8-15mm lens flare

[fish_shooter]

Folks are getting some strange looking flare with the new 8-15mm lens when used under water. See posts #45 and #46 in this thread on wetpixel. http://wetpixel.com/forums/index.php?showtopic=60171&page=3
I made a conjecture in post #50.
I am curious if anyone here has had any similar results.
Tom

[Roland Vink]

It looks like reflections coming from the underwater housing, or an interaction between the lens and housing.

[fish_shooter]

It looks like reflections coming from the underwater housing, or an interaction between the lens and housing.

I am skeptical of this because of the vertical stripes in different colors. They need to be explained. As well, the lens was behind a dome port that protrudes forward of the housing so little chance of reflections off the housing. Only reflecting surface would be the inside surface of the port.

[Bruno Schroder]

As it happens only underwater, it has to do with the specific conditions, water itself or most likely housing. Could it be a refraction of some stray light through the thickness of the port material, some sort of a rainbow effect? ? If yes, it should change with the geometry and material of the port.

[fish_shooter]

As it happens only underwater, it has to do with the specific conditions, water itself or most likely housing. Could it be a refraction of some stray light through the thickness of the port material, some sort of a rainbow effect? ? If yes, it should change with the geometry and material of the port.

The colored lines (near top of frame in pic in post #45 in link given above) are straight and perpendicular to frame edge that seems inconsistent with the radial nature of light coming through dome optics and lens. Is this only an underwater phenomenon?

[Roland Vink]

I meant the dome, not the housing (I'm not an underwater shooter so forgive my incorrect terminology)

The vertical lines above the flare only seem to appear when the flare is towards the top of the image, they are not present in the second image where the flare is central.

I have seen lines like this on my old P&S digital camera when the light is too bright for the sensor. We can discount that, otherwise it would appear every time the sensor was overloaded, regardless of lens or location of the flare.

It's more likely to be a secondary reflection from the dome, from a straight edge in the housing or within the camera itself. Besides the straight lines, the flare itself does rather look like glare coming from the dome.

This is all guesswork, next time you go diving, you could investigate more carefully - take a series of pictures at different angles to the sun, and repeat at different focal lengths and see what combination of factors causes this. If you can see the flare in the viewfinder, then try shading the lens/dome with your hand to see what effect it has. You might be able to find the source and cure it, or you will have to learn to avoid certain angles/focal lengths etc.

[fish_shooter]

It's more likely to be a secondary reflection from the dome, from a straight edge in the housing or within the camera itself. Besides the straight lines, the flare itself does rather look like glare coming from the dome.

This is all guesswork, next time you go diving, you could investigate more carefully - take a series of pictures at different angles to the sun, and repeat at different focal lengths and see what combination of factors causes this. If you can see the flare in the viewfinder, then try shading the lens/dome with your hand to see what effect it has. You might be able to find the source and cure it, or you will have to learn to avoid certain angles/focal lengths etc.

That is a good point - it might be from within the camera! However I do not know which vertical linear feature (if there is one) caused the reflection. The two that come to mind include the frame edge at the shutter opening and the sensor edge. It is possible that this shot was done with a D5 as that is the shooter's primary body at present. However the camera used was not stated. We need more examples before doing any generalizing. Most of my underwater shots done with a fisheye lens have been here in AK where the sun is weaker and lower to the horizon compared to the Caribbean (were the shot was taken; I have not been there in decades). Next dive trip is not until early next year - Hawaii where it tends to be cloudy. For the rest of 2017 I will be shooting salmon. I am not a good candidate for this investigation.

[Erik Lund]

I'm pretty sure you will have to live with it as it is,,, Changing flare behavior is done by using another lens IMHO

[fish_shooter]

I'm pretty sure you will have to live with it as it is,,, Changing flare behavior is done by using another lens IMHO

The other 8-15 lens is also the other brand and would preclude using my Nikon cameras.