UPDATE - Too much light through my scope

[Jose_Luis_G]

Once more I come to the experts in search of good valuable information.
My scope has a 65mm lens on the front and very often my eye gest saturated with light after very few shots, say 15 to 20.
You must take also into account that I have serious problems with my master eye, which cannot be solved by doctors in any known way.
Things go worse (if possible) in winter, because the sun rays reach the target more frontally and there is a higher light reflection from it.
I've tried several filters as well as polarizers, but they only supply lower image sharpness, which is just the oposite of what I need.
Finally I've heard about making a disk collection of different diameters, in order to reduce the incoming light at the front of the scope.
The holes in the different disks should act as the diaphragm of a camera, theoretically.

Have you ever tried this solution? Madness?

Thanks to all of you for your replies, that will be for sure, highly appreciated.

 

[Geronimo Jim]

A March scope that I recently bought came with a disc that screws
into front and really cuts down light.

 

[C.E.Smith043]

I think Burris Signature scopes used to have a dial on the front objectice bell that done a similar thing. It said "Daylight" "Twilight". As you rotated it, it would open and close some circular fins inside just like a camera shutter.

 

[Turbulent Turtle]

You might want to look at a neutral density filter. They come in EV equivalent or reciprocal of the EV. Each number represents half the exposure of the prior number. I would look at an ND2 or an ND4.

 

[Depart123]

The anti reflection tenebraex type screens tend to cut down light, I don't know if those are available for your scope. The ghetto answer is panty hose or similar material stretched tight across the objective bell...don't laugh, it works.

 

[FatBoy]

why not just wear polarized sun glasses?

 

[Depart123]

why not just wear polarized sun glasses?

I don't know about everyone else, but polarized sunglasses really screw with my vision through the scope.

 

[FatBoy]

I don't know about everyone else, but polarized sunglasses really screw with my vision through the scope.

I've shot polarized sun glasses for year. Some are better than others. I find Oakleys polarization is pretty weak compared to most, don't even seeing checkering on auto glass but if they won't work..

OK, maybe colored lenses in different shades? Iron sights?

 

[Turbulent Turtle]

Once more I come to the experts in search of good valuable information.
My scope has a 65mm lens on the front and very often my eye gest saturated with light after very few shots, say 15 to 20.
You must take also into account that I have serious problems with my master eye, which cannot be solved by doctors in any known way.
Things go worse (if possible) in winter, because the sun rays reach the target more frontally and there is a higher light reflection from it.
I've tried several filters as well as polarizers, but they only supply lower image sharpness, which is just the oposite of what I need.
Finally I've heard about making a disk collection of different diameters, in order to reduce the incoming light at the front of the scope.
The holes in the different disks should act as the diaphragm of a camera, theoretically.

Have you ever tried this solution? Madness?

Thanks to all of you for your replies, that will be for sure, highly appreciated.

Let me add a few more thoughts here.

My earlier answer was about the use of ND filters and that will do what you are looking at doing, without changing the optics of your riflescope. They will just make the image progressively darker, the higher you go in opaqueness. Just make sure you buy quality filters.

But more to your question, the aperture reduction device you are talking about will also do the trick, but they will changes the optics of your scope. Starting with your objective lens at 65mm, reducing it by half (one stop) means a disk with 46mm diameter hole. One more stop will mean a hole of 32.5mm diameter and the next stop will be 23mm diameter. Those numbers will give you -1 EV (half), -2 EV (quarter) and -3 EV(eighth) in the amount of light coming through.

The issue will be that as you reduce the aperture, you will increase the depth of field in your riflescope. What this means is that it will become much easier to focus, but that will also mean that you can increase parallax without realizing it, with its attendant issues and this is what I mean by changing the optics of your riflescope. It's not a bad thing, but you need to keep it in mind when focusing, just need to be very picky about the focus. You could always focus first and then add the aperture-reduction disk.

 

[Jose_Luis_G]

First I would like to thank to all of you giving suggestions.
I made a support for several disks (one at the time) to be inserted at the front part of the scope.
The disks were cut according to a percentage of the total lens surface, i.e. 50%, 40%, 30% and so on, down to a 1%.
I soon discovered that above 50% the light control was irrelevant, and below 11% darkness was the result.
This means that a much clear vision can be achieved by using the percentages between 50 and 11%, in order to reduce the incoming light into the scope.
The results show that with the same focus, when you insert the light reduction, the image becomes instantly much sharper than before was.
I have ordered an adjustable iris at https://www.aliexpress.com/item/1-P...32834615025.html?spm=a2g0s.9042311.0.0.IAizYi to replace the hand cut disks.
Just for you to know.

 

[Grimstod]

Get a spair cap and cut a hole in the centure to reduce your aperture. It will reduce the light and actually make the image sharper too. I do this with many of my scopes and binoculars when i am viewing the moon.

 

[Turbulent Turtle]

First I would like to thank to all of you giving suggestions.
I made a support for several disks (one at the time) to be inserted at the front part of the scope.
The disks were cut according to a percentage of the total lens surface, i.e. 50%, 40%, 30% and so on, down to a 1%.
I soon discovered that above 50% the light control was irrelevant, and below 11% darkness was the result.
This means that a much clear vision can be achieved by using the percentages between 50 and 11%, in order to reduce the incoming light into the scope.
The results show that with the same focus, when you insert the light reduction, the image becomes instantly much sharper than before was.
I have ordered an adjustable iris at https://www.aliexpress.com/item/1-P...32834615025.html?spm=a2g0s.9042311.0.0.IAizYi to replace the hand cut disks.
Just for you to know.

In photography, exposure control consists of three items: aperture size, shutter speed and film (sensor) ISO. For spotting scopes and riflescopes, we can only control one of those, aperture size. As I explained earlier, one EV represents half od double the amount of light. To the visible eye anything smaller than 1 EV will not show much change, which is why I was displaying the MD sizes corresponding to a whole EV; 1 half (50%), 1 quarter (25%) and 1 eighth (12.5%). I stopped at 3EV (1 eighth or 12.5%) figuring that would be about as dark as you would ever need. Your observations bear that out completely.

Now, the whole image will become much sharper because as you step down the aperture, the depth of field increases rapidly, especially at the distances we are talking about. That will be most apparent if you are prone and close to the ground all the way to the target (like at Connaught) or if there is a lot of features beyond the target line (trees, mountains, like at Lodi.)

There are formulae that you can use which will calculate depth of field, but for that we need the focal length and f-number of the optic and decide on the circle of confusion criterion. So, suffice it to say that one step down will provide a sizable enough increase in DoF that you will see it in the riflescope.

 

[Papa Charlie]

First I would like to thank to all of you giving suggestions.
I made a support for several disks (one at the time) to be inserted at the front part of the scope.
The disks were cut according to a percentage of the total lens surface, i.e. 50%, 40%, 30% and so on, down to a 1%.
I soon discovered that above 50% the light control was irrelevant, and below 11% darkness was the result.
This means that a much clear vision can be achieved by using the percentages between 50 and 11%, in order to reduce the incoming light into the scope.
The results show that with the same focus, when you insert the light reduction, the image becomes instantly much sharper than before was.
I have ordered an adjustable iris at https://www.aliexpress.com/item/1-P...32834615025.html?spm=a2g0s.9042311.0.0.IAizYi to replace the hand cut disks.
Just for you to know.

That is very cool. Do you think that the adjustment will remain constant when you fire the rifle? Please provide feed back once you have had a chance to use it. I would be interested in your experience.

Good luck,

 

[Jose_Luis_G]

That is very cool. Do you think that the adjustment will remain constant when you fire the rifle? Please provide feed back once you have had a chance to use it. I would be interested in your experience.
Good luck,

At the present time, I have only used it for 22lr, so the fixing is granted, since there are no big shakes.
For bigger calibers I'm thinking of using a rubber band to help the support device to go back to place on every shot.

A different thing is when I finally get the diaphragm from China, and install it on the big bore.
In this case the adjustment changes will not be due to the fixing, because I'm thinking of using a 72mm ring from a filter, but for the heavy recoil when shooting.
I'm sure to find my way to avoid that somehow.

Best of all, in my opinion, is that MD filters also bring some losses, due to the material they are made of. On the other hand a raw hole does not.

Anyway, I will try to keep this post updated with further experiences. It is nice to share findings with other people, and read their opinions as well.

 

[Jose_Luis_G]

After some tests and competitions, I can say it has been a total success.
I bought one of this diaphragms
https://www.aliexpress.com/item/1-P...32834615025.html?spm=a2g0s.9042311.0.0.WkLUej
and glued it to a 72mm ring, since my scope is 75mm oulter diameter.
Now, I can control the light into my eye in a very much convenient way, avoiding any kind of glare.
Just for all of you to know.

 

[Papa Charlie]

After some tests and competitions, I can say it has been a total success.
I bought one of this diaphragms
https://www.aliexpress.com/item/1-P...32834615025.html?spm=a2g0s.9042311.0.0.WkLUej
and glued it to a 72mm ring, since my scope is 75mm oulter diameter.
Now, I can control the light into my eye in a very much convenient way, avoiding any kind of glare.
Just for all of you to know.

Any pictures of the final set up?

 

[Fred Bohl]

As an avid optics experimenter, I love the idea of using an adjustable diaphragm to test the impact on perceived light level. Thank you for sharing your results.

However, a reminder, as you reduce the objective diameter you also reduce the scope resolution (increase the diffraction limit) and with that reduce your ability to see very small detail clearly or to aim precisely.

You may also find some of the http://forum.accurateshooter.com/posts/37046553/ thread informative. Please read the attached PDF in post #1.

 

[Jose_Luis_G]

As an avid optics experimenter, I love the idea of using an adjustable diaphragm to test the impact on perceived light level. Thank you for sharing your results.

However, a reminder, as you reduce the objective diameter you also reduce the scope resolution (increase the diffraction limit) and with that reduce your ability to see very small detail clearly or to aim precisely.

You may also find some of the http://forum.accurateshooter.com/posts/37046553/ thread informative. Please read the attached PDF in post #1.

Probably it is as you say, but my experience is that I have both, a much more clear vision and less glare to stand with.

My scope has a 65 mm lens in the front and that allows a lot of incoming light for my poor, damaged, handicapped eye, which feels much better with the light reduction from the iris.

 

[Jose_Luis_G]

Any pictures of the final set up?

Please see the result
https://www.dropbox.com/s/qt263rbqs719o99/Front view.jpg?dl=0
https://www.dropbox.com/s/ms0lu821lrbbwe7/Glued to the ring.jpg?dl=0
https://www.dropbox.com/s/g04q1xa8gc182fq/Mounted in the scope.jpg?dl=0
https://www.dropbox.com/s/tgtb7svztu5dtd2/Rear view.jpg?dl=0
Important: note that the c clamp must be placed to the front. If you do the opposite, the whole iris will come in parts in short time, as the c clamp gets loosen and comes out of place shortly.

Sorry for the poor image quality.

 

[Papa Charlie]

Ok that looks pretty cool. Does the shutter shift from the recoil?