"fit to screen" results in odd percentage zoom and blurry image

[builthatch]

regarding Photoshop CC, has anyone noticed that if you "fit to screen", that it goes to an odd percentage and the image looks blurry, but if you zoom in or out from there it goes to a normal zoom number and sharpens right up? for instance, on my monitor, if i do fit to screen, it will put it at 25.1% and it'll be slightly blurry. if i zoom in, it'll go to 25% and be perfectly sharp. the .1% makes a huge difference. i have googled this and seen some stuff regarding cs4 but can't find anything in particular related to the latest CC. this occurs when using my Nvidia Quadro card as the GPU or the integrated 630 graphics. either/or, no difference. i run a loaded Precision workstation with a Dell Ultrasharp as a secondary display and Photoshop CC 2018.

[D Fosse · Accepted solution]

Why is this unexpected? Of course fitting a random pixel number to screen, with a fixed pixel size, will result in an odd zoom percentage.

And an odd zoom ratio inevitably means sub-pixel resampling. One image pixel may now be represented by, say, 0.765 screen pixels.

1:1 is the only accurate view. Other than that, use even zoom ratios as much as possible.

[builthatch]

if what you are saying is the plain fact of life about zoom (and it certainly makes sense), the behavior is unexpected to me because Photoshop should use the closest even zoom ratio, automatically. defaulting to an odd number is problematic as it adds an extra step or two to your workflow to get the view to be usable.

this particular case is insulting because it's .1 percent away from being usable.

i was thinking that if Photoshop was going to ignore this obvious fact, and zoom to oddball ratios to fit the window, then i figured there was some sort of adjustments or capabilities within the program using the GPU that should be taking place to allow the oddball zoom numbers to work to a satisfactory degree.

[D Fosse]

Yes, I agree, it could allow for some rounding if it was that close. Anything under 1% for instance.

Actually, one of the big selling points for starting to use the GPU at all (which happened with CS4 in 2009), was smooth rendering at all zoom ratios. There used to be so many complaints about jaggy and harsh screen scaling. But many people found OpenGL smooth to the point of mushy, and I was one of them.

It all boiled down to 1:1 for critical assessment - which is the only way to represent the image pixels truthfully. And even ratios beyond that.