7x35 Aculons, Featherweights, and 7x35 Porros in General (3 Viewers)

[Binastro]

Henry, do uncoated Porro prisms have 4 surfaces, each losing 4% or slightly over?
My hands are not great, so I just use overhead bulb without magnifier.
The reflections in eyepiece are confusing, maybe from aspherical surface.

I suspect one single coated surface and 2 obvious green MC.

Maybe secondary spectrum is included in lab transmision figures.
I also think less than 70%.

I do look at crows at 2a.m., but they sit in our oak tree. A married couple I think.
I've also seen them sharing with an owl.
Correction. It was the 2 pigeons sharing with the owl.
Either pigeons or crows use the oak tree at night, but not at the same time.

Fog supposedly 100metres, but here more like 200metres. Sun quickly burnt it off.
2 small sunspots today.

 

[henry link]

Yes, the same face on each prism serves for both entrance and exit. Light transits 4 glass to air surfaces altogether, unless they are cemented, which i"m sure is not the case here. I'm just walking out the door, back on Monday.

Henry

 

[henry link]

Binastro,

I was able to take a brief look at an 8x42 Aculon in a store today. I'm quite sure the prisms are uncoated and the exterior surfaces are multicoated. As for the interior lens surfaces, I think the ones I could see are probably single layer coated. Initially their bright reflections look uncoated compared to the dimmer green multicoating, but they look less bright than the dazzling pure white uncoated prism reflections and appear to me to be slightly tinted a very pale violet. I would guess that a binocular with this combination of two multicoated surfaces, four single layer coated surfaces and four uncoated surfaces might have around 75%-80% transmission. The biggest loss is from the prisms, which might have cost an extra dollar to coat and that would have added at least 10% to the light transmission. A case of bean counters working overtime, I guess.

Henry

edit: I just noticed there is an Allbino's review of the 10x50 Aculon from last year.

http://www.allbinos.com/286-binoculars_review-Nikon_ACULON_A211_10x50.html

They give the light transmission as 78.2%, but if you look at the spectral transmission chart it's quite uneven, going from a high of around 82-83% in the red at around 650nm to around 78% at the 550nm peak of daylight eyesight sensitivity and then falling through the blue to about 65% at 450nm. They also noticed the lack of coatings inside.

 

[Binastro]

Thanks Henry,
I wasn't sure if the lens surfaces inside the 10x42 Aculon were uncoated or single coated. I thought a mixture.
The 10x35 EII at night on Jupiter and the moons was 25% brighter, but this might be partly due to the higher accuracy of the surfaces as well as better transmission.
The 10x42 has nominally larger objectives, and I think my pupils were bigger than 4.2mm.
But the EII is clearly a lot brighter at night.

During the day the gain seemed to be 20%.

If the later model EII has 88% to 90% transmission?, I would think the Aculon might be 74%?? with less quality.
It could be that Aculons vary.
I know that the Revelation 15x70 varies a lot in transmission, depending on batch.

 

[henry link]

Looked just now at Allbinos earlier reviews of Action EX (2013) and Action VII (2011) models. Both mention a lack of coating on some internal surfaces, so it looks like Nikon has been cutting these corners for a while in their low priced lines.

Henry

 

[OPTIC_NUT]

So a 3-element eyepiece with an aspherical field lens,
quite like the ubiquitous Meade MA25 eyepiece, wouldn't be odd at all.
A 4 or 5 element EP with the typical (non-7x50) 12mm eye relief would be
very strange....at such a low number..

People do enjoy the Aculons...a nice view for the money.
However, there are limits. 3-element EPs (Kellner-style or 'MA')
are well-known for a lack of ghosting when not thoroughly coated.
It goes with the design. Fewer interfaces reduces the loss too.
Acrylic lenses have a nice even white response and lower loss...so; not bad.
(but do not clean with solvent!!)

The only special measure you need for an aspherical field lens
is more alignment (parallelism) precision. Thus the tight focuser.
I prefer the old fully-coated all-glass models with alloy arms, meself ;-)

 

[Red_Shoulder]

After all the discussion, I thought I should reiterate : these are good, serviceable binos for birding.

Quit nitpicking a $65 to death. Its a good binocular. So far I've resisted nitpicking the posts in this thread. So far.......

 

[OPTIC_NUT]

Only a year ago they got raves....here. The mood comes and goes,
sometimes it's time the "The Princess and the Pea".
If some surfaces aren't the tops, they have designed for proper
scattered light management accordingly. They are nice to look through.

When you have 6 glass-air in the eyepiece, and 2 of them are through low-loss acrylic
(field lens), life isn't anywhere near as dire as when you have twice as many surfaces
and they are to glass of high index....and any surface film or spec emissions disperse to the
wall much more gradually. Of there is an issue with the material of the low-diopter field
lens, let those without plastic eyeglasses cast the first stone, and them with Lasik cower ;-)
It's all relative, and the scene looks good.

 

[Roadbike]

After all the discussion, I thought I should reiterate : these are good, serviceable binos for birding.

Quit nitpicking a $65 to death. Its a good binocular. So far I've resisted nitpicking the posts in this thread. So far.......

+1

 

[Vwapy]

I really like my 7x50's from the JT-II and MIOJ period, but I have really warmed up to the 7x35's lately. They have a lot going for them:

1. Closer focus

2. Generous 5mm exit pupil

3. Smaller size

To name a few of the advantages. I recently purchased a pair of 7x35 Aculon. Would they make my older binoculars obsolete, with the new coatings? I had wondered. How good will sharpness be?

Also, I thought I would do a bit of a review, in case someone was interested in getting into birding, but didn't want to spend a lot of money. The 7x35's are good to start with, and if you feel the need to move up later, you'll have a pair for the spouse, kids, etc. Please keep reading for other considerations, though.

Granted, I use and like the older, larger 7x50's, but the 7x35's seem fairly small. I think these would be small enough for most people. While lightweight, the body and focuser seem to be metal, and that's most of the binocular. I was expecting more plastic, probably partly due to the rubber coating, and when I looked closer, had a happy surprise.

There are smaller binoculars available, but some have a much smaller exit pupil, requiring more precise eye placement, which is a bit of a hassle. Though not too bad, I suppose. The 7x35's are fairly compact, though, and I've found 5mm to be fine for eye placement.

The 7x35 Aculons are featherweights. Wide field, relatively compact 7x35's with good performance in the center that falls off at the edges. It is personal preference as far as preferring the purer view or the wider one. It was amazing how similar the profiles of the Nikons were to other, older, featherweights. Hopefully I'll get around to posting a photo.

The lack of flare/glare is impressive, and would probably beat some much more expensive binoculars. I was getting the sun in the field (very dangerous, don't do this!) trying to get a problem with flare! Got a bit on the edges, but not the center, maybe not even all the time. Impressive performance in this important test.

I still plan on using my older binoculars. The 7x50's have a purer field, as can narrower field 7x35, which is nice. Also the older binoculars seem sharper, with wider sharp field (I am not sure about wider sharp field, and need to test more. Weirdly, seems to vary on the Aculons? ) But the newer coatings on the Aculons give better color and contrast. Its probably personal taste as to whether the differences in coatings and sharpness are pronounced. I didn't want to stop using my oldies anyway, did I?

I'd be interested in a size and performance comparison between 7x35 and 8x42 Aculons, as they seem similar in many ways. The 12x50's weren't that far behind the Monarch and Terra, it seemed, although I just looked at the store, and may have looked at the center more than the edges. I wasn't convinced there'd be real differences in the field between these 3, they seemed close.

If you mail order, you may need to send them in immediately if they arrive out of collimation. Mine are ok, maybe having a bit of an issue (or is this normal at closer ramges?) But they seem lined up at distance. Hopefully, Nikon checks collimation on these.

I have read about a 25 year no fault warranty. Mine arrived with a lifetime warranty against defects. I would think most defects would become apparent in the first couple weeks, or immediately, so I don't get that excited about a lifetime warranty anymore.

But if I could send them in to get collimated for $20+the cost to ship 1 way, that would be very important. I don't think you can get these collimated, for less than they cost new, here in the USA.

Of course, with porros, you may be able to conditionally align them yourself, which is potentially a huge advantage. A big part of the reason I go with older ones. I'm generally not willing to tear in to new binoculars and void the warranty. I think it is important to consider collimation.

Really happy with the close focus ability of the 7x35 Aculon, they're down around 10 ft. The shorter focal length of the 35mm objectives vs 50mm helps here.

Also eye relief seems decent, and they have retractable eyecups.

These are good binoculars. If you are interested in birding, but don't want to spend a lot, or just want a backup, or pair for the kids, these are a good place to start.

I have a vintage 1960's era Nikon 7x50 featherweight binoculars and want to mount them on a tripod. The tripod adapters available use 1/4"-20 mm thread to screw adapter into binocular. Since it is an older binocular the screwsize that would fit has to be 5 mm or 3/16" diameter. Are you aware of any suitable binocular tripod mount for this older binocular?

 

[John A Roberts]

Hi Vwapy,

Presumedly a Feather-Weight like this one on Simon Spiers' flickr stream?

https://flic.kr/p/8kGP5B

An alternative is Nikon’s own 'Tripod Adaptor - SE Series' (part #7806). It clamps to the exposed axle and so can be used on many older binoculars.
As can be seen in the first image, both the top and bottom jaws have a synthetic insert, so they can clamp tight without damaging the finish on the axle.
While not the cheapest option, it's secure, durable and adaptable.


John

 

[Vwapy]

Hi Vwapy,

Presumedly a Feather-Weight like this one on Simon Spiers' flickr stream?

https://flic.kr/p/8kGP5B

An alternative is Nikon’s own 'Tripod Adaptor - SE Series' (part #7806). It clamps to the exposed axle and so can be used on many older binoculars.
As can be seen in the first image, both the top and bottom jaws have a synthetic insert, so they can clamp tight without damaging the finish on the axle.
While not the cheapest option, it's secure, durable and adaptable.


John

Many thanks for the information John. My Nikon Featherweight is exactly the same as shown in the photo. It looks like the Tripod Adapter #7806 should work perfectly.
Don

Hi Vwapy,

Presumedly a Feather-Weight like this one on Simon Spiers' flickr stream?

https://flic.kr/p/8kGP5B

An alternative is Nikon’s own 'Tripod Adaptor - SE Series' (part #7806). It clamps to the exposed axle and so can be used on many older binoculars.
As can be seen in the first image, both the top and bottom jaws have a synthetic insert, so they can clamp tight without damaging the finish on the axle.
While not the cheapest option, it's secure, durable and adaptable.


John