Yukon Photon zero shift with doubler

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Nexus180
Posts: 7
Joined: 09 Oct 2013, 09:29

Yukon Photon zero shift with doubler

Post by Nexus180 » 03 Oct 2018, 21:05

Hi all - I am aware that there have been similar previous posts on various websites, but with no real conclusion that I can find. I have a Photon (the original model) on my .22LR to which I have added a doubler using Marky's adapter (ie the push on plastic type). The adapter fit was pretty tight and I used exactly the sealant stuff that was recommended to stick it on with. I certainly find the doubler to be a great addition, but the (relatively minor) problem I have found is that each time I take the rifle out the zero has shifted (sometimes by up to 10" at 5m) and needs resetting (despite handling the rifle extremely carefully at all times so as not to knock it/ the scope/ doubler) - so I end up faffing around to zero it for about 20mins before I can head out.

I was wondering if anyone has found a solution to this issue? I gather there was a chap in Portugal (Pinto?) who used to sell metal screw-in doubler adapters for the photon, but I can't see that he still does unfortunately - is anyone aware of any other screw in adapters? Has anyone tried drilling some holes through the plastic adapter to then add some bolts to add extra grip to the photon?

Cheers

Davesniper
Posts: 134
Joined: 18 Mar 2016, 00:38
Location: Knutsford

Re: Yukon Photon zero shift with doubler

Post by Davesniper » 03 Oct 2018, 21:42

I have the pulsar LRF on my rimy with the Daniel Pinto adaptor proper jobby one where you remove the front houseing and screw it in which allows me to fit the Sony lense ....and it is always looseing zero , I just got into the habit of zero checking it before proper use ...I dont think you will ever sort out doublers moveing the slightest knock and there off target.

Ttocs
Posts: 31
Joined: 13 May 2018, 09:19
Location: Northumberland uk

Re: Yukon Photon zero shift with doubler

Post by Ttocs » 04 Oct 2018, 09:16

Hi, sounds odd. I had a doubler screwed on to my Photon 6x50 and experienced no problems with shift at all on a centrefire. My mate went down the extreme route (17HMR) with his Photon xt using a 135mm lense on a screw in adapter, he has no zero shift problems either in nearly 2 years. If you’ve stuck the adapter on well, there should be no movement at all on a 22LR.

Try zeroing it without doubler and see how well it holds zero over a few outings
Is your Photon an XT; if so, do you note the coordinates for the reticle after you zero? There may be a pattern to the shift.
Have you taken it off the rifle and remounted it to check this for your source of error
After you zero it, give it a couple of hard taps on the gun stock to check if it moves
Have you turned it off and back on agin after zeroing then recheck zero
If it’s an XT, is it possible the whole end of the scope is moving

Ttocs

Ttocs
Posts: 31
Joined: 13 May 2018, 09:19
Location: Northumberland uk

Re: Yukon Photon zero shift with doubler

Post by Ttocs » 04 Oct 2018, 09:21

Just a further thought, 10” at 5m? that’s 200” at 100m i.e. 8’ 4”. I didn’t think a photon has that much adjustment in its reticle especially with a doubler which halves the distance of each “click”
Ttocs

Nexus180
Posts: 7
Joined: 09 Oct 2013, 09:29

Re: Yukon Photon zero shift with doubler

Post by Nexus180 » 04 Oct 2018, 20:02

Thanks for your replies.

Ttocs - sorry; typo in my OP - I mean at 50m not 5m! My Photon is the original Mk1 5x42 version. I used it initially without the doubler and did not have an issue with zero change between shoots, so I am pretty sure it is to do with the doubler - or more specifically the adapter not being "fixed" (ie not screwed in). I have seen in other posts that even the slightest knock to a non-screwed in adapter will make a significant change to zero.

Its just been suggested to me on another forum that as the photon objective thread is 42mm and the doubler is 50mm all I need to get a "step up" ring from 42 to 50mm and then screw the doubler in without the Marky adapter; think I will give that a try.

Nexus180
Posts: 7
Joined: 09 Oct 2013, 09:29

Re: Yukon Photon zero shift with doubler

Post by Nexus180 » 06 Oct 2018, 09:16

Thanks for the comments so far. I have now ordered the M42 adapter from SRB amd I am now looking to buy an SLR lens to use with it. I have looked through lots of posts on selecting the right lens and I have to say I'm completely confused (I'm not in to cameras!). In summary, am I right in saying that I want to search for an "M42 slr lens" with "prime" or fixed focus (or one of the ones where you can press a button on it to fix the focus) and the ideal is a Pentax Takumar - and in terms of size, I think I'm right in saying that 105mm is probably the preferred balance between FOV and magnification (I will be using it for rabbits at night at ranges up to 200m)?

Thanks for any help!

Ttocs
Posts: 31
Joined: 13 May 2018, 09:19
Location: Northumberland uk

Re: Yukon Photon zero shift with doubler

Post by Ttocs » 06 Oct 2018, 11:59

What you’re looking for is an older style lense with M42 thread (modern lenses are generally bayonet fitting). M42 was used by Pentax and many Russian manufacturers (including Zeiss). There are manu aftermarket M42 lenses too. The most popular for the conversion are the Asahi Pentax Super Takumar lenses. These lenses are popular because they have the M42 thread, are optically top drawer; they also have no or old style lense coatings that don’t interfere with IR. 55mm for rats and close range, 100mm for general use (around 10-11x mag or 135mm for long range (around 13x mag). The more mag the narrower the field of view and the bigger the lense. All are variable focus and all have an internal iris that limits the amount of light passing through the lense. Reducing the size of this iris or ‘stopping down’ the lense improves the image quality and also the depth of field (distance over which near and far objects are both in focus).
When you buy a lense, you want on that’s showing little signs of use, has no oil marks on the iris/shutter blades and has no dust or fungus on the glass. It should focus smoothly and the iris/shutter open and close without sticking.
Be aware, some of these lenses may have already been used on by shooters and their internals (multiple lenses and spacers etc) shaken loose, this can be repaired but it’s an additional expense.
These lenses are also available with the later Pentax bayonet, you can’t use ar adapt these lenses.
Ttocs

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