Diagonal Streaks In Sky on Select Shots (NOT Posterization)

Started 9 months ago | Discussions thread
OP Platographer Contributing Member • Posts: 803
Re: Crepuscular rays

GSWayne wrote:

CarlitosM wrote:

Tristimulus wrote:

CarlitosM wrote:

Tristimulus wrote:

GSWayne wrote:

One way to try to verify if it is sun rays would be to use a program (like PhotoPills or TPE) that determines the sun angle at the particular time and place you took the photo and see if the angle matches.

Or just take a look at the foreground of the image...

The shadows in the foreground and the streaks make different angles relative to the horizon. The foreground shatows' angle appear to be smaller. You would expect the opposite if they were both from the sun.

Rectilinear wide angle lens and distortion away from the center spot...

The different rays/shadows should all still come from the same source.

When I tried comparing the angle of the streaks to the angle of the shadows on the pier they were within a few degrees. I think you cannot directly compare the two angles because the angle of the shadow on the pier will depend on both the position of the sun and the relative location of the pier horizontal beam and the object that is causing the shadow. Likewise the exact angle of the streaks in the sky will depend on the location of the clouds that may be causing the streak. I don't have huge confidence in my ability to mentally do the 3 dimensional trigonometry to figure out these angles so I this may not be a correct analysis, but I think the streaks are in the sky, not in the lens. Unless you compare the lenses at almost exactly the same time I would be concerned that you could have changes in the lighting conditions that would make a direct lens comparison difficult.

Thanks for that analysis! Below are three full-res OOC jpegs from the same location taken within 21 minutes of each other with the Tamron 28-200mm. These are the photos best exposed for the sky from bracketed series. You can see the sky streaks in the first one, which was taken at 4:25 pm at 41mm, but not in the other two, which were taken at 28mm and 55mm, respectively. Although we can't see the clouds around where the sun is (since the sun is far out of the frame to the upper right), it does appear that cloud coverage has changed between these photos. Do these photos also indicate that sun rays may have been the cause? If not, why would the effect not show up in the other photos taken so close in time to the ones at issue with the same lens facing the same direction from the same location?

Tamron 28-200 at 41mm and f/11 at 4:25 pm. Streaks clearly visible in the sky.

Tamron 28-200mm at 28mm and f/11 at 4:15 pm. Streaks not visible in the sky.

Tamron 28-200mm at 55mm and f/11 at 3:54pm. Streaks not visible in the sky.

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