Robert Moore
Well-known member
So far I have not noticed any glare issues and have been testing for it. I also have been looking at bright light sources to look for ghosting and have not noticed that yet either.
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B&W Nano coated 46mm clear filters on Zeiss 8x42HT (1 Viewer)
- Thread starter Robert Moore
- Start date
Robert Moore
Well-known member
Thanks Lee,
So far they have proven to be excellent.
So far they have proven to be excellent.
Etudiant,
That may be why Zeiss were concerned about filters as fungus could take hold on glass, metal and rubber.
Andy,
There could be an increase in glare using filters. Maybe lens hoods would help.
Basically, one has to match the optical quality of the filter to the quality of optics it is mounted on.
Top quality, randomly picked B and W filters should be O.K. on most binoculars.
However, with a Zeiss 20x60S, Takahashi 22x60, Japanese and German 80mm binoculars and observation binoculars such as APM, Vixen, Miyauchi etc. they may not be good enough.
Here a Kowa spotting scope filter might be better, as the quality is probably designed for high quality spotting scopes.
The Kowa spotting scope filters may not be good enough for high magnifications on high quality astro scopes.
I would avoid filters altogether here at the front, or use a high quality optical window, which could be very expensive.
Questar filters are probably O.K. up to 200x.
Soviet MTO ~105mm filters are O.K. at 100x.
Filters for top end 600mm f/4 camera lenses are probably O.K. at 100x.
Leica filters should be very good.
Some of these filters and optical windows won't have the best coatings.
Regards,
B.
That may be why Zeiss were concerned about filters as fungus could take hold on glass, metal and rubber.
Andy,
There could be an increase in glare using filters. Maybe lens hoods would help.
Basically, one has to match the optical quality of the filter to the quality of optics it is mounted on.
Top quality, randomly picked B and W filters should be O.K. on most binoculars.
However, with a Zeiss 20x60S, Takahashi 22x60, Japanese and German 80mm binoculars and observation binoculars such as APM, Vixen, Miyauchi etc. they may not be good enough.
Here a Kowa spotting scope filter might be better, as the quality is probably designed for high quality spotting scopes.
The Kowa spotting scope filters may not be good enough for high magnifications on high quality astro scopes.
I would avoid filters altogether here at the front, or use a high quality optical window, which could be very expensive.
Questar filters are probably O.K. up to 200x.
Soviet MTO ~105mm filters are O.K. at 100x.
Filters for top end 600mm f/4 camera lenses are probably O.K. at 100x.
Leica filters should be very good.
Some of these filters and optical windows won't have the best coatings.
Regards,
B.
Robert Moore
Well-known member
On my telescopes for astronomy I only use filters at the eyepiece and not on the objective lens with the exception of solar filters and those are used at the objective lens. Never use solar filters at the eyepiece except for a Herschel wedge Which is designed to only let a small percentage of the light to the eyepiece and the rest is directed off axis
Robert Moore
Well-known member
Robert Moore
Well-known member
That is a beautiful telescope, Robert.
I wasn't aware of these, although there are cheaper commercial Maksutov Newtonians.
A friend has a 7 inch Astrophysics refractor and there was one in Finland at a town observatory.
I ordered a custom British 12 inch Maksutov in the early 1970s.
The optics were completed but the corrector plate split in two on the makers work bench.
He gave up making optics and authoured many fine books.
I refused to take back the money that I had paid up front, and a 12.5 inch f/3.5 f/14.7 windowed thin edge mirror Dall Kirkham was made instead. It took three years and involved about four of the best U.K. opticians.
I was told that one quadrant was not up to their standards, but I never noticed anything amiss in use up to 700x and more.
The optical window cost more than the primary.
This took any power up to 1100x. Uncoated, but I never saw ghosts for some reason.
The 20.5 inch f/3.9 Newtonian primary made for me by one of these workers was 1/20th wave. He is one of the two top U.K. professionals at the time. They made scopes up to 4 metre aperture.
I think that some people using Herschel wedges also use filters also to reduce the heat and radiation. I have never used one.
I only project the Sun with refractors or use the PST at 32x with over 2,000 days drawings. I only observe casually nowadays.
I used to submit planetary, solar and comet observations etc.
I still record NLCs and any fortuitous observations.
This evening there was a very colourful red cloud sunset. These have been reported recently as of volcanic or fire origins, possibly worldwide.
The last few days have been rainy.
Regards,
B.
I wasn't aware of these, although there are cheaper commercial Maksutov Newtonians.
A friend has a 7 inch Astrophysics refractor and there was one in Finland at a town observatory.
I ordered a custom British 12 inch Maksutov in the early 1970s.
The optics were completed but the corrector plate split in two on the makers work bench.
He gave up making optics and authoured many fine books.
I refused to take back the money that I had paid up front, and a 12.5 inch f/3.5 f/14.7 windowed thin edge mirror Dall Kirkham was made instead. It took three years and involved about four of the best U.K. opticians.
I was told that one quadrant was not up to their standards, but I never noticed anything amiss in use up to 700x and more.
The optical window cost more than the primary.
This took any power up to 1100x. Uncoated, but I never saw ghosts for some reason.
The 20.5 inch f/3.9 Newtonian primary made for me by one of these workers was 1/20th wave. He is one of the two top U.K. professionals at the time. They made scopes up to 4 metre aperture.
I think that some people using Herschel wedges also use filters also to reduce the heat and radiation. I have never used one.
I only project the Sun with refractors or use the PST at 32x with over 2,000 days drawings. I only observe casually nowadays.
I used to submit planetary, solar and comet observations etc.
I still record NLCs and any fortuitous observations.
This evening there was a very colourful red cloud sunset. These have been reported recently as of volcanic or fire origins, possibly worldwide.
The last few days have been rainy.
Regards,
B.
Robert Moore
Well-known member
I don’t observe as much as I should. I get lazy and don’t want to mess with it all and that’s one reason I love binoculars. I use to have the big Nikon 20x120III and had them on a geared head Linholf tripod and they were fantastic. I would like to get another large binocular at some point. That 20” scope sounds nice. I use to have a 20” obsession telescope and really enjoyed those lovely globular cluster views.
GoldenBear
Well-known member
I have the exact same filters on my HT 8x42's and love them. I had them for a few months and so far have had no issues with condensation or fogging. I was more concerned that the flat filter surface may cause more glare or flares under certain light angles, but there's been no impact whatsoever.
Absolutely optically invisible as far as I can tell, and I compared them extensively in the field and against resolution charts. Much easier to clean the flat filter surface (especially with B&W's excellent nano coating). They also negate the need for objective covers (although I did but a pair of inexpensive pinch style caps the fit the filters for transport and travel).
Another nice advantage to the B&W fllter compared to most is that the metal frame is brass rather than aluminum which helps reduce he chance of seizing.
With regard to any effect on the image, if anything, when I first put them on I would swear the field curvature of the image became slightly less noticeable. No doubt it isn't optically possible for the filters to change the image in this way, but it sure seemed like it did to me eye.
Absolutely optically invisible as far as I can tell, and I compared them extensively in the field and against resolution charts. Much easier to clean the flat filter surface (especially with B&W's excellent nano coating). They also negate the need for objective covers (although I did but a pair of inexpensive pinch style caps the fit the filters for transport and travel).
Another nice advantage to the B&W fllter compared to most is that the metal frame is brass rather than aluminum which helps reduce he chance of seizing.
With regard to any effect on the image, if anything, when I first put them on I would swear the field curvature of the image became slightly less noticeable. No doubt it isn't optically possible for the filters to change the image in this way, but it sure seemed like it did to me eye.
Robert Moore
Well-known member
Glad to hear someone else is using them. I was checking last night on the moon and the moon was extremely bright and I could not detect and ghosting or reflections of any kind. I found this pair of HT in new condition and I wanted to keep them that way. That is why I wanted to try the filters and see how they performed. To be honest I wasn’t expecting them to be this good. Like you I can see no image degradation whatsoever. At 8x I wasn’t expecting any softening to the image but I thought I might get some glare or ghosting and I just am not seeing any.
GoldenBear,
I am not so sure that a flat glass filter cannot affect rays of light coming at an angle into the optical system.
Whether this can lessen field curvature, I don't know.
I have noticed a change in focus with a 200mm camera lens, Tamron maybe, through a good single plate glass window.
I think that here there might have been some curvature in the window, but I don't see how. It could be a pressure difference, but this was not double glazing.
Regards,
B.
I am not so sure that a flat glass filter cannot affect rays of light coming at an angle into the optical system.
Whether this can lessen field curvature, I don't know.
I have noticed a change in focus with a 200mm camera lens, Tamron maybe, through a good single plate glass window.
I think that here there might have been some curvature in the window, but I don't see how. It could be a pressure difference, but this was not double glazing.
Regards,
B.
With reference to filters in general.
It seems that resin filters reduce the resolution of lenses, when top quality glass filters don't.
I know that the eclipse glasses generally available reduce resolution compared to high quality glass filters, seen with safe filters and unaided eyes on sunspots.
The glass stacks in front of digital camera sensors vary from about 1mm Leica to 4mm. These different thicknesses affect lens resolution and general optical characteristics.
How good lenses are on digital cameras varies with different camera bodies.
High resolution lenses have to be designed for the whole system.
I think I recall that aero lenses were computed to include the glass register plates that held the film flat.
B.
It seems that resin filters reduce the resolution of lenses, when top quality glass filters don't.
I know that the eclipse glasses generally available reduce resolution compared to high quality glass filters, seen with safe filters and unaided eyes on sunspots.
The glass stacks in front of digital camera sensors vary from about 1mm Leica to 4mm. These different thicknesses affect lens resolution and general optical characteristics.
How good lenses are on digital cameras varies with different camera bodies.
High resolution lenses have to be designed for the whole system.
I think I recall that aero lenses were computed to include the glass register plates that held the film flat.
B.
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Gijs van Ginkel
Well-known member
Considering the efforts of binocular producers to supply binoculars with hard, water- en dust repellent coatings the use of filters for protection purposes seem unnessecary to me. I never have had the temptation to use one.
Gijs van Ginkel
Gijs van Ginkel
Sand / silica has a hardness of 6-7 on the Mohs' Scale, equivalent to quartz, propelled by the wind sand will chip or scratch objective lenses.
I have a Zeiss Conquest HD 8x32 with a sand chipped objective not that it interferes with the view, just the aesthetics.
Regards, Steve
I have a Zeiss Conquest HD 8x32 with a sand chipped objective not that it interferes with the view, just the aesthetics.
Regards, Steve
I got about twenty 4 inch f/1.8 lenses as a job lot.
Only two were usable.
The others all had sand blasted front elements, some almost opaque, because the techs forgot to put the front filters on.
They were used underneath aircraft for photography.
I also had a Zeiss 10x40 Classic rubber coated binocular.
The lenses were destroyed by the user who may have cleaned them repeatedly with a scarf on his sandy beach.
The binocular came from a seaside town.
I found it hard to believe anybody would treat optics like this.
But personally, I have almost never used filters even with my Minolta cameras on the beach.
My lenses and cameras still look almost new after nearly 50 years.
The cameras always had an ever ready case that took about one second to drop the front and take a photo, with the close fitting rubber double grip front caps dropping into the front of the case.
B.
Only two were usable.
The others all had sand blasted front elements, some almost opaque, because the techs forgot to put the front filters on.
They were used underneath aircraft for photography.
I also had a Zeiss 10x40 Classic rubber coated binocular.
The lenses were destroyed by the user who may have cleaned them repeatedly with a scarf on his sandy beach.
The binocular came from a seaside town.
I found it hard to believe anybody would treat optics like this.
But personally, I have almost never used filters even with my Minolta cameras on the beach.
My lenses and cameras still look almost new after nearly 50 years.
The cameras always had an ever ready case that took about one second to drop the front and take a photo, with the close fitting rubber double grip front caps dropping into the front of the case.
B.
Alexis Powell
Natural history enthusiast
I don't know how a flat filter would affect field curvature but a flat filter will _definitely_ affect the focal point. The focus adjustment will be need to be different for a lens when used with and without filters at a given distance.
--AP
Alexis Powell
Natural history enthusiast
I've never had a problem with blowing sand scratching camera lenses despite much use in blowing sand in the deserts of Arabia, but I never had a situation where the sand was hitting the lens at high velocity. Generally, a lens hood provides good protection because even wind directly aimed at the front element piles up and creates a dead space immediately in front of the lens. More often, the issue is ricocheting low-velocity sand accumulating around the filter threads etc which requires care (blower bulb, long bristle brush) to remove so it doesn't get transferred to a cleaning cloth and then inadvertently used to scour the lens. A the sea shore, I think the issue is often that salt spray becomes gummy and traps sand and silica dust as it hardens, so it must be removed carefully with a wet method.
--AP
I have a note, relating to my 1978 Leitz Trinovid 10x22C, that says ""plain glass cover plates over objectives".
Not sure if that's true, however. Have other manufacturers done this, in the past?
I don't think they are field-changeable, so perhaps it's just a cost-saving measure by the manufacturer, i.e. it's cheaper to replace the plain cover glass, than part of the objective?
Or perhaps it wasn't true, and I noted it down in error.
Not sure if that's true, however. Have other manufacturers done this, in the past?
I don't think they are field-changeable, so perhaps it's just a cost-saving measure by the manufacturer, i.e. it's cheaper to replace the plain cover glass, than part of the objective?
Or perhaps it wasn't true, and I noted it down in error.
