I am aware of the concept of lens flare, and have like everyone experienced it in photos from time to time. Photoshop even has a filter that simulates it. However when reading about Leica matters it seems flare always comes up-- and people seem concerned with it in much more subtle ways than I had formerly considered. For example, even where it is not obvious in a photo I have heard people say it degrades image quality in general-- for this reason not to ever shoot without a hood. I imagine that it is essentially light that is not tranmitted through the lens in the usual and desired path, but instead is refracted between and within lens elements. Some of this light will inevitably end up on the film and degrades image quality because it has not been aligned and bent though the usual lens path, not contacting the right part of the negative. And in many cases it is probably light from outside the picture area. Anyway, this is my interpretation having just thought a bit about it, but otherwise not have read anything. I would like to start a discussion about what causes flare and the effects it has. Please comment.

-- Silas Larsen (slarsen@mail.colgate.edu), November 02, 2001

Answers

Here's a link to some previous comments - but don't let that stop us from adding new insights on Silas' thread. (By the way, this site IS searchable - you just scroll through the 740 previous threads SEARCHING for the link you know is there.) 8^)

Some more about flare

Seriously, as I said in the link provided, there are several kinds of flare, and any given lens may have none, one, some or all kinds in various kinds of lighting. Your interpretation is generally correct. Flare can come from reflections off the glass, off filters, off the insides of the lens tube or camera body. It can be a sharply focused artifact or very diffuse 'veiling' flare.

Some short teles (e.g. the Nikon AIS 85 f/2) will actually project an image forward into the palm of your hand (one of the concave element surfaces acting like a 'mirror' lens. This image can get re-reflected by the other elements back through the lens to the film and show up as a colored rainbow across one side/corner if you shoot anywhere near the sun without a lens hood (90 Sonnar-G does the same thing). By comparison, the 90 Tele-Elmarit in the same framing throws a smooth even wash-out veil over everything - great for high-key glamour portraits but annoying otherwise.

I'll let someone else take over.

-- Andy Piper (apidens@denver.infi.net), November 02, 2001.