First try at HDR = lessons learned.

[Dave A]

I've been wanted to try HDR so this morning I gave it a try while knowing it would be more a learning experience than producing a quality image. This final image is not good but I did learn a few things that I will not repeat. This was shot handheld combining 5 exposures at one stop apart. Five fast exposures while hand holding the camera does not produce a sharp final product, lesson one. I also found out that more harm than good comes from playing too much with the HDR software controls, lesson two. Once I get the hang of it I'm hoping for a more natural look. The next HDR image I post somewhere in the future will be a big improvement I promise.

Dave

[Shadowman]

The first thought that comes to my mind is: does this shot need HDR treatment at all? I don't think there is anything within this composition that couldn't be captured in one shot, perhaps you felt the tonemapping might give it a bit more punch?

[Dave A]

The first thought that comes to my mind is: does this shot need HDR treatment at all? I don't think there is anything within this composition that couldn't be captured in one shot, perhaps you felt the tonemapping might give it a bit more punch?

You are correct John in that this image could probably be captured in a single shot. I just wanted to try HDR capture and processing to see how it was done and if I could make the snowshoes jump off the page.

Dave

[IzzieK]

Actually, how many images does not one need to be able to do an HDR effect? Just curious...

[Shadowman]

Actually, how many images does not one need to be able to do an HDR effect? Just curious...

Depends on the camera and the subject, some cameras have a better capability of capturing a dynamic range so fewer stops may be needed. If you can safely capture the highlights and shadows within one shot then no need to increase unless like Dave you are experimenting.

[Manfred M]

Actually, how many images does not one need to be able to do an HDR effect? Just curious...

A few of us are discussing this right now on another thread (recent postings towards the end of the thread).


HDR Bracketing: One or two stops?

[dem]

Actually, how many images does one need to be able to do an HDR effect? Just curious...

Assuming that "High" means more than 8 stops, at least one raw or at least two JPEGs are required for HDR. If the dynamic range of the scene is less than 8 stops, there is no need/room for HDR.

[Donald]

Assuming that "High" means more than 8 stops, at least one raw or at least two JPEGs are required for HDR. If the dynamic range of the scene is less than 8 stops, there is no need/room for HDR.

Dem - Not sure what you're meaning here.

If someone is doing HDR photography it means that the dynamic range is wider than can be captured on one frame. Therefore, it cannot be that you can carry out the HDR technique with only one frame, RAW or not.

If you are meaning that you can use one RAW file and adjust the exposure and then make different images to blend, that is quite another thing. It is not HDR technique.

Unfortunately the term HDR has been hijacked over a number of years and definitions attached to it that are not what HDR is about. I think it causes quite a bit of confusion. I would like to see us adopt another word or phrase for the action that I think you are meaning. 'Tonemapping' never seems to have successfully captured broader attention as the descriptor for adjusting exposures and tones in an image

[Manfred M]

Assuming that "High" means more than 8 stops

Most modern cameras have no issues in capturing around 12 stops at base ISO. Mine (Nikon D800) apparently does 14.4 stops and the top contenders are getting close to 15 stops. This value drops as you turn up the ISO setting; so while at maximum ISO, this drops to the 7-stop range on my D800.

If you want to know what your camera can do check at the DxO Labs website: http://www.dxomark.com/.

To my simple mind, high dynamic range is whenever the dynamic range in the scene you are shooting exceeds you camera's ability to record it in a single exposure at the ISO setting you are using.

[IzzieK]

A few of us are discussing this right now on another thread (recent postings towards the end of the thread).


HDR Bracketing: One or two stops?

Thanks for the link..I've noticed the thread but I am not into HDR yet...maybe if I read some I will be interested to move on to it...one day...

[xpatUSA]

Most modern cameras have no issues in capturing around 12 stops at base ISO. Mine (Nikon D800) apparently does 14.4 stops and the top contenders are getting close to 15 stops. This value drops as you turn up the ISO setting; so, at maximum ISO, it drops to the 7-stop range on my D800.

Modern cameras appear to be pretty impressive indeed in that regard.

Ever-curious and as an aside, I looked up my cheap NEC monitor's maximum contrast which is 1500:1. That corresponds to 10.55 stops - meaning that, if were to show a perfect D800 image on my monitor, I would lose almost 4 stops-worth of tonal levels

Not only that but, as my monitor sits in a semi-dark area, my "brightness" control is set down to 75% so - assuming the black level is not altered - there goes another half-stop or so

Makes me glad not to own a D800 - for 14.4 stops, I would need a monitor maximum static contrast of 21,620 and the brightness cranked to max . . . ouch!

All food for pedantic thought - but I can't help feeling that there's something wrong with my logic . . .

If you want to know what your camera can do check at the DxO Labs website: http://www.dxomark.com/

Went there to look mine up, only to discover what I call "The Gap". That's where any 'list of support cameras' or site search engine goes straight from Samsung to Sony with no mention of Sigma. Always the underdog, whine, whine . . .

To my simple mind, high dynamic range is whenever the dynamic range in the scene you are shooting exceeds you camera's ability to record it in a single exposure at the ISO setting you are using.

+1 to that.

[dem]

.

[dem]

If you are meaning that you can use one RAW file and adjust the exposure and then make different images to blend, that is quite another thing. It is not HDR technique.

Thank you Donald, this is exactly what I had in mind. I guess "the HDR effect" and "HDR technique" are not the same thing and I was simply thinking of capturing a scene with a dynamic range that is greater than about 8 stops normally associated with the DR of a JPEG image.

In a couple of years Panasonic and Fuji are going to get their organic sensor out with a DR of 29 stops. Will we be still combining exposures? Probably not. The tone mapping however will still be a big part of image processing as it is now, i.e. adjusting shadows and highlights when processing raw files.

I just read through these two good links

https://www.cambridgeincolour.com/tu...amic-range.htm
https://www.hdrsoft.com/resources/dri.html

and I cannot agree with everything they say. Perhaps incorrectly I did not associate HDR imaging with a 32-bit data format but with the style and the look (aggressive local tone mapping = bad HDR, clean shadows and highlights = good HDR) of the actual image, mainly in JPEG format as viewed on a computer monitor.

[dje]

Modern cameras appear to be pretty impressive indeed in that regard.

Ever-curious and as an aside, I looked up my cheap NEC monitor's maximum contrast which is 1500:1. That corresponds to 10.55 stops - meaning that, if were to show a perfect D800 image on my monitor, I would lose almost 4 stops-worth of tonal levels

Not only that but, as my monitor sits in a semi-dark area, my "brightness" control is set down to 75% so - assuming the black level is not altered - there goes another half-stop or so

Makes me glad not to own a D800 - for 14.4 stops, I would need a monitor maximum static contrast of 21,620 and the brightness cranked to max . . . ouch!

All food for pedantic thought - but I can't help feeling that there's something wrong with my logic . . .

Nothing wrong with your logic Ted. This is why (global) tone mapping is required even for non-HDR images. With ACR for example, a power law response curve similar to but not the same as a gamma curve is applied when the Adobe camera profile is selected. This causes the histogram to shift towards the right. This, in conjunction with contrast enhancement, avoids a very flat and dull look to the image on the display.

The same situation applies to film and digital prints ie the DR of the viewing medium is less than that of the scene. Film had a tone curve built in (chemically) I believe.

Not all scenes require the full DR of the camera anyway, particularly if they are fully reflective light scenes.

Dave

[ucci]

Okay, having been totally bamboozled by all the high tech comments posted above, my brain really hurts. But I did manage to recall a pearl ( probably an imitation one, knowing my luck! ) comment in a video on line all about HDR which suggested that before you meander down the track of HDR shooting, maybe take a test shot, check your Histogram, and from the spread across it then decide whether or not a trip down the HDR trail is required. The message seemed to be the use of HDR for its own sake, rather than need, is a pointless exercise. But then again, what would I know, being just a geriatric street kid?

[Donald]

The message seemed to be the use of HDR for its own sake, rather than need, is a pointless exercise.

Just shows that bambozzled, geriatric street kids with sore brains can get to the crux of the issue straightforwardly and simply.

[MrB]

Okay, having been totally bamboozled by all the high tech comments posted above, my brain really hurts....The message seemed to be the use of HDR for its own sake, rather than need, is a pointless exercise.

I agree - although interesting, it's almost like trying to read a foreign language without even the 'help' of Google translate! However, just trying to clarify the thoughts of another probably addled brain - sort of trying to think aloud here:

If a camera sensor has a dynamic range of 14 and the scene being captured has a dynamic range of 14, presumably a single well-exposed shot will contain all the detail from shadows to highlights? But if our common methods of viewing are generally limited to a dynamic range of about 8 - does that mean there are about 3 stops at each end of the range that would appear as black or white, so we would need to lower highlights and lift shadows in processing to see the detail in those areas?

If that is so, wouldn't that process increase the shadow area noise? So, even though the scene is within the range of the sensor, wouldn't it be better to use the HDR technique (at low ISO) to merge in an exposure where shadow detail is already in the visible viewing range?

Please forgive me if this is nonsense, and try to keep any helpful replies simple - thank you!

Cheers.
Philip

[xpatUSA]

I've been wanted to try HDR so this morning I gave it a try while knowing it would be more a learning experience than producing a quality image. This final image is not good but I did learn a few things that I will not repeat.

Dave

Looking again, I would probably erase that modern lock which jars with ye olde-fashioned snow-shoes. And of course that blue discoloration on some edges and the grass (unless it's bluegrass ;-).

[xpatUSA]

If a camera sensor has a dynamic range of 14 and the scene being captured has a dynamic range of 14, presumably a single well-exposed shot will contain all the detail from shadows to highlights?

Hi Philip,

Yes and no. As always in photography, "dynamic range" has several definitions i.e methods of both calculation and of measurement. The one for a scene is difference than the one for your camera. Even worse, if you go to DXOmark and to DPR you will get totally different numbers for the same camera . . 14 stops at the one site and maybe 9 stops at the other

But if our common methods of viewing are generally limited to a dynamic range of about 8 - does that mean there are about 3 stops at each end of the range that would appear as black or white, so we would need to lower highlights and lift shadows in processing to see the detail in those areas?

Correct, as I said earlier:

. . . I looked up my cheap NEC monitor's maximum contrast [which corresponds to 10.55 stops] - meaning that, if were to show a perfect [14.4 stop] D800 image on my monitor, I would lose almost 4 stops-worth of tonal levels

If that is so, wouldn't that process increase the shadow area noise? So, even though the scene is within the range of the sensor, wouldn't it be better to use the HDR technique (at low ISO) to merge in an exposure where shadow detail is already in the visible viewing range?

Same complaint, "noise" has many definitions but basically the noise becomes more visible even though it's ratio to the signal level doesn't change much.

[dje]

If a camera sensor has a dynamic range of 14 and the scene being captured has a dynamic range of 14, presumably a single well-exposed shot will contain all the detail from shadows to highlights? But if our common methods of viewing are generally limited to a dynamic range of about 8 - does that mean there are about 3 stops at each end of the range that would appear as black or white, so we would need to lower highlights and lift shadows in processing to see the detail in those areas?

If that is so, wouldn't that process increase the shadow area noise? So, even though the scene is within the range of the sensor, wouldn't it be better to use the HDR technique (at low ISO) to merge in an exposure where shadow detail is already in the visible viewing range?

Hi Philip

I think what you are suggesting in the first paragraph I quote above is that black and white clipping occurs. I don't believe this is the case. A pixel in the image whose RGB values are 0,0,0 will be produced as the closest to black that that the monitor can produce (the liquid crystal will always transmit a small amount of light even at black level). A pixel whose RGB values are 255, 255, 255 will be produced in the brightest shade of white the monitor can produce. All other RGB values will give light output from the display somewhere in between. It's just that the ratio of the brightest white to the lowest black is smaller when viewed on the display than it is in the original scene. This usually results in the image looking a little dull and flat. But a thorough understanding of this difference in perception is complex and way above my head.

This article may help describe the situation although it may have more detail than you want. It's about prints rather than LCD displays but the principle is the same.

I think this quote from the article sums it up quite well

"In order to create a photographic image that evokes some resemblance to the original scene, we need to compress some parts of the tone scale and stretch others. We may also use clipping on at least one end. Clearly this process is both subjective and image-dependent. There’s no universal right way, no formula or curve that will work for every image."

As far as lifting shadows is concerned (your second par I quote above), I guess it all depends how dark the shadows are to start with. Blending more than one image with different exposures could give better noise in the shadows but in many cases it simply isn't worth the trouble as lifting shadows in post gives quite satisfactory noise levels.

Dave