There are a few key specs that camera manufacturers and users gravitate toward and that capture headlines when new products are released. However, some of these specs can be misleading, and it is important that you understand what you are really purchasing before you pull out your credit card. Here are four specs to research a bit further before you buy that shiny new camera.
The low-light capabilities of modern cameras have exploded in recent years. A decade ago, decent performance at ISO 800 or 1,600 was the flagship standard, but nowadays, professionals are getting usable images from cameras at ISO 12,800 or even 25,600. I have had no problem delivering clients images shot at ISO 12,800 before, especially after a bit of noise reduction and downsizing for web viewing.
That being said, there has been a minor arms race in terms of quoted ISO capabilities, with some manufacturers offering ludicrous seven-digit values. There really isn’t much stopping manufacturers from going as high as they want with ISOs, but that doesn’t mean every ISO setting on a camera is actually going to give you usable results. The Nikon D6 may offer ISO 3,280,000, but I guarantee no one is shooting with it, except perhaps law enforcement agencies using it for surveillance purposes. Certainly, no professional photographer is delivering images shot anywhere near that ISO.So, when it comes to buying a camera, don’t just take a manufacturer’s quoted maximum ISO as gospel. Instead, check out actual images shot by that camera at various high ISOs. We all have various tolerances for noise depending on client needs, what we shoot, personal aesthetic preferences, and more. You will get a much better idea of a camera’s capabilities relative to your own needs by looking at real-world results than by following whatever ISO range is quoted by the manufacturer.
Speaking of minor arms races, continuous burst rate seems to be the spec du jour, with values pushing well into the realm of video frame rates. These capabilities don’t matter for all photographers; for example, no landscape photographer is firing off 30 fps bursts, but for people like sports and wildlife photographers, having a faster burst rate increases the chance that they will capture that perfect moment.
That being said, a camera’s maximum burst rate is often dependent on a range of factors and may be significantly less depending on the situation. Many cameras will only shoot their maximum burst rate using the electronic shutter, which may not be desirable due to rolling shutter effects. Furthermore, they may only shoot that maximum burst rate using the electronic shutter, with a crop, or when the battery is above a certain percentage. For example, the Sony a1 turned a lot of heads with its 30 fps burst rate, but that has a number of caveats attached to it, such as using lossy compression or JPEGs, a shutter speed of at least 1/125 s (1/250 s if you want continuous autofocus), only using certain lenses, and more. Violate any of these requirements and the maximum rate drops to about 20 fps.
The best way to make sure a camera is going to deliver the actual burst rate you need is to check its manual, which will list all the requirements and limitations. Most cameras have their full manual available in PDF form on their manufacturer’s website.
In the film days and early digital era, most cameras came with somewhere between one and nine focus points, normally clustered near the center of the frame. This caused a few issues: it made tracking moving subjects more difficult, as the photographer had to physically move the camera more to keep a focus point on the subject, and it could be compositionally limiting, as it was harder to compose images with the subject near the edges of the frame.
Nowadays, most new cameras come with hundreds or even thousands of autofocus points, which can make your job a lot easier, but it is important to be aware of a few things. First, check where they are in the frame. Having a lot of focus points is great, but if they are all clustered in the center of the frame (this is more commonly an issue with DSLRs), they will not be as helpful. Next, check what type they are. If you require fast autofocus, you will want mostly phase-detection points, which are generally quicker than contrast-detection points, though the latter is occasionally more accurate.
More so, autofocus points come in many different flavors. The most sensitive are generally cross-type and double cross-type, which can detect focus in both a vertical and horizontal orientation. Manufacturers generally place these at the center of the frame. Next is their sensitivity threshold, given in f-stops. This is the minimum f-stop of a lens needed for the autofocus point to function. For example, an AF point may be rated f/5.6, meaning it only needs a lens with an f/5.6 maximum aperture to function. This can be important for people like wildlife photographers using teleconverters, which will reduce the maximum aperture of their lenses. Remember, this applies to your lens’ maximum aperture, not the aperture you select while shooting, as your lens will normally focus wide open, then stop down to the selected aperture to take the shot. Also, be sure to check a camera’s autofocus sensitivity, meaning how little light it needs to focus, given as an EV value. Modern cameras can generally autofocus down to -5 or -6 EV (the lower, the better), though you should expect their autofocus rate to slow down as the light level goes down. Just like burst rates, the best bet is to simply track down the camera’s manual and take a closer look at its specifications.
4K is the new standard, with almost every new camera having it, and higher-end cameras pushing into 8K territory. However, not all 4K is the same — far from it, in fact. You will want to look deeper into the video specs of any camera you are considering purchasing to better ascertain the sort of image quality you can expect and if that camera’s video capabilities will match your needs. Most cameras these days offer 4K, but you will want to look a little closer at exactly what that means. Frame rates in 4K are normally more limited than in 1080p due to the higher amounts of data, meaning if you want to shoot slow motion, you will likely have to use a lower resolution. Many cameras also implement a crop when shooting in 4K, often a significant one, meaning that if you want to shoot 4K at wide focal lengths, you may encounter some difficulty. Of further concern is bitrate. Simply put, bitrate refers to how much data is being captured at any given time, so a higher bitrate translates to higher data capture rate and thus, better image quality. When you are purchasing a camera for video work, be sure to take a closer look at its video specs than just the maximum resolution it offers.
Most of us look at a few key things when purchasing a new camera, but those specs often don't tell the entire story. Be sure to take a closer look to ensure the camera you are purchasing will actually fulfill your needs.