Making great shots out of snapshots

Nothing to do with over-processing a single photograph. Rather, I am referring to a technique known as exposure blending, where two or more exposures of the same composition are used to create the final image. I use it mainly for interior design, exteriors and commercial spaces, although it can also be very useful for landscape photography.

Every winter I spend some time in the alps and I love to shoot buildings that I find particularly inspiring.
As an example, here you see my exterior shot of Villa Kofler Wonderland Resort, a beautiful hotel in Campitello di Fassa (Trento, Italy).
The shoot was also an opportunity to meet the owner Mr. Ivo, who made history as a climber in the area and showed me some absolutely stunning pictures of frozen waterfalls he took with his phone the day before!

Back to the main topic, I blended 10 exposures to compose the final image below.



Before I show you those 10 exposures, please have a look at a comparison between an average shot I took that day and the final image I pulled off from my entire shoot.

 Move the vertical slider left or right too see a complete 'Before' or 'After'. 

To me, the image produced by blending several exposures is far more compelling than the average one.

Exposure blending comes in handy in quite a few scenarios. For one thing, no matter how great the dynamic range of your camera is, there will always be scenes that exceed it, so that you end up clipping either the highlights or the shadows, or both. Clipping means that parts of your image become completely white or completely black, so that no information can be recovered from them.

When this happens, you are left with only two options:

  1. Take a single shot, with a combination of aperture, shutter speed and ISO that produces a good compromise.
  2. Take several shots (e.g. normal exposure, + 2 stops, - 2 stops) and blend them together in some way.

To get good results using the first method, you need to have a camera with an amazing dynamic range.
It goes without saying that such cameras tend to be expensive and, no matter how good, the result will always be some sort of compromise.

The second method has the potential to lead to perfection and is all about producing a single shot by combining two or more exposures. It also allows for much cheaper gear, as your camera does not need to have such a great dynamic range.
Several tools are available and HDR software is one of them (HDR stands for High Dynamic Range). These programs are usually easy to use, but there is a tradeoff as they do not provide full control over the final result.

If you do want to have full control (guess what? I do!), you are better off using exposure blending. 
The tradeoff here is that exposure blending requires a fair bit of post-processing. To tell you the truth, it sometimes involves a lot of post-processing, especially if you are blending a lot of images.

What you need to do is brush in and out parts of different exposures to compose a blended image in Adobe Photoshop or similar software, using masks to control what parts of each shot are going to be revealed in the final image.

There is actually more to exposure blending than simply being able to produce high dynamic range images with full control. For example, I love to take several exposures of the same composition at different times of the day. For my final image of Villa Kofler Wonderland Resort, I kept shooting the hotel for 1.5 hours, as natural light and artificial lights changed their intensity and quality from before sunset until it was completely dark.

While this is not intended to be a tutorial on exposure blending, here is a tip: if you are planning to get a final image as a blend of several exposures, it is important to shoot those exposures with that precise idea in mind.
What I mean by this is that you should expose for a single feature at a time, ignoring entirely how under or overexposed all the other elements of your composition are going to be in that particular shot, since you will expose them correctly in a different shot.

Now have a look at the bunch of snapshot-looking images I took to produce the final image of this hotel in the Italian Dolomites: 

 
Exposed for the mountain and nothing else.

 
Façade (pretty dark) + some artificial lights.

 
Façade, + 2 stops over (nice white!).

 
First artificial lights appearing on balconies.

 
Balcony lights + Christmas decorations.
 
Artificial lights again.
 
Terrace and artificially lit façade.
 
Best exposure for the sky.
 
Lights/shadows (electric blue sky not good).
 
Restaurant lights (sky pitch black, not good).

 

If you consider each shot in isolation, they all look pretty average at best. Nonetheless, each exposure had a precise purpose and was key to the final result.

I always stop shooting exteriors once the sky gets completely dark. Also, I am not at all a fan of electric blue skies. With no exposure blending planned, I would not have taken the last two shots in the sequence above.

Here is the final image again:

I reckon the result I achieved with exposure blending is well worth the extra time spent shooting and post-processing the images.

Cheers,
Enrico

Why I do NOT need a full frame camera

Some people raise their eyebrows when I tell them I am an APS-C shooter, which means the crop sensor inside my camera is significantly smaller than the 35mm equivalent sensor of full-frame cameras.
Truth be told, I never owned a full-frame camera and, at the moment, I am not planning to upgrade to it.
Full-frame cameras and the lenses designed for them are more expensive than their crop sensor equivalent, but it is not just about the money
The main reason for me is that I doubt it would be a real upgrade in the first place!


Editor's pick on GuruShots.com, Prime Collection on 500px

I believe there are only two fields of photography that really benefit from a full-frame sensor:

  1. Portrait photography (or, in general, whatever field of photography where it is desirable to have a subject in focus and everything else nicely blurred).
  2. Low light (high ISO) photography.

In the above scenarios, the best results are achieved by using fast lenses and shooting them wide open (i.e. at low F-stops, such as 1.2, 1.4, 1.8, etc.).
Now the point: full-frame cameras can take full advantage of the widest aperture indicated on the lens, whereas APS-C cameras cannot.

This is because on crop sensor cameras, you must multiply both the focal length and the aperture indicated on the lens by the crop factor to obtain the values that correctly describe the behaviour of your lens

On APS-C cameras the crop factor is 1.5, the only exception being Canon (1.6).

Example: a 50mm F1.8 lens only behaves as such on a full-frame camera. On an APS-C camera with a 1.5x crop factor such as mine, the same lens behaves like a 75mm F2.7. Definitely a much narrower field of view and over a stop darker in terms of aperture!

FOCAL LENGTH:   50mm x 1.5 = 75mm 
 APERTURE:   1.8 x 1.5 = 2.7

 


Most portrait photographers use full-frame cameras to take full advantage of their fast lenses (maximum aperture such as 1.2, 1.4 or 1.8), thus being able to produce a very pleasant, defocused background known as bokeh.

Fast lenses at low F-stops are also helpful if you shoot in low light conditions, so that the sensor will gather the maximum amount of light allowed by your lens. Once again, full-frame cameras perform better than APS-C cameras in these conditions.
Of course, you could still bump the ISO to compensate for the smaller aperture on APS-C, thus making the image as bright but... the higher the ISO, the more grainy the image

By now you probably see why I am not upgrading to full-frame. Since I am a landscape and wildlife photographer, the limitations above do not really impact my work.

As a landscape photographer, I very often want to have everything in focus back to front and such an effect is more easily achieved on APS-C.
As a wildlife photographer, my main struggle is getting close enough to my subjects to reasonably fill the frame. Since a 300mm zoom becomes a 450mm on my APS-C camera (300mm x 1.5), this is an advantage for me rather than a limitation!

I also love shooting interiors and exteriors and, to have everything in focus, I almost always set my aperture to either 7.1 or 8. This means I do not need to buy an expensive fast lens, because I would rarely (if ever) shoot it wide open anyway!

I want to conclude this post with a sort of disclaimer, just in case one day you see me with a full-frame camera in my hands.
My Sony Alpha 77 Mark 2 has a 24MP, APS-C sensor. That is already quite a lot of megapixels for a crop sensor. On the other hand, I would love to have a 36MP or even a 42MP sensor. 
If one day I ever feel the need to have bigger files for my prints, or to be able to crop more into my images while retaining a reasonably high resolution, that day I will definitely upgrade to full frame.

I think a 42MP crop sensor camera would pay a significant toll in terms of image quality in low light conditions.
Why? Consider a full-frame sensor (a) and an APS-C sensor (b) with exactly the same resolution (e.g. 42MP).
The amount of light hitting the sensor per unit time and unit area will be the same for (a) and (b). But since the sensors have the same resolution and (a) is bigger than (b), the amount of light gathered by each pixel will be less on the APS-C sensor (b), because there will be more pixels per unit area sharing the light hitting that area.
In other words, since the sensors have the same resolution (the same number of pixels), the pixels will need to be more densely packed on the crop sensor (b) than on the full frame sensor (a) because the crop sensor is smaller.

I hope it makes sense. A surprisingly high number of photographers ignore these facts ;-)

Cheers,
Enrico