Why use a DSLR for video

First of all, we must say something that is drawer: cameras are designed to take photos, and camcorders are designed to record video.

For ergonomics and functions, a good camcorder will always be better (more usable) than a photo camera.

But on the other hand, a reflex or mirrorless camera (mirrorless, with interchangeable lenses) can offer image quality and technical performance at least equal to high-end semi-professional camcorders.

Why do SLR cameras offer such video features(Throughout the article we will refer to SLR cameras, but the same would apply to mirrorless cameras with interchangeable lenses)

Sensor size

Home video cameras typically mount 1/6 ″ to 1/4 ″ (3.2 x 2.4 mm) sensors. Semi-professional video cameras typically have 1/3 ″ sensors and professional 1/2 ″ to 2/3 ″ (8.8 x 6.6 mm) sensors. That is, if we compare it with a Full Frame SLR (36x24mm) the difference is enormous.

To give us an idea, an APS-C sensor on a DSLR would be very similar in terms of capture area to the frame of a 35mm cinema film ( Super 35 ).

The trend or evolution of professional camcorders or for use in film projects is towards Super 35 sensors. There are already many models on the market, which combine the characteristics of photo cameras ( Super 35 sensor -similar to APS-C- and interchangeable lenses compatible with reflex or mirrorless systems ) with the ergonomics and extra functions of traditional video cameras.

What are the benefits of a larger sensor size:

  • Greater control over depth of field . Both to achieve the blurring effects of the background of the scene (good bokeh to achieve that cinematic look) and for the opposite: to have more depth of field when recording, since the diaphragm can be closed more compared to cameras with a more sensor little.
  • Better low light performance (lower noise at high ISOs), performance is spectacular compared to home use camcorders
  • Better color quality – better dynamic range. One of the limitations of camcorders with respect to motion picture film has always been their lower dynamic range. However, with larger sensors and with the technological evolution of sensors, the dynamic range has improved considerably.

Disadvantages of large sensors:

  • Large sensors generate more internal heat, and the heat produces thermal noise . It should be noted that in video recording the sensor is working continuously.
  • DSLR sensors have too much resolution (a lot of megapixels). The camera has to reduce the information of each frame so that the result is, for example, that corresponding to Full HD at 25 fps (frames per second). This reduction in resolution can produce unwanted optical effects such as Moiré patterns (the typical optical effect on checkered or striped shirts).

Variety of objectives

Consumer and mid-range camcorders include a zoom lens, they do not have the ability to change the lens.

As we have commented, the current trend is towards the fusion of the two worlds, that of photography and that of video. We can find specialized video cameras, such as the Black Magic, which have models for different lens systems: micro 4/3, Canon EF, PL mount …

Having the possibility to change the objective and use the most suitable one for each situation is essential to achieve quality productions.

Weight and size

These characteristics, especially the size, have a double reading.

More than size, the problem with SLR cameras is that they are designed for certain postures: grip, hold … which have nothing to do with how to operate with a semi-professional or professional camcorder.

To work comfortably with a SLR in video recording (in a professional way or for professional projects) it is almost essential to incorporate a series of extra accessories: support for shoulder support, manual focus assist system ( follow focus ), external viewfinder to be attached to the screen or electronic viewfinder, audio recording system …

However, with the SLR you always have the option to use it as is, without extra equipment. With a professional camcorder you don’t have the option of taking things away to make it smaller.

Price / quality ratio

And here it is, ladies and gentlemen, the crux of the matter.

When it comes to recording video, a SLR camera has some technical and ergonomic limitations, but without being a professional camera it can produce professional video qualities , only comparable to a professional camcorder. However, the prices of camcorders  that compete with (or exceed) the quality offered by SLRs are well above the price of these. Again we would have to talk here about the fusion or confluence of the two worlds, each time these differences will be reduced and it will not be a question of talking about photography vs video , but about specific models that give us the benefits we need for a certain type of Projects.

In other words, more than decent video productions can be achieved from a mid-range reflex / mirror camera. In many cases indistinguishable from productions made with high-end camcorders.

For a professional who works all day on video, in productions that require a very high quality ‘raw material’, it will surely be more interesting to invest in specialized equipment, a high-mid-range camcorder, etc. and will have all the advantages of a tool designed and optimized for video.

But for occasional video projects, for YouTube, video tutorials, even for semi-professional or professional productions, or simply because our budget is not enough for an investment in a professional camcorder: a current mid-range reflex / mirror camera offers more video results than worthy.

Video for non-professional users

A very high percentage of users who buy a SLR camera will do so with the idea of ​​taking photos exclusively.

Another percentage will look for the video option as an essential extra, for example for recording video tutorials, reviews, video blogs, etc. for their YouTube or Vimeo channels

And a very small minority will seek the SLR expressly for professional video production, and they will surely go to slightly higher ranges.

That is, most users of the entry or intermediate range will use the camera as is (without external accessories for video, without follow focus, etc.) and what they need is for the camera to facilitate the recording process, for For example, by using a fast focus system that continuously tracks subjects (for recording moving subjects) and makes smooth focus transitions automatically. See how autofocus works on cameras .

In some comments in forums and in reviews it is said that in video recording only manual focus should be used, that it is not worth looking at continuous monitoring systems, etc. Sure, but this can be done with some external help (the follow focus system for example) and if you are a very experienced user, I would say a lot. Have you tried manually tracking your child riding a bike or playing soccer? It’s very complicated. It is possible that a continuous tracking system sometimes gets confused or that it takes a bit of refocusing in some cases, but 95% of the time it will do better than if we use manual focus (I am talking about myself or any non-professional user)

Does video recording affect the life of the camera?

This is a recurring question that we are going to try to clarify, because many users may think that by using the SLR camera (or EVIL) to record video they are reducing the life of the camera.

The life of a camera is limited mainly by its mechanical parts: the mirror mechanism (reflex cameras) and the mechanical shutter (both reflex cameras and EVIL) are usually the elements that will eventually fail at some point. Then there are many other elements that can logically fail as in any mechanical and electronic device, but statistically, making good use of the camera, a mechanical element will fail before an electronic element.

When we use a SLR camera to record video, the mirror goes up at the beginning of the recording and the same goes for the shutter (the mechanical shutter is not constantly shooting during video mode). From the point of view of using these mechanical elements, a video clip is equivalent to a photo. In general, time-lapse sessions in photo mode affect the lifespan of the camera more than video sessions, which is why many cameras include the time-lapse option in video mode.

Another important issue is heat . Large sensors generate (dissipate) more heat and require more powerful processors to handle all the information in the image (processors that also generate more heat). A SLR / EVIL camera generates more heat than a small sensor camcorder. In addition, cameras are usually smaller, some are sealed, etc. and all that heat builds up inside.

If the camera is well designed, when it detects an overheating of its internal elements it automatically shuts down the system until the temperature drops to acceptable limits. That a camera gets hot when recording video is normal and if its design is correct it should not affect the useful life . But keep in mind that these cameras are not designed to record video continuously for hours. The camera is not going to break down but depending on the model and external conditions we may have a limitation of continuous recording time (due to overheating). If we reach that limit, the camera will turn off or it will go into a safe mode and we will have to wait a bit until all the accumulated heat dissipates.

In summary:

  • The video recording does not affect the life of the camera
  • It is normal for the camera to get warm during video recording
  • A camera is designed to take photos, and optionally allows you to record video with very good quality but with certain limitations that must be taken into account (ergonomics, heat dissipation, limitation of recording time …)

SLR Cameras vs Mirrorless Cameras for Video

In the case of SLRs, the mirror (and thus the optical viewfinder and the phase detection focusing system) are no longer operational during video recording. The visualization has to be done through the rear screen and the autofocus system will depend on the image sensor (by contrast, hybrid, dual pixel ..)

An advantage of mirrorless cameras is that the electronic viewfinder does work in both photography and video, and can be very useful in bright situations. Also the electronic viewfinder offers more information about the image or scene (histogram in real time, etc.)

The image quality and the possibilities regarding the size of the sensor and the lenses will be similar, it will depend on the specific brand and model of camera (not on whether it is reflex or mirrorless). The same goes for the quality of the autofocus system.

Size can also be another factor to consider. Mirrorless cameras are usually smaller and lighter. It will depend on the use that we are going to give the camera.

The battery life is usually much higher in SLR cameras (they can accommodate a larger battery)


As important as the image is the sound quality, especially if we record interviews or tutorials, reviews, etc. You can greatly improve the audio quality of your videos by using some very simple techniques .