Venus 2x First Impressions

I received my Venus 2x Super Macro lens in the mail today and have done some initial shots to see how it performs. I bought the lens in Nikon mount for more flexibility, though all my first tests are using the Canon HRT2i with Nikon-EOS adapter. I did not test it yet at low magnifications, though I can say it seems to focus out to infinity, which is very nice. I bought the lens to use for walkaround macro on my D7000, and am hoping it works well for that. Review in this mode will come later...

First, the lens seems well-built. The helicoid is pretty smooth, though it goes from infinity to 1:2 in maybe 15-deg of helicoid rotation. It might be difficult to get critical focus at f/2.8 for medium subject distances. The full range of infinity to 2:1 happens in only around 180-deg (!!) so this lens focuses very fast indeed. Manually, of course.

Aperture is fully manual. This is great for studio situations with continuous lighting, which is my preference, so I am happy. Some folks might prefer automatic mode, but oh well.

The thing that I found most interesting is the lens is "internal focusing" It does not extend at all when focused. The front lens group sits deep inside the body of the lens at infinity, and moves to the front at 2:1, so it has a built-in lens hood for lower magnifications and best working distance at max mag. Seems a very good design. The result of this is the lens is very compact and easy to use.

The working distance at 2:1 is a bit over 2", which is enough for good lighting flexibility. I had no issues with lighting using this lens.

Now for the images...

The subject is a 1955-S Lincoln Cent RPM #4 in BU condition. I shot in Aperture Priority mode, with -1EV to avoid any hotspotting.

I took overall shots at around M=0.7. This nearly fills the sensor with a 19mm Lincoln Cent. Here is an example shot at f/4, 6-shot stack:



I did an aperture sweep at f/2.8, f/4, f/5.6, and f/8 at M=0.7 and cropped near the center. I like to use Lincoln's beard as the subject for comparisons.

f/2.8


f/4


f/5.6


f/8


The f/5.6 looks sharpest to me, so this would be around f/9.5 effective.

I then took shots at 2:1 magnification with the S mintmark centered on the sensor, and in the lower left corner. I used both f/2.8 and f/4. Here's an example centered shot:



and here is an example in the corner:



Here are the Centered and Corner shots at f/2.8 and f/4 for comparison:

Centered and Corner, f/2.8:


Centered and Corner, f/4:


There is significant distortion of image in the corner, more than I've seen on any other lens I've tested. This will keep the lens from being useful for stitching.

f/4 is sharper in the center and significantly sharper in the corner versus f/2.8.

I saw a fair amount of longitudinal chromatic aberration during my testing. There is a greenish shift focused high, and reddish shift focused low. Here are two example images from a center shot stack at 2:1 to show this effect:

Focused High and Low


This LongCA is mostly removed by stacking since the in-focus planes are true-color, but single images will suffer from color shifts on out of focus areas. This changes the apparent color and can be particularly noticeable and annoying on silver coins. Copper is not as big a deal.