Influence UV long term? (1 Viewer)

Hi all ,
I have been using my 10 x42 swarovision since 2011 quite intensively without any problems.
However , when comparing my bin with a new swarovison in the filed , I have the impression that mine is more dull , and less crispy.Well understood that all parameters are the same while comparing.
My local optics dealer says , that over the years , there could be an influence of the UV in daylight that might degenerate something in the bin. ,like coatings,??
I am not sure , whether this the case.
Some people have negative experience on this

Ps , this very bin was sent to Ausria for a general chequp. For finetuning the focus drive

Thanks for feed back

Hi,

while it is not impossible that some coating ages under UV light it would be most unusual. A slightly more probable culprit is lens cement (nowadays usually some kind of polymer - in the old days often canada balsam which indeed did age - although not necessarily through UV influence - and went yellow). But still, if a noticeable effect was visible after 4 years this should be considered a defect.

I would assume that Swaro gradually improved the coatings without a new marketing campaign... look at Zeiss - T* is around since tens of years under that name and I bet my Conquests that they didn't use the same stuff for all that time...

Joachim

Thanks for reply
Is there any evidence , that since the introduction of the swarovision , coatings have been updated till now?

Arran,

With nothing more than a modicum of pseudo-logic to back me up, we know that manufacturers block the UV part of the spectrum to protect our eyes. Apart from the dura-type protective coatings, I would think this would be the first one on the objective lens that incoming light strikes ...... thus protecting not only our eyesight, but any components of the binocular that are likely to degrade under UV light, be they coatings, lenses, or other. Are your front coatings intact and free from micro-scratches? etc? Perhaps one of the mavens will be along presently to confirm or otherwise ..... :cat:

As for the coatings, it is important to recognise that they are indexed, ie. work as a system in concert with the lenses, prisms etc. So certainly from model to model they would be changed (hopefully upgraded to better performance! , and it is likely that they are subject to continuous improvement in performance and /or cost reductions, introduction of new or modified technological processes, or even to match different component suppliers from time to time ...... again, hopefully one of the mavens will be along presently to confirm or otherwise .....


Chosun :gh:

arran said:

Hi all ,
I have been using my 10 x42 swarovision since 2011 quite intensively without any problems.
However , when comparing my bin with a new swarovison in the filed , I have the impression that mine is more dull , and less crispy.Well understood that all parameters are the same while comparing.
My local optics dealer says , that over the years , there could be an influence of the UV in daylight that might degenerate something in the bin. ,like coatings,??
I am not sure , whether this the case.
Some people have negative experience on this

Ps , this very bin was sent to Ausria for a general chequp. For finetuning the focus drive

Thanks for feed back

Click to expand...

Most UV is stopped about 90% per millimeter of glass. So, how much is getting through a .75-inch of objective? IR just flys through. But, if you consider how much less you're taking in while using a bino--as opposed to just walking down the street, even that is not a problem.

Cheers,

Bill

. With thorium glass, UV light is beneficial in that it reverses the discolouration, usually brown or yellow. But this is usually accomplished with strong UV lights, which need to be protected from our eyes.
It has been suggested that leaving something like an Aero Ektar 7 inch F/2.5 for several weeks in strong sunlight, some benefit can be obtained. This is also used to reverse the heavy discolouration in window glass that has been subjected to radiation.

Whether, any modern rare earth glasses, are affected by UV light one way or another I don't know.
But I would think that with binoculars they are using glasses, which are not affected by UV light to any extent.

If you get some old Pentax and Canon 50 mm fast standard lenses for 35mm cameras, they are often noticeably discoloured. I would think that strong UV radiation over a long period might help to reverse this. With these lenses not only might you see a one-stop transmission loss, but the colour balance is off. With some folding medium format Voigtlaender cameras using Apo lanthar lenses, they actually fog the film. You will also fog the film if you put the Pentax or Canon lenses mentioned on a film for a week. Here it is usually the rear element that is radioactive.

Until somebody produces some evidence for deterioration caused by UV it might be good to look first at the ordinary suspects.

An unpublicized improvement is possible. I would check the appearance of the coating reflections. If there are no differences from any surface it's safe to assume nothing has changed. Small differences could be put down to batch variations, but a big change in a reflection, say from green to magenta, would be be a tip off.

Something I've found is that contrast is reduced even when optics are only slightly dirty, not even dirty enough to notice with a casual inspection. It only takes a slight film to dull the image in a careful direct comparison to pristine optics. Sometimes I clean one side and compare it to the other "almost" clean side and can clearly see the difference in image contrast.

I don't think any significant amount of UV makes it through the lenses.

One has to consider that UV light is not a single wavelength, but different wavelengths. These different wavelengths have different transmissions and different absorptions in different glasses.

In photography, there are some simple but good lenses which are very good for ultraviolet photography, because they allow certain wavelengths in the ultraviolet to transmit rather well. I recently saw a list of these but cannot remember where it was. The list is rather surprising.

In general, I would think that ultraviolet light would bleach glass making it whiter and clearer, rather than making it less transparent. But of course with age some glasses devitrify and some lenses such as the original Canon 300 mm F/2.8 were susceptible to the fluorite crystal deteriorating badly.

Moisture also affects glasses differently.

I don't know if one of the parameters included with glass types is how they behave with exposure to ultraviolet light.

Then there is the question of the near blue wavelength, which probably contributes more to eyesight damage than other wavelengths. I don't know how this behaves with different glass types.

So I don't think it is a simple matter to know what actually happens with different wavelengths of ultraviolet. Although I would think that binocular makers have by now chosen good glasses.

Glass chemistry is a complex subject.

Maljunulo said:

I don't think any significant amount of UV makes it through the lenses.

Click to expand...

Ah, yes, but on binocular forums, we never stop looking for things to worry about or that would cause us to stop creating evermore elaborate solutions to non-existent problems. That's kind-of-a human nature thing! We just like to slay dragons that wear size 7 shoes! :cat:

Bill

For good comprehension , i saw this difference in crispiness another time as well.
When comaring , lenses were throughly cleaned with a new lens cloth , to avoid this parameter
What intrigues me most , is there any evidence that swarovski changed the coatings since the first productions.
E.g. Is there a difference in colourredlection of the objective lenses?