The Basics of Viewfinder – DSLRs, Mirror-less, and the Exposure Triangle


The viewfinder is one thing that always differentiated photographers from the rest of the people using cameras. Viewfinders have always allowed photographers to see better, and focus on making their compositions work, while the normal people had to depend on Polaroids, and then digital cameras, and now mobile phones or the screen of the LCD.

Image by Markus Spiske from Pixabay

There’s a really funny story about a photographer and the viewfinder. There’s a photographer who has a difference between the hair on the eyebrows of left and right eye. In fact, he is almost bald on the right eyebrow. Because he has been doing photography for so many years – the hair that is naturally one of the least susceptible to hair-fall just disappeared into thin air. Or into the viewfinder – as it might be the case.

The viewfinder, the exposure meter, and the exposure triangle are the three things that have helped photographers nail the exposure for years.

The film generation, especially, had no real options. However, things have moved on. Now, we have two types of viewfinders. The traditional optical viewfinder continues to find space in the DSLRs, especially from the house of Canon and Nikon – the traditional camera brands who have survived the digital age.

There’s the new electronic viewfinder that has made its mark since the beginning of the mirror-less and DSLTs, and originally, through the mini viewfinders of the digital cameras.

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The Optical ViewFinder – The True Viewfinder

DSLR’s are short for Digital Single Lens Reflex Camera. DSLR has a mirror placed at an angle of 45 degrees to the sensor. What the mirror does is feeds the images to the viewfinder in real-time. When the shutter is pressed, the mirror goes up, the viewfinder goes black for the duration of the shutter. The light reaches the sensor and the image is recorded.

The Optical Viewfinder shows what the Lens sees. Photo by Jonas Svidras from Pixabay.

The Optical Viewfinder provides true view in the viewfinder, along with some of the exposure settings which are visible just below the frame. These include the shutter speed, aperture, ISO, and exposure compensation meter. These, however, vary from manufacturer to manufacturer and model to model. Optical viewfinder is also always active, and doesn’t require batteries to power-up.

The Electronic ViewFinder – Digitally Powered

The electronic viewfinders are found in DSLTs and Mirrorless cameras, especially the higher-end ones. They display the same image as displayed in LCD on the back of the camera. Since there’s no mirror, there’s no way of the image reaching the viewfinder without the aid of the sensor. So electronic viewfinder is always displaying images as visible to the sensor, instead of, as visible to the lens – as is the case in the optical viewfinder.

In the electronic viewfinders, what you see is what you get.
Image by MikesPhotos from Pixabay.

Since the images displayed are directly from the sensor, there’s also this benefit of seeing the correctly exposed images. This means that you will always be sure of your exposure while shooting in the electronic viewfinder mode, while you will need a knowledge of exposure while shooting in the optical viewfinder mode.

The Exposure Triangle and the ViewFinder Modes

Getting the exposure right is one of the biggest parts of photography. Often, however, modern technology is taken to be a substitute for the knowledge of exposure. WYSIWYG (What You See is What You Get) is one of the most detrimental factors surrounding the art of photography, more so with the advent of electronic viewfinders. Let us take a look at the exposure while we cover both the viewfinder types.

Technology hasn’t altered the exposure knowledge required. Image by Gabriel Doti from Pixabay.

The Optical Viewfinder and the Exposure

Taking lead from the older generation of SLRs, the optical viewfinder is only to help you see what the lens is seeing. Here, you are the controller of the exposure. Usually, there’s an exposure meter at the bottom in the viewfinder that can help you decide the correct exposure settings, along with the values of aperture, shutter speed, and ISO. Closer to the traditional form of photography, this requires the knowledge of the Zone System, and the exposure triangle, and what each of the attribute contributes.

The Electronic Viewfinder and the Exposure

The electronic viewfinder can be both easy as well as misleading at the same time in terms of exposure to set.

When it is so easy as to move a few dials to set the correct exposure and see how it looks, there are a few pitfalls to look out for, especially with the aperture and shutter speed values.

When you reduce shutter speed to improve brightness in the scene, you are adding plenty of blur, but you cannot see that in the electronic viewfinder. However, an electronic viewfinder will give you a false sense of perfect exposure settings. Here, it is about your awareness of exposure, and the triangle to set the correct exposure.

Optical Viewfinder vs Electronical Viewfinder

The Optical Viewfinder: The Advantages

Optical Viewfinders are often sturdier. Image by dujin yun from Pixabay

  • The optical viewfinder shows you exactly what the lens is seeing. This helps a great deal in getting correct exposures in the worst of the situations – like extremely dark or extremely bright. This, thus, helps in better visibility and focusing despite the circumstances. The same isn’t true for the electronic viewfinder. Unless you get the correct exposure settings, you aren’t able to see the scene as clearly.
  • The optical viewfinder is always accessible and doesn’t require any battery to operate. An optical viewfinder can be used to survey the scene and frame the compositions while the camera is switched off. On the other hand, the electronic viewfinder depends on camera battery. As long as an electronic viewfinder is on, it drains the battery. However, when switched off, it goes black. One of the recent complaints with mirrorless has also been regarding the batteries, and somehow they seem to be interconnected.
  • A DSLR with an optical viewfinder can easily have an electronic viewfinder when the LCD shooting mode is used. LCD viewfinder loupe is an effective way of converting a DSLR’s screen into a viewfinder. In live-view shooting mode (LCD one), the mirror is always up, and hence the camera is automatically mirrorless. Although, in studio shoots, the mirror up mode doesn’t work in some systems.
  • There’s no lag in the optical viewfinder, which may happen in the electronic viewfinder. The lags don’t affect normal photography, but in speed photography, real-time clear view of the target is essential. This is the reason why wildlife and sports photographers will perhaps be the last people to move the ship to mirrorless. The technology has been moving fast, but there’s nothing as fast as real-time of the optical viewfinder.
  • The chances of getting a wrong exposure in the electronic viewfinder are similar to the chances of getting wrong exposure in LCD. Unless you look carefully at the peaking and histogram, you are relying on the auto-brightness feature or brightness that you had set. Most of the times, you don’t tinker with the brightness of the LCD (or the electronic viewfinder). So, if you have them boosted up or mooted down to counter extremely dark or overtly sunny conditions, you are likely to be off with your exposure the next time you are shooting. Unless you are cautious. In such situations, what you see is not really what you get.
  • The optical viewfinders are sturdy, and last really long. There’s hardly anything that can go wrong in the optical viewfinder.

The Electronic Viewfinder: The Advantages

electronic viewfinder

  • The electronic viewfinder shows you exactly what is going to be recorded on the sensor. This takes the complexities of the exposure out of the way. Purists may feel otherwise, but if there’s a technology to be used, it should be used, especially if it is letting you focus on the job. The main aim of technology is to simplify lives, and mirrorless does exactly the same.
  • The best part about the electronic viewfinder is that it shows the actual depth of field. Ever heard of the depth of field preview button on Canon and Nikon cameras? It is perhaps the most unused feature because of the placement and relative anonymity of the feature. Very few photographers actually use depth of field preview, and it isn’t an ideal way to shoot either. The electronic viewfinder provides the actual depth of field preview without having to look for a button and press it. It helps to achieve better focusing and composition, and correct focusing on the true subject.
  • The overlays that the electronic viewfinder can display are remarkably great. Consider the focus peaking, for example. It is a dream feature for any photography, especially the ones working at f/2.8 or lower, or the macro modes. With focus peaking, you can easily figure out the right focus points for the picture. While shooting fashion at f/1.2, you might already know the chances of getting the focus on the eyes correctly. It is possible using the LCD on DSLRs, but using LCD with viewfinder loupe is the same as using a mirrorless, albeit with a considerably higher weight and bulk.
  • The electronic viewfinder also comes handy with the highlight or shadow clipping graphs. This serves as a warning when the exposure is going too low or too high. This isn’t possible in the optical viewfinder.
  • A major problem with an optical viewfinder is the usage of ND filter and other filters. Often, a DSLR’s viewfinder goes blind on using ND filters, especially of the higher range. This results in plenty of lapses, exposure calculators, etc. In the electronic viewfinders, there’s no such issue because what you see is what you get. Although, arguably, you still need to calculate exposure while using ND filters.
  • While the sensors have infrared and UV filters, the lens does not. When you use the optical viewfinder, a mirror bounces the light from the lens directly through to the viewfinder. This means that when using an optical viewfinder and shooting directly into the sun can damage your eyes. In the LCD mode, it isn’t so dangerous. And the electronic viewfinder is merely an extension of the LCD mode, and hence it does not harm. Also, you can control the brightness of the viewfinder.

Other Factors

The most important feature of a camera is its “ownership”. Unless the camera can give the feeling of personal “ownership” to the user, the camera does not work. That is why, manufacturers work on different ergonomics, and so on. What’s really important is to understand the differences and requirements of different type of photographer. A DSLR cinematographer would like to simply carry a lighter camera. He won’t even be using a viewfinder for most of the times. For him, a mirrorless without a viewfinder will also work just fine.

Then, there are primarily cinematographers who tend to use their camera for photography as a hobby. They don’t care for the drawbacks of the electronic viewfinders in wildlife or sports photography because it isn’t their main aim. They would be choosing their cameras on the basis of the video features and LCD.

Then come the hybrid users – who use the camera for both photography and cinematography equally. This is where the viewfinder can be a deal-breaker between a DSLR and a mirrorless. With DSLRs, you can get an equivalent of electronic viewfinder via the loupe easily, However, the reverse isn’t true. This is, however, slowly shifting, and except for purists, most of the photographers have accepted the electronic viewfinders.

There are photographers, however, who won’t yet feel comfortable with the electronic viewfinder. It isn’t about the lack of accepting technology but the time lag that it is the case. There’s already a shutter lag and a human speed lag to deal with, adding another one might be difficult.

Optical viewfinders are pure, clear, and accurate, and the professionals still would go for them.

optical viewfinder

Conclusion

The mirrorless cameras have been a revolution in the camera segment, with all the major manufacturers working on their own range of mirrorless cameras. Yet, DSLRs won’t go away, not as easily anyway. The simple design called single-lens reflex with a mirror at an angle that feeds the image to the viewfinder is unbeatable. Not only does this prolong battery life, but it also protects the sensor from being exposed for long periods.

What do you prefer, and why? An optical viewfinder or an electronic viewfinder? Let us know in the comments below.

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Author Details
I’m Raghav Gautam, a professional photographer and cinematographer who specializes in products and fashion. My primary ability is to help sell products via visuals, and more recently, I’ve entered into filmmaking too, hoping to get a big break some day. Till then, happy making short films and videos.
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I’m Raghav Gautam, a professional photographer and cinematographer who specializes in products and fashion. My primary ability is to help sell products via visuals, and more recently, I’ve entered into filmmaking too, hoping to get a big break some day. Till then, happy making short films and videos.

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