In the last four days of the “Photo of the Day” I used the original photo and the three progressively more extreme crops of the photo to highlight the question of when is something close enough Below I provide those four photos again and discuss what makes the correct magnification for a photo.
(As an aid for those using small screens you should be able to click on each photo and have it “fit” to your screen in a lightbox display. Then you can close that lightbox and move onto the next photo to repeat that process to get a full view of each photo on your screen.)

The first picture is the whole frame that I shot in the yard. The flower is floating in a background that inclues other flowers some more and some less in focus with the blurred view of the foliage and the ground as the distant background. This gives an effect somewhat akin to an impressionistic painting. The detail of the flower is only slightly visible.

In the first crop of the original I’ve isolated the flower with only some out of focus bright and shadow outlines to be seen behind it. Now it is clear that the flower has a lot of fine structure that includes what look like fuzz and small filaments of some type.

In the second crop of the original the flower fills the screen. Now the flower is seen to be more akin to some kind of burr with separate pistils and covered in spiky filaments and the filaments covered with finer filaments or hairs.

In the third and final crop we get an extreme magnification of the detail of the components of the flower. The surface of the pistils and the structure of the filaments is clear. The quality of the photo is decidedly poor due to pixilation of the image at such extreme magnification.
Okay, so which is the “correct” magnification? And of course there is no correct answer although we may be able to agree that he final crop is is the wrong answer. Cropping to an extreme magnification reveals the limits of the picture file. The number of pixels being used is very small and so a crude image results. This type of photo would only be appropriate for informational purposes such as a scientific paper discussing the structure of the plant.
So what about the first three photos?
Well, the first photo, the full frame originally taken, might appeal to some people because of the composition. The arrangement of the flowers and the background blur might be seen as soothing. So this photo is a viable choice.
The second photo is a little odd. The flower as I said above begins to show its spiky and complex structure while the background still exhibits the creamy softness of the blurred foliage. I sort of like it. There is some tension to the image. I find it interesting.
The third photo is a macro shot. I like macro. I like seeing the complexity of small living things. All the structure and detail interests me. I think this shot is the best magnification for my tatste.
The fourth shot as a mentioned above is technically poor. Maybe it could be used in a cheap monster movie. Now with a higher magnification lens like a 2X or a 3X macro and with the correct lighting and stage a really quality higher magnification image could be made of this plant’s fine structure. But I was in the yard and even the slightest wind would make that photo impossible.
So as you see there is no right answer, only preference or application. What you like or what you need. But just to show I appreciate everyone going through the exercise I’ll provide a survey below. You pick the magnification you think is best.
