Originally posted by dbs I'm obviously not a pixel peeper ... they all look fine to me and I would be happy with any of them.
Dave
Dave, I'm a self confessed pixel peeper, but not obsessive about it, I'm sure.
By circumstance I was asked to supply guestroom artwork for a hotel we were renovating, the theme was to landscapes of the area where the hotel is located. Over a couple of months I accumulated a series of landscape scenes, then got involved in the printing side, and stretch framing.
Now back to the pixel peeping, I found that it does pay off to get a crisp clear picture when you start to print 40x30in or larger prints. Once I started to print I had to discard so many pictures, because they blurred beyond a certain point of enlargement. It really put my pixel peeping into another level, still not obsessive about it, well that's my story and I'm sticking to it. :-) Sadly I feel that my artistic skill is still lagging way behind.
The easy check I found was to enlarge the picture in Photoshop to the same size as the print you intend to make, then view it at 50% on the screen. It is as close to dammit what you will see on the print.
Regarding the 400mm, I was disappointed to see it so much less sharp than the two 300's. I'll do the test again in cooler weather, just to double check. But as others also noted, the 150-300 is remarkably sharp, and I found an old picture of two young elephants in a scuffle, that I printed on 60x40in and it is super sharp. So yes, my tendency will be to leave the other two lenses at home next time.
Pardon the finger typos....
Edit: just wanted to add that I think the 400mm is an exceptional lens, and my critique does not intend to say this is in any way a substandard lens. The simple test I did was potentially flawed, as well as overly critical of a situation in which I would probably never use it in real life. So pse filter my comments as an extreme comparison, a means of deciding which of my prized possessions cannot join on the trip, because the backpack is only so big, and my ability to carry gear is diminishing every year....