So, I know this is kind of a weird spot to start a video on photography. It's not very photogenic
looking. But, if you can tell, I've actually got my camera positioned right there. And,
from the camera's standpoint, it actually looks a lot better, because there's this long, metal pipe,
and then there's a light at the end of the tunnel.
And it's also kind of a difficult subject to photograph properly,
because the light at the end is just so much brighter than the rest of the photo. So,
either I could take a photo where the light looks good, or where the foreground looks good,
but I can't really get a photo where the exposure is perfect for both of them.
So, a lot of photographers, in a case like this, would use this technique called HDR photography.
So, basically, you could take one photo that's too dark, one photo that's too bright, maybe a couple
photos in between, and then you end up with a shot that looks like this. And, to me, this actually
does look pretty good. But there's a method that I like even more, and that's called image averaging.
So, I do prefer image averaging overall, but before I explain why that is, let me just show
you a proof of concept. I'm going to demonstrate that I can get the exact same looking photo as
that HDR, using image averaging. So, let me do that. I'm going to take a series of four photos.
So, these are the four photos, and I can average them together, and then just boost up the shadows
a little bit, and play around with that in post-processing. And then here's the final result.
Looks very similar to the HDR. And I can also zoom in to the darker shadow areas,
and you can see that the level of noise is basically the same between these two photos.
So, you can see that image averaging can give you a similar result, but why would anyone use it if
HDR already exists? Well, the reason is, HDR is not a perfect technique. There's definitely a few
flaws with it. Number one, a lot of HDR software, at least by default, is going to give you these
really harsh and intense-looking edits. Really not what a lot of photographers are after. Image
averaging doesn't give you something that looks quite like that; to me it's a little bit better.
But really, the main reason to use image averaging instead of HDR is if you have anything that's
moving in your photo. Movement does not play well with HDR photography. Frequently, you'll end up
with these odd artifacts in your photo - either some ghosting artifacts or halos around your
subject. It just doesn't look that good. And image averaging can actually look significantly better.
So, let me move to a different location,
and I'll demonstrate that with a real-world subject that has a little bit of movement.
Now, you can probably tell that it's not even particularly windy right now,
but there is a little bit of a breeze. And whenever the gust of wind comes by, some of
those tree leaves on the palm tree behind me start to move. And, of course, from photo to photo they
might not move that much. But even a little bit of movement can lead to some strange blending
artifacts when I try to make an HDR. So, let me do that right now, and I'll explain what I mean.
I'm going to select three frames and one stop of exposure difference. When this is on, the
camera is going to automatically take that HDR. So, I can take a really quick burst of photos.
Like that. And, here's how the three photos look. Clearly, there's not that much movement,
but when you zoom in, there is a little bit that you can see. The palm leaves aren't in
the exact same spot from photo to photo. And, actually, creating an HDR right here,
I definitely have the potential to have some weird artifacts around the edge of the palm leaves.
This, I think, demonstrates that pretty clearly. And that's not ideal. It would
take a decent amount of time to fix that in Photoshop. So that's why,
at least in this case, I would much rather use the image averaging method instead.
So, to do that, I'm going to actually turn off the auto exposure blending. And I'm also going
to decrease the exposure compensation. In this case, I'm going to do -0.7. And the goal here is
just to have nothing in the photo at all that's overexposed. You can't recover anything that's
overexposed, but this image blending technique lets you recover shadow details really well.
So, now that I've done that, I'm going to take a quick burst of photos. In this case,
I'm going to do four photos in sequence.
And you can see these four photos, again, look very similar between the shots.
But the difference right here is the way that I blend these together
no longer creates these weird artifacts. In fact, my final image average looks like this.
And when I zoom in, any of those areas that had movement
now just kind of look a little bit blurred. And I know that this also isn't ideal - I mean,
in a best case scenario, there wouldn't be any movement here at all - but I think
that it's a lot better than having those weird artifacts. In this case,
it basically just looks like I had used a slightly longer shutter speed in the first place.
And that's why, if I'm taking pictures from a tripod, and there's anything moving in my
photo - even if it's not my main subject - I basically don't do HDRs any more. These days,
I'll either do image averaging, or I'll just try to get the photo correct in a single shot.
And hopefully this demonstration kind of explained why. But I haven't really yet
gone into how to take image averages and blend them together as well as possible.
It's not that complicated, but let me just demonstrate that next.
So, to actually create your image average, you're going to take all those photos that
you just captured, and then put them into some software like Photoshop - anything that lets you
open those photos as layers. So, generally the method that you can use to average them
is to select all of those layers, convert to a smart object. And then go up to the smart
object stacking options, and click "mean." Some photographers tell you to click median;
I prefer the look with mean. But either way, this is going to - after a little
bit of a delay - average your photos together, so that you've eliminated a lot of that noise.
And it's really important when you're averaging these photos
together that there isn't anything in the picture that's overexposed.
This image averaging technique is really useful for recovering shadow detail, but it doesn't help
you for recovering highlights. So, make sure that none of your highlights are overexposed.
Now, specifically, the amount of shadow improvement you can get with this technique
just depends on how many photos that you take. Every time you double the number of photos, you're
going to improve the detail in the shadows by one stop. So, if you take two photos, you've improved
the noise by one stop. Four photos gives you two stops. Eight photos for three stops. And so on.
That brings me to probably the biggest problem with image averaging. If you want more than maybe
three or four stops of improvement, you're just going to need to take a ton of photos.
HDR, you don't need nearly as many by comparison. So, image averaging is mainly useful
when you'd want to mimic more of a basic, maybe, three photo - or at the most five photo - HDR.
Specifically, the math works out where you could mimic a three-image HDR with
four photos through image averaging. But if you want to mimic a five-image HDR,
you'd need 16 pictures to image average for the same result. So,
it's clearly not always going to be practical if you go beyond that point.
And image averaging is also a little bit trickier than HDR because it requires slightly
more specialized software. For example, Adobe Lightroom can easily merge HDRs,
but it doesn't have an image averaging option. That's not really the end of the world;
most photographers probably have software that can do image averaging.
But it does probably mess up some photographers' workflow a little bit.
So, this definitely is not a perfect technique, and the point is not that image averaging should
completely replace HDR. Personally, I still use HDR in cases like this, where there's nothing
moving in the photo, and I needed five images to capture all of that dynamic range. But in
situations where there *is* movement in my photo, I pretty much exclusively use image averaging
these days, and I kind of recommend that you do the same thing. I know that it's not the orthodox
technique, but it works really well, especially if you're photographing subjects like the ocean,
or even if there's just a little bit of wind that could rustle some leaves in your photo.
It's a very useful technique, and I hope that you find it useful as well.
As always, let me know below the video if you've got any questions! And if you want
to see more lesser-known photography tricks like this, just follow my channel and hit the
little bell notification button on YouTube. I'm Spencer Cox, and I'll see you next time.