QUESTION ..Binos

[metz]

Changed post ....as ive just found out even binos sometimews need collimation ....in these high tech days you have to ask WHY ?

[Peter Drew]

So many bits to manufacture and assemble, so many optical components to set up, so many items that have to turn, bend or focus. At the budget end of the market it's surprising they work so well!. High end binoculars can be expected to retain their collimation better because of the higher build quality.

[metz]

So many bits to manufacture and assemble, so many optical components to set up, so many items that have to turn, bend or focus. At the budget end of the market it's surprising they work so well!. High end binoculars can be expected to retain their collimation better because of the higher build quality.

Thanks for reply what about these http://www.telescope.com/control/main i think these are roof prism and i think ???? these dont need collimation ??

http://www.telescope.com/control/product/~category_id=binocular_giant/~pcategory=binoculars/~product_id=09324

[brianb]

Binoculars should be accurately collimated when sold (but cheaper ones often aren't). They should keep their collimation unless handled very roughly.

Recollimating binoculars is not IMHO a job which end users should have to do, neither is it one which many will be capable of doing.

There is no difference between roof prism & porro prism types - either can be assembled incorrectly or knocked out of alignment. Porro prism types are much to be preferred at the low & middle end of the price range as roof prism types require very careful design, very careful construction and excellent coatings to work well.

[metz]

Binoculars should be accurately collimated when sold (but cheaper ones often aren't). They should keep their collimation unless handled very roughly.

Recollimating binoculars is not IMHO a job which end users should have to do, neither is it one which many will be capable of doing.

There is no difference between roof prism & porro prism types - either can be assembled incorrectly or knocked out of alignment. Porro prism types are much to be preferred at the low & middle end of the price range as roof prism types require very careful design, very careful construction and excellent coatings to work well.

cheers for reply brian , thats another idea knocked on the head first was a reflector now the binos ...i will stick to my 102 slt ...flipping minefield out there lol

[jgs001]

I loaned a pair of 10x50 bino's, and they got knocked somewhere. I found a collimation guide online, and recollimated them in a few minutes... it was surprisingly easy. It may not be so easy with every pair of course...

[kniclander]

Are we talking about two different aspects of bino collimation? There's the two oculars being correctly lined up which is easy to test and usually user correctable and then there is the elements within each ocular being correctly positioned which is definitely not user correctable.

In reality, millions of people use bins without even knowing what "collimation" means so I wouldn't let the fact that they are theoretically collimatable put you off. But don't drop them.

[metz]

Are we talking about two different aspects of bino collimation? There's the two oculars being correctly lined up which is easy to test and usually user correctable and then there is the elements within each ocular being correctly positioned which is definitely not user correctable.

In reality, millions of people use bins without even knowing what "collimation" means so I wouldn't let the fact that they are theoretically collimatable put you off. But don't drop them.

Thanks for that matey and you have a point and thanks for info

[brianb]

There's the two oculars being correctly lined up which is easy to test and usually user correctable and then there is the elements within each ocular being correctly positioned which is definitely not user correctable.

And the two barrels pointing in the same direction, which is not at all easy for the user to correct - the cheaper bins have the prisms glued in place which makes it a real bind (involving repeated trial & error with long assembly times & strips of kitchen foil being used as shims), the more expensive ones are easier from the adjustment point of view but tend to be nitrogen filled so you need a pressurized nitrogen clean room to work in if you're not going to lose the (very considerable) advantage of the nitorogen sealing.

Then if you correct the non-parallel axis errors, you're using at least one of the objectives off axis ....

Trust me. If you buy a pair of bins and the collimation is out, return them for repair / replacement. Repeat until you get a good pair or ask for a refund when it proves impossible to find one. With the cheaper models, I reckon you'll probably go through 20 or 30 pairs before you find one that is close to acceptable. With the top end ones, there's a good acceptance rate. That's what you're paying premium prices for.