Canon R5 ISO Sensitivity for Night Shots

[Kyle Jones]

When I get a new camera I try to spend some time figuring out what ISO settings work best for Milky Way shots. To a large degree, ISO is really the only setting I have to make a conscious choice about. The length of the exposure is set by what it takes to avoid star movement and I generally shoot stars with a wide open aperture to get as much light as possible. With this in mind, I'll set up for the shot and then take exposures with identical settings except for the ISO. Once I get them into the computer, I push the darker exposures to give them all the same brightness and look at the results.

I captured this image on what should have been a dark night in Glacier National Park. Some aurora broke the darkness I was planning on, but I can live with that. Each image was captured with my Canon R5, Rokinon 14mm SP f/2.4 lens at f/2.8 (I stop this lens down to f/2.8 for better vignetting performance) and an exposure time of 25 seconds. I captured images at ISO 1600, 3200 and 6400. The full images are shown below, processed identically in Lightroom except for the exposure. I pushed the ISO 1600 image by 2 stops in Lightroom and the ISO 3200 image by 1 stop.

1) ISO 1600

2) ISO 3200

3) ISO 6400

What is clear to me in these images is that the noise in the shadows (look in the trees on the right) gets worse at the higher ISOs: even after pushing the lower-ISO exposures to match the brightness.

Here is a 100% crop in an area that shows relatively bright sky, darker mountains, and dark trees. The top row includes 100% crops of the above images. Just for grins I ran Topaz Denoise AI and included those versions in the bottom row.

Based on this work, I am leaning toward using ISO 1600 for my night shots with the R5. I'll probably continue taking exposures at 1600 and 3200 until I get confident with these results.

 

[JimFox]

Hey Kyle, thanks so much for doing this comparison.

First off I have to say that the ISO 6400 looks really good, the differences look very small to me unless my eyes are just going bad.

Did you just increase the exposure? What about Shadow Recovery? I personally like to use the Shadow Recovery first and then adjust the exposure 2nd. It depends how underexposed and dark the ground layer is, but often I will go with 50% Shadow Recovery in ACR, and then adjust the exposure to get the ground layer looking right.

For those of us doing Timelapse, we don't have the option of shooting at 2 different ISO's, so I would say ISO 3200 would be the best choice. It would give you more flexibility and the Shadow Recovery doesn't have to work as hard.

 

[Ben Egbert]

Thanks for doing this Kyle, very informative. What settings are you using in Topaz AI?

 

[Kyle Jones]

Hey Kyle, thanks so much for doing this comparison.

First off I have to say that the ISO 6400 looks really good, the differences look very small to me unless my eyes are just going bad.

Did you just increase the exposure? What about Shadow Recovery? I personally like to use the Shadow Recovery first and then adjust the exposure 2nd. It depends how underexposed and dark the ground layer is, but often I will go with 50% Shadow Recovery in ACR, and then adjust the exposure to get the ground layer looking right.

For those of us doing Timelapse, we don't have the option of shooting at 2 different ISO's, so I would say ISO 3200 would be the best choice. It would give you more flexibility and the Shadow Recovery doesn't have to work as hard.

My original processing was done on the 3200 image. I just copied the settings and then adjusted the exposure of the others to match. You're eyes are correct, the differences are not large. I will say, though, that with the R5 the shadows are significantly cleaner when pushing an iso 1600 image than in an iso 3200 image with all other settings the same.

Thanks for doing this Kyle, very informative. What settings are you using in Topaz AI?

I ran auto on the iso 1600 image and it picked noise 2, sharpness 17 and recovery 10. I used those settings on the other two images.

 

[Ben Egbert]

Ok, I also start with auto, thanks for the info.

 

[AlanLichty]

Such a shame you had to "put up with the aurora" in your test scene.

Looks like Topaz Denoise AI earns its keep with these tests results. For the record I am not that far off of these results with the 5D MkIV although I prefer to stop at 3200 if I can. I did set my auto ISO limit to 3200 so I can just set it to auto when I want and still stay within my noise limits.

 

[Kyle Jones]

And now, in another wrinkle, I fully processed an ISO 1600 version of the image for which I had previously only processed the 3200 version. Contrary to the results above, I believe the ISO 3200 version has better detail and less noise. I'll share both images in a little while.

 

[JimFox]

And now, in another wrinkle, I fully processed an ISO 1600 version of the image for which I had previously only processed the 3200 version. Contrary to the results above, I believe the ISO 3200 version has better detail and less noise. I'll share both images in a little while.

That will be interesting to see!

 

[JimFox]

Such a shame you had to "put up with the aurora" in your test scene.

Looks like Topaz Denoise AI earns its keep with these tests results. For the record I am not that far off of these results with the 5D MkIV although I prefer to stop at 3200 if I can. I did set my auto ISO limit to 3200 so I can just set it to auto when I want and still stay within my noise limits.

Ha ha, I agree... I sure wish I had to “put up” with an Aurora... although in an upcoming Timelapse from Death Valley I literally ended up with every color of the rainbow I think.

 

[Ben Egbert]

Keep um coming Kyle. Like to see and ISO4000

 

[Kyle Jones]

Keep um coming Kyle. Like to see and ISO4000

I didn't take any at 4000, sorry. I'd expect it to be awfully similar to ISO 3200. My biggest conclusion at this point is that the R5 works pretty darn well at ISO 3200. I've also decided for the best image quality it remains preferable to blend. I have a long (3 minute) exposure at ISO 800 of the ground layer that I will use for the finished image - at least for the dark trees on either side. The other option would be to blend multiple images (which I didn't capture). The easiest way to do this (and it would apply to your time lapse images to create a clean still photo) would be to take something like 6 identical images, process them how you like in RAW or Lightroom, then bring them in to Photoshop as layers. Select all the layers, right click, and convert to a smart object. Then change the stack mode of the smart object to median. This should give you a really clean ground layer but with a blurry sky. Then just mask in your favorite image of the sky and you are all set. With your moving clouds I wouldn't try to stack sky images.

So here is my latest comparison. I ran through my full processing for both ISO 3200 and ISO 1600 images. Both of them included some Topaz Denoise. Looking at these, I think I'll stick with ISO 3200 for the R5. The shadows in the dark areas are cleaner and there is more detail in the rocks.

Full image taken at ISO 1600

Full image taken at ISO 3200

100% crops at a few locations.

 

[Ben Egbert]

Great test Kyle and thanks for the stacking advice, I am going to give that a try.

 

[JimFox]

I didn't take any at 4000, sorry. I'd expect it to be awfully similar to ISO 3200. My biggest conclusion at this point is that the R5 works pretty darn well at ISO 3200. I've also decided for the best image quality it remains preferable to blend. I have a long (3 minute) exposure at ISO 800 of the ground layer that I will use for the finished image - at least for the dark trees on either side. The other option would be to blend multiple images (which I didn't capture). The easiest way to do this (and it would apply to your time lapse images to create a clean still photo) would be to take something like 6 identical images, process them how you like in RAW or Lightroom, then bring them in to Photoshop as layers. Select all the layers, right click, and convert to a smart object. Then change the stack mode of the smart object to median. This should give you a really clean ground layer but with a blurry sky. Then just mask in your favorite image of the sky and you are all set. With your moving clouds I wouldn't try to stack sky images.

So here is my latest comparison. I ran through my full processing for both ISO 3200 and ISO 1600 images. Both of them included some Topaz Denoise. Looking at these, I think I'll stick with ISO 3200 for the R5. The shadows in the dark areas are cleaner and there is more detail in the rocks.

Full image taken at ISO 1600
View attachment 38901

Full image taken at ISO 3200
View attachment 38899

100% crops at a few locations.
View attachment 38900

Hey Kyle,

I read what you wrote about the smart object and then the stacking, and then using that one layer with a layer mask for the timelapse? I often have 1200 to 1500 images in my timelapses, I understand about the median blend for the ground, but I don't have any idea how I would then get to apply to all 1200 to 1500 images?

If you are suggesting 1 stacked ground layer that would then be blended into the 1200-1500 images, that means the ground layer won't ever change? With my night time timelapses the light on the ground layer will ebb and flow, so I am not sure I would want to apply 1 ground image to layer mask over the 1200-1500 if that's what you meant. But I guess I would have to think about it more.

But now I am curious, how would you get the stacked ground layer then layer masked into the 1200-1500 (or how many) other images? I am drawing a total blank. There may be a time that would be cool to do, and it would be interesting to know how. Any chance you could write up a tutorial on it at some point?

And thanks for the updated images, I think these will be helpful for many people as we have a lot of people here shooting with the R5.

 

[Kyle Jones]

Hey Kyle,

I read what you wrote about the smart object and then the stacking, and then using that one layer with a layer mask for the timelapse? I often have 1200 to 1500 images in my timelapses, I understand about the median blend for the ground, but I don't have any idea how I would then get to apply to all 1200 to 1500 images?

If you are suggesting 1 stacked ground layer that would then be blended into the 1200-1500 images, that means the ground layer won't ever change? With my night time timelapses the light on the ground layer will ebb and flow, so I am not sure I would want to apply 1 ground image to layer mask over the 1200-1500 if that's what you meant. But I guess I would have to think about it more.

But now I am curious, how would you get the stacked ground layer then layer masked into the 1200-1500 (or how many) other images? I am drawing a total blank. There may be a time that would be cool to do, and it would be interesting to know how. Any chance you could write up a tutorial on it at some point?

And thanks for the updated images, I think these will be helpful for many people as we have a lot of people here shooting with the R5.

I was more referring to making a still image, as that is where that part of the conversation started with Ben. Since he captured a bunch of images to assemble a video, he should be able to extract plenty of stills for noise reduction. However...

It is possible to mask part of a still image over a video. Take a look at my editing video in Photoshop tutorial. You can place the clean ground image on a layer on top of the video and apply a mask to restrict what gets used. Then the sky can move and twirl while the ground stays still and clean. Obviously this only works if the ground is the same in each frame and the camera doesn't move.

 

[JimFox]

I was more referring to making a still image, as that is where that part of the conversation started with Ben. Since he captured a bunch of images to assemble a video, he should be able to extract plenty of stills for noise reduction. However...

It is possible to mask part of a still image over a video. Take a look at my editing video in Photoshop tutorial. You can place the clean ground image on a layer on top of the video and apply a mask to restrict what gets used. Then the sky can move and twirl while the ground stays still and clean. Obviously this only works if the ground is the same in each frame and the camera doesn't move.

Gotcha, I will have to reread your video tutorial. Thanks Kyle!

 

[Ben Egbert]

Ok, here is one using your tutorial. As it turned out the sky also blended nicely so this is 6 images using Median blend. No NR applied.

 

[AlanLichty]

Ok, here is one using your tutorial. As it turned out the sky also blended nicely so this is 6 images using Median blend. No NR applied.

Impressive result.

 

[Jameel Hyder]

Very nice Ben. I have to try this out one of these days.

 

[Kyle Jones]

Ok, here is one using your tutorial. As it turned out the sky also blended nicely so this is 6 images using Median blend. No NR applied.

View attachment 38933

Very nice - how do the shadows look when you zoom in?

 

[Ben Egbert]

Very nice - how do the shadows look when you zoom in?

The are very clean. Not as much detail as you would get in a day shot, the rocks are great the foliage less so.