CDME2031/3031 Visual Effects digital Photography Techniques 02: Working with Light All images Paul Hazell Faking lighting in Photoshop See Steve Caplins How to cheat in Photoshop page 138 to 171 for fake lighting effects such as artificially created shadows. However this handout concentrates on lighting effects when shooting, as this is not covered in the book. HDR what it is and how it can be used? HDR stand for High Dynamic Range. Using specialist software you can create images with more detail in the highlights and shadows than you can with a normal photo. You can use the technique carefully to create enhanced natural looking photos or you can use it to create dramatic atmospheric. An example of how it can be used for naturalistic effects would be where you have an interior shot in a room with windows. Normally you can only expose for the light in the room leaving the windows over exposed (see example 1) or for the exterior light leaving the room under exposed (example 2). Example 1 Example 2 Using HDR you can merge two or more shots of different exposures (in this example two for the room and one for the exterior) to get the shot to be correctly exposed over all (example 3). Example 3 This technique can be achieved in Photoshop using file/automate/merge to HDR but in my experience the usefulness of Photoshop s HDR tool is very limited until the current version (CS5) where it is much improved. You can also do it manually by painting through layers to very good effect but it is time consuming. The example above was actually done in Photomatix software, more of which below.
What has very popular in resent times is HDR multi-shot Tone Mapping. These are much more dramatic shots typical of the one I have created below using shots I took in my village church. 3 different exposures shots were taken on a D90 with a 10-20mm wide-angle lens using a tripod. These were then combined using Photmatix to create the HDR image above. Source shots This level of effect was not possible in Photoshop until CS5 so a third party plugin Photomatix was used. You can also get a stand alone version form of the same software that in my opinion is more powerful and simpler to use than the plug-in. (You can get a 75% discount on this software as a student). With Photoshop CS5 however, though still not as powerful as Photomatix similar results are possible by going to: File > Automate > Merge to HDR. If you were not in the lecture follow this link to see in more detail how this type of image was created: http://www.vanilladays.com/hdr-guide/
Issues to consider when shooting for HDR. Use 3 shots about 2 stops apart. Use only shutter speed to change the exposure and leave aperture the same. This is so you don t change the depth of field over the three shots. You will need to shoot on a tripod to make the images line up. You will need to use self-timer, cable release or a remote to trigger the shutter so the camera is not jogged (as shutter speeds are often slow). You will need to shot in manual mode for best results. To get things like clouds to work best you will need shoot in burst mode using AEB (Auto Exposure Bracketing). Single Shot HDR You can also create single shot HDR shots, though they are not as dramatic as multi-shot versions as the tonal range is much less. However it means you can get a similar effect to the one above but of objects that move such as people, cars, animals etc. Original shot Single shot photo realistic HDR More dramatic single shot HDR
To achieve this you need to shoot in RAW to get the maximum detail in the shadows. You can then open the picture in Photoshop and using file/save as save it as an uncompressed TIFF. You need to save three copies but two should be artificially over and under-expose by 2 stops using image/adjustments/exposure. These TIFFs can then be opened in Photomatix and tone mapping can be carried out as for multi-exposures. Alternatively you can use three PSD with Merge to HDR in PS CS5. Long exposures Some very pleasing results can be achieved buy setting your camera to manual and choosing a very small f stop such as f32. You can slow the shutter speed further using Neutral Density or ND filters. These come in different levels of shading but do not affect the colour. You can then use quite slow shutter speeds in daylight to get parts of the shot to blur. This works particularly well with moving water. The camera of course needs to be mounted on a tripod so the non-moving parts of the shot are not blurred. You can even combine this technique with HDR to get shots such as the one below. A stream in Mortimer Forrest using slow shutter speed for the water + HDR The slow shutter speed can be taken even further for night-time photography (moving car lights being a typical example) but you can also capture stars tracking across the sky or even photograph the sea when it is dark. For star tracking you are looking for very exposure times of 15 minutes or even an hour or so a cable release and a warm coat is essential!
Examples on flickr: http://www.flickr.com/photos/jamalq8/2788142178/in/photostream/ http://www.flickr.com/photos/patrick-smith-photography/3050755004/ Paul Hazell