Since mirrorless digital cameras first appeared on the scene in the late 2000s, the debate over DSLRs versus mirrorless has been rife in astrophotography. In those early days, professional photographers continued to lean towards the familiarity and grandeur of the DSLR – or ‘Digital Single Lens Reflex’ camera – while casual users and hobbyists opted for the smaller, lightweight mirrorless models.
Over the years, however, the technology has changed, and investment in mirrorless cameras has grown. The line between the two has blurred – and many pros can be seen opting for mirrorless equipment. As mirrorless options have become more widespread, the most up-to-date technology has gone into updated models, while DLSR units – although still trustworthy and high-performing – are sporadically updated, with the release of new models billed as rare.
We have a beginners guide to astrophotography for anyone looking to take their first steps into capturing the night sky. But if you're still trying to wrap your head around the best cameras for astrophotography, read on to discover the key differences between DSLR and mirrorless.
Spot the difference
The fundamental difference between the two types of cameras is how the light is reflected and captured within the unit. DSLRs use the technology of old film cameras, where the light enters through the lens to hit an angled mirror, before being reflected up into an optical viewfinder. This is how the user sees what lies in front of the lens. As you press the button, the mirror lifts to unveil the image sensor. The ‘click’ you hear is the mirror moving out of the way for the image being projected onto the sensor and the photograph being taken.
As suggested in the name, mirrorless cameras don’t have this function. Instead, the light enters through the lens and is projected straight onto the sensor. The image is then displayed on the viewfinder of the camera. By pressing the button, you are essentially ‘recording’ the image reflected onto the sensor.
Some cameras, like the Canon EOS Ra and Nikon D810A are designed especially for astrophotography, with specially designed filters over the sensor to better capture the wavelengths that come from space.
Size and weight
For a long time, DSLRs were branded the heavier alternative – while mirrorless cameras gained praise for being a smaller, lightweight option. Traditionally, this was certainly the case – with DSLRs giving the impression they were more suited to professionals who lugged around heavy gear as standard, while mirrorless appealed to beginners and intermediate users, who didn’t care for the hassle that came with heavy equipment.
Over time, however, this notion has changed. Mirrorless cameras now appeal to customers at all levels of expertise, meaning some high-end options – such as the Panasonic Lumix S1 – are just as large and heavy as their DSLR counterparts. One of the reasons for this is that sensor sizes have grown in popularity, with full-frame units leading the market. The matching lenses tend to be bulkier. Smaller, lighter weight cameras, such as Olympus models, are a good option if size and weight are a priority.
Lens options and availability
Old faithful DSLR brands such as Canon, Nikon and Pentax offer everything from telephoto 800mm to wide-angle 18 to 24mm lenses, with third-party manufacturers – such as Sigma and Tamron – making lens options more affordable. Popular mirrorless lens needs are covered well too – with only the rarer lens requests being harder to source. Remember, the mirrorless market is growing constantly – so if there is a lens missing for your chosen brand, it likely won’t be long until the gap is filled. You can also often use DSLR lenses on mirrorless cameras by investing in an adaptor.
If you want to use your camera in conjunction with one of the best telescopes, then you're in luck, as either kind can be attached with the help of adapters.
Vigorous testing shows DSLRs offer better battery life, sometimes allowing up to double the number of shots in one charge. This is simply because DSLR batteries are often bigger, holding more power. High-level processing and powering electronic viewfinders on the mirrorless cameras, drain the battery quicker. If your heart is set on the latter, and you are likely to use your camera for long periods each day, the easiest solution is to carry a second battery – or invest in a model that offers USB charging.
Mirrorless cameras certainly lead the way when it comes to speed shooting – purely thanks to the lack of a mirror that needs to move out for the image to be captured. For example, professional favourite, the Canon EOS-1D Mark III, shoots at 16 frames per second (fps). Meanwhile, current standard mirrorless cameras shoot at 20, or even 30fps. Some mirrorless models claim a 60fps speed use an electronic shutter, however these set the focus at the first shot and can cause banding.
Autofocus and video
DSLRs have long been the go-to for precision and autofocus quality. Once again, however mirrorless technology has proved there are some natural limits to what DSLRs can offer. Mirrorless units tend to offer more focus points than a DLSR, and usually with points positioned closer to the edge of the lens – a particularly valuable feature when photographing in low light, people or wildlife. The silent shooting ability is handy, too.
For many years, the Canon 5D has led the way in quality video making, with the Mark III being a particular full-frame favourite with professionals. While 4K video is the norm on high-end DSLRs, the quality of video is rapidly increasing on most mirrorless counterparts – with some newer models are offering 6K or 8K, a rate DSLRs simply can’t match. In addition, mirrorless technology offers a trustworthy live autofocus, making filming much more user-friendly for the user. As these features become standard across mirrorless units, it is unlikely DSLRs will be able to compete.
Other important features
When it comes to the basic functions, both DSLRs and mirrorless tend to come up on par. The stabilization function on DSLRs is matched on mirrorless bodies by an in-body image stabilization system (IBIS). DSLRs and mirrorless cameras both allow the user to photograph in either JPEG or RAW formats and retain complete manual control over exposure settings. Newer users can feel equally comfortable with the option of automated controls.
With fast continuous shooting, up to 8K video frame rates, high ISO and a live monitor with the possibility of overlaying histograms and gridlines on top of any video or image – mirrorless processing certainly trumps the DSLR. That said, the experience and trustworthiness of long-standing camera technology can’t be substituted, and the DSLR has the advantage of a reliable battery life coupled with tried and tested quality.
Entry-level mirrorless cameras are very affordable but don’t expect them to offer snazzier features such as viewfinders, which are really helpful when you're trying to reduce noise in astrophotography.
This option aside, DSLRs are generally less expensive than their full-featured mirrorless editions. As with most technology, both types of cameras come down in price as newer, more efficient models are released. However, we know this is likely to happen far more frequently with mirrorless cameras than with DSLRs. Professional-level cameras tend to sit around the same price bracket anyway – with little difference between the types.