AboutJoe Appel Expertise I can answer questions related to many areas of photography, but most specifically relating to photojournalism. I can also offer advice on using digital and 35mm cameras, Adobe Photoshop, and digital photography in general. Once upon a time I was pretty good in a darkroom too.
Experience I have been a staff photographer for a major metropolitan newspaper group (over 100,000 circulation) for 12 years. Concurrently, I have maintained a freelance photography business.
Organizations belong to National Press Photographers Association
Publications Rolling Stone, USA Today, Pittsburgh Tribune-Review, Cleveland Plain Dealer, Palm Beach Post, New York Daily News, Philadelphia Inquirer, Super Street Bike, Motorcyclist, Sport Rider, Cycle World, Roadracing World, T.W.O. (Two Wheels Only), the ABA Journal.
Expert: Joe Appel Date: 7/4/2007 Subject: Quick Question
Question Hello,
I am a new student to photography and I was curious if, after you focus a zoom lens, can it remain in focus as you change the focal length? Also, what is Paralax error? And why is it a problem when using an SLR camera? Any help would be appreciated.
Regards-Skyler
Answer Skyler,
A good zoom lens won't change focus when you change focal lengths, but many of the less expensive models will.
Paralax error is when the image you see in a viewfinder is off from what is actually being exposed. This occurs in camera with twin lens reflex or rangefinder designs.
SLR's were designed to prevent this from happening. You're actually seeing the image that is being exposed, so paralax isn't a problem with SLR's.
