Quantaray 500mm f8 Mirror
Most Quantaray lenses were made by Sigma and some were made by Tamron and Tokina. This lens performs like a Sigma Mirror lens. It is reasonably sharp if you can hold it steady. It has the typical ringed bokeh we see from mirror lenses. Contrast is surprisingly high. While it is not a Zeiss or even a Tamron in quality, it is still far better than any of the off-brands flooding the market.
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I was hoping to get a good copy of this lens but I didn't. Sure, it's clean and working perfectly, but it suffers from 'third party lens syndrome'. These lenses were often inconsistent.
I have noticed fringing up thru f8 on light and dark edges.
Vignetiing is noticeable at f4.
Corner sharpness is low and uneven. It's possible that there i a misaligned element. Dispersion is the major problem with this lens.
It performs best at f11. Contrast is low at 210mm but sharpness is comparable to 70mm. F4 is very soft, full of chroma, and fringing.
Macro mode is not user friendly or useful.
I have seen pics from other Sears 70-210's that compete with prime lenses but this lens doesn't even come close.
ISO 400 - f8 - 70mm
ISO 400 - f8 - 210mm 100% crop
ISO 400 - f4, f5.6, f8 - 210mm
ISO 400 - f4, f8 - 70mm - 100% crops