Would love some advice on image stacking (specifically clouds!)

[s15]

Hi All

It's been a VERY long time since I dabbled with my camera, and last time I did anything I was using Photo V1.

So, this is my first time using V2, and I'm having some unusual results with cloud photos in particular. I recall when using V1 getting lovely creamy smooth cloud movement, and I'm not getting that in V2... (I suspect the issue is me, and that I'm missing something )

I don't have very dark filters so I have stacked 15 x images that are each 6 seconds long. However there are noticable clumps in each image, presumably from the gap between images (the camera needed to "reduce noise" which also took roughly 6 seconds). From what I can remember this is nothing different to when I did it before, yet got lovely smooth results...

Anyway, the photos:

(1) Using Stack, set to Mean, which gave me the smoothest results..

(2) Using focus Merge

(3) Using stack, set to Maximum

(4) Manually added all images and set each layer blend mode to Average

basically, anyone who has success with long exposure and clouds, I'd love some feedback on the process you use. I suspect the huge gap between each image is the issue BUT that said, that would have been no different to how I did it before, and yet got lovely results...

Thank you :0)

[NotMyFault]

9 hours ago, s15 said:

(1) Using Stack, set to Mean, which gave me the smoothest results..

(2) Using focus Merge

(3) Using stack, set to Maximum

(4) Manually added all images and set each layer blend mode to Average

Hi,

method 1 is best when the images are already aligned (shot on tripod).

method 2 will detect and amplify sharper areas, the opposite of you want

Method 3 will emphasis brightest areas, not what you want

method 4 is almost same as 1.

If stacking images, try to deactivate in-Camera noise reduction (for long exposure).

another method is to separate sky/clouds from rest of image and simply apply a motion blur to it. 

[smadell]

If you are trying to emulate an ND filter, stacking is your best option (setting the mode to Mean or Median). If you are taking 6 second exposures, your ISO is probably already pretty low, which would minimize noise. Also, the mere act of stacking multiple images would mitigate noise on its own. Long story short, turn OFF the camera’s Long Exposure Noise Reduction. If your camera has a built-in intervalometer or the equivalent, use it. Your goal should be to have as little time between exposures as possible. That should let you avoid the “clumping.” (Also, from past attempts at ND emulation with clouds, using more than 6 images is often better!)

[NotMyFault]

Here a rough example of motion blur on sky

 

[s15]

16 hours ago, NotMyFault said:

Hi,

method 1 is best when the images are already aligned (shot on tripod).

method 2 will detect and amplify sharper areas, the opposite of you want

Method 3 will emphasis brightest areas, not what you want

method 4 is almost same as 1.

If stacking images, try to deactivate in-Camera noise reduction (for long exposure).

another method is to separate sky/clouds from rest of image and simply apply a motion blur to it. 

Thanks for explaining each of the methods, that makes it much clearer, and method 1 looks the best fit for me  I will look into deactivating the camera noise - I hadn't thought of that! And the motion blur idea is brilliant too - I shall give it another go with all those ideas - thank you!

[s15]

14 hours ago, smadell said:

If you are trying to emulate an ND filter, stacking is your best option (setting the mode to Mean or Median). If you are taking 6 second exposures, your ISO is probably already pretty low, which would minimize noise. Also, the mere act of stacking multiple images would mitigate noise on its own. Long story short, turn OFF the camera’s Long Exposure Noise Reduction. If your camera has a built-in intervalometer or the equivalent, use it. Your goal should be to have as little time between exposures as possible. That should let you avoid the “clumping.” (Also, from past attempts at ND emulation with clouds, using more than 6 images is often better!)

Thank you smadell. I hadn't even considered turning off the noise reduction! What a numpty!! 😅 I used 15 shots, and had 3 ND filters on, ideally I need an nd64, but from recollection they are pretty expensive (i use cokin p-series) so i have a couple of others, 2 x nd8 and a graduated filter - not ideal really and hence why the longest i could go was 6 seconds. However that said if I can reduce the times between each exposure by changing the noise reduction settings, then hopefully I can continue with this setup until i have the pennies for the 64  

[s15]

5 hours ago, NotMyFault said:

Here a rough example of motion blur on sky

 

Thats perfect, a much better outcome! I think all the suggestions posted here, along with the motion blur, and I should be able to get something much smoother!

Thanks so much both!! 

[smadell]

As another example, I was in Daytona Beach last year and did not have an ND filter. I wanted to take some "long exposure" photos at the shore. For this particular shot, I put my camera on a tripod and took 15 exposures similar to this one (below). It was taken at f/22, ISO 64, and 1/40 second. So, nothing fancy about the camera settings.

Later on, at home, I stacked all 15 photos (used "Mean" as the mode) and did some extra editing to soften it up. The result is nice and "creamy smooth" and I was really happy with it.

[Old Bruce]

36 minutes ago, smadell said:

For this particular shot, I put my camera on a tripod and took 15 exposures similar to this one (below). It was taken at f/22, ISO 64, and 1/40 second.

Wow, I wouldn't have thought that the result would be that good with a fortieth of a second exposure, I always thought I would need an eighth or longer. I guess I will have to rethink my method of work, this opens up a lot of possibilities.

[smadell]

1 hour ago, Old Bruce said:

I always thought I would need an eighth or longer.

I wanted to keep my aperture tight (for depth of field purposes) and my ISO low. I took a few series of shots like this that day. This one had 15 stacked images; another used 35 images. The more images in the stack, the smoother the result. Also, on that particular day there were very choppy waves, so smoothing all that out required more images in the stack. If I had used a longer exposure, I could have relied on fewer images. The number of images-to-smoothness ratio would have changed significantly!