Introduction There's a good chance you've owned a Canon or Nikon camera as these both lead in market share in the photography domain by large margin. And if you're a newbie, you probably own an entry level body. The natural upgrade from an entry level is a mid-range which has much more advanced features for enthusiasts and hobbyists. Users tend to stick to the same brand since changing brands means changing your existing lenses, especially if you've been heavily investing into lenses which is a real hassle. But even then there are quite a few users who aren't content with their brand and wouldn't mind switching brands while choosing a mid-range option. There are also those who would want to invest in both brands and enjoy the advantages of both camera systems. Some even opt directly for a mid-range skipping the entry level option altogether. If you have plans to switch brands or are investing in a mid-range DSLR as your first camera then knowing pros and...
Canon vs Nikon - Mid range Autofocus System: How both implement viewfinder Autofocus
Canon vs. Nikon - Mid range Autofocus System: How both implement Viewfinder Autofocus
Autofocus systems are one of the most important systems in a camera. They often end up in top highlights while advertising a camera and work as a key selling point. Many buyers often choose one system over the other depending on the autofocus system features and performance the manufacturer provides, especially if one intends to shoot fast action sports or wildlife. Hence knowing some key differences between AF systems of different manufacturers is the key. Here we will be discussing and comparing the very important viewfinder autofocus systems of Canon and Nikon cameras found in their mid-range cameras, particularly the 80D and D7500.
This article will help give an idea as to how the AF systems differ by design, implementation and functionality in cameras from both companies and not just in 80D or D7500. So this can also be used for autofocus systems of the newer 77D and 800D as both of them use the same viewfinder AF system as the 80D. Same goes with the Nikon camp as the D7200 uses the same Multi-CAM 3500DX II AF system found in D7500. The D7100 which uses the Multi-CAM 3500DX AF system, also basically is the same except for the better performance and low light capabilities (-3EV vs. -2EV) in the mark "II" AF system. With that said, the lower end and older models may not sport certain advanced settings & customizations or some new features found in the 80D and D7500, e.g. the D7500 now features group AF previously reserved only for higher end models while the 77D drops the tracking sensitivity, acceleration and AF point auto switch customization function found in the 80D.
This article is also a part of the series on the Canon 80D vs. D7500 and can be called as an extension to the "80D vs D7500 - fine differences" article in the series, since both systems happen to have advantages in some areas over the other, but the detailed autofocus section earned its own post as a lot goes into making and describing the well refined AF system of a DSLR.
This article is also a part of the series on the Canon 80D vs. D7500. You can find the other parts here:
We are confining this discussion only to viewfinder phase detect autofocus as the live view AF is a forte of the Canon side thanks to its renowned "Dual Pixel" hybrid AF system.
Now let's get started. Canon vs. Nikon Autofocus System
Viewfinder Autofocus -
AF points - The D7500 has 51 autofocus points thanks to the Multi-CAM 3500DX II AF system, while the 80D has 45, all arranged in approximately the same area with the Nikon having a slightly larger coverage along the width. Having 51 points allows Nikon achieve a higher focus point density. This means that there is a greater chance that one of the AF point is already coincident on the area/region you are trying to focus on, e.g. the subject's eye. This could slightly reduce the need for focus-recomposition as compared to the 80D.
80D's viewfinder: The 45 point all cross type AF system is a major improvement over the 19 point of the 70D. This creates a denser set AF points facilitating subject tracking. As compared to the 51 point array in the D7500, it is slightly narrow horizontally. The AF point density isn't uniform, with the central array of 15 points being sparsely placed and expanding vertically than the other two arrays on either side. Also notice the AF area modes on top. The one selected will be highlighted.
D7500's viewfinder: The D7500's array of AF points has more or less uniformly sized AF points, with the central block of 15 points being the more precise cross type points and being slightly sparsely placed, hence extending a bit more vertically. The vertical and horizontal electronic level is much more intuitive and natural looking on the D7500 than the 8 direction sign on the 80D which also only senses the horizontal tilt.
Cross Type - The Nikon has only 15 cross type AF points at its center (central 3x5 group), while the Canon has all of its 45 AF points as cross type. Cross type points have higher focus precision. With all cross type points the 80D gets uniform precision across the focusing area unlike the D7500.
Double cross type - Double cross type AF points allow you to precisely focus with f/2.8 or faster lenses. The 80D has its central AF point as a double cross type. The D7500 has none.
F/8 autofocus - The D7500 supports f/8 autofocus only for the central AF point. The 80D also, for almost all lenses supports f/8 autofocus only with the central AF point, but with the Canon's mark III 1.4x teleconverter, coupled with 200-400mm f/4L IS or 100-400mm f/4.5–5.6L IS II you can use 27 AF points, 9 of which will be cross type.
Autofocus arrangement - While in the D7500, all AF points are uniformly distributed with equal spacing between them, in the 80D the central block of 15 AF points are sparsely placed as compared to the two sets of 15 points on either sides. This means there is slightly less chance of 80D's AF point coinciding with your intended point of focus in the central 15 point zone.
Autofocus modes - While doing viewfinder photography both support single (useful for stills) and continuous (useful for fast moving subjects) autofocus, along with automatic switching between the two.
In Nikon world it's called AF-S for single, one time autofocus, AF-C for continuous autofocus and AF-A for the automatic switching mode.
In Canon terms they're called One-Shot AF, AI Servo AF and AI Focus AF respectively.
In live view, both support only continuous AF and one time AF.
Autofocus area selection - This is customization allows you to select or control the number of autofocus points (and hence the area) which will perform autofocus operations during a particular instance.
To start with, both have the standard single point AF. Multipoint AF in Nikon's terminology is called Dynamic-Area AF, whereas it's Zone AF for Canon.
In D7500 we can change the size of dynamic area AF from 9 point AF, 21 or all 51 points, whereas for 80D we can select 9, 15 or all 45 points.
Canon 80D's 9 point Zone AF. All 9 possible positions are shown above. Note that moving horizontally, the 9 point zone can only be in one of three large 15 point zones.
One point to note here is that while using 9 point zone AF in the Canon 80D, when you shift the zones up or down, the 9 point zone will shift only by a single row, and there are 3 such selectable focusing zones (top, central and bottom) in any of the 3 larger 15 point vertical zones. When you go sideways, you switch between one whole 15 point zone to the other instead of shifting by a single AF point column (this means that you are completely switching from one large 15 point AF zone to another without overlapping both). This isn't the case with D7500 where switching either vertically or horizontally takes place by single row or column respectively.
The Canon 80D's 15 point large zone AF can assume any of the given 3 positions.
As mentioned above, there also exist larger groupings of three vertical 15 point zones, left, right and center. These selected zones, like the smaller zones shift by a whole zone horizontally (and not by a single column) hence giving only three selectable zones.
AF area focus point priority - Now in autofocus area mode you have a cluster for AF points. But at any given point only a single AF point will be in focus. Both Canon and Nikon implement this in different ways:
Nikon basically makes its dynamic area modes work similar to the single point AF. Here the central AF point is given the first priority for achieving focus. If it fails then it tries to achieve focus using the peripheral AF points, which work as a fall back.
On the other hand, Canon sets equal priority for all its AF points in a given zone. But focusing will be done on the object nearest to the camera, and the AF point coinciding with this object will be shown in focus.
This could explain the reason for different implementations of multi point AF for Nikon's dynamic AF and Canon's zone AF. While the Nikon's AF area always shifts in increments of single points, Canon tends to shift the zone as a whole block since unlike Nikon, there doesn't exist any initial priority for a single point in Canon. If Nikon were to implement shifting by a while zone then vertically only the central column of these three will ever get the first priority.
Having said that, Nikon too has its own implementation which is similar to the zone AF of Canon - with the Group-area AF you get a group of 5 AF points working as a single unit, with the priority given to the one closest to the subject, just like zone AF of Canon. This differs from "Dynamic Area" modes which gives priority to the central point. Group AF helps reduce focus misses by reducing chances of focusing on the background (especially when the background is closer to the subject and the subject is small, e.g. birds or a distant subject) since it will try to always focus on the nearest subject.
Both have automatic area modes - in Nikon it's called Auto-area AF while in Canon's 80D it's called 45-point Automatic Selection AF.
Color tracking system - Tracking autofocus systems employ color information from RGB metering sensor to track the color of a subject. This works best when the subject has a distinctive color as compared to the background (So the camera will perform tracking better when tracking a person wearing red shirt with a green background as compared to a green bird with green leaves in background).
The Nikon D7500 performing 3D tracking: It uses the 180K RGB metering system to assist the autofocus system in tracking color.
The Nikon D7500 employs its renowned 3D-tracking technology which tracks subjects across all its 51 AF points with the help of RGB meter. It is expected to have improved tracking performance when compared to the D7200 as it now uses the top end 180K pixel RGB meter found in flagship D500 and D5. To use 3D-tracking you need to switch to 3D-tracking option in AF-Area mode.
Color Tracking with the Canon 6D Mark II which uses the same 45 point AF system and 7560-pixel RGB+IR metering sensor.
The 80D on the other hand also does color tracking; in fact it does so (by default) in normal modes like 9 point zone, 15 or all 45 points. Hence there isn't a dedicated tracking mode in 80D. This default operation can be disabled in menu. On the flipside, the 80D does not employ Canon's advanced EOS iTR (EOS Intelligent Tracking and Recognition) system which is Canon's equivalent of Nikon 3D-Tracking. This means that tracking performance could generally be slightly lower than the D7500.
Tracking customization -
As far as customization is concerned both the D7500 and 80D have Tracking sustenance/steadiness control i.e. the control of how faithfully the tracking system follows a subject when faced with another subject as a distraction. In the D7500 it's called "Focus Tracking with Lock-On" while it's "Tracking Sensitivity" for the 80D.
Apart from this, the 80D also has two more tracking features not found in the D7500 -
"Acceleration/Deceleration Tracking" (control of how sensitive the tracking system is to sudden changes in subject speed for adapting accordingly to avoid missing focus).
"AF point auto switching" (How gradually or abruptly the focus changes from one AF point to another in the selected zone when subject moves).
These settings make the 80D's tracking system a highly customizable one which can make it yield better results when configured correctly for a given situation, thus compensating for its existing shortcomings.
Conclusion - The 80D with its 45 point all cross type autofocus system marks a substantial jump in the AF department for Canon in its mid-range lineup. This is a big improvement over the 19 point AF system found in the 70D and which makes the ability to track subjects meaningful with a denser set of AF points covering a large area. This also takes it at par with the 51 point AF system of the D7500. The 80D with its all cross type points has an edge in focus accuracy as Nikon only give central 15 points as cross type to D7500. But then again with 180K RGB metering system and the proven 3D AF tracking, the D7500 should have an edge while tracking fast moving subjects. Not just this, the D7500 now also has group area AF for reliably focusing on smaller or distant subjects. And although the 80D has numerous settings and customization improve performance to compete with Nikon, the D7500 seems to have a slight edge overall in the viewfinder autofocus department.
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