UV Focus Calibration Photo Gallery by www.macrolenses.de at pbase.com

UV Focus Calibration

Old UV transmitting lenses need an UV focusing indicator, like the well know IR red spot.

So the "blue spot" turned out to be at the (closer focus) f8-f11 indicator of the DOF scale
for this 100mm triplet lens (this cannot be generalized). All shots were done at f5.6
(Rows 1 - 3)

A second test with the same lens design, but a 50mm lens confirmed this finding.

A third test with a different lens design and 135mm focal length showed nearly no focus shift at all (Row 4, Macro test Row 8)

Reference Shots:
1) Coastal Optics Micro Apo UV 105mm (Row 5) @f11
2) Nikon UV Nikkor 105mm (Row 6) @f11
3) Details for comparison (Row 7, 8, 9)

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100mm Lens: Visual Reference Shot	100mm Lens: UV focus set at 0	100mm Lens: UV focus set at 4
100mm Lens: UV focus set at 8	100mm Lens: UV focus set at 11	100mm Lens: UV focus set at 16
100mm Lens: VIS	100mm Lens: UV Calibrated at 8	100mm Lens: UV-VIS Calibrated at 8
135mm Lens: VIS Calibrated at 0	135mm Lens: UV Calibrated at 0	135mm Lens: UV-VIS Calibrated at 0
Coastal Optics 105mm: VIS Reference	Coastal Optics 105mm: UV Reference	Coastal Optics 105mm: UV-VIS Reference
Nikon UV Nikkor 105mm: VIS Reference	Nikon UV Nikkor 105mm: UV Reference	Nikon UV Nikkor 105mm: UV-VIS Reference
135mm Lens: UV-VIS Calibrated at 0, Detail	Coastal Optics 105mm: UV-VIS Reference, Detail	Nikon UV Nikkor 105mm: UV-VIS Reference, Detail
135mm Lens: UV in bw Calibrated at d11, Detail	Coastal Optics 105mm: UV in bw Reference, Detail	Nikon UV Nikkor 105mm: UV in bw Reference, Detail

pages 1 2 3 4 5 6 7 8 9 10 11 ALL

click on thumbnails for full image