Error in on-screen rendering of pictures when zoomed out? (3.4.1)

[dreed]

Whilst browsing some of my photographs from last weekend at a waterfall, I noticed something very odd: when I was zoomed out in LR, the rendering of the water showed dashes. The kind of dashes that I'd expect to see if I was photographing snow falling under street lights. So I zoomed in. Nothing wrong. Completely straight line of water.

I've attached two extracts of a screen shot - dots.bmp shows the "problem" and "lines.bmp" shows fully zoomed in.

What's going on here?

Is this something like a moire problem?

Under what conditions can I expect to run into this? (It's a bit disconcerting!)

Looking at the same pictures using Window's "Live" photo viewer, there's something a little bit similar going on, but it isn't nearly as distinctive and broken up as LR.

[madmanchan]

Hmm, that looks like a low-res preview image.  Normally, LR will show you a lower-quality (but faster for initial feedback) preview, but then replace it with a higher-quality preview.  What happens if you try changing the "Fit" option in the Navigator?  For example, choosing 1:4 instead of Fit View?

[dreed]

Experimenting with various view options, it seems that this problem is at its worst when I'm doing side by side viewing of images in compare mode (screen resolution on the laptop is 1600x900 and it's in full screen mode, no menu bar or filter bar or tool bar. The photo is a raw capture from a 5D Mark2.) I've attached a section of the screen that shows compare mode with two different photos of the same scene, each with the error appearing in it.

FWIW, this picture is in portrait mode, so doing a fit does not use a whole lot of horizontal screen space.

If I then go on to "develop" mode, the issue is gone, even in the "fit the picture to the screen" mode.

In loupe mode, the streams of water appear striped rather than as dashes.

It sounds like this just might be a by product of the "quicker algorithm" used to generate the on screen picture and that there's no real possible fix for it, lest the rendering speed be slowed down too much?

[Nigel Johnson]

dreed

It would be worthwhile checking what your preview image settings are in the Catalog Settings since the Library module uses the cached previews to produce the on-screen images whereas the Develop module creates its own full-size preview which is kept in a separate cache.

Regards
Nigel

[dreed]

I've attached 4 cuts from a screen grab when LR showing the picture in 1:2, 1:3, 1:4 and in "compare".

[Richowens]

You might try 3.5 RC, released today.

http://labs.adobe.com/downloads/lightroom3-5.html

[Nisa]

Thanks for the link to Richowens, I found it very useful