Gehmann Superfilter?

Jordan1s · Post by **Jordan1s** » Sat Oct 01, 2011 3:55 am

Hello,

I was wondering if anyone had any experience with using these; I am considering buying one, but the one factor holding me back is that I don't know if the dual focus effect of the superfilter will interfere with my shooting glasses and cause an even more blurry sight picture; I shoot 10m air rifle by the way.

thanks!

-Jordan

xnoncents · Post by **xnoncents** » Sat Oct 01, 2011 9:02 am

I have one, but have been unable to mount it. I have the old style Anschutz rear sight, the threads are fine but the filter will not seat properly secure due to the way the elevation/windage mechanism works. I am going to machine a brass and plastic washer to attempt to get it to fit. Make sure it will work with your sight before ordering. Once I get it to fit, I will let you know if it is an improvement.

tenring · Post by **tenring** » Sat Oct 01, 2011 9:16 am

I've read that it ok to wear corrective lenses for your normal distance prescription. Gehmann's recommendation! They say they don't guarantee you'll see any improvement if you have + factors to help you see the front sight.

Tenring.

GaryD · Post by **GaryD** » Mon Oct 03, 2011 3:34 pm

I have had a look at the Gehmann Superfilter on their site, but does anyone know how it works ?

It looks interesting!

KennyB · Post by **KennyB** » Tue Oct 04, 2011 4:06 am

I believe that it is a "Zone Plate" : http://en.wikipedia.org/wiki/Zone_plate
There has been some debate as to whether these will be legal for use in ISSF or other competitions.
The cynic in me would say that there MUST be a downside to the thing - some testing using SCATT or Noptel would determine if there's any improvement in accuracy of aiming. I imagine that it cuts down light transmission quite significantly...

GaryD · Post by **GaryD** » Tue Oct 04, 2011 5:56 am

Hi Kenny,
I just had a look at the Wikipedia site and I agree with you that it looks like a Zone Plate.

The Gehmann web site says and I quote

"The Gehmann Superfilter AOS MicroSight TM
must be reasonably aligned with the front sight. If large movement of the rear sight is required for wind or long range,
the rear sight should be aligned with the front sight when in the middle of the range of rear sight adjustment.
(This is similar in concept to the 20 MOE scope bases for long range use.)

Closing down the rear iris too far cuts out the dual focus effect. Try aperture settings a little bit larger than usual"

As you also said, it appears that it will cut down the light a bit, but if it improves my sight picture then it may be worth trying.

But why does everything for shooting have to be expensive

Hopefully Xnoncents can supply us with more information on it

Jason · Post by **Jason** » Tue Oct 04, 2011 9:02 am

I have one and it is darker but I haven't actually tested it with live shooting. Some of the long-range prone shooters in the U.S. have recommended that if you shoot with a 1.1 mm rear aperture then you should open it up to 1.5 or even 1.6 mm and start testing from there.

I've also heard unconfirmed reports that the lens is optimized for a 27" barrel length. I use a 10" tube on my 27" Anschutz barrel and in my backyard testing my sight picture isn't any better using my current setup. I didn't get the chance to try it at shorter distances.

Once my rifle is back from the smith I'm going to tinker with it some more before the snow flies. I think head position is going to be a critical factor with the lens because of it's construction -- it kind of feels like a high-power scope with a tiny exit pupil.

Jason

GaryD · Post by **GaryD** » Tue Oct 04, 2011 11:13 am

Thanks for your comments Jason.

It seems then that I might have the same problems that you might have, as I have a barrel length of 26" and shoot with a 1.1, 1.2 rear aperture.
I also have a 12" tube as well. But I have only used it for testing its effect on the sight picture, as I can slide the foresight up and down along it's length.

The critical head position that you mention might be a good thing as it would make you align your head centrally in the rear sight with more accuracy, this could help me

One of the problems that I get is that is after aligning my head to the centre of the rearsight and with the foresight in the centre as well, I then have to move my head slightly to get a decent sight picture. Which is very annoying.

Hence my other post on the forum about printing a target at a shorter distance so that I can experiment at home with various setups

Levergun59 · Post by **Levergun59** » Tue Oct 04, 2011 11:46 am

Isn't this the same type of filter that Stallings makes for the AR service rifle? They say it has multifocal capabilities so you can see the front sight and the target clearly. They call it a phased zone plate. I saw it in 2011 Champions Choice wishbook.
Chris

bluetentacle · Post by **bluetentacle** » Tue Oct 04, 2011 6:04 pm

I have been using it on an AR service rifle. I'm very satisfied with it, not because it made me shoot better, but because it greatly relieved eye strain. The side effects are:

-You'll get a darker sight picture.
-Contrast will be worse.

For those service rifle shooters having constant problems focusing on the front sight, the Microsight *could* be the great savior and result in improved scores. For those of us with good eyes, it still brings the benefit of reduced eye strain, but don't expect it to improve your shooting.

I assume the same will hold for smallbore shooters. One thing to look out for is that this device is designed to work at a certain sight radius. Also, your shooting eye must be corrected for distance vision.

I'm seriously considering getting one.

GaryD · Post by **GaryD** » Wed Oct 05, 2011 4:19 am

I was wondering as to the overall length of it, because if you are using it with a rear sight with filters etc, then it could be quite long resulting in having to move the rear sight way forward over the breech.

Jason · Post by **Jason** » Wed Oct 05, 2011 11:39 am

GaryD wrote:I was wondering as to the overall length of it, because if you are using it with a rear sight with filters etc, then it could be quite long resulting in having to move the rear sight way forward over the breech.

When I test-fitted it the front edge of my rear sight overlapped the breech area by almost a centimetre. I run 12 mm risers so I wasn't worried about brass hanging up on it or having trouble loading, but it does look kind of weird.

I couldn't find any pictures of the MicroSight installed, but here's what my rear sight position looked like without it:

Given that the MicroSight is almost a quarter inch long, you can see how much forward that would move the rear sight. I've also moved the rear sight ahead since this picture.

Jason

sbrmike · Post by **sbrmike** » Wed Oct 05, 2011 1:40 pm

I don't have the greatest vision anymore but still compete and do not wear glasses. I don't have a problem focusing on the front sight; there are times that I wish the aiming black was a little darker and more distinct though.

I tried a friend's SR Microsight at a match. It sharpened the front post bigtime but made the target much worse. I preferred my bare sights to the Microsight.

GaryD · Post by **GaryD** » Wed Oct 05, 2011 3:11 pm

Thanks for the picture Jason,

If it is only about a quarter of an inch long, it should not be a problem (I Hope),
I think I will order one and if it doesn't work I can always sell it on E-Bay.

Jason · Post by **Jason** » Wed Oct 05, 2011 10:06 pm

Don't hold me to the quarter inch length, it's likely a bit more. I'll dig it out tomorrow and take another picture with it installed.

Jason

GaryD · Post by **GaryD** » Thu Oct 06, 2011 2:50 am

Thanks Jason,

I probably will not order it untill next week anyway so I will wait until you post a picture of it.

Many Thanks
G

xnoncents · Post by **xnoncents** » Thu Oct 06, 2011 9:28 am

The superfilter adds precisely .5 inches extra to your sight presuming it seats completely. I have yet to be able to mount it proper for lack of machining time. Don't you hate it when life gets in the way of shooting?

The best test probably would be a scatt before/after test. I have not bought my electronic trainer yet, so that will be up to someone else. What I am more interested in is the MEC Microsight.

Jason · Post by **Jason** » Thu Oct 06, 2011 1:49 pm

Found it. See below:

Just a smidge over 1/2 inch:

More testing needed.

Jason

GaryD · Post by **GaryD** » Fri Oct 07, 2011 7:05 am

Once again Jason thanks for the pictures, and xnoncents for his comments.

I think I will order one next week and see what it is like, I know that bluetentacle said "but don't expect it to improve your shooting" but having a lousey sight picture is really annoying me so it might be worth a try.

By the way xnoncents what is the MEC Microsight that you mentioned

xnoncents · Post by **xnoncents** » Sun Oct 09, 2011 8:31 am

GaryD, and anyone else who spent any time trying to find a 'MEC microsight', sorry for my momentary brain seizure. What I meant to say was MEC Duplex sight.