What is the max size of sd card on a t1i

[cottenrg]

Need to find out the max size sd Card on a t1i use  a 16 gb can I get to a 32 or 64 gb card

[Waddizzle]

I would assume that the "maximum size" would be whatever size was availble a year or so before the camera was introduced.   

Why a year prior to release?  Design time.  Engineers have to design around well established, existing hardware, not what might be available when their product is released for sale to consumers.

[ScottyP]

I suspected that the size of card was not the only hitch; they have changed the SD card over the years, creating newer more advanced types that are not backwards compatible with older cameras.

I found this old 2013 answer to your question in, of all places, this forum.  See:

"Hi BillyDee,

While your camera is compatible with SDHC memory cards with a capacity of up to 32GB, it's not compatible with the larger SDXC memory card used by your 128GB card."

So you need to find older type SDXC cards, and then you can go up to 32GB.

[cottenrg]

Great I will change out to 32 sd/hc1