I am a newbie here so please bear with me. Just got a Canon C100 for my non-profit. I noticed it doesn't have an automated zoom control like traditional camcorders so you can ease in and out when shooting. Is there any 3rd party accessories or methods that you can add to get this feature? Thanks in advance.

I have good and bad news for you. First the good, yes Canon sells a servo lens for the c100. Now for the bad... it costs $31,000 . https://www.bhphotovideo.com/c/product/1043629-REG/canon_9785b001_cn7x17_kas_s_cine_servo.html

The Cinema line is intended for static shots like interviews where there is no zooming. The Sony Fs7 with the kit lens would be a more appropriate choice. On a tight budget you'll need to do without zooming.

There is also the very new Canon 18-80mm that is getting some good reviews from early users, at a mere $5,200:
https://www.bhphotovideo.com/c/product/1246187-REG/canon_1714c002_cn_e_18_80mm_t4_4_compact_servo.html
I think it's only fully compatible with the C100 MkII.

I am a newbie here so please bear with me. Just got a Canon C100 for my non-profit. I noticed it doesn't have an automated zoom control like traditional camcorders so you can ease in and out when shooting. Is there any 3rd party accessories or methods that you can add to get this feature? Thanks in advance.

Yes you can buy the very reasonably priced Canon EF-S 18-135mm f/3.5-5.6 IS USM Lens ( about £400 here in the UK ). This has a zoom servo attachment, the Canon PZ1, which attaches underneath and is powered by batteries. Not used it myself bit have seen examples on line and it seems a very smooth zoom. Again not very expensive.

The next step up from this as pointed out by Seth Bloombaum is the Canon 18-80mm.

isnt there a standalone zoom mechanism you could mount on rails like a follow focus or something, that would work with any lens, with a rocker control that mounts on a tripod arm? there has to be.

It isn't as automated as I would like, but I think the autofocus on my C100 is good enough that I use my manual follow focus to operate the zoom and let the camera take care of the focusing. Works just fine for what I do, Might not work for everybody but I think it's a step up from rotating the zoom ring directly by hand. It gives me reasonably smooth zooms when the camera is on a tripod or monopod, which for me is almost always.

I did think of that too. havent tried it yet with mine.

Fully agree with Jim, works really well in this configuration. I have had some great results with the follow focus used as a zoom control. The 55-250 STM is much smoother zooming than the 18-135 STM, however works for both (I have a few of each and found the same stickiness on all the 18-135s, but you can live with it).

Next challenge will be trying the FF as zoom control on my 150-600 Sigma lens (with 2X extender). I've been playing with the lens on my C100 (well, maybe it's a case of having the C100 on the lens rather than the lens on the C100!) and now just have to work out a secure way of putting the rails on the lens's mounting foo..

Many folks get a base plate that mounts on the bottom of the cam that can accommodate rails. Then you leave those on all the time, don't mess with the lens mounting feet at all (take the collar off, even), use a rails-based lens support for the heavier lenses instead. Makes it easier to switch out lenses and you can always mount stuff on the rails no matter what lens.

I'd thought about that but was concerned about side to side support for the lens while carrying it. I looked at this one

https://www.bhphotovideo.com/bnh/controller/home?O=&sku=1007353&gclid=CMjIxuemy9ICFQx_fgod9PcI_Q&is=REG&ap=y&m=Y&c3api=1876%2C92051678402%2C&A=details&Q=

and it seems to have a provision for securing the lens to the support.

FInally settled on this one - it would give me the option of using it either fastened to the bottom of the lens foot or without the foot. Should have it to try next week.