Minox bf 8x42 br honest review,be warned. (1 Viewer)

[truculenter aspicientis]

Ok you may of seen my post last week that I bought some of the above binoculars.
Well optically they were good, not brilliant, build was good, well so I thought, now I know why not to buy the cheap ones made elsewhere but not Germany.
Having spent an hour out on the local marshes two days ago in the blistering sun all was ok to start with, with binoculars round neck I had been walking around for about an hour.
I looked through them and something distracted me from what I was looking at, something in the field of view.
I looked to the edges and noticed a small semi circular shape at the edge of the field of view, having not noticed this before I wondered how I could of missed it,I carried on and within the next 30 mins about six of these appeared in the right ocular and 4 in the left one.
I discovered that what it was is the sun shining into the eyepiece had started melting the"must be plastic" field stops, obviously because the lenses were magnifying the sun increasing the intensity, bit like a magnifying glass.
I have never in any binoculars even cheap ones had this happen before.
Straight away these were taken back within 30 mins of finding this out, this is why I like buying from local shops.
They agreed with my findings and asked would I like to swap them.
I said no, not for minox, well unless they're made in Germany, which I'm sure would use better quality parts and not plastic.
Anyway,I swapped for helios ultra sport 8x42.
I have to say these optically knock spots off the cheaper minox in every way, much sharper, brighter and clearer sort of more transparent to look through.
Anyway I don't know if anyone has heard of this problem before but for me if I do buy minox again they will be made in Germany.
Now I know why they were cheaper.
Thanks
Garth

 

[Binastro]

. Amazing, Garth.

With telescopes the sun shining in from the objective end can damage plastic components and also destroy the cement in the eyepieces.
That is why 2 element Huyghenian eyepieces are used for projection combined with long focus objectives.

I've often used 10 x 25 roof prism binoculars to project the sun's image onto white card and I've never apparently damaged the eyepieces but I probably wouldn't try this with a 10 x 50. I probably wouldn't use a very expensive 10 x 25 anyhow.

I wouldn't have thought the elements of the eyepieces in the M I N OX binoculars would be large enough or shaped enough to cause this damage but it seems they have.

The terrible sun filters that used to be sold with telescopes are very dangerous as the sun's heat can shatter them in a short period of time and if one is looking through the eyepiece permanent eye damage can occur either from the excessive heat and also from near blue radiation but also from splinters of glass.
If anyone finds these with telescopes just throw them in the bin.

I wonder if anybody else has experienced the problem that Garth describes?

 

[Binastro]

. This morning I discussed solar damage to optics with a friend.
We have written papers on lenses together.
I asked whether he had met damage to photographic lenses from solar radiation and he said not.

However, with another friend they tackled the rumour of old Leica cameras having their shutter blinds ruined by the sun.
They did not want to sacrifice a valuable Leica camera so they got some shutter blind material and using the standard lenses set up to mimic the cameras they proceeded to expose the material to the sun.

Within three seconds damage began to occur and within 30 seconds a hole was burnt in the material.

They mentioned this to a very experienced camera repairer and he said this was a notorious problem and he frequently replaced shutter blinds damaged by the sun.

Furthermore with old large wooden cameras such as the Sanderson, if these were placed in photographic shop windows with the lens uncapped then after a sunny day there would be a U-shaped burn in the wood and the bellows would also be burnt.
Bellows material burns very well.

I asked if the film in a 35mm camera would catch fire and he said that with acetate-based film it would be difficult to set it alight but with nitrate film it would probably ignite easily.
That is why old movies has been saved before the nitrate stock self ignited.

I don't know if the modern DSLR cameras suffer at all from exposure to the sun but the Sony NEX cameras I think have a warning that you should keep the lens covered with the lens cap. Although looking through the instruction book I haven't found the reference yet.

It would have been very nice to have photos of the damage to the M I NOX binocular eyepiece field stops as this is quite interesting.
One would have thought the makers would have known this problem and I wouldn't think that metal field stops can cost much at all.

 

[truculenter aspicientis]

I agree with what you are saying, and with not hearing about this problem before I'm wondering if it's a one off or not.maybe they ran out of metal field stops so had to bung a cheap set of plastic ones in.I'm waiting to hear off minox to see what happened.never had this before though even with cheap binoculars.

 

[Binastro]

. Further to the post above the following may be of interest to binocular users.

Next Monday, June 17 at 5:30 PM BST there is an episode of Neighbours that is called the eclipse.
this is on channel 5 in England.
I think that towards the end there is a case regarding eclipse blindness involving retinal damage.

I have researched solar eclipses and concluded that at an average eclipse partial or total the average number of persons receiving permanent eye damage is of the order of 80 to 250.
This varies very greatly depending on whether the eclipse occurs over heavily populated areas or areas with few people.
It is also of course dependent on whether it is cloudy or not over the path of the eclipse.
In addition it depends on the amount of advertisement of the eclipse.
If there was no news of it most people would not know the eclipse is taking place.
But nowadays millions of people will know.

When I see on the television scenes of masses of people looking at the sun, many without special solar filters or eclipse glasses I realise that some people will be permanently damaged.
I actually know personally of people who have this permanent eye damage.

There are safe ways of observing an eclipse.
Eclipse glasses have a shelflife of five years normally and they must have a British standards or EU stamp or probably a similar US safety stamp.

Welders glass number 14 is suitable but again this must have a safety stamp.
In Britain number 14 is difficult to obtain and there may be a minimum order.
It is possible to use a number 13 and tilt it until it is exactly tuned to the correct brightness. But it should be the bigger size to enable this to be done safely.

One should never stare at the sun with an unaided eyes and definitely not through binoculars.

As a solar observer I try never to allow the sun into the binocular field and I don't think this is ever occurred.

I don't know how many of you have actually had this happen.
It may be if your side vision gets exposure to the sun for less than 1/10 of a second you may be okay. At the worst there might be a retinal burn to the side of the eye and you may never know this has occurred.

You definitely don't want your central vision exposed to the sun even for 1/10 of a second.

 

[gunut]

I agree with what you are saying, and with not hearing about this problem before I'm wondering if it's a one off or not.maybe they ran out of metal field stops so had to bung a cheap set of plastic ones in.I'm waiting to hear off minox to see what happened.never had this before though even with cheap binoculars.

Did Minox ever get back to you on this problem??....Iv had a couple pair of the older style bf 8x42 binos or a couple years now....no problems so far but I don't use them a lot outside......use mostly to watch the birdfeeder or other animals around the yard/garden..........seem like real nice optical glass with a nice build for the price.....was also wondering if this could be a problem in the NEW redesigned bf 8x42??....