I love my T1i to death, but I grown to dislike the noise at around ISO 800 and with a kit lens, I've found myself constantly having to push that high.
I have no experience with the 5Dc's ISO noise, but appropriate exposure can have a huge effect on noise. If you get a faster lens for your T1i, you might find yourself not having as much of an issue with it.. But a lot of people complain about the ISO at around that range even for the 7D, etc, so there's not much you can do some times... When do you find yourself pushing the ISO, and find it lacking..?
Looking at the pictures on dpreview, it looks like the 5Dc will give you about 1.5(ish) stops of ISO over the T1i, which isn't necessarily a revolutionary advantage.
Many people say that I should get a better lens like the Canon 28mm 1.8 or Canon 17-55 2.8 but I do want to go FF some time in my life and I don't want to buy EF-S lenses seeing that will put me further away from purchasing a FF camera.
First off, if you are die-hard feeling that you won't buy an EF-S lens, because you eventually want to go full-frame, then by all means, I recommend you go full-frame, and no longer be limited by that mentality, because you really do need to expand your lenses to really take advantage of your camera, and to expand your skills.
If, though, you are just "thinking" that, and can be convinced otherwise, you should look at, if nothing else, the ultra-wide angle EF-S lenses (the 8-ish-20-ish mm zoom lenses).. And check their price out NEW, and then check the going price of uses ones on ebay. That will give you an idea of how much such a lens will "cost" you in terms of ownership, when eventually going full frame (assuming you don't wind up keeping a crop camera around..). Then, consider if you'd be willing to buy one used, and your ownership cost will essentially approach zero, when it comes time to sell.
You can also watch lensrentals.com for their used lenses.. they are priced very well, and they keep them in tip-top shape, so you know you're getting a good used lens..
If you ask me, there's no reason NOT to buy an EF-S lens, if you have an EF-S camera. In fact, it's rather silly to avoid EF-S lenses, for their obvious advantages: cheaper (due to less glass..) and smaller/lighter! I guess if you are huge, size doesn't matter.. but shoving 10 lenses in a bag adds up.
I also don't want to buy EF lenses because I feel like they aren't used to their full potential on a Crop body.
I'm not sure what you mean by EF lenses not being used to their full potential on an EF-S body.. Do you mean...
a) if you buy a wide-ish walk around zoom like the 24-70mm 2.8 lens, and you're not able to get the full wide angle 24mm's out of it? - this is true.. But on the flip side, that 70mm becomes more like 110mm, so you gain on the other end.. To get wide angle on a crop body, you really need a dedicated wide angle EF-S lens, anyway.. (And to get wide angle on a full-frame, you really need something like the Canon 14mm..)
b) the EF lenses throw a larger image circle, and you are "throwing some of that image circle away"..? - If you ask me, this is something to not think twice about.. I won't argue that the lens is going to be BIGGER, and you could do the same thing with a smaller EF-S lens.. But just because you're throwing away some image circle doesn't mean you're not using it to its full potential.. In fact, you're using the "sweet spot" of the lens, so you're actually getting more lens than you really paid for... and when you do upgrade from your crop body to full frame, you might be like "what the heck... now the edges look worse than they used to..".. And then it'll be lens-upgrade time, and you'll be shelling out 1.5 to 2K for the next-best lens..
c) that 1.2 aperture doesn't give you the same bokeh on a crop as on a full frame, when framing someone the same for portaits? - yup, you're right, and there's nothing you can do about it.. But you can still buy the EF lens now, and use it to take significantly "better" (aka different) images than you could have without it.. To really blow your mind with bokeh, regardless, you're going to be spending big $$, so it's not really something to fret about for the moment.. (Or just take a person and pull them way away from their background for the shot, I guess..)
d) other reason you're thinking? Those were the only ones I could think of..
Talking to my girlfriend's mother, who is a photographer, made me think about something. She's had a Canon XTi ever since it was first released. She never upgraded her body, yet she still is able to produce fantastic images from her camera.
What lenses does she have..? Can you use/borrow any of them? Because that's an EF-S camera.. What did she make you think about? The 5Dc? (PS I had that camera, too, and it was great.. The T1i (I have one as a "beater" camera..) has better ISO (about 1 stop advantage), and higher resolution..)
Do you think my want for a 5Dc is complete sane? or is the 5Dc not a viable option anymore.
There's surely nothing wrong with the 5Dc. But they are getting old(er).. So you really need to make sure you find one with a low-ish shutter count. The cost of a shutter replacement is like 250-ish, maybe. And I just read a post that indicated if the shutter count is over 100,000, they force you to replace another part (at and additional $200). The 5D has a shutter life of 100,000, btw.. I'm not saying it's not worth the shutter replacement.. it's just another added cost on top of the "hey I'm buying this 5Dc for really cheap, aww yea!". (If you grab one for 700, say, and wind up paying another 500 for shutter replacement soon down the road, that's $1200..)
But right, I digress.. Here's the rest of what you're going to need when you get your 5Dc..
a) The 5Dc
b) some lens you can do general photography with (be it the 24-105 or 24-70..) (or the 40mm pancake as someone recommended, but if it's only that, it's going to leave you very limited without other lenses..)
c) a portait lens (canon 85 1.8, or maybe sigma 85 1.4.. at the minimum..)
d) hopefully (b) will cover your landscape requirements, else you're looking at the 17-40, etc..
So you're still going to be needing to unload a lot of money on top of the 5Dc..
I might recommend before getting the 5D, maybe look into the Canon 85 1.8 (or the Sigma 85 1.4, if you can swing the $$).. It's decently priced, and will be a great portrait lens for your T1i. Heck, you should go out tomorrow and buy the Canon 50 1.8, if you don't have one. It's like $100, and will give you a good idea of how the 85 1.8 will look on a full-frame.. But maybe you won't be able to get over how cheap that lens is, hence the 85 1.8 recommendation.
Anyway, right.. The 5Dc can be great, but don't necessarily push yourself away from your T1i before you actually give a fair chance, I guess? That's my take. You're limiting yourself by not getting lenses for the T1i.
I know this is kind of really bad idea, but what's a good non-L EF lens that can work well with the Canon 5Dc. I'm asking about lenes like the Canon 28-135, Canon 28-105, or any other EF lenses.
Supposedly the Tamron 28-70mm is an excellent and cheap one. However, I would personally recommend a lens with image stabilization of some kind for your everyday lens..