Lightroom and horizons

From RAW conversion to image editing and printing
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Omega892
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Lightroom and horizons

Unread post by Omega892 »

I have noticed something of late and this is many shots taken are slightly off horizontal, even those where I know the camera had no chance of moving off level by being on a tripod or the top of a stone wall (at Ardnamurchan lighthouse).

When editing in Lightromm and straightening surprisingly most corrections are at exactly +0.85 which feels like a 'detent' i.e. the grid snaps to this setting on moving the slider.

This strongly suggests that Adobe knew about something when producing this software or maybe it is just coincidence.

Anybody else noted this?

BTW I would be interested in feedback on the price of Lightroom, I consider £180 a bit OTT particularly as for reasons stated elsewhere I am not keen on spending huge sums on CS and thus getting a discount as offered recently.
'Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety.' - Benjamin Franklin
David Kilpatrick
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Re: Lightroom and horizons

Unread post by David Kilpatrick »

It's more likely that you camera has the sensor or screen mask misaligned by 0.85 degrees (which is quite a lot). The copper foil mask which sits between the focusing screen and the information overlay screen defines the sharp edge of the viewfinder. This mask is supposed to drop into exact place, but can be disturbed and put out of true. It is also possible for the sensor itself to be out of line, as many Canon (high end) buyers have found - it's actually very difficult to buy a Canon 1Ds MkIII where the sensor agrees with the finder view. Sony use a 95% finder view, which means that 0.85 degrees probably does not cut anything off once corrected, relative to the view you composed.

However, it's very annoying to have such a misalignment. Lightroom and ACR do have increments so it may not be exactly 0.85, but that will be closest click to the actual angle. I suggest you do some very careful tests to see whether you really have a misaligned sensor/screen mask.

One problem with the A300/350 live view is that unlike off-sensor live view, it is prone to exactly the same misalignment that can happen between sensor and screen, as it views the screen. It also has a further stage of possible rotational error in the alignment of the viewing CCD camera. 'Real' live view has zero error; QuickView LV has two steps of possible error.

David
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