DaveD65 wrote:
...many people have said that the EOS 77D is the replacement for the 70D...
DaveD
Hi David,
Those people are wrong. 77D is not a replacement for the 70D.
The 80D is the replacement for 70D. These "xxD"models are a step down from the 7D-series, but a step above the Rebel/Kiss/xxxD models. Current Canon EOS DSLR models from most entry level to most advanced are...
APS-C: Rebel T7 (2000D), SL2 (200D), T7i (800D), 77D, 80D, 7D Mark II.
Full frame: 6D Mark II, 5D Mark IV, 5DS/5DS-R, 1DX Mark II.
In spite of its name, the 77D is actually a top-of-the-line Rebel-series model and replaced the Rebel T6s (760D outside N. America) model. I can guess why Canon decided to change the naming convention with the 77D... but if anything it's just caused confusion. The model should have been called a T7s in the N. America market, if they'd followed past practice.
Intro'd in 2013, the 70D is 20MP with a 19-point AF system that's sort of a dumbed down version of what was introduced in the original 7D (2009). Like all the other xxD models (other than 77D), its viewfinder uses a true pentaprism and it has a higher specification shutter with top speed of 1/8000 and a 1/250 flash sync. It's shutter is probably rated for 100,000 actuation durability. 80D was upgraded to 24MP and introduced a new 45-point AF system. It also uses a pentaprism with it's 100% viewfinder and has similar specification shutter.
Now T7, SL2, T6i, T6s, T7i and 77D all use essentially the same 24MP sensor as 80D (among the APS-C models, only the 7D Mark II doesn't use that sensor now... it used the same 20MP as was in 70D). However instead of a pentaprism, 77D and all these other models use a penta-mirror based viewfinder to save weight and cost. This makes for a little less big, bright viewfinder. They all also use approx. 95% coverage viewfinders (as opposed to 100% on 80D and 7DII). The T7i and 77D use essentially the same 45-point AF system as the 80D (T6i and T6s used 19-point similar to 70D's). All Rebel series use lower specification shutters: 1/4000 top speed and typically 1/200 flash sync. Rebel-series shutters are also usually durability rated for about 75,000 actuations. (Canon doesn't publish shutter durability ratings for all models, so this is just a guess... but even published ratings are just a prediction of "mean time between failures" anyway... many/most cameras actually deliver much more.)
Canon Rebel series tend to be a little slower shooting, a bit more plasticky and less well sealed for weather-resistance than the more upscale models.... and the 77D is no exception in this respect.
Canon Rebel series are updated more frequently than the more upscale models. In a sense, 77D is two generations newer than 70D. As a result, the 77D has in some ways surpassed 70D (more resolution, more advanced AF system).
Something I noticed and found a bit surprising is that Canon DOES NOT offer a vertical/battery grip for the 77D and T7i. In fact, the cameras don't appear to be designed to accommodate one (third party manufacturer Vello makes one... but it's sort of a kluge with limited controls and external wiring). In contrast, Canon offered "BG-series" vertical/battery grips for T6i, T6s and their predecessors. They also offer them for 70D, 80D and the rest of the xxd series models (other than 77D)... and for 7D-series and all the full frame models. These grips not only double battery capacity and allow one to take twice as many shots, they also provide a convenient grip and secondary controls for vertical orientation shooting. A lot of folks who use them also think the grips help with balance when using larger lenses. I've used grips on all my DSLRs (and similar power boosters, motor drives or winders on my film SLRs in the past).
Don't get me wrong, the one year old 77D is a fine camera in its own right. It's the very top of the line, latest and greatest of current Rebel models for all practical purposes. In some significant ways a 77D can be considered an "upgrade" over a 70D, which is now a five year old model that was replaced by 80D in 2016. But the 80D remains a "step up" from 77D. I think it's unfortunate that Canon decided to use the confusing naming convention for the 77D, though it's fairly obvious why they did so.