AboutSteve Pearson Expertise Try me for 35mm or darkroom issues. I am a professional photographer in Australia. I work solely in 35mm digital format, after 35 years of colour and monochrome film in many formats. I have darkroom experience and for many years belonged to my local camera club. I conduct photography workshops around the state on any and most subjects relating to photography and often judge photography exhibitions and competitions.
Experience I hold a Diploma of Applied Science in Forensic Investigation, with part of my studies involving photography. I spend most days with a camera and am into digital photography in a big way. I was given my first camera in 1965 and have not been without one since. I spent nearly 20 years as a forensic investigator with my state Police Force, and since retiring a couple of years ago have concentrated on commercial photography - especially weddings.
Expert: Steve Pearson Date: 5/22/2004 Subject: what does it mean....
Question Hello Steve, I am beginner photographer who is really interested in making a living out of phorography. I've been taking pictures for not to long and I have jad some good and some bad results. I would like to start a business of a gallerie in Ecuador, my home ground. I live in the USA for now and I want to take some lenses with me. for now, I am using Sigma lenses, they were very cheap, but to get incredible pictures, I guess I need better equipment. Could you please tell me what does all those leters in the names of the lenses mean. I am interested in nature photography as well as landscapes. I would like a lens that gives me sharpness and a good depth of field range. What does it mean when they say that the lens is constructed in different groups and elements. Does that really mean something. What is it exactly that I need to look in a lens. I know I have bombed you with so many questions and I apologize for it but if you could help me out, I would really appreciate, Thank you.
Marco Vinicio Aguilar
Answer Marco. Thanks for your question/s. Let me start from the beginning - and I'll be very blunt with you here as I don't believe in pretending. For you to make a living out of photography you need to know a hell of a lot more that you're displaying here. It is a cut-throat business and unless you're living in a dirt poor society, then you will not make a living out of it. Sigma lenses are cheap but they are not nasty. Sigma is a lens manufacturer and makes damned good lenses. I have one or two. It is not necessary to buy name brand lenses to get the best quality. All the letters on the lens (I think you mean numbers) designate the speed and focal length of the lens. Speed means how far the aperture of the lens will open to allow in light. For instance if a lens is a f1.8, it is 'faster' than an f2.8 lens. Another number you will find on a lens tells you the diameter of the filters that will fit it. Another number may tell you the focal length (50mm or 70-210). Depth of field is dictated by the focal length and the ablility of the lens to close down to its smallest aperture. A wide-angle (28mm) lens has a greater depth of field than a medium (135mm) telephoto lens. Groups and elements refers to the number of glass 'lenses' in a camera lens barrel and how many groups of them there are. For instance a lens may have 11 elements in 4 groups. That means there may be 3 elements (or glass lenses) together, then another 3 together in another group, then 3 together in another group, then 2 together in another group - all within the lens barrel itself. It varies depending on the focal length of the lens and whether or not it is a fixed lens or a zoom lens. When buying lenses look for a known brand. There is certainly nothing wrong with Sigma lenses. Hope this helps. Cheers - Steve.
