Experts “in their” field are sometimes called to testify during a trial. These experts vary depending on the subject that needs to be clarified or explained. Experts share their views, opinion and, knowledge to the subject through science, experience or study which is beyond comprehension of an ordinary citizen and translated which is comprehensible.
It is in the discretion of the court of who to allow as expert because of this, anybody can be a “expert witness” this is if they can establish, convince and satisfy the judge that he possess the necessary experience, expertise, training, education of that particular field. There are however rules and procedures for accepting such testimony. Because of this an expert testimony might be ignored again, depending on the foundation or weight of the expert’s testimony.

As all expert testimony their opinion are without doubt, there will always in some degree question since most of the testimonies are based on scientific fact. It is therefore important to be impartial and objective. Experts depending on their field use a variety of equipment from high definition cameras on field to boom stand microscope on laboratory. This is to ensure that testimonies are properly backed up by strong evidence whether solid or analytical.

There are a number of experts that can be called upon, this article list those fields on the areas of expertise. Here are some of the following:

Ballistics - is a well established science and mostly accepted by all courts. From the bullet itself, striation patterns and gunpower residue are the most widely accepted showing during court. Since actual demonstration during court proceedings are prohibited, results from the laboratory such as analyzing a bullet under a boom microscope and matching it with the weapon are used.

DNA – this is another field where a boom microscope is used. Although now commonly widespread in used due to breakthroughs, results are still challenged.

Document examination – involving fraud, experts in this field ascertain documents in question of their authenticity or handwriting analysis which may include character analysis. With the use of a boom microscope it can analyze a 100 times better discrepancies or unusual characteristics, such as ink, paper or tampering of the document.

Firearms identification – in relation with the ballistic expert a firearm expert might be called to support claim and to match bullets to the firearm. An expert in firearm identification is capable of examining cartridges or shell casing of all types. Through the use of a boom microscope it can use to match grading of the weapon and the bullet.

Polygraph examination – although not generally accepted because of its unreliability it may still be accepted if both parties of the defense and prosecution agrees to such in undertaking. Mostly used by investigators rather than expert witness.

Toxicology – an expert in the field of chemistry or medicine. He may be involved in drug or alcohol identification but may also be called to lend his expertise involving poisons, narcotics, blood or other that may involve bodily fluids.

An expert in such field usually does not determine the outcome of the case, nor will be the basis for prosecution or dismissal; it is usually in support of all other factors such as eye witness account and testimonies. Read more on this subject