Collimation of 804 3b

[chrisbower]

Chaps, - As a complete newbie, I was interested in acquiring a good quality set of bins without lashing out too much cash. I had always rather fancied a pair of Jenoptems but a couple of reviews led me to believe that the Swift Audubon was a sharper instrument and considerably better value for money. After reading the excellent paper by Edward M. Huff and Renze de Vries I settled on a pair of MKII 3b (Gold band) I found on Ebay (I can almost hear the gasps as I write this). The commonest problem that they are prone to seems to be mis-collimation. I understand that (in the case of Audubons) this is corrected by rotating the eccentric rings supporting the objective lenses.

Is anyone aware of a tutorial that demonstrates how to check collimation and, if there are unacceptable errors, adjust the rings?
TIA
Chris

[delia todd]

Hi Chris I see this is your first post so may I welcome you on behalf of all the staff and moderators at Bird Forum.

I'm sure someone will be along before too long who can give you some advice.

D

[matt green]

I'm not sure about this...but

I think the older audubons are actually better at holding their collimation.

it's the older style rings that hold the prisms in place better,as appose to
the newer models which are held in place by a screw and spring.

someone may confirm this

matt

[ceasar]

I think you (and the rest of us) are going to have to wait for Henry Link, or Elk Club and other enthusiasts of Swift to weigh in on your technical question. And if the rest of us are like me we await the discussion with great interest.

Cordially,
Bob

[elkcub]

Chaps, - As a complete newbie, I was interested in acquiring a good quality set of bins without lashing out too much cash. I had always rather fancied a pair of Jenoptems but a couple of reviews led me to believe that the Swift Audubon was a sharper instrument and considerably better value for money. After reading the excellent paper by Edward M. Huff and Renze de Vries I settled on a pair of MKII 3b (Gold band) I found on Ebay (I can almost hear the gasps as I write this). The commonest problem that they are prone to seems to be mis-collimation. I understand that (in the case of Audubons) this is corrected by rotating the eccentric rings supporting the objective lenses.

Is anyone aware of a tutorial that demonstrates how to check collimation and, if there are unacceptable errors, adjust the rings?
TIA
Chris

Hi Chris,

Congratulations on buying a very nice historic instrument. ;) Collimation problems are not inherent in early Audubons, but the eccentric ring method used on them does take knowledge and experience to do properly. If the instrument is in excellent condition otherwise, e.g., not obviously dropped or have internal lens fractures, my suggestion would be to bite the bullet and send them off to a Swift repair station in the UK or Europe. Here in the US, the cost would be about $70 for an overhaul including recollimation. I did this recently with a (Type 2) 7x35 Holiday that had quite a bit wrong with it. The results were excellent (although it's not my favorite Swift binocular by any means.)

These Audubons are heavy by current standards, and not multi-coated, so a lot depends on how much you paid for them as well as how much more you're willing to invest. As for doing the adjustment yourself, Henry Link or Bill Cook might provide some practical hands on advise.

Let us know how it works out.

Enjoy the view,
Ed

[chrisbower]

Hi Chris,

Congratulations on buying a very nice historic instrument. ;) Collimation problems are not inherent in early Audubons, [snip]
Let us know how it works out.

Enjoy the view,
Ed

Thanks for the input. I found a site that suggested the use of a bright star. The idea is to focus on it and then close one eye and re-open it to see if the star jumps around. The test should be conducted with the star in the centre and in the extreme top, bottom, left and right.

The good news is that collimation is fine (well - no worse than my normal eyesight...) so no need to start dismantling the bins just yet.

I am astonished at how bright and clear the images are in comparison to my ancient Tascos. The porros give a pleasing 3D image and the weight is not unacceptable. I have no doubt that a pair of Duovids would show an improvement of some sort, but at less than 10% of the cost I am very pleased with my purchase. Ebay came up trumps this time. |:d|

[elkcub]

Hey, good for you Chris. If you have ancient Tascos for comparison the view must be simply stunning. ;)

Ed

[WJC]

Chaps, - As a complete newbie, I was interested in acquiring a good quality set of bins without lashing out too much cash. I had always rather fancied a pair of Jenoptems but a couple of reviews led me to believe that the Swift Audubon was a sharper instrument and considerably better value for money. After reading the excellent paper by Edward M. Huff and Renze de Vries I settled on a pair of MKII 3b (Gold band) I found on Ebay (I can almost hear the gasps as I write this). The commonest problem that they are prone to seems to be mis-collimation. I understand that (in the case of Audubons) this is corrected by rotating the eccentric rings supporting the objective lenses.

Is anyone aware of a tutorial that demonstrates how to check collimation and, if there are unacceptable errors, adjust the rings?
TIA
Chris

Hi Chris:

You will have to go back 3 generations of Swift Audubons to find an eccentric ring model. Unfortunately, while the eccentric ring method is preferable for longevity of alignment, if you are out of collimation badly, it means that at least one prism has shifted and that means someone is going to have to go inside. You can have it repaired correctly or inexpensively. But unless you find a master craftsman who's starving, you won't find both options under the same roof.

Cheers,

Bill Cook, Chief Opticalman, USNR-Ret.
Founding Editor, Amateur Telescope Making Journal

[imac]

If anyone does need any work doing on their Swifts, Pyser are the best bet, good service and a quick turnaround. Their charges are not that unreasonable either.

[elkcub]

If anyone does need any work doing on their Swifts, Pyser are the best bet, good service and a quick turnaround. Their charges are not that unreasonable either.

For owners in the US, I highly recommend Nicolas Crista, who was the head of Swift's repair department until the company moved to the San Jose, CA recently. He did great work on my 7x35 Holiday, including expert alignment.

He also holds the US patent for Swift's new retractable eyecup with locking detents.

Nicolas Crista
Swift Optics and Instrument Repair
25 Crescent Place
Hanson, MA 02341

Ed

[Simon S]

In my opinion Swifts hold Collimation unless abused, Jenoptems seem to go out of alignment far to easily. I also think the Swifts are sharper than the Jenoptems and have a wider field of view. They are bulky items though, and sharpness goes off fairly quickly towards the edge of the frame.

[elkcub]

In my opinion Swifts hold Collimation unless abused, Jenoptems seem to go out of alignment far to easily. I also think the Swifts are sharper than the Jenoptems and have a wider field of view. They are bulky items though, and sharpness goes off fairly quickly towards the edge of the frame.

Right, but here's where I part company with pure flat-field lovers. The "sweet spot" covers 2/3 of the apparent field, a good ±23 deg. from center. The normal eye typically operates in this range to bring targets of interest to the fovea. So the designers hit upon a beautifully human engineered system where the periphery operates, as it should, to provide low resolution motion cues. That is why I believe the Audubons are so easy and natural to use.

I've got three small-body 804s, (in addition to several older large-body types) — the 804R (1985), 804 HR/5 1994, and 804Ed HR/5 (1993). I use them all and enjoy their small differences, even the 804R which is superb. So far they have all been quite robust, although admittedly I'm very easy on my equipment. Each has its own padded case and gets brushed off after each use in the field. They are my favorite Porros by far, and, frankly, my three Nikons simply sit on the shelf helping me to resist buying old Zeiss porros.

Blue skies,
Ed