All of the lenses that you used on your 30D should work with the 1300D.
The major differences will be a higher resolution image sensor, 18MP, and body build.
" Is it a "step up" from the 30D?"
I would say, no, it is not. The 30D or any xxD Canon camera is an intermediate level model. The T6 or any Tx model is a beginner entry level camera. That is not to say it isn't capable of nice photos it is! And, any camera that works is better then one that doesn't. All of the xxD models can accept EF and EF-S lenses, it uses an APS-C sized image sensor as does the T6 or any Tx model.
I agree.. any lenses you used on your 30D will fit and work on a 1300D (which is known as a Rebel T6 in N. America or a Kiss X80 in Japan).
However, it is only partly an "upgrade".
Yes, the T6/1300D has a higher resolution 18MP sensor (30D is 8MP). Also the 30D is a 12 bit camera, where all (?) cameras that came later are 14 bit, which helps a little with color rendition... slightly more color depth and slightly more dynamic range.The T6/1300D has a larger, brighter rear LCD screen.
The T6/1300D can shoot HD video. The 30D has no video capabilities.
Surprisingly considering the age difference, they have nearly the same low light/high ISO rating (not very good) from DXO.
The T6/1300D is ten years newer (2016 vs 2006), so you would expect significant improvements... but they are actually relatively few and far between.
While both 30D and the T6/1300D are APS-C format cameras, the latter is a very "entry-level" model with a lower specification shutter, slower frame rate (3 frames sec vs 5 frames sec), more plasticky construction, less sealing for dust and moisture, lower durability and a smaller, less bright "penta-mirror" viewfinder. The 30D's VF uses a true pentaprism and has slightly higher magnification.
The 30D is more a "mid-grade" camera with more direct access to controls, a more robust build (rated for 100,000 clicks versus 75,000), a higher specification shutter (1/8000 top speed vs 1/4000), better sealing for dust and moisture resistance, ability to be fitted with a vertical battery grip (none avail. for T6), larger battery capacity,
The autofocus systems of the two cameras are essentially the same. A 9-point array with only the center point a higher performing "dual axis" type. The entry level xxxxD Canon still use this primitive AF system that was first seen in the 20D around 2005.
In the end, I'd call it a very mixed bag. Yes, the T6/1300D would be a bit of an step up from a 30D. But in a lot of other ways it might be considered a step down. I used a pair of 30D for several years, shooting sports professionally. They were very good cameras in their day and never let me down. I worked with some other photographers using Nikon and was able to get usable images at higher ISO with my 30D than they could with their more expensive, contemporary Nikon D200 cameras. I also got utterly soaked once by a sudden downpour while out shooting with my 30D. I turned off the power immediately, then carefully dried out the cameras (and lenses, flashes and myself) for several days. No harm done! Everything continued to work as it should. I later "graduated" to Canon 50D (15MP), then to 7D (18MP), then to 7D Mark II (20MP).
Below is a rough hierarchy of Canon APS-C format cameras...
I presume the T6/1300D you are looking at is selling for somewhere in the $150 to $180 range. Frankly, looking at used Canon APS-C DSLRs on the MPB.com website (where I got that price estimate), there are any number of cameras that cost the same or just a little more... or even a little less... that I would recommend instead of a T6/1300D.
There may be some other deals but I'll stop with this short list of alternatives. I'm sure you get the idea. Any of these cameras can use the lenses you already have for your 30D... probably. If they are Canon lenses, no worries. However if any of them are 3rd party lenses (i.e., Sigma, Tamron, Tokina, etc.) there sometimes can be problems using those on newer cameras. Most work, but occasionally one won't. For example I have a Sigma 28-70mm that worked fine on my EOS-3 and Elan 7 (EOS 30) film cameras, as well as my DSLRs up to the 30D... but not on any more recent Canon DSLRs. Also, even with Canon you might find various performance improvements and better image quality from a newer or more upgrade lens. Often lenses will make a bigger difference in image results, than a camera upgrade will.
A couple examples shot with EOS 50D...
A couple examples shot with 7D...
You can see from the above why sealing against dust is important to me! 🙄
@Saluki what's your budget?
You mentioned the 70D elsewhere.. Your sort of running all over the map.
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