Help wanted stepruva 9x35 binocular eyepiece layout

[DavidDench]

Not sure where to turn and usual searches have drawn a blank.

I have a pair of 1960s ( I think ) Ross Stepruva 9x35 binoculars that I am attempting to clean .

I have cleaned all the easy bits but have had to dismantle one of the eyepieces to clean some internal elements.

Being ham fisted I have muddled the elements and can't fit them together in the right order.

I don't want to dismantle the other eyepiece as I suspect that I will b****r that one up as well.

Does anyone have any specs or have a layout of the eyepiece elements to allow me to get the right order.

Many thanks,

 David

   

[markse68]

it should be a 5 element Erfle David. You should be able to identify the eye lens from damage to its outside surface. Then there should be a singlet lens in the middle and another cemented doublet on the other side. 

Something like this

The spacers you will have to play around with

Mark

[DavidDench]

Many thanks Mark. My ham fists are itching to give it a whirl.

Best wishes,

     David

[DavidDench]

OK, one step forwards etc.

I now have another problem.

First let me say that the binoculars were working fine before I started but has some fungus that I needed to clean off.

After putiing the lenses and spacers in a variety of arrangements I have a nice view through my left side binocular and my right

side binocular. Unfortunately the views are at substantially different focal positions and the exit pupils of both sides when  held at arms length

are a different size.

I cannot put the spacers in any other configuration that makes any substantial difference or allows the components to fit in the

eyepiece barrel.

I have obviously changed something but am at a loss to work out what.

Any suggestions ?

Thanks,

    David

[DavidDench]

OK I have a working binocular again and now have a bit of a mystery.

I dismantles my other eyepiece and found it was not in an Erfle configuration.

The singlet was the field lens ( bottom ).

I arranged to match the one I had b*****d up and configured as an Erfle as above.

Now focus is matched and the exit pupils are the same ( as expected ).

However the Erfle configuration has a smaller exit pupil than the original (to me) configuration.

Don't know what to make of that, but at least a decent performing pair of binoculars.

Best wishes,

     David

[Peter Drew]

It could be that the singlet component  has different external curves even if they look the same, might be worthwhile swapping them round if you haven't already tried this.     🙂    

[markse68]

Sorry about that David, I thought it was an erfle and have found others stating it was but it seems there’s a lot of variation on binocular eps! To add to the confusion i found some photos of an 7x30 Stepnada i dismantled for cleaning and it’s different again! Sounds like you’re sorted now though so that’s great- enjoy the views!  These old Ross bins are lovely and sharp

Mark

Edited August 19 by markse68