A small lens, although it is made entirely of metal does not feel solid. It seems to be a toy. However, appearances can be deceptive, is very durable. The focus ring works fine. Regulate small aperture ring on the front of the lens. At the same time it is the turn off threaded filters. The lens has excellent resolution and good behavior to the light. Bolted to the intermediate rings can get surprisingly good results in macro photography.
Focal length [mm]: 50
Maximum aperture: 16
Minimum Aperture: 3.5
Maximum size: 24x36
The method of focusing: manual
Fixing: M42x1 and M39x1
Viewing angle [degrees]: 45
Number of diaphragm blades: 7
Diameter [mm]: 50
Length [mm]: 28
Weight [g]: 75
Resolution (in the middle / on the edge) to 110/75
Minimum focusing distance [m]: 0.45
Filter Diameter [mm]: M36x075
Good resolution, highly resistant to light flare. Outstanding properties of the macro.
Despite the fact that it is so small it is convenient to use. It's so small that you can carry it even in your wallet.
Build quality: ★★★★★
Snail sharpening can easily catch dust and dirt - there is nothing covered. On the other hand, this allows for easy maintenance.
Market value / value of subjective: ★★★★★
Less than $25 is a super opportunity.
Photos taken with the Sony A37 with the use of intermediate rings.