The Laowa/Venus 100mm F/2.8 2x APO for Close-Up
This lens caught my eye primarily for several reasons. It was a macro lens that went to 2x magnification. That I liked. Secondarily, it claimed to be apochromatic (APO), that is: highly corrected. And third (and last in importance), it was inexpensive at around $500. And the Sony E-Mount version has 13 aperture blades, which also seems a plus.
The lens took its time to be released, but finally arrived. However, it would not accept any of the chipped adapters for Sony-E lenses to the Nikon Z7 mirrorless cameras. So, I found and ordered a Kipon “dumb” adapter, which had to come from China so it also took a while. It works fine. Now I could see if the lens does the job for the kind of work I do, which is close-up focus stacking.
Right off the bat, the length of the Laowa 100mm APO was quite long, 8.5 inches (not collapsible), so it really hangs off the adapter on the Nikon Z7. And it weighs 1.4 lb (638 g). A little too long, IMO.
And to get to the promised 2x magnification, you have to almost touch the subject with the end of the lens AND make sure you have enough light, since the lens itself can cast a shadow or overshadow the subject. That I don’t like much, either.
Something I like even less was the severely short focus throw for doing stacked images. The focus throw for the lens is about 150-degrees, but almost half of that throw (46%) is for the range from 40 cm to infinity. That does not leave much room for close work, which this lens is designed for, especially for 2x magnification where even a tiny adjustment of the helicoid makes a large difference. It is the smallest focus throw of any macro lens I have ever used, and that is a not-fixable problem.
Perhaps, for single-shot images there is no problem, but even then, we still have to turn the helicoid to get the focus sharp. But for stacking images, where many layers need to be spaced very close together, it’s not very acceptable. I found myself having to mount the Laowa 100 APO on a focus rail and let the rail control the “focus throw.”
Still, I wanted to see how “APO” the “APO” for the lens was. So, I compared the Laowa 100mm APO to a few lenses that can get up really close and magnify to that degree, the Schneider Macro Varon 85mm f/4.5, the Macro Nikkor 65mm, and the APO El Nikor 105mm f/5.6. And that’s what we are going to look at here.
Yet, as mentioned, for my work stacking focus, the Laowa 100mm APO already has several strikes against it, IMO.
That being said, when I looked at the results of actually photographing with the Laowa 100mm APO and a classic like the Multiphot Macro Nikkor 65mm f/4.5 and the others, the Laowa 100mm did very well, but there is a caveat.
Stacking the Laowa 100mm APO using the lens’s heliocoid showed that the focus throw was too small, as mentioned above. You can easily see smears where the turning of the helicoid (even a tiny bit) was too much for the focus stacking software to bridge the gap. However, if the same shot was done with the Laowa 100mm placed on the camera and then both camera and lense are mounted on a focus rail, it looks very good, certainly good enough.
Conclusion
My takeaway is that the Laowa 100mm APO is apochromatic enough for my stacking work, provided it is used on a focus rail. The focus throw without a rail, is pitifully short, a very thoughtless design parameter for any close work. The same goes for its use without a focus rail, since focusing for a single-shot photo may also require exact focusing and that is way too difficult IMO. The length of the lens with hood is too long and heavy, IMO, and results in almost physically touching the 2x subject and also weighs heavy on the dumb adapter needed to hang it from the Nikon Z7.
So, I may hold my nose and keep the lens or I may not. The results from other APO lenses, like the Schneider MacroVaron, Macro Nikor 65mm, and Nikon APO El Nikkor, which are MUCH more expensive are as good and IMO better than the Laowa 100 APO lens.
I offer two examples of the Laowa 100 APO, one stacked image using the helicoid of the lens and the other with the lens mounted on the Nikon Z7 and the camera/lens then mounted on a focus rail. If you look at the two of them, it is easy to see the artifacts introduced by the helicoid due to the inability to make tiny steps with the helicoid. The gaps appear as smears.
With the focus-rail version, there are no (or very little) artifacts. What this means is that the focus rail should be used for stacking, although the focus-rail method is not as ideal for any stacking-software as using a helicoid with a proper focus throw.
I see no particular value (for me) in using the Laowa 100 APO beyond close-up work (like for landscape or infinity work) compared to many other suitable lenses that most of us have. It would be convenient for me to just say the Laowa 100 APO is lousy and reject the lens, but that’s not true. It is a lens that is pretty well corrected. All of its other detriments, however, make it a pain to use, IMO. And I’m not done testing it, but I have seen enough to determine that it is not useful for my work. I will return it.
