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: 9/1/2004 Subject: Wide Angle Lens Problem
Question I recently got a wide-angle lens (19-35mm) as a present. I popped it right on my Canon Rebel and fired away....when I got the prints back, every single one of them has a black arc on the lower third of the print. Doesn't matter if I zoom in or out, or how bright the light is, or anything that I can figure out. Can you please tell me what I'm doing wrong? I'd love to use this lens, but right now I just avoid it.
Answer Chris. Thanks for your question. Firstly, without seeing your photos with the black arc, I'm finding it hard to work out what went wrong. However I'll go through the variables so you can eliminate them one at a time. An extra-wide angle lens such as 19mm has to be what is called 'retro-focus'. What that means is that the business end (the back end) that's inside the camera when it's fitted, actually protrudes into the camera body more than an ordinary focal length lens. What could be happening is when you take a shot, the reflex action of the mirror lifting out of the way is being limited by the lens itself. Do this for me. Remove all lenses. Now, with no film in the camera open the back and set your shutter speed to a couple of seconds. Hold the camera up towards the light (outside) and looking through the back of the camera fire the shutter. The shutter blinds should open and you will be able to see daylight through to the front of the camera and beyond. For this to happen, the mirror will lift up all the way for the time of the exposure, then fall back into place again. Now fit the 19-35 lens and do the same thing again. Does the mirror go all the way up or is it hitting the back of the lens? If it is hitting the lens then there's your problem. That's the only thing I can think of that's giving you the black mark on the bottom of your photos. If it was top and bottom I would blame too many filters or a lens hood. If it is the mirror hitting the back of the lens, don't be confused by the fact that the mirror is at the top of the frame and the black mark is at the bottom of the photo. Your film is actually loaded upside-down. The image hits the film inverted. Therefore the mirror at the top casts its 'shadow' on the top of the image (the bottom of the neg as it's loaded.) Just to explain focal length a bit more to help you understand why a wide-angle lens is closer to the film than a standard lens - try this. Get yourself a 35mm slide mount and hold it 100mm from your eye as you look through it. You are seeing the same view as a 100mm lens. Bring it back to 50mm from your eye and you are seeing the same as a 50mm lens. Bring it back to 19mm from your eye (ouch, that's close) and you will be able to see more of the view. Yes? If you want to go to the extreme, place the slide mount 8mm from your eye and you will see what an ultra-wide angle lens sees - nearly a fish-eye. Cameras that use these lenses need the mirror locked up before they can be fitted or the mirror just won't go anywhere. Please let me know if this was the problem. I have a feeling it will be. If you like, scan and send me a copy of a problem photo to spear@hwy.com.au .
Hope this helps.
Cheers,
Steve Pearson
PS - You say that zooming in and out doesn't help. To be truthful, there's not much zoom between 19 and 35 mm in such a lens.
