How big can I print?

My brother is interested in hanging up some of my images in his home, but is looking for extremely large sizes (8ft at the widest/longest). I shoot with a 7d and the largest I have printed so far was a 24x36 on canvas that looks pretty good. I have told him if I stretch the image that much it won't look good unless from very far away. Is there a way that it is possible to upsize a 7d file to meet his needs and have the image appear suitable at such a size? He keeps pestering me that photographers such as Peter Lik offer images of that size and that I need to start offering those sizes. I know for the most part of my limitations with my gear, though he doesn't quite understand. Any help is greatly appreciated.

The interpolation features on Photoshop CS 5 and later are really quite good. You'd be surprised at the comparative quality of very large images.

I scanned historical photos and postcards for Fountainhead Antique Auto Museum and blew them up to 84 inches on the long side. You can see a sample in the background here. The effort required isn't trivial, and if you need to make adjustments afterwards they can take a long time to apply (there and amazing number of pixels, after all). But you can get display quality. Faces are probably the most challenging. On this page, scroll down to the middle photo in the Historic Alaska row to see a postcard to 84" item.

To me, it largely depends on two thing : expectations, and the quality of the initial file and enlargement.

If someone is expecting crystal clear detail on a print that large from a foot away, they may be disappointed. But most people really aren't at those sizes. Case in point would be the prevalence of large canvases, which inherently rob images of some amount of small detail.

If you have an excellent (very sharp and low noise) file to begin with, it can be enlarged more and still look good. As Jim mentioned, most software interpolation is very good now, and with some good sharpening you won't lose detail - you just won't be creating more.

If I were you, I'd enlarge the image to the 8ft size in software, and then print a smaller portion of it - say 11x14 - that is representative of the whole. Then put it on the wall and see what you think. That should give you a good idea of what you're dealing with.

As far as comparison's to other photographers and the sizes they make, gear is definitely a factor. Peter Lik, and others that make large prints their business, tend to use large format film and digital backs - which capture more detail that any smaller sensor digital cam. But you might be surprised what you can get from your 7D starting with an excellent file and enlarging from there.

Thanks Jim and David. I'll have to look into this a bit. My brother doesn't understand the difference some cameras make and why some are tens of thousands and others just over a thousand. I have told him that looking at an image that large from my camera will disappoint in image quality, though I know that images that large are not intended to be viewed that close.

David's list is a great course of action to follow. Basically your sensor is 5184 pixels wide, so an 8' print would be 54 dpi when printed. As long as your brother stands 9 feet away or farther, you'll be fine. That's pretty normal distance for a print that large. So, on your next photo outing, mount a 50mm or equivalent zoom set to that, turn the camera vertical and shoot a massive pano with 8 or more images, overlapping at least 30% to give Photoshop some seam to work with. Then you can print a mind-blower for your brother!

Great point on taking pano's Paul. If you do find, Peter, that enlarging your 7D images isn't getting what you want, and you're willing to spend the time, you can get amazing results doing stitched pano's. I've got some that are 30 or more shots that I could theoretically print out at 8 or 10 feet long with the same amount of fine detail I get from my more normal 12x16 size.

That's a bit extreme, but even taking a 4 or 6 shot pano will add lots of extra detail, and isn't too hard on the processing time aspect.

But I'd still try to see what I'd get out of a single file if I thought it was a good one for a large print.

Thanks, I occasionally do panos, but for some images it is just easier to get it in one shot. I'll have to look into it a bit more and try experimenting to see how large I can get my files to print at a high quality.