Any willing to help me these weird colored patches/blotches on the photo please ?

MonikaO

Mu-43 Veteran
Joined
Sep 15, 2019
Messages
437
Location
Netherlands
Real Name
Monika
Hi all.
Here is a photo I took the other day.
Blue sky and very bright winter sun behind the building.
Taken with my Panny gx80 and 12-32 kit lens.
Settings were:
200 iso- f3.5-12mm. No lens hood.
I exposed for the highlights.

When I opened this photo in photoshop and started to edit it, this is what I saw.
Please look at the under side of the building at all the blue/pink/green splashes/blotches there.
Oh and the histogram said nothing was over or under exposed.
Do you have any idea what causes this ?
Maybe a tip also how to fix it in PP for Photoshop cc ?

I noticed it in a few more photos I took that day.
Not as bad as in this one but still.
My quess when seeing it might be extreem harsh light in combination with shadow areas ?
But I dont have a clue really :)

Any tips/ideas/help is much appreciated :)

Original :
Subscribe to see EXIF info for this image (if available)


Now the photo in Photshop Raw filter and only clicked on auto adjust.


Subscribe to see EXIF info for this image (if available)
 
Joined
Nov 21, 2015
Messages
285
Location
The Netherlands
Real Name
Roel
Seems to me you are having color noise as you brightened the shadow area of the photo quite a bit. Even if the histogram doesn't warn/show something is under/overexposed there still can be darker areas that can not be fully "recovered" e.g. made as bright as the rest of the photo.

The histogram gives a warning if something is underexposed to the point that shadows are turned in to pure black or overexposed that highlights are just pure white (no information captured besides pure black or pure white).

In this case, the shadow wasn't pure black to start with (no histogram warning) as there are still details in the photo. But if you brighten the shadows too much there can still be too little information captured in the shadow area. Now you end up with an interpretation of the camera's sensor of what color there was in the shadow (this "guess" mostly results in some purple/green stuff e.g. noise).

This color noise can be reduced in post-processing/editing but the results are mostly nowhere near the regular image when staying within the dynamic range* of the camera.

Having said that I must say that I do like image 1 a lot better. The shadow, for me, enhances the structure of the building and give it some depth. Keep in mind that there is no light without shadow ;-)

* Maximum difference between the darkest and lightest tones in an image that the camera can correctly capture.
 
Last edited:
Joined
Nov 21, 2015
Messages
285
Location
The Netherlands
Real Name
Roel
An additional tip: If your objective is to get the whole building equally bright on the final image, in this case, you should have overexposed the sky (there is hardly any detail, so no problem if you do lose some information here). That would have resulted in a bright building with no/less shadow and a quite bright sky (which you could dial back to normal when editing without introducing color noise as you are darkening the sky).

You could also shoot multiple photos (one underexposed, normal and overexposed) and combine them. The result is called HDR (high dynamic range) and the process of shooting multiple images is called bracketing. I guess the Panasonic GX80 possibly can do this directly in-camera or you could do it yourself when editing.

If you shoot a subject that is moving (waves for instance ) where it's not possible to shoot multiple exposures you can also revert to using graduated ND-filter. These enable you to darken some parts of the image with a filter (and thus reducing the difference between the brightest and darkest parts of the image) when taking the shot. Basically the filter is helping the camera to keep everything within its dynamic range.
Using a filter system is not something I would recommend at all if you are starting out. But it is a solution (albeit fiddly and quite expensive) to shoot a scene with a very high dynamic range. E.g. a beach sunrise with huge differences between the darkest and brightest parts of the image when HDR is not an option.
 
Last edited:
Joined
Nov 21, 2015
Messages
285
Location
The Netherlands
Real Name
Roel
@MonikaO I thought of one additional tip that came to mind after the earlier posts. Maybe it is something that you already know or maybe it's a bit too technical.. but hopefully, it will be of help to someone.

Lower ISO always results in less noise in the final image. If you know you need to recovery/brighten the shadows quite a bit it is especially important to keep noise to a minimum.
So if you know that you are going to want to recover dark/shadow areas it's best to keep ISO to it's lowest base setting (ISO 200 or ISO 100).

The ISO 200 is your camera's base ISO. The camera base ISO is the setting with the least amount of noise. Most camera's also have a "Low" setting (on the GX80 it's ISO 100). The "low" setting can come in handy if you need the maximum shadow recovery and are willing to "trade" recovery options in the highlights/brighter areas.

Low/IOS 100 is basically the same as the ISO 200 but with a shift in dynamic range (capturing more information without noise) to the darker/shadows at expense of less dynamic range in the white/bright areas. When shooting at Low/ISO 100 you simply capture more details in the shadows at the expense of the detail captured in the highlights vs the same image shot at ISO 200.

So:

ISO 200

Shadows Highlights
|------[ Dynamic range ]------|


ISO 100

Shadows Highlights
|--[ Dynamic range ]----------|


ISO 100 should be used intentionally in specific cases (trading highlight recovery capability for more shadow recovery) for all other shots ISO 200 would be the lowest ISO (resulting in overall the lowest amount of noise and well-balanced shadow/highlight recovery capabilities).
 
Joined
Nov 21, 2015
Messages
285
Location
The Netherlands
Real Name
Roel
Dumb question: what if you don't click on auto-adjust? Do you get the same problem?
The auto-adjust feature is trying to adjust the exposure to reach a balanced image (every part of the image almost equally bright/dark).
So in the photo above, it is (over) recovering the shadows to the point that you get a lot of noise (green/purple color specks) as well as completely removing the shadow itself.

In this case, not using auto-adjust would mean that you are adjusting the settings yourself and have freedom on how you want your photo to look. Maybe you want to leave the shadows a bit darker or even go for a very low-key look like for example:

c5065144-cef4-4951-a740-ba8c1e8c4225.jpg
Subscribe to see EXIF info for this image (if available)
 
Last edited:

RS86

Mu-43 Veteran
Joined
Mar 26, 2019
Messages
256
Location
Finland
Was the photo taken with electronic or mechanical shutter? I have read that electronic shutter can give such problems in shadow areas. Anyone have more information on that?
 

Hendrik

Mu-43 All-Pro
Joined
Feb 27, 2015
Messages
1,441
Location
Wayland MA
Real Name
Hendrik
Maybe a tip also how to fix it in PP for Photoshop cc ?

Now the photo in Photshop Raw filter and only clicked on auto adjust.
You make no mention whether this was shot raw or jpeg. The Camera Raw Filter works for either. You would have more latitude for correction with a raw file. As always, start by duplicating the layer and work on the duplicate.

In the Camera Raw filter (or in Adobe Camera Raw if shooting raw), select the detail tab (two pyramids). This is where the noise reduction sliders live. I was able to get rid of the pattern (almost moire) by shifting the luminance slider all the way right and the color slider halfway. This kills a lot of fine detail which you might not like to lose on the building face. One way to fix this is to select the adjustment brush (third from right, over the image) and pull the noise reduction all the way to the left (in essence, off) and paint whatever detail you wish to restore with this adjustment. Using the mask (check box at bottom of adjustment brush panel) and low feather will allow you to be pretty accurate about where you wish to apply noise reduction.

One other way to accomplish this (or to go further than this allows you) is to do the following. After making adjustments in the Camera Raw Filter, save out to Photoshop. Select the object you wish to work on (for this image, the polygonal lasso tool is most convenient) and then choose an adjustment layer (Levels, Curves, etc.). I used a Curves layer but Levels could also work. I clipped the adjustment layer to the pixel layer below - in this case the Background Copy layer (Layer/Create Clipping Mask) and darkened it. The mask limited the darkening to the underside of the building. I felt some of the color pattern was still there so I used a Hue/Saturation layer (also clipped to the pixel layer) to desaturate the area. These can all be made as subtle or dramatic as you wish by varying the Opacity of each layer.

Subscribe to see EXIF info for this image (if available)


Important: If you wish to be able to return to the Camera Raw Filter and adjust previous edits, initially you will need to convert whichever layer you will be adjusting into a Smart Object. When you're certain you have the results you want, you can rasterize that layer which will again make it possible to do real pixel-based editing on the layer. Think cloning, healing, content-aware, etc.
 
Joined
Nov 21, 2015
Messages
285
Location
The Netherlands
Real Name
Roel
Was the photo taken with electronic or mechanical shutter? I have read that electronic shutter can give such problems in shadow areas. Anyone have more information on that?
Some implementations of electronic shutters do decrease bit depth (amount of information the camera sensor captures) and thus increase noise (basically the dynamic range is a bit less "wide" so you run in to noise faster when brightening shadow area's) some other cameras do increase the overall noise a bit as they use a different implementation.
In real life this would only be a problem when you are brightening the shadows quite a bit (lets say recovering the shadows ~+2 stops).

Basically if you want the least amount of noise in your images (when you need to do quite a bit of recovery, in most camera's it's otherwise hardly noticeable) you are best off with mechanical shutter. If you can not use the mechanical shutter (need to limit shutter vibrations making the image not sharp) you do have the option to use “electronic front curtain shutter” (EFCS) or the electronic shutter (if you need to shoot completely silent). Both have their pros/cons in specific situations but when needed are very handy.

Keep in mind that on recent camera's it's hardly, if at all, noticeable. And when you need to shoot EFCS or electronic shutter there is no need to fuss over the potential slight increase in noise. A sharp image with slight increased noise (only visible when recovering al lot of shadow detail if you need to do this) is still better than a blurry image due to shutter shock. And if you recovery the shadows al lot the noise can be edited out if needed.
 

Walter

Mu-43 All-Pro
Joined
Aug 6, 2016
Messages
1,036
Location
Germany
@roelwillems
Try reducing noise (luminance and colour) by 100% and these structures are still to be seen.
So I don't think this to be the cause. Noise usually shows everywhere in a photo, not just in one (here shadow) part. As far as I see there is absolutely no noise in the sky. To me it looks more like a moiré effect.
 
Joined
Mar 25, 2018
Messages
1,880
Location
The Royal Town of Sutton Coldfield, UK.
Real Name
Richard
Looks like colour noise to me.

With a static subject like that, if the opportunity arises, take two shots one exposing for highlights, one for shadows. Open as layers in photoshop. Auto align them, then use blendif to merge them. Don't forget to alt-click the slider and separate it to get a smooth transition.

@MonikaO is already pretty adept with Photoshop so probably doesn't need this tutorial, but it might help someone else :thumbsup:

 

RS86

Mu-43 Veteran
Joined
Mar 26, 2019
Messages
256
Location
Finland
Some implementations of electronic shutters do decrease bit depth (amount of information the camera sensor captures) and thus increase noise (basically the dynamic range is a bit less "wide" so you run in to noise faster when brightening shadow area's) some other cameras do increase the overall noise a bit as they use a different implementation.
In real life this would only be a problem when you are brightening the shadows quite a bit (lets say recovering the shadows ~+2 stops).

Basically if you want the least amount of noise in your images (when you need to do quite a bit of recovery, in most camera's it's otherwise hardly noticeable) you are best off with mechanical shutter. If you can not use the mechanical shutter (need to limit shutter vibrations making the image not sharp) you do have the option to use “electronic front curtain shutter” (EFCS) or the electronic shutter (if you need to shoot completely silent). Both have their pros/cons in specific situations but when needed are very handy.

Keep in mind that on recent camera's it's hardly, if at all, noticeable. And when you need to shoot EFCS or electronic shutter there is no need to fuss over the potential slight increase in noise. A sharp image with slight increased noise (only visible when recovering al lot of shadow detail if you need to do this) is still better than a blurry image due to shutter shock. And if you recovery the shadows al lot the noise can be edited out if needed.
This is where I read it, it's from September 2019 by Robin Wong.

"Dealing with High ISO Shooting on Olympus OM-D Cameras

DO NOT USE SILENT SHUTTER

When shooting at high ISO, silent shutter will amplify the visible noise in the images
. I am not entirely sure why this is the case, but when silent shutter, or electronic shutter is engaged, the resulting image suffers more degradation, with higher amount of noise grains and artifacts in comparison to normal mechanical shutter use. Furthermore, in the shadow area of the image, there are ugly green color cast that appear as patches and blotches which are very difficult to correct or remove in post-processing. These ugly green blotches are not present when normal mechanical shutter is being used. I'd only advice to use the silent shutter when absolutely necessary - shooting a piano recital for example. In other cases when shutter sound is not a concern, using the normal mechanical shutter will ensure you better high ISO results."

https://robinwong.blogspot.com/2019/09/dealing-with-high-iso-shooting-on.html
 

Bagrphotography

Mu-43 Regular
Joined
Dec 28, 2018
Messages
96
This may seem a random question.
The 'blotches' on the under-side of the building - are there any tiles or reflective surfaces below? (on the ground as an example)
otherwise, could they be faint light reflections from the glass-windows?
 

MonikaO

Mu-43 Veteran
Joined
Sep 15, 2019
Messages
437
Location
Netherlands
Real Name
Monika
This may seem a random question.
The 'blotches' on the under-side of the building - are there any tiles or reflective surfaces below? (on the ground as an example)
otherwise, could they be faint light reflections from the glass-windows?
Here is another photo from under the building @Bagrphotography .
Looking at it better you will see the same thing going on.
Not as bad but its in the floor tiles and on the tires of the bicycles.

I also noticed in other photos from that day with the very bright light
but in totally different locations.

_1050010 copy LL.jpg
Subscribe to see EXIF info for this image (if available)
 
Last edited:
Links on this page may be to our affiliates. Sales through affiliate links may benefit this site.
Mu-43 is a fan site and not associated with Olympus, Panasonic, or other manufacturers mentioned on this site.
Forum post reactions by Twemoji: https://github.com/twitter/twemoji
Copyright © 2009-2019 Amin Forums, LLC
Top Bottom