Bart_van_der_Wolf
pro member
Hi folks.
I recently acquired a 24mm tilt and shift lens and experienced how difficult it is to get the horizon level (and the lens is almost free of distortion, so that's not the reason). Since the lens is capable of producing an even wider FOV by exploiting its shift capability, it became even more important to get things leveled properly.
I know that the stitching software allows to correct for horizon and verticals, but sometimes it only adds time in postprocessing, and it may cause the need for some cropping. Also, there are subjects that don't give good clues for control point placement (e.g. rough landscapes), or require an accurate display of the angles that are designed by e.g. an architect.
Having come to the conclusion that the various bubble level fitted accessories only have a limited degree of accuracy (and can also get misaligned a bit in use), I spent some time in finding a better tool for when eyeball-ing isn't accurate enough.
For indoor architectural use I already used an automatic leveling laser guide which is quite accurate (+/- 0.5 degree), but a bit delicate and bulky in transportation. It does work fine in combination with Live View or tethered shooting, provided that there is not too much (sun)light falling on the subject (up to 6 metres distance before it gets too dim anyway), and that it can be positioned to align with the edge of the frame or one of the lines that can be superimposed over the Live View display. Aligning with the camera's viewfinder is error bound, due to slight rotation misalignments between the groundglass and the actual sensor.
I now purchased a relatively compact electronic level (via eBay), after comparing several similar devices. The one I chose is more accurate than some of the others, yet relatively affordable. It is the Digi-Pas DWL80Pro . The Pro version offers 0.05 degree accuracy versus 0.1 degree for its cheaper non-Pro sibling. It therefore also allows to calibrate more accurately, and verify the need for recalibration.
While more expensive than a bubble level this device allowed me to see that the built in levels in my Pano gear are not accurate enough, which explains why I had to correct in post processing which also costs, time=money.
This is a very good companion to my RRS BH-55 with rotating PCL-1 clamp. It allows to set the rotation plane level, and now I nolonger have to rely on inaccurate bubbel levels or plumb lines.
I'll probably now will find out how far off the sensor is mounted in my camera ;-) , but at least I will have a good reference to use when squaring things up before the shoot. I can now at least use a known rotation offset to compensate for any sensor misalignment should it manifest itself.
One more variable quantified/eliminated.
Cheers,
Bart
I recently acquired a 24mm tilt and shift lens and experienced how difficult it is to get the horizon level (and the lens is almost free of distortion, so that's not the reason). Since the lens is capable of producing an even wider FOV by exploiting its shift capability, it became even more important to get things leveled properly.
I know that the stitching software allows to correct for horizon and verticals, but sometimes it only adds time in postprocessing, and it may cause the need for some cropping. Also, there are subjects that don't give good clues for control point placement (e.g. rough landscapes), or require an accurate display of the angles that are designed by e.g. an architect.
Having come to the conclusion that the various bubble level fitted accessories only have a limited degree of accuracy (and can also get misaligned a bit in use), I spent some time in finding a better tool for when eyeball-ing isn't accurate enough.
For indoor architectural use I already used an automatic leveling laser guide which is quite accurate (+/- 0.5 degree), but a bit delicate and bulky in transportation. It does work fine in combination with Live View or tethered shooting, provided that there is not too much (sun)light falling on the subject (up to 6 metres distance before it gets too dim anyway), and that it can be positioned to align with the edge of the frame or one of the lines that can be superimposed over the Live View display. Aligning with the camera's viewfinder is error bound, due to slight rotation misalignments between the groundglass and the actual sensor.
I now purchased a relatively compact electronic level (via eBay), after comparing several similar devices. The one I chose is more accurate than some of the others, yet relatively affordable. It is the Digi-Pas DWL80Pro . The Pro version offers 0.05 degree accuracy versus 0.1 degree for its cheaper non-Pro sibling. It therefore also allows to calibrate more accurately, and verify the need for recalibration.
While more expensive than a bubble level this device allowed me to see that the built in levels in my Pano gear are not accurate enough, which explains why I had to correct in post processing which also costs, time=money.
This is a very good companion to my RRS BH-55 with rotating PCL-1 clamp. It allows to set the rotation plane level, and now I nolonger have to rely on inaccurate bubbel levels or plumb lines.
I'll probably now will find out how far off the sensor is mounted in my camera ;-) , but at least I will have a good reference to use when squaring things up before the shoot. I can now at least use a known rotation offset to compensate for any sensor misalignment should it manifest itself.
One more variable quantified/eliminated.
Cheers,
Bart
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