Xtreme Lens Play

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Novice1
Posts: 44
Joined: 05 Jan 2014, 18:48
Location: North west

Xtreme Lens Play

Post by Novice1 » 05 Jul 2018, 11:39

Hi all

I'm looking for some advice.

I have a 6.5 photon xt that I've tried to xtreme. I have the srb adaptor. I originally bought a pentax takumar 105mm lens for the conversion. Got it at a good price and took a punt. After a bit if heartache it appears that the barrel has too much play in it to ensure consistent zero. You can physically see the crosshairs moving if you pull on the end of the lens, if that makes sense.

I've now splashed out on a replacement lens of the same spec. I've paid a lot more for this one from a UK seller. It's been serviced and tbh it's in much better cosmetic appearance and I've no reason to doubt that it's not been serviced.

However, on fitting it, there appears to be some play. Maybe not as bad as the earlier lens, but its there.

Now, I've now gone and returned the original photon lens to the unit for comparison. Here's the thing. It appears to me that I can replicate the crosshair movement to some extent when pulling on the end of the lens.

My question is, is this normal? Should i expect some movement and live with it, so long as the crosshairs return to where they're meant to be and zero is maintained?

I'm obviously not going to be pulling on at the end of the lens, but I'm now worried about whether normal knocks and bumps while out at night will mean I've never got a consistent zero.

Hope that all makes sense and i look forward to comments.

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fizzbangwhallop
Posts: 1869
Joined: 18 Oct 2011, 11:27
Location: north herts

Re: Xtreme Lens Play

Post by fizzbangwhallop » 06 Jul 2018, 10:07

I can recommend Dave ......

http://nightvisionforumuk.com/viewtopic ... ng#p137162

Nb the bit that he’s probably not there on a Friday...and mention that it’s for an nv scope so he uses a thicker grease.
:thumbup:
Fizz
8-)
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A correct grip on the butt & cheekweld is imperative for accurate shooting. :crazy: :lol:

Novice1
Posts: 44
Joined: 05 Jan 2014, 18:48
Location: North west

Re: Xtreme Lens Play

Post by Novice1 » 06 Jul 2018, 12:05

Thanks Fizz, i was hoping you'd chip in at some point.

So are you saying there is always going to be an inherent level of play in the barrel with these lenses, which can be addressed to some extent by using a thicker grease on their moving parts?

As I say, the latest 105mm takumar lens I have has been serviced and is in pretty good nick. However if I pinch my fingers right at the end of it and wiggle it, you can see the crosshairs move.

I'm guessing that's not cool and I'm interested to know whether you'd experience the same if you tried it, or are you saying yours is rock solid?

Cheers

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fizzbangwhallop
Posts: 1869
Joined: 18 Oct 2011, 11:27
Location: north herts

Re: Xtreme Lens Play

Post by fizzbangwhallop » 06 Jul 2018, 14:15

Novice1 wrote:
06 Jul 2018, 12:05
Thanks Fizz, i was hoping you'd chip in at some point.

So are you saying there is always going to be an inherent level of play in the barrel with these lenses, which can be addressed to some extent by using a thicker grease on their moving parts?

As I say, the latest 105mm takumar lens I have has been serviced and is in pretty good nick. However if I pinch my fingers right at the end of it and wiggle it, you can see the crosshairs move.

I'm guessing that's not cool and I'm interested to know whether you'd experience the same if you tried it, or are you saying yours is rock solid?

Cheers
Wotcha,

I did have a discussion with Carl Moore on the Drone Pro stand at one of the Shooting Shows on the merits of camera lenses compared to, say, those in the DP... the focus mechanism in camera lenses were/are never going to be as tight as that used in nv lens systems. On top of that, dried out grease in these older m42 lenses leads to more wear in focusing threads.

I never really looked for a loose lens problem with 2 of mine on the .20Prac and the .17Rem as they were just knocking foxes over on a regular basis.... I don’t remember thinking any of the poi’s being drastically different from the poa’s. Even when others were describing the cross-hair moving around as the adjusted the focus, I never looked as it would only start sowing the seeds of doubt as I lined up on a shot.

I was pretty picky on waiting for good condition lenses though and had them all serviced by Dave when I picked up a loose one.....cheap enough. His turnaround time is really good too, usually less than a week.

I’ve been using the Wardy thermal on the .243 for the last 18months or so now..that’s Shooting really well so the .20P and the .17R haven’t been out much.... I’ve also got 55mm lenses on the .22rf and the air rifle and they’ve been consistently good.

Cheers,

Fizz
8-)
Image

A correct grip on the butt & cheekweld is imperative for accurate shooting. :crazy: :lol:

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