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High fixed-mag option for Swaro scope - advice needed

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Old Sunday 20th February 2011, 18:56   #1
Sancho
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High fixed-mag option for Swaro scope - advice needed

A propos of discussion on zooms, fixed ep´s etc. on some other threads, a thought occurs to me. I have a Swarovski ATS80HD with 25x50 zoom. This meets all my requirements, and I´m very happy with it as a "default" ep, as it covers practically everything without the hassle of changing ep´s in the field. Supposing, however, I wanted a high-mag ep, for those extremely rare occasions when I want to ID a very distant but stationary bird in good light. Is there any way I could increase the mag of the zoom, or is there any adapter-plus-astro ep that I could use, to give me, say, 70x fixed on this scope?
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Old Sunday 20th February 2011, 19:23   #2
SteveClifton
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Hi Sancho, I went through the same thing a few years ago when I got my ATS 80HD.

I did a bit of research and found that someone in the US had posted on BF about his quest to find the best high mag eyepieces for his (same) scope. Based on his findings I bought the Swaro Astro adapter (now no longer in production) and a used 5mm Televue Nagler eyepiece from Ebay.

This eyepiece gives 92x on the 80mm body, which is useable in good light, but a stable support is needed to get the best from it, with no wind to cause vibrations. If it is windy, forget it. Accurate focussing is also very critical at this mag, but when sharp it is very sharp, just as Swaro's own eyepieces are. FOV is a wapping 82 degrees I think, but to get this you have to press your eye so tight up against the lens that it's uncomfortable. Eye relief of this EP is very short! Too short for my comfort, and the exit pupil is very small.

To calculate the mag of an astro eyepiece on a terrestrial scope, divide the focal length of the body by the FL of the eyepiece. In this case:

460mm divided by 5mm = 92x

If you wanted something less powerful then a 6mm eyepiece would give 76.66x, and so on.

If you wanted to go down the same route, then you'd have to acquire a used astro adapter if possible, or talk to someone like SRB Griturn, or perhaps knock something up yourself! I remember reading somewhere on BF about someone making an astro adapter for their Kowa 88mm using plastic tubing.

A couple of things to bear in mind though:

Some astro eyepieces will not focus to infinity on the Swaro scope

I also tried a Baader 5mm, but returned it very quickly-didn't find it as sharp as the TV

Televue also make a range of Radian EPs, with longer eye relief, but I'm not sure if they reach infinity focus on my/your scope

Henry Link (I think?) also recommended the TMB Planetary eyepieces, which are much cheaper than the TV ones, but I'm not sure how well they work, if at all?

Lots to think about, and to be honest, I only use my TV eyepiece rarely. I have the 20-60x zoom which I find enough for 99% of occasions, but with max 50x I can feel your need! Ace Optics of Bath have an astro dept and sell some of the TV eyepieces I mentioned. They might be able to help you out re. which eps will work, as they also sell terrestrial scopes like yours.

Best of luck, and do ask if you have any more questions.

Steve

I presume you saw this thread already:

http://www.birdforum.net/showthread.php?t=190087

Last edited by SteveClifton : Sunday 20th February 2011 at 19:39.
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Old Sunday 20th February 2011, 19:40   #3
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A booster is a quick and dirty way to get high magnfications. That's what I do when I use the 24x WA on my ED III, with the Zeiss 3x12 Mono I get 72x. Sure, the image quality isn't perfect and the field of view is *really* narrow, but it's alright to get an ID on a bird that's too far away for 24x. Using the booster is a lot quicker than changing the eyepiece. I've fashioned an adapter that allows me to push the booster into the eyecup and I'm ready to go.

I've also used the booster to get about 90x with the ED III, but that's pushing things a bit. The image quality is, shall we say, "marginal", but I do get a bit more detail on the bird than with the zoom at 60x. With your Swaro you should be able to use ~100x no problem if the conditions are right. A really good tripod with a good head is a must, obviously.

BTW, I'm thinking of getting an ATM80HD with the 25-50x myself. There are a couple of good deals on the Swarovski at the moment, so I may well take the plunge. I also need higher magnifications than 50x quite regularly, so I'm interested in hearing from people who've used the Zeiss Mono with the Swaro zoom.

Hermann

Last edited by Hermann : Sunday 20th February 2011 at 19:43.
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Old Sunday 20th February 2011, 19:51   #4
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Hermann, in my personal experience, the benefit of using even a 92x ep on the 80mm Swaro is marginal, compared with the zoom at 60x. There is a benefit, but in over 95% of real life situations, it's not worth bothering with the hassle of carrying the astro ep and adapter. I can imagine that using a booster, either with the zoom or a lower powered fixed like the 30x wide, would be of no real benefit as dimness, accurate focussing & shake would all make viewing much harder.

To sum up, the questionable benefit of using a booster would IMHO be more hastle than it is worth.

If high mag is a real priority, for e.g. if you do a lot of colour ring reading, observing distant waders, geese etc, then the astro eyepiece route would be worth exploring further.

Last edited by SteveClifton : Sunday 20th February 2011 at 19:56.
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Old Sunday 20th February 2011, 20:06   #5
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Originally Posted by SteveClifton View Post
Hermann, in my personal experience, the benefit of using even a 92x ep on the 80mm Swaro is marginal, compared with the zoom at 60x. There is a benefit, but in over 95% of real life situations, it's not worth bothering with the hassle of carrying the astro ep and adapter. I can imagine that using a booster, either with the zoom or a lower powered fixed like the 30x wide, would be of no real benefit as dimness, accurate focussing & shake would all make viewing much harder.
You're right, it's only a very small number of situations where high magnifications make sense. However, in these situations they may make the difference between getting the ID or not getting it. Focussing is not that much of a problem with the Zeiss Mono, I normally focus with the scope and do the fine tuning with the Zeiss Mono. That works very well in my experience. The limiting factor are usually the atmopheric conditions that more often than not make using magnifications above ~50x impossible.

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Old Sunday 20th February 2011, 20:18   #6
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You're right, it's only a very small number of situations where high magnifications make sense. However, in these situations they may make the difference between getting the ID or not getting it. Focussing is not that much of a problem with the Zeiss Mono, I normally focus with the scope and do the fine tuning with the Zeiss Mono. That works very well in my experience. The limiting factor are usually the atmopheric conditions that more often than not make using magnifications above ~50x impossible.

Hermann
OK, experience obviously speaks more truth than theory. Perhaps it's possible that you will see some real benefit to using the Zeiss mono with 50x eyepiece, but with max 60x I think the benefits will be much more marginal.
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Old Sunday 20th February 2011, 20:36   #7
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Sincerest thanks folks, that helps no end. I´ll research the suggestions you´ve kindly made!

Steve, I see that Televue Nagler make a 7mm eyepiece. This would give magnification of 65.71 on the Swaro 80mm, which is probably as high as I´d like to go. Could I ask you a non-urgent favour - would you be able to post a photo of your Swaro eyepiece adapter, so that I might be able to figure out how to knock-up a workable copy with plastic tubing, sticky-tape, paper-clips, chewing-gum and dog-hair? No problem if not possible, and this is not a matter of life-and-death!

Last edited by Sancho : Sunday 20th February 2011 at 21:22.
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Old Monday 21st February 2011, 21:52   #8
John Russell
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Originally Posted by Sancho View Post
I see that Televue Nagler make a 7mm eyepiece. This would give magnification of 65.71 on the Swaro 80mm, which is probably as high as I´d like to go.
Sancho,

That would give you an exit pupil of 1,25 mm, which is probably a practical lower limit for terrestrial use. On the other hand, the benefits compared to 50x would be rather marginal.

I expect to replace my old straight Diascope 65 with a new angled DiaScope or ATM65 HD in the near future, when I get the opportunity to do a direct comparison.
For various reasons I don't like zooms so, in addition to the OEM 30x eyepieces, the opportunity to use astronomical eyepieces on the Swaro as well as the Zeiss, would level the playing field.
I am told that a new astro adapter has been developed independently and is awaiting Swaro's approval. Will keep you posted.

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Old Monday 21st February 2011, 22:23   #9
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For various reasons I don't like zooms so, in addition to the OEM 30x eyepieces, the opportunity to use astronomical eyepieces on the Swaro as well as the Zeiss, would level the playing field.
I am told that a new astro adapter has been developed independently and is awaiting Swaro's approval. Will keep you posted.

John
Very good of you John, I appreciate it. I do recommend that, even though you don´t like zooms, you have a look at a Swaro 25-50 if you can. At 25x, the fov is wider than the 30x fixed ep. Okay, it´s not quite as comfortable a view, but the ability to pump it up to double the mag is wonderful, and I don´t see notice loss of resolution or light at 50x. Yesterday I was down at Tacumshin in Wexford, looking at waterfowl. There were reputed to be two Green-Winged Teal there, among the regular Teal. When I was there, most of the Teal were silhouetted in the sunlight, and it was difficult to see their wing-bars at 25x. But when I "upped" the mag to 50x, I could pick out the wing-bars easily, even on silhouetted ducks, in strong low "head-on" sunlight.
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Old Monday 21st February 2011, 23:03   #10
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[quote=Sancho;2066886]Sincerest thanks folks, that helps no end. I´ll research the suggestions you´ve kindly made!

Steve, I see that Televue Nagler make a 7mm eyepiece. This would give magnification of 65.71 on the Swaro 80mm, which is probably as high as I´d like to go. Could I ask you a non-urgent favour - would you be able to post a photo of your Swaro eyepiece adapter, so that I might be able to figure out how to knock-up a workable copy with plastic tubing, sticky-tape, paper-clips, chewing-gum and dog-hair? No problem if not possible, and this is not a matter of life-and-death![/QUOTE




Will post some pics tomorrow Sancho,

ATB

Steve
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Old Tuesday 22nd February 2011, 10:14   #11
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Could I ask you a non-urgent favour - would you be able to post a photo of your Swaro eyepiece adapter, so that I might be able to figure out how to knock-up a workable copy with plastic tubing, sticky-tape, paper-clips, chewing-gum and dog-hair?
LOL - I could try to do it when I get home tonight. It is a very simple, thin metal ring with bayonet fingers and a locking screw. It brings the eyepieces a couple of mm's up, which means that some eyepieces can't be brought into focus at infinity. I have a 77x eyepiece, which does come into focus, but I don't like it very much... and a Zeiss 3x12 "tripler/booster", which I do like a lot.

Hermann - I also have the Swaro 25-50x and just realized that I probably have never used the tripler with it. I will let you know how they work together. Seems like our viewing habits are quite similar.

Best regards,

Ilkka
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Old Tuesday 22nd February 2011, 14:15   #12
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... and a Zeiss 3x12 "tripler/booster", which I do like a lot.

Hermann - I also have the Swaro 25-50x and just realized that I probably have never used the tripler with it.

Ilkka
Thanks Ilkka - now I´m into uncharted waters, so my questions will seem very basic. Can the Zeiss tripler be used with a Swaro eyepiece, and how does it attach? And if it does attach, does it mean that you could conceivably set the Swaro zoom eyepiece at 25x and attach the tripler to get 75x magnification?
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Old Tuesday 22nd February 2011, 15:14   #13
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Hermann - I also have the Swaro 25-50x and just realized that I probably have never used the tripler with it. I will let you know how they work together. Seems like our viewing habits are quite similar.
Yes, looks like it ... :-) I'm really quite interested to hear how the Zeiss Mono and the 25-50x work together. If that combination works out alright I've got a good excuse to finally switch over to one of the modern zooms and replace my trusty Nikon EDIII.

Hermann

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Old Tuesday 22nd February 2011, 16:14   #14
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Pics of the adaper with a ruler showing the depth in mm that the barrel of the 5mm Nagler sits inside the scope (about 22mm, plus a further 6mm for the thickness of the top of the adapter.
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Old Tuesday 22nd February 2011, 16:37   #15
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Pics of the adaper with a ruler showing the depth in mm that the barrel of the 5mm Nagler sits inside the scope (about 22mm, plus a further 6mm for the thickness of the top of the adapter.
Sincerest thanks, Steve. Shame they stopped making those. A bit complicated to rig a DIY copy, I think!
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Old Tuesday 22nd February 2011, 17:41   #16
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Sincerest thanks, Steve. Shame they stopped making those. A bit complicated to rig a DIY copy, I think!
Actually, it just occurred to me to try the Nagler with the scope, and leave the adapter out of the equation, and guess what?

It works just as well as with the adapter, but just don't let go!

A little more detail:

I hadn't realsized before, but even with the adapter, the eyepiece 'bottoms out' when it hits the metal surround to the cover glass inside the eyepiece opening. This works perfectly well 'hand held'. There is about 1mm of play on each side around the eyepiece's steel barrel, but this small amount of movement doesn't appear to cause any problems (like vignetting) due to not being perfectly centred. This could easily be packed out with electrical tape around the ep to provide a more snug fit between the bayonet lugs inside the scope.

Attached are a couple more pics showing the eyepiece hand held, and also with a roll of electrical tape around the eyepiece, which fits perfectly. With this fitted the eyepiece still focusses in the scope, though I will need to try this again tomorrow to see if it still focusses to infinity (with the tape fitted the eyepiece is sat a little higher in the opening, though I'm sure this could be sorted with either a thinner roll of tape, or as you said, chewing gum or elastic bands

Still might be an option? Also, I think I read somewhere yesterday that Swaro might be developing a new astro adapter. We'll have to wait and see...

edit: I read it here!! (post 8)
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Old Tuesday 22nd February 2011, 19:18   #17
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Excellent, Steve! Many thanks for the pictures. It shouldn´t be too difficult, then, to sort out some kind of temporary DIY measure, and wait in hope for Swaro to bring out a new adapter. I really wouldn´t use the Nagler very much, but it would be nice to have in the bag for those very rare occasions when the zoom doesn´t reach far enough.
Thank you again for taking the trouble to explain and for posting the photos.
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Old Tuesday 22nd February 2011, 20:32   #18
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Excellent, Steve! Many thanks for the pictures. It shouldn´t be too difficult, then, to sort out some kind of temporary DIY measure, and wait in hope for Swaro to bring out a new adapter. I really wouldn´t use the Nagler very much, but it would be nice to have in the bag for those very rare occasions when the zoom doesn´t reach far enough.
Thank you again for taking the trouble to explain and for posting the photos.
If you do intend buying one, then Ebay is certainly worth keeping an eye on. I bought mine used about 4-5 years ago from Ebay, for about £120 Sterling. They used to come up every 3-4 weeks on the used market. Perhaps someone more familiar with the astro market can recommend somewhere else that's worth trying for a used one here in the UK?
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Old Tuesday 22nd February 2011, 22:27   #19
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Thanks Steve for the detailed pics - my adapter is identical to yours and it indeed was thicker than I remembered . I was thinking that the plastic cover cap of the scope body should fit perfectly to the eyepiece mount and might well serve as starting material for a cheap DIY adapter... ? (Couldn't find mine for closer examination though)

My Zeiss Mono 3x12B came with two plastic adapters and the larger one equipped with some layers of masking tape fits quite snugly inside the rubber eyecup of the 25-50x eyepiece. At the moment I was only able to view the targets inside the house, but I liked the view at 75x and, to my surprise, even at 150x... I probably shouldn't mention to my wife about the spiderwebs that I saw on the ceiling lamps . Yes, there was more CA, the image was dark, ER & FOV were limited, but still I would rather use this kind of an add-on multiplier than switch eyepieces in the rain and wind.

Best regards,

Ilkka
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Old Wednesday 23rd February 2011, 07:30   #20
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Thanks Steve for the detailed pics - my adapter is identical to yours and it indeed was thicker than I remembered . I was thinking that the plastic cover cap of the scope body should fit perfectly to the eyepiece mount and might well serve as starting material for a cheap DIY adapter... ? (Couldn't find mine for closer examination though)

My Zeiss Mono 3x12B came with two plastic adapters and the larger one equipped with some layers of masking tape fits quite snugly inside the rubber eyecup of the 25-50x eyepiece. At the moment I was only able to view the targets inside the house, but I liked the view at 75x and, to my surprise, even at 150x... I probably shouldn't mention to my wife about the spiderwebs that I saw on the ceiling lamps . Yes, there was more CA, the image was dark, ER & FOV were limited, but still I would rather use this kind of an add-on multiplier than switch eyepieces in the rain and wind.

Best regards,

Ilkka
It would be nice to see a side by side comparison between the astro eyepiece and your Zeiss mono.

That thing is smaller than I imagined!!

I suppose the Swarovski doubler performs a similar function. I wonder how that works in practise?

Last edited by SteveClifton : Wednesday 23rd February 2011 at 07:33.
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Old Wednesday 23rd February 2011, 07:56   #21
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It would be nice to see a side by side comparison between the astro eyepiece and your Zeiss mono.
Steve,

That is my intention - maybe this weekend. The 'spiderweb test' wasn't meant to be too convincing...

And yes, the Zeiss mono is tiny compared to the Swaro doubler. I would guess that the 50-100x power (with the doubler) would be optimal "additional" power, but I really like how easily you can just slip the Zeiss Mono on almost any eyepiece. The same adapter diameter works eg. with the Nikon 8x32SE, old Swaro 20-60x zoom and the 20/30/45xSW.

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Old Wednesday 23rd February 2011, 14:10   #22
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Here's a low cost alternative to the Zeiss. It might work just as well. The booster scope is at the end of the optics train and only a small area of the center of its objective is actually used, so it doesn't really have to be all that good to fully reveal the main scope's resolving power.

http://www.opticron.co.uk/Pages/uta.htm

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Old Wednesday 23rd February 2011, 15:34   #23
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but still I would rather use this kind of an add-on multiplier than switch eyepieces in the rain and wind.

Ilkka
Yes, that really is the problem. I like this idea of boosters and adapters. Today for giggles I set up my Swaro at 25x and used a Leica Monovid 8x20 as a "booster" to give me 200x! A pointless exercise, but good fun.
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Old Wednesday 23rd February 2011, 18:06   #24
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Yes, that really is the problem. I like this idea of boosters and adapters. Today for giggles I set up my Swaro at 25x and used a Leica Monovid 8x20 as a "booster" to give me 200x! A pointless exercise, but good fun.
Many moons ago a friend and I did a similar sort of thing - we used the Zeiss 7x42 as a booster with the Leica Apo 77. With the zoom set to 20x we got 140x, a bit much for the Leica Apo. But it was fun.

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Old Wednesday 23rd February 2011, 20:32   #25
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I took the 5mm Nagler out today, just to remind myself of how useable it really is compared to the 20-60x zoom. It must be at least a year since I last used it.

It will focus to infinity quite easily, but only if seated at the base of the eyepiece opening, or at most, if it is raised by no more than about 2mm above it.

I set the zoom to 50x, to give a more realistic comparison to the 92x of the Nagler.

It wasn't as dim at 92x as I remembered. To give a rough idea, by viewing through the scope, and then looking at the same view without the scope, it seemed ever so slightly darker through the scope. The Swaro zoom at 50x always seems a little brighter to my eyes, even on a dark day.

Sharp focus was quite tricky, and once focussed the view looked slightly, but noticeably less crisp and contrasty than the zoom (no wonder, as it is almost twice the power!) I think this was partly due to the 'seeing' being a little wavy due to air movement/turbulence. It's amazing how easy this is to see at this power compared to 50x, when none can be detected at all. Still, it was clear enough to see that on a brighter day, the image would even clearer and more contrasty, giving a greater impression of sharpness.

Does the Nagler give any real benefit over the 50x of the zoom? Well it's marginal, but there is a slight difference.

The best example I could find of it was a Pink-footed Goose feeding about 1/2-3/4 of a mile away in a field. Through the zoom its bill just looked dark, but through the Nagler I could clearly see the paler subterminal bill band, though I couldn't detect whether it was pink or orange-it just looked an indeterminate colour, but clearly it was there.

Likewise, I could see the pale edges to the other geese's scapulars slightly more clearly through the Nagler, but there wasn't a huge difference. If I zoomed up to 60x then the difference was even less.

The last time I remember using the Nagler was when looking at Geese in Norfolk. There were both white morph Snow & Ross's geese in the area, and the eyepiece allowed be to see the bills well enough to know which was which at a similar range.

I'll have to try again in better light, but for know, I realise why it's been so long since I last used it.

Last edited by SteveClifton : Wednesday 23rd February 2011 at 20:46.
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