To expand a bit on the above answers:
1DX-series... Full Frame, modest resolution (around 20MP), ultra fast frame rate (up to 14 fps), top-of-the-line autofocus with a separate dedicated chip running it, in addition to dual image processors, very high durability shutter (latest are rated for 450,000 actuations), metal shell, top weather resistance, very high ISO capable, large format battery for extended shooting, dual memory card slots, built-in grip/dual controls for horiz. & vert. orientation. Targeted at pros and especially sports/action photographers.
1D-series... No longer in production, but pro-oriented and similar to 1DX models which superseded them, except they use a slightly smaller APS-H size sensor. (1D, 1D Mark II, 1D Mark III, 1D Mark IV)
1Ds-series... No longer in production, but pro-oriented and similar to 1D-series, except they use full frame sensor and slower frame rates. (1Ds, 1Ds Mark II, 1Ds Mark III) Essentially superseded by 5Ds-series.
5D-series... Full frame "semi-pro" models at a much lower price point than the 1Ds series, they use a single processor for everything (no discrete chip for AF). Recent models use AF system similar to 1D-series, though not as high performance. Older models used a pretty simple and basic AF system. Slower frame rate and lower shutter durability rating, 150,000 clicks. Use mid-size batteries, accessory (removeable) vertical/battery grip available separately. 5D Mark IV still in production. Prior models 5D, 5D Mark II, 5D Mark III.
5Ds and 5Ds-R... Full frame "semi-pro" models very similar to 5D-series, except the 5Ds and 5Ds-R use an ultra high resolution 50MP sensor (compare to 30MP in 5DIV). 5Ds-R doesn't have an anti-alias filter, in order to capture the last little bit of fine detail, but at some risk of moire in images. The 5Ds models use dual processors to handle their large image files, but don't have a discrete chip to handle AF (the way 1DX and 1D/1Ds models do).
7D-series... APS-C format "semi-pro" models which are similar to 5D-series in many ways, except for the crop sensor and design for high frame rate, action shooting. 7D Mark II uses a unique AF system that's supported with a discrete chip (1D-series style) and dual processors to handle 20MP images at up to 10 frames per second. It has a magnesium shell and high durability shutter, too (200,000 click rated). Original 7D that preceded it used a slightly simpler but similarly high performance AF system and slightly lower durability rated shutter (150,000 clicks). 7D-series have built-in flash (wimpy) and so far there have been original 7D and 7D Mark II.
All the above have 1/8000 top shutter speed. Most 1D-series and 7D-series have 1/250 flash sync. 5D-series and 5Ds models have 1/200 flash sync.
6D-series... Full frame "advanced amateur" models with single processor, single memory card slot, slightly lower "moderate" durability rated shutter (100,000 clicks), 1/4000 top shutter speed, 1/180 flash sync. Current 6D Mark II got a much improved AF system, as well as a modest increase to 26MP.
xxD-series... 2nd generation. APS-C advanced amateur models, need to be sorted into two separate groups. "2nd generation" 60D and later models use more plastic construction, single SD card slots, mid-size batteries (same as 6D, 7D, 5D-series), separate battery/vertical grips available, articulated LCD screens, built-in flash (wimpy), with different control layout. 100,000 click rated shutter with 1/8000 top speed and 1/250 flash sync.
xxD-series... 1st generation have controls, construction and design more similar to 7D-series, except for single memory card slot, single processor for everything (no discrete chip for AF). All are APS-C/crop sensor. 50D, 40D are fairly modern (15MP and 10MP respectively), while 30D, 20D (both 8MP) and 10D (6MP) are a bit simpler. These models have similar spec and durability rating to the 2nd generation models.
All the above use true pentaprisms which make for bigger, brighter viewfinders than the models below, which all instead use a penta-mirror to reduce cost and weight.
xxxD-series... are known as Rebels "i"-series in N. America and Kiss models in Japan. The rest of the world gets models called EOS 800D, 760D, 750D, etc. In N. America those are the Rebel T7i, T6s,T6i, etc. (I have no idea how they are named in Japan). These are "step up models" with more features than the entry-level models below. They use a lower specification and durability rated shutter.... 1/4000 top speed, 1/200 flash sync and 75,000 click rated, typically. All the more recent xxxD models use smaller size batteries than the above models. Apparently just to confuse things, last year Canon introduced an EOS 77D model world wide... That camera's specifications actually position it as a Rebel model, an upgraded replacement for the T6s/760D. There have been a BUNCH of models over the past dozen years or so. Too many to try to list!
Canon designed the T6i/750D, T6s/760D and earlier models to be able to use accessory battery/vertical grips, which they offered separately. They discontinued this with the most recent T7i and 77D. All models below have no battery/vertical grips available either.
xxxxD-series.... are the most entry-level and inexpensive models. In N. America they are Rebels such as T6, T5, T4. In Japan they are Kiss "something". Almost impossible to find in the U.S. is the Rebel T7, while the rest of the world gets EOS 2000D and predecessors. Those were T6/1300D, T5/1200D, etc. (I have no idea what happened to the 1400D thru 1900D... Canon skipped all the way from 1300D to 2000D, which are nearly identical cameras other than their image sensors. All of these are relatively low specification cameras with fewer features, more automation, and less direct access to manual controls (though user interaction is still possible).
Two more outliers are the SL1 and SL2... which are the smallest and lightest DSLRs anyone has ever made. The SL1 is known as EOS 100D outside N. America and is a pretty entry level camera. Aside from their respective sizes, the SL1 is almost identical in specs to the T6/1300D. The SL2/200D is significantly upgraded. Other than it's AF system, it's got many of the same features as the T7i/800D.
Canon must have a bunch of left-over sensors and processors. Wwhy else would they still be using Digic 4 in the T7/2000D.... 2017/18 models were fitted with Digic 7 and the latest now use Digic 8! In addition, they're offering an even more entry-level model than the T7/2000D.... not available in the U.S., but elsewhere in the world you can find the 4000D with an 18MP sensor (leftovers from T6/1300D?). In further effort to confuse things, in some places the 4000D is being marketed and sold as a 3000D!
Sometimes I think the marketing folks at Canon are drinking too much sake and plum wine at lunch.
graybeard wrote:
Actually, I think 77D is superior model. It has Canon's latest Digic7, 80D had Digic6. Many of 80D's "superior" features are of the scale of 7fps vs. 6fps, which is meaningless to me. Same 24mp, same 45 point AF. The spec that is most disparate is the $$$$, big advantage to 77D. But back to the point, there is no real way to tell, by the model number itself, where a model fits in with it's stablemates.
No, the 77D is definitely NOT "superior to the 80D".
They share the same 24MP sensor and the 77D has a newer Digic 7 processor (which isn't the latest, either... Digic 8 is now in M50, EOS R and EOS RP models).
They appear to use the same 45-point AF system, but not quite....
80D has Micro Focus Adjustment feature, which allows the user to fine tune focus accuracy on up to 40 lenses.
77D doesn't have MFA.
80D uses a pentaprism for a bigger brighter 100% viewfinder with 0.95X magnification.
77D has a penta-mirror for lower cost and lighter weight with a 95% viewfinder with 0.82X magnification.
They have the same articulated, 1 million pixel, 3" rear LCD Touch Screen on the rear.
80D has a shutter with top speed 1/8000, 1/250 flash sync, rated for 100K clicks.
77D has 1/4000 top speed, 1/200 flash sync and is rated for 75,000 clicks.
80D uses a mid-size LP-E6N battery and is CIPA rated to take 960 shots per charge.
77D uses a smaller LP-E17 battery with CIPA rating for 600 shots per charge.
80D can optionally be fitted with BG-E14 battery grip to double battery capacity and add vertical controls.
There is no Canon battery grip available for the 77D and it's not designed to work with one.
{Vello makes a grip for the 77D and T7i, rather crude, only provides a shutter release and connects with an external wire)
80D has sealing for some level of weather resistance.
77D has none.
77D has a higher ISO range: 100-25600 (expandable to 51200)
80D's ISO range is 100-1600 (expandable to 25600)
HOWEVER, DXO rates the 80D's low light capabilities significantly higher.
77D has a slightly larger buffer able to handle 27 RAW files before it needs to pause to clear.
80D is rated to handle 25 RAW files before pausing.
77D has 5-axis in-camera digital stabilization ONLY WITH VIDEO.
80D doesn't have in-camera stabilization.
I think 77D has faster frame rate HD video.
80D has a headphone jack, 77D doesn't. Both have a microphone jack.
80D is a successor to the 70D and 60D.
77D is a successor to the Rebel T6s/760D. In fact, most 77D specifications are identical to the Rebel T7i/800D (which superseded the T6i/750D), the primary difference between them being that the 77D has added controls and an additional LCD display on the top, right shoulder.
77D is about $300 less expensive than 80D, slightly smaller and a little bit lighter weight. Currently the 77D is offered for $700 ($200 discount off $900 list price). In fact that's the same $700 price as the usually less expensive T7i (currently $50 off it's $750 list price). The 80D is currently on sale for $1000 ($200 off it's $1200 list price).