWM comes in handy.
When the bird is in the sun against a darker background, the camera wants to blow it out. HWM will prevent that.
When the bird is against a middle-tone background, HWM acts like matrix metering.
The trick is that HWM will sometimes underexpose a little more than we'd like, but with ISO invariant cameras it's easy enough to bump up exposure in post. The biggest trick is you don't want that bird against a sky in HWM - it's drop everything to middle tone gray. However, against terrestrial backgrounds it can work really well to keep highlights in check (and it doesn't have to be a white bird, I was just using it as an example).
Oh, and it also works well for strong backlight. I was in FL last month and had some strong backlight to deal with. The birds were flying in and out of shadow and the amount of backlight was all over the place and the intensity of the light varied constantly. HWM saved the day. Although some of the images were on the darker side, it was easy enough to bring them back in post. (As a side note, in strong backlight it's often a good idea to switch the camera to HWM and View Mode to "Ease Of Viewing" since it can make the viewfinder really dark. Just remember to switch it back to "Show Effects Of Settings" when you're done. Again, this is for strong backlight, not normal backlight.)
thanks. helpful but to me HWM is a black boxAs I understand it, Nikon's Highlight Weighted Metering doesn't adjust such that the highlights are midtone (i.e. 18% reflectivity) but does identify the highlight areas and tries to keep them from being completely clipped. I haven't seen any published algorithms or numeric testing but based on my experience with it I'd guess it tries to limit the highlights to about a stop and a half to maybe two stops above midtone gray.
Here's a couple of articles about it with some examples and the recommendation that this works best when shooting raw and the potential need to then recover the shadow detail in post:
How to Supercharge Your Photography with Highlight-Weighted Metering
If you shoot with a Nikon you may want to read this and try out Highlight-weighted metering mode if it's available on your camera.
Using the Highlight-Weighted Metering Mode
Learn when to use the Highlight-weighted metering mode that is featured in select Nikon DSLRs.
Personally I've used it a bit but only in fairly dynamic situations where things are changing fast enough and my subjects are moving around so much that it's tough to just dial in exposure compensation. IOW, things like a Bald Eagle or Osprey flying past changing backgrounds on a day where the light is also changing due to things like smaller clouds coming and going fairly quickly.
Those are tough shooting situations as the changing light discourages full manual mode with manually set ISO, the changing backgrounds and fast moving subjects makes exposure comp changes on the fly difficult and the subjects coming and going make it tough to take test shots and adjust based on the histogram or blinkies. In situations like that I'll still try to use exposure comp intelligently but can buy myself a bit of insurance on the brighter white feathers by switching to Highlight Weighted Metering. But when I do I expect to spend more time with each image in post as I'll likely have to pull up the shadow detail and possibly the overall exposure due to the biased metering.
thanks. I'll try it
Agreed, the first time I tried HWM was with flying Osprey on a day when the light was constantly changing due to small clouds rolling through. HWM alone wasn't enough to save the bright white head feathers but adding a bit of negative exposure compensation along with HWM got the job done. Though as posted in this thread many of the images needed work in post to recover shadow detail.
IOW, I haven't found HWM alone all that useful but in very dynamic situations it can help a bit though it still pays to think about some exposure comp in tricky situations.
I also agree with the post that HWM was likely intended for things like spotlit stage performers and not really for the wildlife situations we encounter though like a lot of tools we find ways to apply them or figure out that they don't help much and ignore them.
EricKlees
Well-known member
I used it most of the time on my D850 and D500. It protects the highlights. For example, for a Bald Eagle, it looks at the scene and sees any white such as the white feathers, it will meter for the white feathers. With DSLRs, i would generally keep the meter from -.7 to +.7 or if you shoot Auto ISO, you would just dial in anywhere between -.7 to +.7 exposure comp.
If shooting in Auto ISO, it will adjust the ISO to properly expose the white feathers.
In essence, it will underexpose the scene. So knowing this you you shouldn't use for dark scenes or backlit subjects as it will expose for bright areas in the background.
With my Z9, i find zero use for HWM, I only use matrix meter. Especially with real time "blinkies" for blown highlights in the EVF in stills mode. It's virtually impossible to blow the highlights in a photo.
If shooting in Auto ISO, it will adjust the ISO to properly expose the white feathers.
In essence, it will underexpose the scene. So knowing this you you shouldn't use for dark scenes or backlit subjects as it will expose for bright areas in the background.
With my Z9, i find zero use for HWM, I only use matrix meter. Especially with real time "blinkies" for blown highlights in the EVF in stills mode. It's virtually impossible to blow the highlights in a photo.
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I find it useful for shooting spotlit animals at night on safari. The spotlights often are odd colors as well. Sometimes it does need some exposure comp but often it is pretty close as-is. For instance here is one of an Aardwolf I shot a few weeks ago in Botswana. This was with highlight-weighted metering on the Z9, -1/3EV
