There is some lens flare problems here, the colored dots
Who is a pixel peeper ? This expression sounds funny. Pixel peeper is used for a man (I don’t think about such a woman, but perhaps exist) who see the pictures 100% on the computer all the time in all possible combinations / variations of different equipments.
What does it mean
Check all image from a given camera at all iso settings, all shutter speeds, or even different noise reduction settings, pictures of a lens at any aperture, different light directions, check all the lens or camera artifacts and even analise and compare them to other lenses and cameras.
Other thing to check if there is a stabilizer in the lens, how it is working, how many stops we can gain.
But many people won’t stop there check the distortion of the lens, how much the corners are darker than the center, if there is a magenta cast around the high contrast areas how pixel wide these are and many other things.
I am afraid I fell in the category at an extent hehe :), but I guess there are even more enthusiast pixel peepers out there, perhaps you ? :).
Is it worth it ?
No. Better to go out and shoot, learn photography, travel, enjoy life in many form. Before buying equipment perhaps quickly check the main points.
How to pixel peep ?
I most like to check lenses. I usually make pictures at wide open aperture, at f/4 f/5.6 f/8 f/11 f/16 to give an idea. From these images I can have a good idea about the lens optical qualities. If the lens is bright I make pictures at all setting around the wide open aperture.
The two more important thing for lenses are the contrast and colors. Basically a lens with high contrast and nice colors easily outperform a lens with high resolution and low contrast.
For cameras high ISO and dynamic range is the most interesting apart from general picture quality. But it is possible to check the different sized and compressed Raw and Jpg files how they processed etc.
Better you check the equipment in reality because the pictures can be misleading. Some pictures made from very close distances, others are post processed and very hard to get a fair judgment especially of telephoto lenses, where the precise focusing is also a must.
Other important thing is the shutter speed. To test a lens high shutter speed is the best, perhaps the image will get grainy but you will see how sharp the lens is.
Pixel peeper website
There is a website dedicated to such people the pixel-peeper.com where we can check full sized images of different cameras and lenses or if you like different camera and lens combinations as well.
There are many lens and camera can be found in their database, but they use Flickr images for this.
You can select a camera, lens or even ISO or aperture value as well, the minimum size of the image you want to check, and after you can check all the results.