Lense Hood

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I'm using a Canon Ftb, getting used to it and have 50mm 1.8 S.C and a 50mm 1.4 S.S.C lenses. I use both with a skylite cap on the front of each lense.

My questions, 1.Do the skylites affect the picture quality or are they just for protection of the lense. 2.What is a lense hood and how does it work? How does it fit on the lense? Why do I need one.? 3.What is the best way to take a picture of the full moon on a clear, crisp winter night (hand held).


-- Tom Koman (hiramm@us.ibm.com), February 18, 2000


Tom: 1. A skylight filter is a UV filter with some slight warming added. A UV filter reduces the effects of atmospheric haze produced by UV light. For the most part, these filters are used to protect the front element of the lens. Some experts say not to use these filters for protection because the add surfaces that could cause problems, but I was at the camera shop the other day and saw a SMASHED filter that protected a front element. I have them on ALL of my lenses.

2. A lens hood projects from the front of the lens and is used to keep stray light from entering the lens where it can reflect from surface to surface causing image-degrading flare. Generic lens hoods usually screw into the threads on the front of the lens. Canon hoods twist onto the little ridges near the front of the lens. Be sure to use the correct hood for the lens. For example, for your 50mm lens, you would use either a BS52 or BS55 hood(depending on the filter size of the lens). (Most of the above information was taken from Canon Classic Cameras by Bob Shell and Harold Francke.)

3. The moon, especially a full moon, is just a big sunlit rock. A good starting setting would be f/16 at the shutter speed that is close to the reciprical of the film speed, ie 1/200 for 200 speed film. If you have any more questions, please email me at: kirbyc@prodigy.net Good luck, Kirby

-- Kirby Chilton (kirbyc@prodigy.net), February 20, 2000.

In general, film is more sensitive to blue to UV light, so a UV or Skylight filter removes some of this light. A Skylight filter removes the UV and some of the blue, a UV filter, just the UV.

As long as you use a quality filter, and it is clean, there should be little image degradation. In some conditions, like a shot where the sun or bright light is in the frame, or just out side it, the extra glass surfaces may cause flare (bright areas or spots on the negative). A multicoated filter will help avoid this, but in these cases it is best to take the filter off.

A hood projects from the front of the lens and offers shade to the front of the lenses to avoid flare. It also will protect the front of the lens from damage.

For yor two lenses you need a BS-55.

-- Terry Carraway (TCarraway@compuserve.com), February 28, 2000.

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