For many people outside of the photography community, and even some of them, the term “DSLR” has long been used to describe just about any digital camera with interchangeable lenses. This is an understandable mistake. For several decades, the vast majority of digital cameras have fallen into the category of single-lens digital SLRs. This designation has a specific meaning, and it’s relatively easy to tell the difference once you know what you’re looking for.
How do digital SLR cameras work?
The short answer is simple: a mirror. The DSLR grade “reflex” bit refers to a mirror inside the camera body that sits between the back of the lens and the film plane and the camera shutter. . When you’re not taking a photo, the mirror reflects the image passing through the lens, into a glass prism (or multiple mirrors) in the viewfinder, and possibly into your eyeball.
As soon as you press the shutter button to take a photo, the mirror quickly flips up to let light pass through the shutter and onto the digital sensor. When you take a picture with a DSLR, you will notice that the viewfinder turns black for a brief millisecond during exposure. This is because the mirror is no longer in place to reflect the image back to your eye.
When shooting with a DSLR, it should be noted that the viewfinder will usually not show you the entire image captured by the sensor. You’ll see over 90% of the total scene in the viewfinder, but the final image will usually include additional edge information that you couldn’t see while shooting.
The “S” in DSLR stands for “single,” which differentiates it from older dual-lens SLR cameras like the Rolleiflex or the Mamiya C series. LRTs, as they are called, have two objectives stacked on top of each other. The upper lens composes and focuses your shot, then the lower lens contains the actual shutter to let light into the film.
The history of the digital SLR
Thinking back to the timeline of camera history, the digital SLR was a natural evolution from the film SLRs that came before them. The digital transition started as early as the 1980s, but it was the Nikon D1 that really kicked off the consumer DSLR movement in 1999. The 2.7 megapixel D1 (a decent resolution at the time) used the same. basic layout as the company’s flagship product. D5 film camera. It had a built-in vertical grip like Nikon’s current flagship, the D6.
Canon’s first commercial DSLR debuted in 2000. The 3.1MP D30 sparked a DSLR feud with Nikon that would escalate dramatically for over a decade.
Eventually, mirrorless cameras arrived promising smaller bodies with more advanced features, which drastically reduced the market share of DSLRs. As the name suggests, mirrorless cameras eschew the moving mirror and instead rely on real-time readout from the camera’s imaging sensor to compose shots. Today, Nikon, Canon, and Pentax still make solid digital SLRs, but the first two companies quickly began to focus on the mirrorless market.
Current SLRs allow shooters to switch between a variety of lenses to suit the manufacturer’s mounting system. For example, Canon’s SLRs use the company’s EF mount lenses, which have been produced for decades. However, if you buy a modern Canon DSLR, you cannot use the company’s old FD film SLR lenses because the mount is different.
Nikon digital SLRs use the Canon F mount, which also accepts many lenses dating back decades. This includes older lenses intended for film cameras. Sony’s recently discontinued Alpha SLR line was compatible with Sony’s A-mount lenses, as well as some older Minolta models.
If you have SLR lenses from previous cameras, most of them can be easily adapted for use on mirrorless cameras from the same manufacturer. So if you buy Canon EF lenses, you can use them on Canon mirrorless cameras like the Canon R5 and R6 with the addition of an adapter. Native mirrorless lenses, however, will not work on DSLRs.
DSLR vs mirrorless cameras
As the name suggests, mirrorless cameras avoid the need for a mirror by letting the image sensor handle everything from capturing photos to focusing. DSLRs typically rely on independent focus sensors, which read the light coming from the mirror. If this sensor deflects slightly, it can cause the camera to focus incorrectly with almost every shot. This is why digital SLRs generally require semi-regular calibration.
Mirrorless cameras usually also offer more advanced focus tracking thanks to the focus pixels that exist on the imaging chip itself.
Most of the major manufacturers, including Canon, Nikon and Sony, have shifted their focus heavily towards mirrorless and away from digital SLRs. That said, Canon and Nikon still have some very popular DSLR models in the middle and at the top of their ranges. If you are a die-hard mirror fan, Ricoh is still fully committed to DSLRs.
Some things to know before buying a digital SLR
When shooting with a DSLR, it’s a good idea to check the focus calibration on a semi-regular basis. DSLRs rely on a self-contained focus sensor which can derail and cause out of focus. Mirrorless cameras generally avoid this phenomenon because they rely on the same sensor to focus and take the picture, which allows for easier alignment.
Because the mirror has to physically move every time you take a photo, it is particularly susceptible to wear and tear. The mechanism may break and require replacement. Finally, the mirror gets dirty over time with dust and grime. This will appear in the viewfinder when you look through the camera. Mirrors are generally easy to clean, but the extra protective layer in front of the actual sensor can make wiping off more difficult.
Some things to know before buying a digital SLR
If you’re trying to buy a modern DSLR, your options are somewhat limited compared to just a few years ago.
Canon digital SLR cameras
Canon still sells more digital SLRs than any other manufacturer.
- The flagship 1D X Mark III sits at the top of the range with its $ 6,500 price tag and premium professional features.
- the $ 2,499 Canon 5D Mark IV is the company’s workhorse camera, which still regularly finds its way into the bags of professional photographers.
- the $ 1,400 6D Mark II offers a full-frame sensor and pro-grade features at a lower price, more accessible to enthusiasts and useful as a backup body for pros.
- the 90D is an avid level camera aimed at shooters moving from an entry-level model. It offers a smaller sensor than the 6D Mark II, which allows it to pair well with Canon’s cheaper EF-S lenses.
- the Rebel T8i is a consumer digital SLR camera that offers useful features for beginners learning to photograph, but its body is not as durable or weatherproof as its professional gear.
- the Rebel SL 3 is by far Canon’s smallest DSLR, but it’s still compatible with its entire line of EF-S lenses.
The other big player still in digital SLRs offers even more individual options.
- The flagship D6 costs $ 6,500 and directly competes with Canon’s 1D X Mark II. It has a 20.8 megapixel sensor and super-fast burst rates for sports shooting.
- For $ 3,000, the D850 features a high-resolution 45-megapixel sensor that can capture up to seven full-resolution images per second.
- Nikon’s mid-range full-frame digital SLR, the D780 offers a mix of resolution and speed that is appealing to wedding photographers and portrait photographers.
- the $ 999 D610 represents Nikon’s entry-level full-frame body, which offers more beginner-friendly features but maintains high image quality.
- the $ 1500 D500 uses a smaller APS-C sensor than its full frame siblings, but it’s built with a rugged body and fast 10fps burst speed for sports and wildlife shooting.
- the $ 1,000 D7500 is like a scaled-down version of the D500, which is much more affordable, but not as durable.
- For beginners or those on a very limited budget, the D3500 starts at just $ 600. This makes it the most affordable DSLR on the market today.
Although they’re nowhere near as big as Canon or Nikon, Ricoh still sells a full line of Pentax digital SLRs.
- Building on the lineage of Pentax film SLRs, the $ 7,000 645 Z offers an imaging sensor 1.7 times the size of other professional full-frame cameras. This gives it a unique look and a depth of field suitable for portrait and studio photographers.
- the Pentax K-1 II is the company’s full-frame flagship, offering ultra-rugged construction and fast performance for under $ 2,000. It also has access to an extensive line of Pentax K-mount lenses that date back decades.
- With its smaller APS-C sensor, the K-3 III Also costs $ 2,000, but it emphasizes speed and features over sensor size.
Should you buy a digital SLR?
While mirrorless cameras are quickly eating up the DSLR category, there are still many great DSLRs on the market. As more and more people switch to mirrorless, it becomes easier and easier to find great looking DSLR lenses in the aftermarket at discounted prices. Some shooters still greatly prefer digital SLRs because of their optical sights. Mirrorless cameras rely on electronic viewfinders which introduce at least some lag into the equation. This can be a deciding factor for filming fast-paced action like sports.