Unusual colours from using filter

[2.8photography]

Firstly, merry christmas!

Just returned from a trip to Hong Kong and got the opportunity to head out of the city for a walking tour in the Hong Kong Global Geopark of China. The scenery was great so I strongly recommend it to anyone going to HK, definitely a change from the shopping and busy streets.

I got round the shooting the sunset and found that I got very weird results. Both weren't proper shots (just put the camera on a rock and hoped for the best) so do pardon the composition.

This first shot was a test shot. 1/30", f/16, ISO 100, manual WB at 10000K, with a GND 0.9 (dark part to the sky)

Second shot was with a B+W ND110. 30", f/8, ISO 100, manual WB at 10000K, also with the same GND in the same position

I guess I can accept that the exposures are more than 10 stops apart as the sky was getting darker. But what is quite puzzling is that the colours are extremely different. Also, the vignetting on the latter shot is really very pronounced. I've used the 10 stop ND before (sometimes for sunrise or normal day shots) and the results, comparing with and without filter, have been different but only slightly (usually with a slight brownish tinge when the filter was used). Is this correctable? Or could it also be some auto setting on the camera's response to the filter?

I know nothing much can be done about it and the red is actually pretty nice, but would just like to know what's going on. And if this is a common 'problem' faced by all ND110 users.

Thanks in advance

 

[New2digital]

White balance issue. As the sun set, colour temp changes.

 

[banana0ne]

White balance issue. As the sun set, colour temp changes.

B+W ND110 got red cast even at high noon it can get really red. only way to change it is thru playing with color settings in LR or CS

 

[catchlights]

yes, color temperature changes thru out the day, it is more obvious during sunrise and sunset.

there is no optimum color temperature for sunrise and sunset, I usually adjust to my taste during post production.

 

[GRbenji]

Most, if not all, filters do give color cast. Stacking them made it worse.

 

[Octarine]

Actually a good example why UV filters are so useless for DSLR in terms of filtering UV. The red colour cast of GND reveals how much of the blue spectrum of light is removed / absorbed by optical glass.

 

[Wizongod]

Also, the vignetting on the latter shot is really very pronounced. I've used the 10 stop ND before (sometimes for sunrise or normal day shots) and the results, comparing with and without filter, have been different but only slightly (usually with a slight brownish tinge when the filter was used). Is this correctable? Or could it also be some auto setting on the camera's response to the filter?

I've only used square filters before, but I'm quite aware that stacking, especially with a wider angled lenses will cause vignetting. You mentioned you used both GND and ND, so that is probably the cause of vignetting. You only use the ND in most situations right?

Also, vignetting is a common correction done in post-processing, just google for tutorials on your favourite software!

 

[2.8photography]

thanks for all the replies so far.

but was the colour temperature really that different? the shots were taken within 1 minute of each other. anyway if that's the case, shooting raw should help (?)

my GND is a square filter (cokin) so i didn't think the vignetting that would be that obvious

 

[Octarine]

my GND is a square filter (cokin) so i didn't think the vignetting that would be that obvious

It's rather "Vignetting by the scene". You can see something similar if you remove all filters and just heavily underexpose the scene by manual settings. The sun is the brightest spot with a rapid fall off of light towards the borders.

 

[Wizongod]

thanks for all the replies so far.

but was the colour temperature really that different? the shots were taken within 1 minute of each other. anyway if that's the case, shooting raw should help (?)

my GND is a square filter (cokin) so i didn't think the vignetting that would be that obvious

Colour temperature changes with the length of the path of light the sun takes (some physics at work here: Rayleigh Scattering) and that changes pretty fast at sunset especially with clouds. Towards the end of the sunset, you might notice each exposure you do has to be +1/3 from the previous or so, so yes, conditions can change pretty fast. RAW will definitely help, as colour temperature can be adjusted really easily with post-processing in that manner. But the difference in colour between the two pictures you posted are really great, so it could be the filter. Anyway, not much to worry about, just a minor tweak in post processing and it'll be alright.

As for vignetting, have you tried the filters individually? You should be able to isolate which filter is responsible for the vignetting. If you don't get vignetting, then it just proves that the stacking is what's causing it.

Just as a general add-on about the problem with stacking filters (these problems worsen the more filters you use): Colour cast, vignetting, image quality degradation, flare.

EDIT:

It's rather "Vignetting by the scene"

Oh yea, it could be that too. Quite common for sunsets, but yours looks kinda round, with the focus in the center of the image which isn't where the sun is ("natural vignette" will center around the bright source) so it may or may not be. Either way, just give your filters a test to isolate what's causing the effect!

 

[sinned79]

B+W ND filters usually have a warm color cast.

I took this photo in Lombok in Sept. A 3 min exposure near sunset end (was late and sunset almost over) using auto white balance. Photo unedited.

I am using the same filter btw.

As long as u shoot in raw format... u can correct it later.

 

[Octarine]

EDIT:
Oh yea, it could be that too. Quite common for sunsets, but yours looks kinda round, with the focus in the center of the image which isn't where the sun is ("natural vignette" will center around the bright source) so it may or may not be.

Clouds will block light. Look at the position of the clouds in the pic. Heavily over or underexposed pics reveal interesting details

 

[donut88]

Just to let u know that your horizon in the photos are not straight......

 

[daredevil123]

thanks for all the replies so far.

but was the colour temperature really that different? the shots were taken within 1 minute of each other. anyway if that's the case, shooting raw should help (?)

my GND is a square filter (cokin) so i didn't think the vignetting that would be that obvious

The culprit is IR light.

Check this out. Confessions of a Sensory Addict: Color cast problems caused by ND and GND filters

 

[2.8photography]

once again thanks so much your replies have been most helpful. will definitely take note and start shooting raw for this kind of shot.

Just to let u know that your horizon in the photos are not straight......

yup haha with a rock as a tripod and i couldn't find a flat one.

 

[AdyH]

E trick i use if i'm using the B+W ND110 is to reduce the WB by 1000K to make it more neutral. Can try it out.