This is the Canon USA website. Most of the folks visiting here are in the US or N. America. There are different names for Canon models in the US, so some people here may be unfamiliar with the camera models as you listed them:
- Canon 3000D also sells in some parts of the world as a 4000D. But it has been sold as a Rebel T100 in N. America.
- Canon 1300D sold in N. America as a Rebel T6 (not T6i). In Japan it sold as Kiss X80.
- Canon 600D sold in N. America as Rebel T3i and in Japan as Kiss X5.
I agree with kvbarkley's response... There is no such thing as a "600D III" or "3000D II". The 600D was replaced by the 650D, 700D, 750D, 800D and current 850D. (In the US the T3i was replaced by T4i, T5i, T6i, T7i and now the T8i). So a "600D III" would be an 800D (or Rebel T7i).
All three cameras are 18MP and Canon's APS-C format (i.e., not full frame). All three are designed for ease of use and have tons of automated support for beginners.
The 3000D (aka 4000D, Rebel T100) is the newest and only one of these models that was still in production recently and can be bought new in some retail stores. I don't know if it's still in production or not. If it is not, there also has not been a subsequent model of it offered. This camera was an extreme budget model... it is the most entry level model Canon has ever produced.
The 1300D is the second oldest and has been superseded by the 2000D (Kiss X90 in Japan, 1500D in some countries, Rebel T7 in N. America). At the time it was introduced, the 1300D was the most entry-level DSLR Canon was offering, but the series it's in is considered one step up from the 3000D/4000D/T100. But because the 1300D is a generation older, it is actually pretty comparable to the 3000D.
Of the three, the 600D (T3i) is the "nicest" of the bunch, even though it's the oldest. While it is definitely designed with ease of use and beginners in mind, it also has a bit more room for growth in the future. The 600D has an articulated rear LCD monitor that's higher resolution than the other cameras and significantly larger than the 3000D's.
The 600D is the only one of the three with a self-cleaning sensor (runs automatically each time you turn the camera on or off). The other two cameras will require occasional manual sensor cleaning. How often is really hard to say... it depends upon your shooting conditions, how often and how carefully you change lenses... and to some extent how lucky you are. Years ago I shot under very dusty conditions a lot with cameras that lacked self-cleaning sensors and would need to do cleanings approx. monthly. Using newer models with the self-cleaning feature, I probably only need to clean a couple times a year, if that often. With one of my cameras I held off buying, in part until a version with a self-cleaning sensor was available.
There are other features the 600D has that the two other cameras lack. Even so, the T3i is still considered a beginner's camera, with a lot of easy, automated modes. So even though the 600D is the oldest, it is the most desirable of the three.
Assuming you are looking at used cameras, the only thing to be concerned about is how much wear and tear the older model has seen. It is entirely possible that a newer camera has seen more actual use. But it's difficult to know for certain. In some cases you can get "shutter count" as sort of "mileage" on cameras. I don't know it this is possible with these three.
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Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7DII (x2), 7D(x2), EOS M5, some other cameras, various lenses & accessories
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