HDR tips, please!

Yesterday I took this picture with lots of contrast between sky, sunny part of mountain and shade:


It obviously got me thinking of HDR, especially since my Gorillapod has just arrived.

My camera can auto-bracket up to +/- 1 EV, or I can manually set Exposure Compensation as high as +/- 2 EV. Should I use the simpler auto bracket, or the bigger range by adjusting manually?

I have not yet read much, at this stage I am not sure whether there is any advantage in shooting in RAW as opposed to JPEG?

Software -- Photomatix seems widely recommended, and the Light version is quite cheap. Any comments on Light vs Pro? Any other suggestions?

Mohamed Ellozy said:

Yesterday I took this picture with lots of contrast between sky, sunny part of mountain and shade:

It obviously got me thinking of HDR, especially since my Gorillapod has just arrived.

My camera can auto-bracket up to +/- 1 EV, or I can manually set Exposure Compensation as high as +/- 2 EV. Should I use the simpler auto bracket, or the bigger range by adjusting manually?

Click to expand...

HDR is a process of combining parts of the same scene taken at different exposures. IMO, it is better if you can avoid it.

Start with an image that is taken at the maximum exposure before you get blown out pixels. (Use the histogram to find this exposure. Some cameras will also flash any blown out pixels for you.) You can do this by bracketing or shoot, compensate, and repeat--whichever you prefer. Then adjust the density scale in post-processing to bring out the dark parts.

For instance, if I take your image and increase the gamma by 1.3, it brings out the detail in the trees. (Adjusting the gamma is one form of density scale modification.)

I have not yet read much, at this stage I am not sure whether there is any advantage in shooting in RAW as opposed to JPEG?

Click to expand...

Definitely. JPEG is limited to 8 bits-per-color-per-pixel. RAW usually has more (up to 14 or 16 depending on the hardware) and can do a better job of representing the detail in dark regions of the image. You will then have to process the image on your computer to produce a JPEG.

Many cameras can produce both simultaneously. If I'm not sure if I will need the RAW, I shoot both and choose later. (For instance, this shot of the moon was shot raw and processed to bring out the features. The moon is pretty low contrast and looks pretty dull without enhancement... http://mysite.verizon.net/dbpwebjunk/misc/moon-0649-lz.jpg )

Doug

Like DougPaul said, HDR is best avoided if possible, as it can create surreal images instead of a natural looking dynamic range. I have a friend who uses HDR heavily to create surreal artwork; interesting as art, but as photography I am not certain.

However, if you have a composition that is contrasty enough that you feel it is warranted, HDR can create some great images if used gently. Some situations in which I have used HDR are; a waterfall in a dark ravine with bright sunny sky above; a silhouette (of anything) against a sunset/sunrise, where I want to show the foreground detail; and architecture... houses, buildings, and other angled structures really seem to shine with a little extra dynamic range.

What EV values you use depend upon the situation. I find that +/- 1ev works fine in most situations, but it depends on the contrast you are encountering. If I have the time and think it is worth the effort, I will expose a long range from -2 to +2 in 1/2 increments, just to make sure I get the values I am looking for.

As for software, I've grown fond of Photomatix Pro. In this post (click here), I used Photomatix Pro with +1/-1 EV values on at least half of the photos (you can probably guess which ones). Whether or not this creates a natural or unnatural look or is desired or undesired is up to the beholder. I've heard opinions ranging from one extreme to the other.

Hope this helps a little bit. I'm still just playing a little bit with the whole thing.

I have to agree with the general sentiment expressed thus far about HDR. It's neat, but it rarely produces a natural effect without a tremendous amount of tweaking (and even then the effect is rarely better than what you'd get with a grad ND.)

Of course, I think that this is generally the case with landscape and nature photographers simply because they like the natural look. There's nothing wrong with it... it's just not a popular look in this type of photography.


In any case I've dabbled with it, but haven't tried many specialized programs. Photoshop has an option to merge to HDR that works pretty well.

As for RAW... Always, always, always shoot RAW. A DougPaul mentioned, the increase in color depth is well worth it, but the real beauty of RAW is that it doesn't produce a final raster image until you tell it to. Think of it as a digital negative rather than a print (JPEG.) It's a flawed analysis, but it gets the point across.

RAW is lossless whereas JPEG is lossy. With RAW, you can do things like losslessly (for the most part) change the white balance after shooting. You can also adjust exposure parameters with much greater freedom in processing.

I could go on, but I won't.
RAW is superior to JPEG in every single way but size and portability. As mentioned, shooting RAW + JPEG can be a good idea, too.


And I'll leave with one final thought. Even if you aren't planning to shoot HDR, bracketing is still a very good practice in any sort of high contrast situation as it allows you to manually blend two exposures. Bracketing can more or less serve as a much more versatile digital equivalent to a grad ND filter.

As an example:


That's a two exposure blend. I did one for the sky and one for the foreground. You can see precisely where the two meet by looking at the faint line across the ridge. If I wanted to, I could have created a mask and precisely tailored the sky exposure to the sky. I sometimes do that, but in this one I liked the look of what a grad ND would have looked like had I used one. I find sometimes that division makes a scene more interesting.

In any case, definitely bracket even if you don't shoot HDR. I've pulled off many shots that wouldn't otherwise be possible (without a GND, anyway) by bracketing.

Mohamed, I'll skip the technical stuff as the previous replies have covered that. My reply is of a subjective, aesthetic nature. I really like the picture you posted because of (not despite) the high contrast. My eyes are immediately drawn to the beautiful color of the peaks. And we know those peaks are that color only at the time of day when that foreground is in the "dark". I think brightening that foreground (either by ND grad filter, or by HDR) would detract from your nice photo.

Most of the HDR photos I've seen look like Thomas Kincaide (sp?) paintings, and that's not a compliment. Heck, I even think too many of the non-HDR photos I see are over-photoshopped. I like the natural look.

But a little bit of HDR (gently applied) can sometimes look cool. For instance, bringing out the color of wildflowers in the foreground while holding the sky from washing out.

I've done a bit of HDR with Photomatix and Enfuse, but only a couple times. And I haven't really liked the results I've gotten. I use ND grad filters most of the time.

The problem I have with common HDR is that it destroys local contrast. Grad filters are often described as removing contrast as well, but there are really two very different kinds of contrast in a photo. There's overall contrast, which is what you have in the first photo where a specific region is much darker than another region. Then there is textural contrast, which has to do with light and dark areas on the surface of things, like the side of a rough rock being lit by the sun from the side. You don't want to lose textural contrast because it defines 3-dimensionality, this is why HDR often appears flat.

If your DSLR is fairly new, you probably don't even need multiple exposures. Many newer DLSR sensors can hit 13 or 14 stops of dynamic range in RAW. This is usually enough to capture the full range of light and dark in a scene if the light is not too overpowering (like mid-day sun). What you can do import the RAW with +/- EV adjustments in the RAW software, and then treat them like separate exposures.

If I want multiple exposures, I usually blend them by hand. You can do this with layer masks in Photoshop. This way you don't lose any textural contrast, and you can be as precise as you want as far as how much to lighten or darken something. But it is time-consuming and can be a bit challenging at first. This is the technique closest to the burning and dodging they do in the photo lab with film.

My recommendation on the first photo would actually be to use a shorter exposure, let the foreground go black, bring a darker richer red color to the mountain summits, and preserve some blue in the sky. I think it might be more dramatic in this case.

Before any of this, think about composition first. People get carried away taking a "picture of something" instead of seeing the whole picture as the way different things interact together. This means, think not only about capturing the glow on the mountain summits, but what else you want in the photo that will balance the composition.

Technetium said:

If your DSLR is fairly new, you probably don't even need multiple exposures. Many newer DLSR sensors can hit 13 or 14 stops of dynamic range in RAW. This is usually enough to capture the full range of light and dark in a scene if the light is not too overpowering (like mid-day sun).

Click to expand...

Mohamed is using a Panasonic DMC-FZ28 super-zoom with a 1/5.7 (of 35mm film) sized sensor. This gives a 1.7 micron maximum pixel size. The closest camera in Table 3 of http://www.clarkvision.com/photoinfo/digital.signal.to.noise/index.html only shows a sensor dynamic range of 11 stops for a pixel spacing of 2.3 microns. (Smaller sensor pixels reduce the available dynamic range.)

So he is not going to get 13 or 14 stops of range by using RAW, but 11 stops is still better than the 8 stop limit of JPEG files.

Note: the above ranges are the sensor dynamic ranges--there are a number of other factors (eg imperfect lenses or reflections within the camera) which serve only to reduce the available range.

Doug

I use HDR on occasion, but I do it manually in Photoshop (Elements 5), for a less obviously manipulated-looking result, vs. using one of the tone mapping programs. This is only my personal opinion, but those tone mapping programs do not produce images that I find appealing. They look "overcooked" to me.

Important to note, and perhaps somebody's already said it, that HDR images have less contrast than non HDR images. Sometimes a lot less. Some are extremely flat and dull looking.

In addition to using split density filters, Levels and/or Curves can also be quite helpful for high contrast images. In the field, I find it preferable to underexpose a bit (eg expose for the highlights) and then try to recover detail from the dark areas. Not much you can do to recover blown highlights.

Fill flash is also occasionally helpful to reduce contrast when taking the photo... although not so much with a mountain scene such as your sample image.

I used my Samsung TL500's "smart range" feature on a recent hike... in camera HDR, and you don't even need to use a tripod. But I was ambivalent about the results.

Ken Rockwell, rarely at a loss for an opinion, writes well about the subject of contrast and dynamic range here. I am not sure I agree with him completely... but his "it's not that complicated" point of view is refreshing.

I echo, and am glad to hear that I am echoing the the sentiments in this thread. I don't use HDR, and use Grad Filter, and an occasional double processed RAW to get the desired range.

It's actually become quite easy to blend two exposures together in photoshop by hand, and will yield FAR more natural results than a computer trying to tell you what a midtone is....