dslr or dslm

DSLR or DSLM? What are the key differences, and what are the advantages and disadvantages of the two systems?

About seven years ago, SLR cameras were still the alpha and omega. And if you wanted to shoot at a high level, you could not avoid buying a DSLR. But for some years now, the SLR cameras have received serious competition from the mirrorless system cameras (digital single-lens mirrorless, DSLMs). Although they had some teething problems in the first few months and years, they have recently caught up vigorously and are sometimes even superior over the DSLRs. For this reason, many customers ask the question before buying a new camera: DSLR or DSLM?

The Crucial Difference between DSLR and DSLM

First of all, let’s talk briefly about the one crucial difference between DSLR and DSLM. This difference is basically pretty quick to the point: SLR cameras have a mirror construction in the interior while mirrorless system cameras – as the name implies – do not. What exactly this means for the DSLRs or DSLMs and which advantages and disadvantages the different construction methods entail will be clarified below.

Mirrorless are smaller and more manageable.

Let’s start with a difference that is probably the first thing that strikes the eye when it comes to the question of DSLR or DSLM and when looking at different models: a mirrorless system camera is smaller than a single-lens reflex camera and therefore lighter. The lenses are often a bit more compact. The reason for this is obvious – as previously mentioned, DSLMs do without the elaborate mirror construction in the interior which makes a more compact design possible.

The smaller size is a big advantage in many cases. If you’re often out and about with your camera all day, you’ll love the lighter weight and smaller camera which is simply more mobile and fits a smaller hand. But there are exceptions – people with extremely large hands, for example, sometimes find DSLMs too small. In addition, some people prefer really large handles which the mirrorless cameras often cannot offer.

The different designs affect the viewfinder.

Let’s talk again about the “decisive difference” in terms of construction. What is the purpose of the mirror construction inside a DSLR? If we want to express it in a simplistic way … the light falls through the lens when using a SLR camera and then strikes the inside of a mirror construction which reflects the light (and thus the image) and guides it into the optical viewfinder. Therefore, when we look through the viewfinder, we see the “real” picture of what’s going on in front of the lens. If you now press the shutter button, the mirror folds up briefly and the light is no longer in the optical viewfinder (which is briefly black) but on the sensor where the image is then captured and stored, so to speak.

Clearly recognizable: The mirror construction is in front of the sensor which guides the image into the optical viewfinder.
Clearly recognizable: The mirror construction is in front of the sensor which guides the image into the optical viewfinder.

With a DSLM, this whole mirror construction is missing. However, many mirrorless system cameras have a viewfinder to offer. How can that be? Quite simply, it is not an optical viewfinder which shows a “real” picture. Instead, it is an electronic viewfinder (abbreviated as EVF). This electronic viewfinder is basically nothing more than a small display. In a DSLM, the light does not fall on the mirror. It falls directly on the sensor where the picture is simply “processed” and then output again in digital form on the EVF. In other words, it’s an artificially created image and not a real picture.

Anyone who calls a DSLR with Live View mode his own, has a “mirrorless” camera, more or less, because the display on the back is virtually nothing more than the display of an EVF – apart from the huge size difference. In the live view mode, the mirror box is simply folded up, and the image is processed on the sensor and then output to the display (as with a DSLM).

Electronic Viewfinder vs. Optical Viewfinder

We have now talked about the meaning and purpose of the mirror box and the fundamental differences between optical and electronic viewfinder. But what is the better choice for DSLR or DSLM: OVF or EVF? In general, you cannot say which is better because both come with advantages and disadvantages. For example, in an electronic viewfinder you can see the image in the form in which you will later find it on your memory card. That means, if you change settings such as the ISO sensitivity, you can also see in the viewfinder how this will affect the picture. This is not the case with an optical viewfinder where we are, so to speak, only looking into a mirror and perceiving the subject in front of the lens as we do with our human eyesight. It is just from the perspective of the camera.

In most cases, this is a clear advantage for the electronic viewfinder, although some photographers still prefer the “real” images of an optical viewfinder as they are sometimes sharper and brighter with a better image quality. In addition, the optical viewfinder has a general speed advantage. With an electronic viewfinder, the image must be processed (as already explained) and output on the small display. This can lead to some delays and so-called lags. However, the EVFs of more expensive mirrorless-system cameras have improved so much that no lags are visible. In general, however, anyone who takes pictures in the sports, action, or wildlife sector and often moves a camera around quickly is generally better with a DSLR (also because of the differences in autofocus – see explanation below). But of course, you always have to judge the individual models. As previously stated, now there are also extremely fast cameras with instant electronic viewfinders. Magnification and field coverage play a crucial role as well.

Whether you prefer an OVF or an EVF and thus DSLR or DSLM, everyone has to decide for themselves. Both systems have advantages and disadvantages. But for the cheaper class, if you have 500 euros to spend, the SLR cameras come out ahead because many DSLMs in this price range have no viewfinder. However, in the eyes of many photographers, the electronic viewfinder with all of its fades and the possibility of displaying the finished image with consideration of the settings is the better choice. However, one must always look at the viewfinder of each model. Professionals prefer OVFs because their tastes are often very different.

A Canon DSLR with an optical viewfinder in live-view mode (source image: Jim Lin / YouTube)
A Canon DSLR with an optical viewfinder in live-view mode (source image: Jim Lin / YouTube)

Picture Quality

For many photographers, an excellent image quality is an extremely important criterion, so a comparison of the DSLR vs. DSLM is necessary. This is a point we can handle amazingly fast because whether it’s a DSLR or DSLM camera, the differences in image quality is not fundamentally complicated. The image quality depends primarily on the built-in sensor, the megapixels, and the sensor size, and both DSLRs and DSLMs can work with large or small sensors as there are no limitations on either system. In the expensive full-format range, the selection available in the DSLRs is currently a bit bigger.


A larger difference in the question of DSLR vs. DSLM is the matter of autofocus. There are two different technologies: phase detection AF and contrast AF. SLRs use a phase detection AF that is faster than a contrast AF and performs its services more reliably, especially in low-light conditions. A few years ago, there were only DSLMs with contrast AF which was a clear advantage for the DSLRs. These rely on an additional autofocus module in the camera housing (in which the phase AF is housed) which is something the DSLMs could not come up with.

However, for some time now the manufacturers of expensive mirrorless system cameras have also installed phase detection measuring fields on the sensor itself! In addition to the phase AF points, quite often there are also contrast AF points. The whole thing is called hybrid autofocus. In terms of speed, there are now no more advantages for the DSLRs in the more expensive price ranges. Nevertheless, wildlife and sports photographers often feel more comfortable with DSLRs because of the higher reliability in low-light conditions. However, videographers will generally prefer DSLMs as they have several advantages on their side. In addition, the mirrorless models often have more fields to offer.


Let’s take a closer look at the video features just mentioned, especially the autofocus in video recordings. Why can one answer the question of DSLR or DSLM superiority clearly with “DSLM” in this area? Well, let’s review what we described earlier in this article:

In the live-view mode, the mirror box is simply folded up, and as with a DSLM, the image is processed on the sensor and then output to the display.

The image is processed in the live-view mode only on the sensor itself, so unfortunately, the additionally built autofocus module with the brisk phase detection AF is not available. Instead, DSLRs can only work with the often inferior contrast AF of the sensor. So whether you are using the viewfinder or the live-view mode photographed as a user of a DSLR, it makes a big difference in terms of autofocus – for all who did not know that yet.

When recording a video with a SLR camera, the mirror also has to be flipped up, just like in live-view mode. Logically, it is only as long a picture is being taken. This means, however, that here again only the contrast AF found on the sensor itself is available. As already mentioned, mirrorless system cameras have the advantage of the phase AF being installed on the sensor itself. That means this is synonymous with video recordings available and is a clear advantage for the DSLMs! Furthermore, mirrored users can currently work with higher resolutions such as 4K.

Lenses and Accessories

The smoother autofocus in video recording is a great thing, but professionals will often focus manually which emphasizes this advantage again. From the point of view of professionals (whether videographer or photographer), the SLRs again have an advantage on their side because they have a much larger selection of lenses. In addition, there are generally more accessories for DSLRs, even at relatively affordable prices, so this is a clear advantage for the SLR cameras. However, it should be noted that many mirrorless system cameras can now rely on a sufficiently large range of lenses. The reputation here is often worse than what is actually available. And who needs “only” two or three ordinary lenses anyway when you can access a DSLM without any problems?

A Nikon DSLR with numerous lenses. (Source image: Bharat Mirchandani / Flickr (CC BY-SA 2.0))
A Nikon DSLR with numerous lenses. (Source image: Bharat Mirchandani / Flickr (CC BY-SA 2.0))

Burst Speed

In the case of an SLR camera, the mirror must be moved in front of each image, but that is not the case with a mirrorless one. So, you guessed it – that generally results in a speed advantage for the DSLMs. Of course, it does not mean that individual DSLRs cannot be faster than certain DSLMs.

Another advantage of a DSLM is the fact that it can be used in addition to the mechanical shutter and an electronic shutter. Often even shorter shutter speeds are possible, and the release sound is much quieter. Some models do not even make any noise at all which could be especially interesting for wedding or concert photographers.


If you ask an ignorant customer which housing of DSLR or DSLM cameras has higher quality, many will probably instinctively choose the DSLR. This is simply because it looks bigger and thus more robust. The emphasis here is on “appears”, because mirrorless can have just as robust and high-quality processing as SLR cameras. Weatherproof models can be found in both camps.

Battery Life

Finally, in our comparison between DSLR and DSLM, there is another rather important feature – the battery life. Here the DSLR in comparison to the DSLM is in the lead, because thanks to OVF, there is no electronic viewfinder to be powered. If you take pictures with a DSLM and are out and about the whole day at a wedding or during a trip, you should probably get one or more replacement batteries.

Only 290 pictures can be shot with one battery charge of the Sony A7r II
Only 290 pictures can be shot with one battery charge of the Sony A7r II

Conclusion: DSLR or DSLM?

Should you buy DSLR or DSLM? In general, one cannot easily answer this question. Both systems have advantages on their side, and we are convinced that both systems will exist side-by-side for many years to come. The mirrorless have caught up significantly in recent years and have many points in their favor in terms of construction, video, electronic viewfinder, and partially with the autofocus. However, the DSLRs can still play their strengths of an optical viewfinder, wide range of lenses, and a more reliable autofocus. Every photographer should consider what is personally important to them before buying a new camera. You should also ask yourself a few questions:

  • Do I prefer an electronic or an optical viewfinder? (Try themout!)
  • Do I take a lot of pictures in the wildlife or sports area? (DSLR)
  • Is a compact case important to me? (DSLM)
  • Do I value the video features? (DSLM)
  • Do I need a large selection of lenses? (DSLR)

You see, it is not an easy decision whether you choose DSLR or DSLM. For many people, the fact that mirrorless system cameras are somehow “newer” certainly plays a role, and you do not even have to rationalize and justify that your gut feeling may tend more to a mirrorless for this very reason. First and foremost, photographing (and using the newer camera models) should be one thing – fun.

Finally, the explanations in this article may not always be 100 percent correct from a technical point of view, but that should not be the focus here. Instead, we are concerned with an understandable explanation, not with correctly describing the complicated design of cameras down to the smallest detail. However, if a gross technical error has crept into our explanation, please leave us a comment.

Anyway, what is your opinion? DSLR or DSLM? We are happy to hear your opinions and suggestions!


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