Dynamic Range


		High Dynamic Range Pictures Prepared by:- Siegfried Seierlein Last Updated:- 5th September 2008



	HDR or high dynamic range photography is a very interesting discipline. HDR photography was developed because the digital sensor has a limited dynamic range. Generally photo editing software use 8 bit JPEG files. Compact cameras typically use 10 bit conversion and SLR cameras use 12 up to 14 bit conversion rates. What is the link you could ask? Generally speaking a sunny day can have a dynamic range of between 16 to 20 “bits”. This is a very simple comparison I know BUT frightening close to reality. Dynamic range is used very generally today and personally I think to little thought is invested when statements are made about different cameras and dynamic range. Many factors contribute to dynamic range and its wrong to say the sensor is the main contributor. That said, one should keep in mind that HDR is only one type of photography. Another, and often more exciting is applying good exposure and photo editing techniques. With HDR photography one typically take three or up to 6 pictures at different exposures. Each of the pictures will expose one of the key areas in the picture correctly. If one add all these pictures on top of each other then its possible to hide the bad areas and its possible to show only the well exposed areas. When one then look at the final picture, then the complete picture is well exposed.To build these HDR pictures various software packages can be used today. I have learned that it is fun using them and at the same time it requires a lot of practice using them correctly.

HDR from one RAW picture.

I have read a lot about using one RAW picture to build a HDR picture. The picture below was processed without any adjustments from the RAW picture.

After that I developed three pictures from the one RAW picture, the first was “exposed” for the mountains, the 2nd for the houses and the third for the grass in the front.

Those three pictures I then entered into EasyHDR and the result is the picture on the right.

The colors were not optimized in the above picture. It is still possible to do fine adjustment on the final picture.

My next project will be to take the three RAW converted pictures and to combine them in Elements 6.

The difficult part is to apply a mask in Elements.


	DRI Pro Plug In


		I saw this interesting Photoshop Plug-in, called DRI Pro. I installed it and its a great and simple tool. It requires 2 identical pictures, one under exposed and the other over exposed. The plug-in will combine them without much questions and all you need to do is to do the finishing touches...

	I took 2 pictures with the G7 and combined them using the DRI plug-in.


	Interesting Video giving good tips of taking HDR pictures

How much information can one retrieve from the shadow area?....

My wife and me were out enjoying the lovely weather in Lucerne when I took this picture. I did not have a tripod with me to take three differently exposed pictures so I decided to go for the RAW option. I did not yet processed a RAW file but what I did was to apply some selective editing on the JPEG file. Keep in mind that when a picture is under exposed or alternatively said, exposed for the highlights, then it will happen that the shaded areas will have a lot of noise. Does it mean we have a bad camera at work, NO, any picture poorly exposed will result in noise. It is similar to heat, when a camera was in the sun then it will also have more noise in the pictures

I think its mostly about the visual effect and if you go and casually show the edited picture to people in the office then they will say WOW, and one or two will start talking about their trip to Lucerne.




		Edited with Photoshop Elements




	Not edited, straight from the E-410

The picture below was processed with EasyHDR. I took the above E-410 picture in RAW format and processed them with Olympus Studio to have 4 different pictures at 1EV exposure difference each. Studio has a interesting function that will improve the shadow detail, I used that. These 4 pictures were loaded into EasyHDR and then processed as a HDR picture. I saved the EasyHDR resulted file as a 48bit TIFF file, to limit any image information to get lost. That I then loaded into Neat Noise removal, saved it in JPEG and sized for the web using PSE 6.




		Base Exposure



			Plus 1 EV




			Plus 2 EV



				Plus 3 EV

This was an extreme example and better results can be expected when 4 differently exposed pictures was taken. That will prevent the noise one get with the above method.

The interesting part is that it is possible to “rescue” almost the impossible when using RAW in combination with something like EasyHDR.