08/24/11

Tutorial: Realistic HDRs with Photomatix

In the last years I’ve seen a lot of people abusing of this technique (me too at the beginning), creating irreal, oversaturated and noisy captures, usually made with Photmatix. I think that Photmatix is a very nice software but keeping always in mind its weaknesses, otherwise it’s easy to get fatal results, so that’s why I wanted to share some tips and personal recommendations about how to get slightly more realistic results with this program.

Not every scene will be better in HDR (High dynamic range), this technique is appropiate when the scene we’re capturing has some very dark or very bright parts (completely black or white parts). Sometimes our eyes can see these differences properly, but the camera’s sensor has less dynamic range than our eyes so some information will be lost. For example, a very bright sky but with dark shadows on the ground is a typical situation. But even in this kind of situations, it’s good to ask yourself which result do you prefer, getting all parts of the photo correctly exposed, or take advantage of this contrasted lights and get just the silhouettes of the mountains. In that case it wouldn’t be necessary to make an HDR.

For this tutorial I’ll suppose you know how to use the basic features of Photomatix, to get at least “ugly” results.

Before starting with the photomatix options, it’s important to say that to get a good result, it’s very important to start with a good set of photos. The typical bracketing option of the DSLRs usually offers +1, 0 and -1 steps between each of the three photos it does. I always to it manually, because I think sometimes it’s not enough with three photos, and sometimes I prefer doing the photos with less than 1 step between each one. I usually do 2/3 of a step between each one. I also start with the brightest frame, then I take several shots, lowering each time 2/3 of a step, and I do the necessary photos until I think it’s dark enough and it’s useless to make more photos. I recommend that if you can do more than three, do it, and once processing, you can choose if it will look better with three or more captures. The only two possible disadvantages of not using bracketing is that you may move slightly the camera while changing the exposure of each shot, and the other disadvantage is that you need to be quick if you’re capturing a landscape with clouds, because if it tooks you more than some seconds the clouds won’t be at the same place on the next photos. This last thing is something you need to avoid, because once in photomatix, when aligning the whole set of captures, it’s possible that the program uses the clouds to align instead of your main subject!


Also, photomatix allows you to make Pseudo-HDRs with only one RAW file, and then it does the bracketing, but this way the results tend to be much more noisy, so I recommend doing always separate captures, except when the scene has motion, in which case it wouldn’t be possible. My recommendations are the same for both methods, but my example will be with only one photo (on the right, 6″ exposure, ISO 400 and f/4.5). I tried to make a proper exposure because I just had the opportunity to do one photo (I was the last visitor that day).

Now these are the controls which I consider more important:

  • Strength: The name says it clearly, the more strength, more irreal and contrasted will be the result. I think that what it does is to let the darker captures manifest more than the bright ones. If you really want a real result, keep it low. This will also help to improve the noise of the photo. If lowering this parameter the photo becomes too bright, you can control this using the next parameters, do not increase again the strength just to get it nice exposed!

 

  • Color saturation: I personally like it a little saturated, this way I have the enough color information on the photo to increase or decrease it later in Lightroom. Even when I know that the photo will be in b/w I save it in color, maybe I realise later that it could be more interesting in color.

 

  • Luminosity: One of the most important controls, keep it as low as you can, it’s true that will be hard to get all the parts of the photo correctly exposed, but believe me, if you start with a good set of captures with slight exposure differences, this won’t be a problem. The error a lot of people does is to put a lot of luminosity, when I see these captures I think “oh, he used Photomatix”, because it’s very typical to get blurry and false results with this control, so keep it low!

 

  • Light Smoothing: One of the controls people thinks is cool at the beginning but also betrays that you used Photomatix. Depending on the position, different parts of the photo will be nice exposed, but as you get more parts good exposed, is when you get irreal results again. In very low or low, equals science fiction, so try to use always high or very high. Very high is the smoothest choice, which will expose especially the center part of the photo. Sometimes is better the High option, which affects to the whole photo and depending on the capture can give better results, its your choice to see which one fits better with your photo, but I don’t recommend using a lower value of this control.

 

  • Microcontrast: Another important control, in combination with Luminosity, affects dramatically to the overall result, and I recommend to move it as high as you can. If you used a very low Luminosity you can decrease a little this value to get a little more of light if you need it, but you’ll also lose contrast.

 

  • The White Point and Black Point is a personal choice, using a higher black point will give darker results, which you can compensate with the white point, but any radical choice will result in an irreal result or more noise, or both.

 

  • Temperature: I use the same for most of my captures. If you don’t touch the temperature control, after processing several photos you can observe that it give kind of orange/yellow tone to all the photos, so to compensate that, I use a lower temperature (usually -3 or -4) to get the correct color.

 

  • Micro-smoothing: This control can give more textures and details to your photo when it has a low value (typically 2), and you can even get more details with 1 or 0, but with this slight changes the noise of the photo can dramatically increase, so again, if you want real results, try to use a value greater than 2, there’s no problem if you move it very high.

There are some other controls but I think they’re less important, you can even leave them by default, but one thing I noticed is that’s complicated to get sharp results using only Photomatix. I usually export the file to tiff format and import it in Oloneo software (http://www.oloneo.com), just to increase the sharpness of the result, otherwise it may look dreamy or even blurry.

 

I hope this was helpful to somebody, below there’s the resulting image processed with Photomatix, then Oloneo for increase sharpness, and then imported to Lightroom to do some slight changes of contrast and temperature. In fact
this photo is not very realistic, but what I wanted was to explain how to get more real results.

Luxury colors

07/19/11

RAW Quality Infrared Photography

One of the typical issues I had when doing infrared photography is that when shooting in RAW format, when we import a photo in Adobe Photoshop or Lightroom, everything turns reddish again, as if we hadn’t used a proper white balance.

That happens because at least both Adobe Photoshop and Lightroom aren’t capable of using temperatures lower to 2000º K, and when we import a RAW file that had a lower temperature than that (which is usual in infrared photography lol), Photoshop sets the temperature to 2000º K because it can’t go lower.

We need a quite lower temperature so even if we swap red and blue channels to get the proper colors, the result will be still much worse than what we could have obtained when processing with the correct temperature.

(See image 1 for bad temperature example)

The solution? Use another software, at least to import the RAW file.

When I saw this problem I tried other applications and I personally like Oloneo PhotoEngine (www.oloneo.com), which is more a HDR Software than a RAW processing tool, but works great to solve the problem with infrared photography (They offer a 30-day trial).

In Oloneo, we just need to import the RAW file and adjust whatever we want, EXCEPT temperature.

As soon as we touch the temperature slider, Oloneo will try to change the temperature to the original and in this case the result will be horrible again, because Oloneo’s lowest temperature is 2500º K, still not enough! Then, do not touch the slider and change whatever you want (I find very useful the detail strength slider, it really enhances a lot of details).

Once done, we export as TIF format.

(See image 2 for good temperature example, exported with Oloneo, imported in Photoshop and then swapping red and blue channels)

 

Now we can import the TIF file in Photoshop or wherever we want without temperature problems and with RAW image quality!

 

Here’s a different perspective of the same place, using some split toning done with Lightroom:

Natural leading