What is causing these color spots?

[callousparade]

Hey all, I'm new to photography and this is my first post! Yay!

So I was messing around with long exposure photography, and noticed two purple tinted blotches in the attached image. 30 second exposure, with f/16 and ISO100. Using a nikkor 35mm f/1.8 lens and a Tiffen 10stop ND filter with tripod.

I can remove those in lightroom fine, but I still want to get to the bottom of it. Since one spot is right above center, and another smaller one angled away from the sunlight and through that center one, I've been calling it lens flare, but is that correct?

I was shooting with liveview so the mirror should have been locked up, preventing light from going through the viewfinder (which I've read might be an issue). I also saw the spots in my 15sec and 10sec exposures. I think it was actually worst in the 10sec (larger aperture obviously), but don't have that image on hand right now.

Any suggestions would be greatly appreciated! Looking forward to learning a ton on these forums.

[deetheturk]

Welcome to the forum, no picture showing, please take a minute and fill in your profile that way we will know your name and where in the world you are!

Cheers David

[callousparade]

Oops. Fixed it!

Working on that profile as we speak

[deetheturk]

Hi Paul, we are quite a friendly bunch on here so its nice to address each other on first name terms, as for the blotches, I would guess at lens flare but maybe one of the more experienced members will keep us right

[Mike Buckley]

I can't see the issues you are describing. If you upload a larger image, perhaps it will be easier to see your issues and it will definitely be easier to appreciate the nice qualities of your photos. I upload using TinyPic at 1920 x 1080, which is a common native resolution of many monitors being used to view photos.

[callousparade]

Mike, here it is at 1024x768 which seems to be the highest that tinypic will let me do (what's with that?)

The spots aren't hard edged, more of a subtle tint in two places that almost looks like it could have actually been in the sky, but they don't show up at all in my 1/200th shot.

When i get home this afternoon i can edit the shot to accentuate the problem if it's still not visible.

Thanks!

[Mike Buckley]

I'm still not seeing the problem apparently because the coloration you describe really could happen in a sky and because so many of the clouds are displayed with a purple tone.

I have no idea why you're not able to upload a larger image using TinyPic. Perhaps it was a temporary glitch, so don't give up.

By the way, once you have posted 10 messages (I think that's the requirement), you can add an automated signature to the bottom of your posts.

[Polar01]

Paul try putting something over the view finder, ya your mirror would have been lock up out of the way, however light can leak in from the view find. That is why I now always shoot with a cloth or something over the viewfinder. Never had any leaking with my c-crop cameras but it is a real problem with my full frame one. So try it with something blocking the viewfinder.

Cheers: Allan

[Mike Buckley]

A cap made to be placed over the viewfinder was probably shipped with the camera.

[callousparade]

Yep i have the cap for the viewfinder, but wasn't using it at the time. Was my first long exposure shot. But we live and learn haha

I'll upload a more obvious shot later. It maybe the sky, but I thought the spots seem too round to be natural. Maybe not though!

Thanks all for the help so far!

[Saorsa]

You may be seeing shadows cast on clouds perhaps by other clouds.

You can see shadows in the mist here.

[Jim B.]

I see the two spots near center of the frame. Pinkish. Could it be the filter? Does look a bit like lens flare.

[callousparade]

Hmm I hadn't considered that, and that does look similar to the effect I (thought I) was seeing.

The more I mess with it, the less inclined I am to believe myself. It does seem to just be a variation in the light in those two clouds, and the line it's making with the sunlight is just a coincidence. I'm still only screwing around with a jpeg that I emailed myself, so I still want to take a look at my unaltered raw file when i get back home.

Is there anything that I need to watch out for when setting up a shot with a filter screwed onto my lens? By that, I mean does having the cam in a particular orientation relative to the light source cause flare (or any other aberrations)? Also, should I always be using a lens hood, and what's the difference between the round ones and the ones with little wings?

[callousparade]

I see the two spots near center of the frame. Pinkish. Could it be the filter? Does look a bit like lens flare.

So I'm not completely crazy! Wonder if it's more noticeable on higher contrast screens, since on my note 4's high contrast amoled it looks very obvious but less so on my calibrated monitor

The filter is a ten stop Tiffen XLE AXENT (no ir absorption) which I have seen good reviews for. I was worried about tightening it too much, but it was snug.

[Mike Buckley]

To reduce the possibility of flare, you should always use a lens hood. Even if the sun is behind you, a direct reflection produced in the scene could send light toward the lens and cause flare. I can't think of any reason not to use a lens hood so long as it fits when using a particular filter and so long as it doesn't cause a vignette.

[callousparade]

Ohhhhh the headlights... I was right on the curb, maybe the cars causing the flare?

[callousparade]

Also, what is the correlation between the color of lens flare and the color of the light source? Most examples I see only show flare as being the same color and "attached" to the source (like a star pattern), but sometimes I see like blue or orange hexagons that are cast far from the light.
I realize that might be a complicated question

[zen]

I think it's quite a nice image, and see nothing that should not be there. If you are referring to the lateral purple streaks just above the center tree tops and between the street light poles, they look perfectly normal and natural to me. The colors are common to sunsets.

Hope you get the question resolved to your satisfaction.

Zen

[callousparade]

Thanks Zen!

This is the final shot that I ended up using. It was a 15second exposure.

https://500px.com/photo/102844039/fi...paul-croasdale

Edit: is there a way to get 500px photos inline?

[callousparade]

Here's a shot where the spot is worst. I cropped the image so the blotch is centered at the top.