For an HDR picture you need:
1) A digital camera with manual mode ( or with an automatic mode called BRACKETING - see the technical specs of your camera for that- )
2) A solid tripod ( a tripod is not necessary if you are shooting outdoor with the automatic bracketing mode; but without a tripod you'll have some limitations…)
3) A software like Photoshop ( or an HDR software like Photomatix Pro or EasyHDR )
( BRACKETING:
http://www.digitalcameraworld.com/2012/11/13/bracketing-explained-what-you-need-to-know-about-maximising-detail-in-your-photos/ )
In High Dynamic Range photography you have to take different shots of the same scene with different exposures and merge all pictures in a so called "Tonal Mapped" image by a specific software.
First of all, put your camera on a solid tripod (it's very important NOT to move camera between shots).
Select the MANUAL exposure mode on camera.
If you're taking pictures of long, big dino-models select a f/8 or even closer iris stop on lens (so you'll have better depth of field and the model will be ALL in focus).
Now select a proper exposure time on camera; you should start with something around 1/50 sec and see the result. If the picture is too bright or too dark, select a different exposure time (1/100 , 1/250 , 1/25 ) until you'll find the perfect exposure time.
Take a picture with the perfect exposure time and delete all other shots.
Now you need almost 3 other shots with increasing overexposure and 3 with increasing under exposure ( you can even decide to have a wider range and shoot 4, 5 or more pictures)
An example: perfect exposure time is 1/50; you'll have to select 1/100 and take a picture; then 1/200 and take a picture ; then 1/400 and take a picture. Now you have 3 pictures with different under exposure.
Same in over exposure: 1/25 then 1/12 then 1/6 .
Now you have 1 picture with perfect exposure, 3 with under exposure (darker) and 3 with over exposure (brighter).
Use Photoshop to merge all images ( a tutorial
http://photoshopcafe.com/tutorials/HDR_ps/hdr-ps.htm ).
Now you have an HDR image with Tonal Mapping inside Photoshop.
You can use all Photoshop tools to increase color, bright, saturation and so on...
Then export the result in 8 bit Jpeg image: job done!
