Just bought some inexpensive 10x70x70 bins

[mylatestwhim]

Picked these up new from farmers market for £25 (Haggled from £35) and are really quite good. Clear optics, chunky rubber feel, caps and bag. Found them on fleabay for similar money so think I did ok.

They have a funky zoom lever too which is quite usefull. Tried them last night an they produced good results and good in the day too.

(Made in China)

Sorry about the dust on them it was blowing a gale at the weekend..

[michael.h.f.wilkinson]

You cannot go far wrong for that kind of money, can you. They look tiny compared to my 15x70 bins. Is the aperture really 70mm? looks more like 50-60 to me.

Still, you should have fun with them.

[ismangil]

They have not one but two of no-no features :

• Zoom - hard to hold collimation
  
• Ruby coating - less light gathering
  

Anyway, use them and enjoy, that's what's more important!

[NGC404]

You cannot go far wrong for that kind of money, can you. They look tiny compared to my 15x70 bins. Is the aperture really 70mm? looks more like 50-60 to me.

Still, you should have fun with them.

I was thinking the same. They look like 50mm bins to me.

(regardless what it says on them)

Have a quick meassure of the objectives and let us know.

[Ad Astra]

You will want to be careful with the zoom feature. They are usually made with either a plastic or metal strap that transfers the torque to zoom both sides at once. They strap can break or foul if you try to zoom too quickly or with too much force.

You will also find that they will give much sharper views at night when you keep them on the lowest zoom setting. Zooms are notorious for both narrow field of view and low light transmission at their higher powers, which limits their usefulness for astronomy. If you keep them on low power and save the high zoom for day time use (birding and football!), you will have a good time with them.

As others have said, zooms are not highly prized for astronomy, but you can make use of even the most humble equipment as long as you know the limitations, and how to get the most from your kit.

Enjoy them and let us know how you get on.

Dan

[BinocularSky]

Owing to some less-than-competent control in the manufacturing process, a number of Sakura binoculars have incorrect data printed on them. The ones I am aware of (there may be others) are:

The 10x-70x70 is a 10-70x50 (as people on here suggested).

The 20x50 is a 10x50.

The 10x90x80 is a 10-90x60

The 30x60 is a 15x22

The 20x-180x100 is a 20-180x70

[michael.h.f.wilkinson]

Owing to some less-than-competent control in the manufacturing process, a number of Sakura binoculars have incorrect data printed on them. The ones I am aware of (there may be others) are:

The 10x-70x70 is a 10-70x50 (as people on here suggested).

The 20x50 is a 10x50.

The 10x90x80 is a 10-90x60

The 30x60 is a 15x22

The 20x-180x100 is a 20-180x70

"Less than competent" is a clear misnomer, fraudulent springs to mind. It is really cheating when you misrepresent the size and/or magnification. 30x60 = 15x22 in which system of units?

[NGC404]

Like many others here, I,ve seen them 50mm bins on ebay with 70mm in the description, and on the bins themselves

All buyers have left glowing feedback :p

[michael.h.f.wilkinson]

Like many others here, I,ve seen them 50mm bins on ebay with 70mm in the description, and on the bins themselves

All buyers have left glowing feedback :p

Many people are ignorant of the meaning of the specifications. They would not know they are being had.

[BinocularSky]

"Less than competent" is a clear misnomer, fraudulent springs to mind.

I was merely applying Hanlon's Razor.

All buyers have left glowing feedback :p

Many people are ignorant of the meaning of the specifications. They would not know they are being had.

All of which supports my belief is that final stage of quality control is the customer, most of whom will be less stringent than a proper optical QC bod with a modicum of self-respect. I've actually witnessed returned budget binos being thrown straight into the dustbin and replaced with another box off the shelf -- obviously cheaper to replace than to fix (usually collimate).

Connected to this, I also believe that there is no such thing as a decent zoom binocular (for astronomy or for anything else) on the market and that anyone who tries to tell you otherwise is either dishonest, ignorant, or self-delusional (we can apply Hanlon's Razor again ).

The reasons for this are simple. Not only must the eyepieces zoom to within 1% of exactly the same rate (which means absolutely no perceptible rocking of the bridge), but a zoom binocular requires a system with movable optical elements that must hold collimation, ideally to better than an arcminute where step (aka dipvergence, aka supravergence) is concerned if one is approaching ×30; for the ×125 that I have seen advertised for some zoom binoculars, this translates to better than 15 arcseconds! Now, consider how many good quality centre-focus 30× binoculars you know of – I don't know of any, and I am sure that part of the reason must be that it would be a feat of technological brilliance (not to say expense!) to bridge two eyepieces in such a way that they maintain collimation to within the tolerances that are required. (And remember that it is unlikely that they will have a "base tolerance" of zero error.)

According to Seyfert, zoom binoculars were developed as a “gimmick to stimulate sales” on the back of the success of zoom lenses for cameras. He also asserts that the frequency with which they fail results in their being disproportionately represented at binocular repair facilities. He also states that he has never seen a zoom binocular that can hold collimation.

[michael.h.f.wilkinson]

I was merely applying Hanlon's Razor.

I usually refer to Napoleon's dictum, which uses the word incompetence rather than stupidity.

Not only must the eyepieces zoom to within 1% of exactly the same rate (which means absolutely no perceptible rocking of the bridge), but a zoom binocular requires a system with movable optical elements that must hold collimation, ideally to better than an arcminute where step (aka dipvergence, aka supravergence) is concerned if one is approaching ×30; for the ×125 that I have seen advertised for some zoom binoculars, this translates to better than 15 arcseconds! Now, consider how many good quality centre-focus 30× binoculars you know of – I don't know of any, and I am sure that part of the reason must be that it would be a feat of technological brilliance (not to say expense!) to bridge two eyepieces in such a way that they maintain collimation to within the tolerances that are required. (And remember that it is unlikely that they will have a "base tolerance" of zero error.)

According to Seyfert, zoom binoculars were developed as a “gimmick to stimulate sales” on the back of the success of zoom lenses for cameras. He also asserts that the frequency with which they fail results in their being disproportionately represented at binocular repair facilities. He also states that he has never seen a zoom binocular that can hold collimation.

I agree. I have also noted I have yet to work with a pair of centre focusing binoculars that truly hold focus. Almost all have a degree of wobble incompatible with night-time observing (i.e. when the pupil is fully dilated, and therefore has least depth of field).

[BinocularSky]

I agree. I have also noted I have yet to work with a pair of centre focusing binoculars that truly hold focus.

Permit me to introduce you to my Opticron 10x42 . I know roof-prisms aren't considered to be best VFM for astro-binocs, but these take a lot of beating for that size.