EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12592
Loc: Cumberland, R I , USA42N71.4W
|
|
package arrived last night
Vixen Foresta 7x50 porro (they also make a Foresta roof)
I first saw this binocular at NEAF when Daniel Mounsey walked me over to introduce me to Mike Fowler from Vixen. Daniel picked up this binocular and said, this is the brighest binocular I've ever seen.
Well now that I have one in hand, I'll run it thru the complete set of tests that all the other small binoculars have been subjected to and I'll include it in my article on 7x50s. It will have some stiff competition from the Nikon Prostar.
I said it before, but I'll say it again, holding this binocular is like hoding a Nikon SE. This Vixen Foresta 7x50 is similar in feel and shape to my Nikon SE 12x50. Considerably smaller in heft than the Nikon Prostar 7x50 and the WO 7x50 ED.
Weighs only 33 ounces (930g.), by far the lightest weight 7x50 I've used. Body is aluminum. It's only 60% of the weight of the WO7x50ED. Most of the other 7x50s I've used weigh over 50 ounces (1.4kg.). The Captain's Helmsman is much larger, but is the closest next lowest weight 7x50 at 41 ounces (1160g.).
Loupe/scale measured aperture shows between 48-49mm. Caliper measured exit pupil at 6.9mm confirms very close actual to specified. So, I'd say very close to 7x49. No internal baffles infringing on light path.
Standard specified AFOV of 50°, similar to all the other 7x50s in this test.
Has long eye relief. needed to twist eyecups out one click for best placement and still see the entire fov while wearing my eyeglasses.
triplet Objectives - we'll see what correction they provide in future testing.
It's waterproof, fog-proof, nitrogen-purged, and has a very tactile rubber coating. FMC. $269.
we'll find out much more about it in coming weeks.
First impression - very nice.
edz
|
KennyJ
Reged: 04/27/03
Posts: 10155
Loc: Lancashire UK
|
|
Sounds promising Ed .
Does one detect a slight increase in appreciation of what the humble 7 x 50 can offer ? :-)
Kenny
--------------------
If everyone is thinking the same thing , no-one is thinking - General George S.Patton
Zeiss 7 x 42 BGAT
Captain's Helmsman 7 x 50
Nikon 10 x 42 Superior E
Swift Audubon Kestrel 10 x 50
Helios 15 x 70 Observation
Strathspey 20 x 90
Televue 76 APO
Zeiss 85 Diascope
Helios 102 f5 refractor
Various eyepieces barlows tripods mounts etc.
Panasonic Lumix DMC - TZ5 digital camera
|
Rick
Carpal Tunnel
Reged: 04/12/05
Posts: 2575
Loc: Tokyo, Japan
|
|
FWIW, I see nothing in the Vixen Japanese website/brochure that indicates it is a triplet. It does say it is "fully multicoated" which on Vixen's coating scale is a notch below their PFM "perfect fully multicoated" available on the 2-3 remaining bins in their ULTIMA line. Basically means the prisms are not multicoated.
TFOV is listed as 7.1° (124m@1000m) with an AFOV of 49.7°. Eyerelief is 20mm with close focus of 6m. "Waterproof" but no indication to what JIS standard. No indication of being Nitrogen purged unless it is written on the prism housing?
I would be interested to know if your sample has perfectly round exit pupils. That has been an issue for many of the small Vixen porros I have seen.
clear skies,
Rick
--------------------
www.japanastro.com
|
EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12592
Loc: Cumberland, R I , USA42N71.4W
|
|
I obtained my info from the Vixen Japan website and from OPT a Vixen dealer in CA.
I tested the objective with a green laser pointer. It does indeed appear to be a triplet.
the prism surface facing the objective end is multicoated. I doubt they would multicoat one prism and not the other.
The exit pupils are perfectly round. There is one very slight edge of prism seen when looking down into the barrel. It is imperceptible in the exit pupil.
edz
--------------------
Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
|
Rick
Carpal Tunnel
Reged: 04/12/05
Posts: 2575
Loc: Tokyo, Japan
|
|
Vixen Japan has recently done a pretty good job of translating most their Japanese site into English. You can see the Foresta Porro page here and their glossary for specs including coating technology here.
Rick
--------------------
www.japanastro.com
|
EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12592
Loc: Cumberland, R I , USA42N71.4W
|
|
Quote:
Sounds promising Ed .
Does one detect a slight increase in appreciation of what the humble 7 x 50 can offer ? :-)
Kenny
Yes it does.
Every good binocular needs to be judged on its own merit.
edz
--------------------
Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
|
Patrik Iver
sage
Reged: 07/29/03
Posts: 201
Loc: Kaarina, Finland
|
|
Quote:
It's waterproof, fog-proof, nitrogen-purged, and has a very tactile rubber coating. FMC. $269.
Checked out the Vixen-Europe website. The European price of the binoculars is given as EUR 349,-. Corresponds to $543, which is more than twice the Americal price... Including 16 % sales tax, but still...
Generally prices for Vixen equipment have been "reasonable" in Europe compared to prices of many other brands. Apparently no more...
I did not mean to hijack the thread, but I just had to tell you guys on the west side of the Atlantic how lucky you are when it comes to product availability for reasonable prices...
--------------------
Best regards,
Patrik Iver
60°N, 22°E
|
Rick
Carpal Tunnel
Reged: 04/12/05
Posts: 2575
Loc: Tokyo, Japan
|
|
I had a chance to look through these today at the Tokyo Bird Festival. They seem to have pretty nice optics. Don't care for the cosmetics but they are VERY lightweight and easy to hold. Very different design from the old Foresta porro I had. I wanted to ask the reps more about them but the wife was pressuring me to feed her.
clear skies,
Rick
--------------------
www.japanastro.com
|
EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12592
Loc: Cumberland, R I , USA42N71.4W
|
|
tested aperture with laser this morning. maximum aperture is 48mm. Light beam is perfectly centered and perfectly balanced, a very good sign. Has a very narrow range (~5%) across the center of the objective that transmits 100% of the entire 5° wide beam. The average of the best binoculars have an area ranging from 20-30% wide across the center of the objective that transmits the entire 5° wide beam.
edz
--------------------
Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
|
Wes James
Carpal Tunnel
Reged: 04/12/06
Posts: 2460
|
|
EdZ-
Could you describe in further depth the laser test you're describing above?
--------------------
Wes
Atlantic Beach, FL
Some bino’s from Miyauchi 5x32 Binon's up through Garrett 20x110 Signature's,
Some telescopes from a Stellarvue 80mm NHNG up through a couple of 8” reflectors…
And a wonderful 4.25" Delmarva Shiefspiegler!
Some good friends, made here on C/N.
Oh- several cats and a wonderful wife!
Anyone want a cat???? :-O
"When your work speaks for itself- Don't Interrupt" -Gamble Rogers
|
EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12592
Loc: Cumberland, R I , USA42N71.4W
|
|
It's completely described in the Small binocular posts - Aperture. It takes too much effort to describe it again.
edz
--------------------
Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
|
RichD
sage
Reged: 11/08/07
Posts: 211
Loc: Derbyshire, UK
|
|
"I did not mean to hijack the thread, but I just had to tell you guys on the west side of the Atlantic how lucky you are when it comes to product availability for reasonable prices... "
You guys in the States do indeed have great choice and prices over there.Here in the UK we seem to pay on average around 75-100% more for the same item.
--------------------
Clear skies
Rich
|
EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12592
Loc: Cumberland, R I , USA42N71.4W
|
|
Quote:
It's completely described in the Small binocular posts - Aperture. It takes too much effort to describe it again.
edz
here's a link. Perhaps you will remember this discussion from before.
Small binoculars - Exit Pupil & Aperture
also discussed in these tests
GO Gemini 20x80 and Oberwerk 25x100 ?Aperture?
--------------------
Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
|
Wes James
Carpal Tunnel
Reged: 04/12/06
Posts: 2460
|
|
Thanks for the links, EdZ- I appreciate it. There is so much information there that sometimes I forget- or can't find it. I have been trying to just peruse through there frequently when I have some spare time so I can keep familar with what's in there.
Wes
|
Ragaisis
member
Reged: 05/16/08
Posts: 76
Loc: Mequon, WI
|
|
I'll be interested in seeing the final report. I'm ready to drop a little cash (up to $500) in order to upgrade my old Celestron 10x50 Outland LX porros. I'm looking for the ability to hand hold the glasses (the Celestron's don't work that well in that department for me), have a decently wide field, center focus, and be waterproof and fairly rugged. Oh, and better optics than the Celestron would be a bonus. 
I'd pretty much convinced myself to go for the Vortex Viper 8x42. It seems to fit all my criteria. And along comes the Vixen Foresta 7x50 and it sounds good...and less expensive.
I'll eagerly wait for your report, EdZ.
Chris
--------------------
Televue TV85 APO
Vortex Razor 8x42
|
EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12592
Loc: Cumberland, R I , USA42N71.4W
|
|
Checked field sharpness. Aprox measures - 60 arcsec seen out to 75% of field, about 120 arcsec total aberration at 100%. About equal with the Oberwerk Mariner. Better than all the other 7x50s except for the Prostar (which is on the order of 4x-5x better).
At 70% out about half to 2/3rds of aberration is curvature. At 100% about half to 40% is curvature. At edge seems like mostly astigmatism, but compared to all others is well controlled. Overall, I'd say field sharpness rates very well.
Checked resolution. Normal resolution = 11.5 arcseconds line pairs. that's 80 arcseconds apparent res. Excellent, equal with the few better results obtained, puts it into the top ten. Equalled the Prostar. the WO7x50 exceeded that resolution. Boosted 6x resolution also very good, 4.8 arcsec, in the top 12 best.
Rechecked light beam transfer. Very well balanced, no tilt. However, shows the least area of 100% full beam of all 7x50s tested. Out of 15 different 8x40/42s and 7x50s, 10 show a wider area of the objective lens that projects a full 100% beam into the exit pupil. The Fujinon BFL 8x42 shows a full 100% of a 5° beam transfered into the exit pupil from every position anywhere with the center 50% diameter of the objective lens. The Prostar shows the full beam from the center 30% of diameter. The average of all binoculars is 20%. Half of all the roofs show 0% to 10%. The Foresta shows only 5%.
Almost fast focus from 30m to 100m, with 75° of focus dial turn. Very slow focus from 30m to 4m, almost 1 complete dial turn.
edz
--------------------
Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
|
Wes James
Carpal Tunnel
Reged: 04/12/06
Posts: 2460
|
|
Quote:
Rechecked light beam transfer. Very well balanced, no tilt. However, shows the least area of 100% full beam of all 7x50s tested. Out of 15 different..., 10 show a wider area of the objective lens that projects a full 100% beam into the exit pupil. The Fujinon BFL 8x42 shows a full 100% beam transfered into the exit pupil from every position anywhere with the center 50% diameter of the objective lens. The Prostar shows a full beam from 30% of the center diameter. The average of all binoculars is 20%. Half of all the roofs show 0% to 10%. The Foresta shows only 5%.
EdZ-
This is a confusing test (to me, at least). Can you amplify on what you're saying- or explain in different terms? It sounds like you're saying that up to 50% of the area of the objective is about the maximum of any bino's that transfer 100% of their light through to the exit pupil- all the way down to 0 to 5%? How can that be?
Wes
|
EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12592
Loc: Cumberland, R I , USA42N71.4W
|
|
Once again, I would encourage you to read all the previous explanations of these tests. Frankly, it gets complicated to try and explain this stuff over and over, which is why I have documented all this stuff elsewhere in this forum. Sorry that you may not have been present for the weeks of lengthy discussions, but it's all out there for the reading. I've been posting these test results for several years and there were months of discussions in hundreds of posts. It simply takes way to much time to get involved with all that time and time again. This is all documented under the vignette tests, and has been refined several times along the way.
Read illumination of the exit pupil in Small Binoc Series tests.
Small Binoculars - Illumination of the Exit Pupil
To quickly answer your one burning question here, as an example, some binoculars have so much vignette that perhaps only 20% of the light entering at the outer reaches (edges) of the objective lens reaches the exit pupil. Just because a binocular has a nominal size of 20x80 and shows an exit pupil of 4mm doesn't mean that the 4mm exit pupil is evenly illuminated. It will always be brighter towards the center and dimmer towards the edges. Some binoculars show a drop off of two full magnitudes from center to edge.
edz
--------------------
Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
|
EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12592
Loc: Cumberland, R I , USA42N71.4W
|
|
Quote:
Checked field sharpness. Aprox measures - 60 arcsec seen out to 75% of field, about 120 arcsec total aberration at 100%. About equal with the Oberwerk Mariner. Better than all the other 7x50s except for the Prostar (which is on the order of 4x-5x better).
At 70% out about half to 2/3rds of aberration is curvature. At 100% about half to 40% is curvature. At edge seems like mostly astigmatism, but compared to all others is well controlled. Overall, I'd say field sharpness rates very well.
Hmmm, checked field sharpness again last night. this time with specific placement measures.
Actual TFOV was measured at 7.1°, equals specified fov.
Has 60 arcseconds of total distortion between 65%-70% out from center. Has about 100 arcseconds distortions at about 90% out and no more than 120 arcsec at 100% out. At 50% out distortion is negligable. I'd estimate it at 10-15 arcseconds.
So within the central 50-55%%, the correction is excellent. At 65% out it begins to approach the average correction of most other good-better binoculars, but not the best. By 80-90% out it is average.
The amount of curvature measured at 70% out was half of the total distortion. So curvature is responsible for approx 30 out of 60 arcseconds distortion at 70% out. By 90% out most of the distortion was caused by other than curvature, seems like mostly astigmatism, and could not be focused out.
Net sharp fov for detail (to 1 arcmin distortion) is 5.0°. Net usable fov could be considered wider for scanning, perhaps 6.0°.
edz
edz
|
EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12592
Loc: Cumberland, R I , USA42N71.4W
|
|
Had the 7x50 Vixen out last night for some viewing. So I compared them to a few other binoculars.
Vixen Foresta 7x50
Nikon Prostar 7x50
Oberwerk Mariner 7x50
Fujinon FMT-SX 10x50
Sky was about mag 5.1/5.2. I could easily see the mag 5.05 star in Sagitta
On the star cluster field IC4665, including the vertical 5-6 star string to the west
Vixen saw 20 stars
Nikon saw 20 stars
Ober saw 19 stars
Fuji saw 23 stars
On M71, a very faint globular cluster in Sagitta
Vixen very difficult averted
Nikon just seen directly
Oberwerk not seen
Fuji seen direct easily
On NGC 6934, a faint globular south of Delphinus
Vixen saw averted
Nikon saw averted
Ober saw averted just barely
Fuji saw direct
on Cr399, the Coathanger, testing limiting magnitude
Vixen several at 9.1, suspected 9.3, could not see 9.2
Nikon several 9.1, saw 9.1/9.3 pair, glimpsed 9.5
Ober fewer 9.1, could not see 9.3
Fuji all 9.1/9.3/9.5, 9.8/9.9 easy, saw two at 10.0/10.1, suspected 10.3
not quite enough variety in either the cluster for counting, or near the LM range of 9.1 to 9.4.
Earlier while waiting for deeper darkness, I observed the half moon
Vixen, slight false color on axis, CA band gets broader nearer edges, green towards extreme outer fov edge on right (fully lit edge of moon, not terminator edge), red on inner edge of moon (fully lit edge of moon) with moon towards left edge of fov.
Ober very little false color on axis, CA band gets less nearer edges, slight green towards extreme outer fov edge on right, more red on inner edge of moon with moon towards left edge of fov.
Nikon little to no false color on axis, thin yellow band towards extreme outer edge of fov with moon towards right, no CA noticed with moon towards left.
Fuji no false color noticed on axis but same as Vixen near edges of fov.
Towards the end of my evening, I spent some time simply scanning around Cygnus. First time I've observed in a few weeks. Very nice night, got better as the night got late, but by midnight I was just to tired to stick with it. Looked for the North America nebula in the Fuji and Vixen, but could not see it in either one. All in all an enjoyable night.
edz
--------------------
Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
|
Previous
Index
Next
Threaded
Edit
Reply
Quote
[Re: 