Usually, I use a tripod to make my HDR photos. The use of a tripod for this kind of photography is important for the clarity of the images, to align themselves and to avoid blur. The main reason people recommend a tripod with HDR works, is the difficulty getting the 3 images to align properly. However should be considered that is not always possible to carry on a tripod, in all these cases you can still make a HDR shooting the exposures series holding the camera in your hand.
It ‘better to take more than 3 images for a normal HDR to increase the dynamic range. But when we’re shooting without a tripod you should rest on the 3 shots, not going over. Series of different exposures are difficult enough to do holding the camera steady in your hand for 3 shots, let alone for 5 or 7…
If you’re shooting an handheld HDR we have to consider more the shutter speed. In fact, by setting the camera to aperture priority, and setting a number of shots equal to 3, we should consider that every time the camera moves to the next band of ‘A Stop’, the shutter speed will be half. Since we set up our camera (-2, 0, +2), means that each step is actually 2 stops. If we set such that we will have a speed of 800 it will be: (0) = 800; (-2) = 3200 = [(800 * 2) * 2] and (+2) = 200 = [(800 / 2) / 2] whereas 500 will be (-2) = 1500; (+2) = 125. We can easily calculate that such an opening of 125 can be just 1/30. My advice is to never fall below the threshold (0) = 250 so you will have at most one (-2) = 1/60 that remains in the hands of an acceptable level for alignment.
Follow the light
It ‘important in these cases, follow the direction of light. Without a tripod in darkness conditions will become even more difficult to find a way to handheld a HDR. So stay away low-light conditions unless there is a support to lean on, avoid to shot an HDR holding the camera in your hand if you don’t have enought light and therefore you are forced to overstretch the exposure times. It is very difficult shooting without a tripod a good long exposure photos, considering the length of +2…
Pay attention to the ISO
Usually, using a tripod, ISO values shoud be kept as low as possible to avoid the possible noise in our photos. In the case of HDR handheld this speech may not apply, because a lower ISO valour is a lower shutter speed. If the camera shakes during shooting you run the risk of blurred images and therefore useless. If you face situations where a low shutter speed is difficult to handle, pull on the ISO, as always trying to stay within the limit of low values. Better slightly noisy images than useless.
Consider the external elements
An example of these can be represented by the force of wind and soil conditions, found a good and safe position to take your photos and at the same time keeping the camera in a stable manner.