OK, You have a 20Mpx image. Lets do some math.

• 18" at 300 ppi

• 54" at 100 ppi

• 108" at 50 ppi

50 ppi is TOTALLY FINE for a photo that big.

That is a pixel arround of half a milimeter.

If you are really paranoid Xo) you could double the resolution with a bicubic Sharper option on Photoshop. I mean 200% (Not 123.456% or anithing else) Perhaphs you can aply some sharpen after the resampling.

Yes, you could rent a half million dollar camera... you will only get a picture of 80Mpx, probably a sharper image, but you will only get 100 ppi at that size.

Just remember to make your texts and logos in vectors.

OK, You have a 20Mpx image. Lets do some math.

• 18" at 300 ppi

• 54" at 100 ppi

• 108" at 50 ppi

50 ppi is TOTALLY FINE for a photo that big.

That is a pixel arround of half a milimeter.

If you are really paranoid Xo) you could double the resolution with a bicubic Sharper option on Photoshop. I mean 200% (Not 123.456% or anithing else) Perhaphs you can aply some sharpen after the resampling.

Yes, you could rent a very expensive camera... you will only get a picture of 80Mpx, probably a sharper image, but you will only get 100 ppi at that size.

Just remember to make your texts and logos in vectors.

A note:

I'm not sure anyone would even notice the quality reduction.

If you are in an art gallery, yes, there is a chance someone could be picky looking at a wall sized image at 90 cm !?. Besides that... No.