Filter Size
49mm
f/Stop Range
3.5-22
Minimum Focus Distance
1.4'
Magnification
1:2 (1:1 with lifesize attachment)
Zoom/Focus Control
Not applicable
Angle of View
25 Degrees
Groups/Elements
4/5
Length
2.6"
Maximum Diameter
2.6"
Weight
0.57 lb
Note my version was marketed as a Phoenix brand. The lens can be found under the names of Phoenix, Vivitar and Cosina.
This is a real surprise of a lens. It is dirt cheap and comes very close to rivaling the name brands in image quality. In fact the sharpness of this lens puts it in line with some of the best. It's a freak of a sharp lens! Color may be very slightly flat, but not by much and that's an easy fix.
The lens is super light weight and very easy to hand hold. The 100mm f3.5 is the best macro lens for hand held photography I've ever used in fact. The light weight does come at a cost, don't drop it! It's built cheap and it shows. The auto focus performance is decent but loud. The lens tends to rattle around as if it may fall apart at any time, but never has.
For true 1:1 image magnification one has to use the supplied adaptor. I never used this because I always used the lens on a Dslr. On a Dslr one achieves close to 1:1 magnification without the adaptor. I believe I read that when using the adaptor the lens becomes somewhat more difficult to use and may loose infinity focusing.
Basically this lens is up to par for professional use in the image quality department, just don't drop it!