Reducer Ring

[Centerfire]

Jackie S. refers to a reducer ring for his 50x March scopes.
Being new I have not seen one of these units.
Do not know if something like this is available for a Leupold.
Anyone have a picture?
How and why does it work?
Centerfire.

 

[Fred Bohl]

Jackie S. refers to a reducer ring for his 50x March scopes.
Being new I have not seen one of these units.
Do not know if something like this is available for a Leupold.
Anyone have a picture?
How and why does it work?
Centerfire.

The item in question is provided with the March scopes which they call a Modifier Disk. It is a thin disk with a 35 mm hole and is equipt with a threaded mounting ring that fits the objective end of the scope. When in place, it will:

Reduce light through the scope 50-55%. -- This may be usefull under bright conditions.

Increase depth of focus about 50%.

Reduce resolution by 33%. -- In bad seeing conditions (including particulate air pollution and mirage particularly with changing wind conditions), the normal high resolution of the scope may show too much detail for the user to interpret usefully. Reducing the resolution reduces the visibility of detail without having to reduce scope power.

Using the Modifier Disk can be very helpful in those afternoon relays when the mirage and wind would otherwise make target sighting and analysis very difficult.

The Modifier Disk works by reducing the clear objective diameter (aperture) which in turn reduces the visibility of small details (reduces resolution).

I'm not aware of anything similar offered as an accessory for any other scope. However, it would be relatively easy to make one. The keys are to center the hole, make it thin near the edge of the hole and try for a light absorbing finish at the edge and inside (to minimize reflections into the scope). I've made workable versions using a spare screw in scope cap for my Weaver T-36s and also the elastomer caps for the Leupold competition sold by Sinclair.

 

[R. G. Robinett]

Here's a SWAG . . .

Jackie S. refers to a reducer ring for his 50x March scopes.
Being new I have not seen one of these units.
Do not know if something like this is available for a Leupold.
Anyone have a picture?
How and why does it work?
Centerfire.

It's probably a 'screw-on' aperture (possibly adjustable) to change/vary the objective diameter: reducing the diameter will increase the depth-of-field (focus). This works just like "F-stops" on a camera:the larger the "opening", the shallower the depth-of-field, and vice-versa. OH, with aperture reduction, resolution will diminish, thus the mirage appears to diminish. It amounts to "light tricks" . . . but, without top quality glass, these "tricks" don't work - at least not well! RG

 

[jackie schmidt]

Randy

That's all it is, a thin ring, threaded to fit the scope bell, that has a smaller hole in the middle. It is attractive, has a nice knurled OD shoulder stop.

It does seem to work. The world just looks better with the ring in place. Maybe my eyes are more screwed up than I thought........jackie

 

[R. G. Robinett]

Jackie, you're in pretty bad shape!

That's all it is, a thin ring, threaded to fit the scope bell, that has a smaller hole in the middle. It is attractive, has a nice knurled OD shoulder stop.

It does seem to work. The world just looks better with the ring in place. Maybe my eyes are more screwed up than I thought........jackie

NOT! With the quality of the March optic "glass", without choking out some light, you can just see too much to suit your fancy. By reducing the resolution and INCREASING depth of focus, you're getting the most usable picture [for your situation] which an excellent tool can provide! RG

 

[Dick Grosbier]

It's probably a 'screw-on' aperture (possibly adjustable) to change/vary the objective diameter: reducing the diameter will increase the depth-of-field (focus).

Thats exactly what it is Randy but not adjustable .

 

[cassidy]

F Rigs

Back about 25 years ago Leupold sent me a set of 4 of these each with a differet size hole in them. They were made to go on the 36x scope ad worked well--just like changing a camera's F Stop settig. Believe I still have them.
Cassidy

 

[Gary Walters]

Picture of Reducer Ring

Jackie S. refers to a reducer ring for his 50x March scopes.
Being new I have not seen one of these units.
Do not know if something like this is available for a Leupold.
Anyone have a picture?
How and why does it work?
Centerfire.

Here you go.

 

[B. Harvey]

It is common knowledge that even the highest grade of camera lenses do not give their finest performance at their widest aperture settings. Most of the top lenses, while very good 'wide open' actually reach peak resolving capability around F4. Since the reducer ring darkens the sight picture by 50%, that is effectively one stop down from wide open, which to my eye (like Jackie's) improves the quality of the sight picture.

Go here for more info

http://old.photodo.com/art/Unde7.shtml

 

[Rewinder]

Scope aperture adjust.

Burris had such a item in their Signature line of scopes . Daylite-Twilite adjustment. Built right into the scope. RANDY

 

[Fred Bohl]

Aperture Reduction Caution

Before the enthusiasm for using the March Modifier Disk or any other aperture reduction gets out of hand please remember that with the potential benefits there are also some performance sacrifices. Attached is chart (PDF format) that shows key performance parameters for the March 40x, 50x and 60x fixed magnification scopes both without and with the Modifier Disk.

I purchased my March fixed 50x and 60x scopes to attain three goals (in order of importance):

1. Stable (rock solid) windage, elevation, and parallax adjustments.

2. High magnification for aiming precision and target analysis.

3. Sufficient optical quality and resolution to analyze 6mm bullet holes at 600 yards under most conditions.

My opinion on use of the Modifier Disk is based on my experience over the last season. At or over 300 yards I only use the Modifier Disk under extreme mirage conditions do to the loss of resolution needed for aiming and analysis. For 100 or 200 yards there is sufficient resolution with the Modifier Disk on for use in moderate or worse mirage. However, I have also found that the more I use the scopes without the Modifier Disk and thus train my visual system to deal with the more data rich images, the less I feel the need to use them and the better I am able to aim precisely and analyze my bullet hole patterns.

 

[HovisKM]

Fred,
I know your very well versed in lens/optics. Are there any tests you can run that are not available to us common people or ones we can run if informed.

Also, I would like for you to explain the best way of setting focus. I know you covered it on another thread but I believe that was in General Discussion. I think setting these March scopes up properly will resolve some of the issues people are having.

First reflective surface.

Hovis

 

[Fred Bohl]

Hovis

There are many tests on scope performance that we all can run with a little knowledge. Most of the more important ones do require some very specific tools and equipment to do with precision. Some can be done with home-made gear that will produce useful but not very repeatable (differences due to who does them and with what) results.

One of the big problems for typical users testing scopes is that they are not objective unbiased observers. We all have a tendency to be biased toward supporting decisions we made without adequate research. Say I read the posts on the new Brand Q scope and it sounds like the answer to my wishes so I go buy one. Then at the range my shooting buddy has a new Brand Z that he is convinced is the best. If we do a side by side Q versus Z comparison are the two of us objective or unbiased observers that will produce a result you would depend on to make your buying decision?

Then we add the problem that you and I look through the same scope with different visual systems. We have different visual acuity, different color perception and most importantly different visual experience. What we see is the sum of our visual training/experience with our individual system and our personal prejudice as what a quality image should be and/or what is important about that image.

Another big issue is the limitations of our common language when we try to describe what we saw. In another thread for example Jackie Schmidt and I had an issue in a pair of posts that was due to our not having a matching definition of what we understood "resolution" to mean. In that case I was too sure of my strict engineering definition of what I understand optical resolution to mean and never gave a thought to Jackie's "Real World" definition as a measure of "optical clarity".

Enough of my soap box ramblings. Some questions for you:

1. What tests would you want done or do yourself?

2. Are you asking for my procedure for doing eyepiece focusing or image focusing (aka - parallax adjustment) or both?

3. Is your reference to "first reflective surface” related to posts I've done on centering cross hairs?

4. Are you asking for my thoughts on the issues several posters on this and other forums have had with less than expected image quality from otherwise high quality high magnification scopes?

 

[HovisKM]

Fred,
I have on and off worked with lasers and optics used on missiles for intercept purposes since 1989 and I don't know squat compared to your knowledge. Basically, I was asking you to enlighten us in simple terms on what we are actually seeing in scopes. The reason I brought up the crosshair centering, is it's always best to have all the lenes in alignment for the optimizing the capability of a scope. That's one reason I like my centered and locked up leupold scopes on adjustable bases.

Hovis

 

[Mustafa Bilal]

Thank you Fred,
I am very interested to hear your answer to Question #4 in your post. I look through photographic lenses almost everyday, and BR scopes not as much (unfortunately). I'm always amazed and bewildered by the conversations and differing perceptions regarding image quality from high-end optics. These opinions are common between photographers as they are among shooters.

Mustafa

 

[Bob Kingsbury]

Fred Bohl

All four items, would be of great interest. I for one have
stared thu scopes of different Quality, not really knowing
what I'm doing.

 

[jackie schmidt]

"The Real World"

I am certainly not an expert on "Optics". Heck, most of the technical aspects of lens's, light gathering, resolution, etc sort of makes my eyes glaze over. I am learning, though.

But, the reality of the situation is this. I could care less what some big glossy add in a magazine says about the superior optics of their product. The only thing that interest me is what I see when I sit down at the bench and look through the scope. I have stared through enough top end scopes, (and some not so top end), to understand what I am looking at.

Benchrest Shooters tend to be on the old side. I will turn 60 in a few days. My eyes are so screwd up that there is very little that any body will offer that will suddenly make a target appear like it was laying on the table in front of me. For instance, I can see reasonably well out past 25 yards, but my "up close" vision is so bad that I amdarned near blind at anything close that 4 feet. This require a set of bi-foculs that are +375. When I am shooting without these, everything on the bench is a blurr, but I can see downrange quite well. I have got the eye piece on my 50x Marches screwed darned near all the way out si I see a good sharp cross hair. That might not be right, but that uis the way it works for me, and my eyes.

I probably never noticed too much with my 36x Leupolds because of the lower magnification. Maybe with the new crop of higher power scopes, we are seeing things that simply did not appear before, and it bugs us.

Switching from a 36x scope, even one with glass as good as the old Leupolds, to a 50x does take some getting used too. Regardless of the optical quality,more magnification does bring on a new set of "problems", but it seems most of these are the type of thing that it just takes getting used too.

But do keep in mind, the reqirements of 100-200 yard Benchrest have not changed. That being, a scope that will hold Point of Aim 100 percent, and not weighing so much as to make in impracticle for use on a 10.5 pound Rifle. All of this other stuff is simply window dressing. If you can see the target well enough to shoot sub .200 aggs, then that is about as much as you can ask for........jackie

 

[Fred Bohl]

High end scope image quality perception

Hovis, Mustafa, Bob

I'll try to put together something on this topic since you have all asked. Maybe I can even do it without too much technical diversion and brief enough to avoid being boring.

Jackie,

Loved your post this morning. Based on your history and results I doubt that your eyesight is near as bad as you say.

You did hit on an important part of the issue with that "... it seems most of these are the type of thing that it just takes getting used too." I think you’re my kind of engineer (even if hiding it well) - have a thought, go to the shop, make some chips, then take it to the range to see if it works.

While I cogitate on my reply to the good old boys query, could you share with us some gulf coast savvy on your comparative results with and without the Modifier Disk in your March 50x experience?

 

[bryan]

For what it's worth........

A year ago, I just put my hand on the objective of my scope with my fingers spread apart and saw a difference in the clarity of the target. Next, I put black electrical tape over the objective (top, bottom, and both sides) and was shocked by the increase in clarity.
Wanting to be just a bit more "high tech" I took a Butler Creek flip up scope cap that fit my Weaver 36x and cut a .750 hole in the cap. I plug it with a cork.
The end result is that I can see rings and bullet holes when conditions normally would make that difficult. Mirage seems to be reduced as well.
Numerous shooters have looked thru my scope then flipped the cap open and said "What the..........." I shot this setup all of last season.
Mustafa is the likely candidate to thoroughly explain why this works the way it does.
By the way, Leon Gass has a similar setup that uses a Sweets bottle fitted to the objective. He just takes the cap off to shoot!
Bryan

 

[Mustafa Bilal]

Hi Bryan,

I don’t have much to add to Fred’s explanation in post #2 re. the increased depth of focus with a modifier disk. In photography, one adjusts the f/stop (lens opening) to increase or decrease the depth of field, and bring in or out of focus subjects that are at different distances/focal planes.

What one perceives through a lens is highly subjective, and the vocabulary that goes along with describing it can be even more vague. People’s eyesight vary as much as their definition of sharpness, contrast, flare, resolution, etc. That’s why it would be interesting to read what Fred has to say about all this.

In photography, the proof of performance for a camera/lens combo can be seen on an enlarged sheet of film or digital file. However, in the BR world, we are often relegated to personal opinions that are biased by young or old, fresh or tired vision, as well as a healthy dose of personal preferences and experiences.

The trick is gleaning enough information to make an educated guess as to what may work for you before actually spending money and time to see what actually does work for you. And that’s the fun part.

Mustafa