Discussion in 'Beyond the Basics' started by arana, Jan 27, 2006.
Can anyone give me exactly definition of lens flare?
Search and you shall find.
I know, but the problem is that I don't know english very much...I'm from Croatia and new in photography, so I need a little bit easier definition...in one sentence...(for exam)
It's a bit pretty difficult to do in one sentence.
Essentially, when you point a lens at a bright light source like the sun, there may be unwanted light effects within the lens. Reflection, refraction and distortion may all contribute to the effect known as lens flare. The end result is a bright part in your photograph which is usually undesirable.
Thank you..And how can this be prevented? Using the filters and lens shades??
Filters won't usually help, but a lens shade will if the sun is just outside the frame. If it's inside the frame, there's not much you can do except point the camera someplace else.
A UV or haze filter may cut down some glare in the shot. A polarising filter also can cut down reflections in the shot. A ND4 would probably also do it, but be prepared to have your exposure lengthened by about 13 stops!
However, as Mark points out these won't actually stop the problem - which is reflections and loose light within the lens. The sun is just too bright to be stopped with mere bits of glass!
A lens hood will certainly help as Mark says when the sun is at an angle i.e. it isn't in front of you directly.
Prime lenses tend to be less affected than zooms due to the lower number of internal glass elements to scatter and reflect light.
Thank you guys!
Also, could this have anything to do with the fact that, at least on my prime, the glass is about a half inch deep inside the tube? So that the lens casing itself almost acts as a little hood?
I have yet to shoot many outdoor shots with the prime, so I haven't had a chance to see if flare is a problem. However, with the 28-80mm, I do get lots of flare, and the lens' glass is a lot closer to the end of the lens tube.
This was in here
Lens flare - When light passes from air into glass a small proportion is always reflected. When a lens has a number of elements (and all modern lenses do have quite a few) then there is a loss at the surface of each element and this loss is cumulative - up to 45% of light entering a lens can be lost in this way.
If this reflected light was all reflected back towards the subject then there wouldn't be much of a problem. But a fair amount, after bouncing around inside the lens a number of times, emerges from the back element as an unfocussed diffuse illumination. This results in loss of contrast and subtle tonal variations.
Modern lens design, glass technology and the practice of coating, or 'blooming', the lens reduces this flare to a minimum.
If, however, bright obliquely angled lights are present then light that is not part of the image will still enter the lens and increase the amount of flare. For this reason a lens hood should always be employed.
It's always a good idea to try using the TPF search facility before asking a question - 99 times out of 100 it's a question that has been asked before
Internal reflections from your lens translated on film. It makes bright spots and reduces contrast.
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