...and it's slightly disappointing.

I just got into 4x5 recently. I thought it was infinitely, phenomenally resolving and high-resolution. Until yesterday when I printed a big enlargement. I shot a 4x5 HP5 negative of my work building. I shot it handheld at f/11, 1/100 with my Angulon and speed graphic. I did not focus with a loupe, but I focused wide open and then stopped down.

It looked very nice at 8x10, but I put a 75mm lens on the enlarger and printed the center of the negative onto a sheet of 8x10 paper with the head all the way up. My calculations show that this is equivalent to a crop from about a 50x40 print. I observed several things

--It didn't look sharp anymore
--It wasn't because of grain
--it didn't look motion blurred

Previously, with other formats it always seemed like resolving small details was about having fine grain. Now, even at this enlargement size, the image is blurred far more than the grain is obtrusive. In other words, grain has ceased to be a problem, and now it appears to be optical limitations. The fine grain reveals very smoothly the blurry detail. To my eyes, this looks terrible, because I mean, my smaller format cameras can at least resolve down to grain level; the only time I ever see grainless blurring is in a pinhole camera or an OOF shot. I need to remind myself that 50x40 is really big, but it was a new experience seeing this kind of blurring that is coming from the lens and not the film. Also, this kind of blurriness looks far better to the eyes than pixelization. I just kind of expected to be able to read the 4-inch 'handicap' sign on the door about 75 yards away. But when I zoomed in, I found that my resolution went away far before the image got grainy.

I suppose were I 'worried' about it, I would

--get a better lens
--use a different aperture
--make sure to focus better
--use a colored filter