While at the Oregon Star Party last week, I finally got the chance to spend some time looking through Mr. Bill's Lunt MS 16x70s. I've been wanting to compare my Fuji FMTs with them all summer but the monsoon weather pattern hasn't been cooperating enough for us to meet in our usual central Nevada location like we usually do.
First, a little background. I've been enjoying my Fujinon 16x70 FMTs for about 14 years now; they are the last iteration of the "old" FMTs purchased just a year of so before the new "SX-2" model came to market. The newer, current model may come from a different OEM source as outwardly they are slightly changed in construction and materials. Internally, I can't say. I've never heard anything about the whys and wherefores of this change in the Fujinons and have never seen a direct comparison between the two iterations in the field.
When Kunming United Optics came out with their 15x70 BA8 series around 2006, the Fujinons were one of the two "alpha" 70mm Japanese binos; the Nikon 18x70 being the other. EdZ tested these BA8s and found them to be a worthy, price conscious alternative to the Fujis even though they still had limited eye relief and didn't match the flat field of the Fujis. The coatings and field illumination of the BA8s were a definite improvement over the previous Chinese offerings and were determined to be competitive with the Fujis.
Both iterations of the FMTs are true "mil spec" binos with sealed bodies, rubber armored objective lens assys and use the robust eccentric ring objective lens collimation convention. The BA8s, as many Chinese produced binos do, use an adjustable tilt prism shelf collimation convention instead. The FMTs have firmly attached, rugged pebble grained coverings while the BA8s have thick, heavy rubber coverings that may or may not be firmly attached to the body underneath.
Enter the new Lunt/APM magnesium 16x70s... These appear to be a completely new design, not just a new iteration of the BA8s. The first thing that struck me is their lightness; the magnesium frame construction makes them 10.2 oz. lighter than the FMTs and 22 oz. ligher than the BA8s! When I first picked them up I was amazed how much lighter they felt than my Fujis. I would have guessed they were more than just 10 oz. lighter. Their balance is noticeably different than the Fujis; even though they are longer, the objective end feels much lighter, I'm assuming partly due to the Lunt's lack of the thick rubber armoring around the objective lenses that the FMTs incorporate and partly because of the lighter body material. Bill felt that the extra heft of the FMTs made them a bit easier to steadily hand hold from a lounge chair; I agree but I rarely hand hold. It's quite clear to both of us that hand holding a 16x70 bino is way less than ideal and we see much more detail when mounted.
The Lunts have grippy, solidly attached pebble grain coverings similar to the FMTs. The mechanical feel is similar as well. The hinge movement is firm but smooth as are the individual focusers, unlike the stiff, rough feel I've experienced with the BA8s. The collimation convention is similar to the BA8s with a tiltable prism shelf via screws under plugs on the prism covers. They lack the rubber armor around the objectives that the FMTs have which makes them seem a bit less rugged but that's pretty subjective. We'd have to do the "drop test" like EdZ did accidentally with his FMTs to really see how they would come out. I try really hard not to drop any of my binos...
Comparing the coatings with my FMTs, the Lunts appeared to be a small but noticeable improvement, showing fainter, less detailed reflections. Coating technology is moving on and the Lunts are embracing it! I neglected to inspect the internal reflections off the prisms on the Lunts; maybe Bill can look inside them to determine how the coatings on the prism faces look and get back to us. The Fujis don't appear to be FMC on the prism faces though every other surface does.
The real treat with the Lunts is in the eyepieces; while the FMTs have poor eye relief around 9-10mms effective, the Lunt's 8 element design nearly doubles that. I didn't measure it but it is obvious it's close to the claimed 20mm. I have to roll back the eyecups to see the full FOV of the FMTs even without eyeglasses; with my thick + corrected glasses, I can only see about 50% of the FOV. When I put the Lunts up to my glasses, eyecups rolled back, I was able to see the full FOV! Amazing to me as I've never seen any bino that allowed this. Luckily, I wear contact lenses 90% of the time but for eyeglass wearers this is a real blessing. The eye lenses are much larger than the FMTs as well, surely adding to the eyeglass friendliness of the Lunts. The eyepieces are large, though, so those with narrower IPDs may still have issues. Diopter range on the Lunts is greater than the FMTs; they are claimed to have a ± 10 diopter range while the FMTs are closer to ± 7-8 diopters. I could focus the Lunts without my corrective lenses; I had to have Cory Suddarth modify the focuser range on my FMTs to reach focus, another plus for the Lunts.
Comparing daytime CA between the two binos while examining distant campers and shiny aluminized scope covers, the Lunts had a bit less off axis CA compared to the FMTs but with careful eye placement, neither bino was putting up a level of CA that I would call distracting. The Lunts have a longer focal length which should be a slight help but I think lateral CA from the eyepiece may be a contributor as well. For astronomy use at 16x, CA doesn't really figure into the equation much for me anyhow. Neither of these two binos use ED glass. If I want a view free of CA in a bright daytime image or looking at the Moon, I still would rather bring out the WO 22x70EDs. They have the advantage of a long f6 focal ratio and an ED glass element.
Under the stars, I was surprised that I failed to see an appreciable difference in the views of the two binos. The FOVs were the same; if there's a tenth of a degree difference as the specs indicate, it was not obvious. Contrast differences in faint structures were imperceptable to me on multiple targets as well; each showed both arcs of the Veil with direct vision and Pickering's Triangular Wisp was seen with averted vision. The same applied to to the extent of the North American nebula seen. I kept switching back and forth between binos but neither showed more detail than the other to me.
I also studied dark nebulae; a good test of contrast. Barnard's "E" next to Tarazed in Aquila was resolved equally in both as an upper dark "C" shaped structure with a larger "Q" shaped structure looping beneath it reaching east nearly to Tarazed, the "C" forming the two upper legs of the "E" and the tail of the "Q" forming the lower leg. It was clear that there is no upright connection between the upper two legs of the "E" and the lower leg; it was quite apparent in both binos. The same applied to the B92 and B93 obscurations in the middle of the M24 Sagittarius star cloud with the dark arcs of the "lobster claw" pointing downward to the SW away from them. I saw no detail in one that I couldn't see with the other, try as I may. 16x70s show these objects with so much more detail than smaller binos!
Concerning edge of field sharpness; perhaps I'm not the best judge of this anymore. Fourteen years ago I found the FMTs to form sharp star images to about 85-90% of the FOV with field curvature making stars blobby beyond that. Now that I'm in the second half of my 60's my accommodation has diminished to the point that stars in the FMTs only remain sharp to about 75-80% maximum. The Lunts also have a flat field design and performed just the same. Younger folks should expect the 85-90% sharp FOV from the Lunts as well, I'd expect.
Summing up, both binos give great views and ran neck and neck through the areas of sky that I studied. The obvious difference to me was in the ease that the Lunts allowed me to enjoy the sky and keep a comfortable, usable eyepoint. Longer eye relief allows viewing at higher angles with less neck contortion, allowing you to tilt the binos further upward on your brow bones before the image blacks out. The big eye lenses and long eye relief of the Lunts just plain made the experience easier on my eyes.
At around 2/3 the price of the FMTs, the Lunts certainly look like a "Best Buy" to me. They do everything the FMTs do but with greater viewing comfort. I'd love to check out the 20x70s as well!