35 replies to this topic

[revans]

Rick, this is very good information and I appreciate your posting it.  I have Explore 20x80s as well; my left eye is not quite right due to prior retinal surgeries and I've written off a little intermittent double vision as related to that, but I will check the collimation/alignment carefully and tweak a little if I need to.

 

I'm finding these binoculars to be really, really good and fun to use on doubles, my main use for them at the moment.

I am very impressed with these Oberwerk 20x80 Explore.  They are exactly what I wanted as a sort of support binocular for my main use binocular, the 15x70 Explore (or sometimes the Deluxe although it is heavier to hold).  This way I don't have to get up from the ZGT to check what I'm looking at in the 15x70s against my BT-82.  

 

I was a little dubious that I could handhold the 20x80s in the ZGC, but thankfully I can.  The quality is much the same as the 15x70 Explore but the view is a little smaller and a little more detailed.  For the money, these are a really good deal.  I've got to be more careful with the eyecups though.  I've been zipping them up and down and am starting to feel a little rachety-ness in the left one that wasn't there initially.  I need to slow down and be more patient.  Maybe the answer is WD40 but I'm not comfortable using it so close to the eyepiece.

 

Rick

[pat in los angeles basin]

Turn the eyecups all the way up and see if there are 3 spiral slots about 120 degrees apart on the inner surface of the twist up eyecup section. You can also feel along the bottom edge of the eyecup to see how firmly attached the rubber surface is attached to the plastic or metal shell of the eyecup. There might be 3 brass screw with heads that ride in the slots, that's where the lube might be needed. I'd try either a small acid brush/ painters brush with the WD on that and paint the slot- minimize the amount of lube on the surface. Worst case scenario can be to peel the rubber eyecup off and remove, there should be easy access to the srews to remove them and clean the 2 overlapping surfaces to minimize the drag. Pat

[revans]

Turn the eyecups all the way up and see if there are 3 spiral slots about 120 degrees apart on the inner surface of the twist up eyecup section. You can also feel along the bottom edge of the eyecup to see how firmly attached the rubber surface is attached to the plastic or metal shell of the eyecup. There might be 3 brass screw with heads that ride in the slots, that's where the lube might be needed. I'd try either a small acid brush/ painters brush with the WD on that and paint the slot- minimize the amount of lube on the surface. Worst case scenario can be to peel the rubber eyecup off and remove, there should be easy access to the srews to remove them and clean the 2 overlapping surfaces to minimize the drag. Pat

Initially both eyecups were smooth and fine.  The right eyecup (the eyepiece with the diopter adjustment) is still fine.  But the left one isn't smooth anymore.  When I extend it outwards all the way, I can see 6 thin raised vertical lines molded in the plastic of the eyepiece barrel. The rubber part of the eyecup has a distinct wobble back to front that the opposite eyecup does not have.  I can see what looks like the head of a set screw making a little bump in the rubber of the eyecup near its end.  The action isn't smooth anymore and wants to hang up when twisting it inward or twisting it outward.  I am not sure that graphite or fine oil is the answer.  It will need some thought.

 

Update: Ah.... I see the issue now.  An very extremely minute set screw had worked its way out under the left eyecap rubber and was catching on those vertical ridges when the eyepiece was twisted up or down.  All I have to do.... and it might not be easy because of the very small size of this set screw, is to put it back in place with a jeweler's screwdriver (which I fortunately have). But even with the set screw now out from under the eyecap rubber, the action is smooth again.  But I'll try and put it back in.

 

Rick

[pat in los angeles basin]

the twist up  eyepices with the rubber coverings can typically be forced off as they commonly have a bit of contact cement keep them from moving in relation to the plastic shell. Once the covering is off, the setscrew that run in the  angled slots  that translate to twist into a rise fall are apparent. Go a bit easy on the screws if the shell and eyepiece underpart are plastic- way too easy to overtorque a fine brass thread in a softer threaded hole, stripping it. Mebbe you can  have inscribed on the binos "triple tested- shades of bushnell" now as the makers checked them, Obie and Kevin checked em, now you did  as well!

[revans]

the twist up  eyepices with the rubber coverings can typically be forced off as they commonly have a bit of contact cement keep them from moving in relation to the plastic shell. Once the covering is off, the setscrew that run in the  angled slots  that translate to twist into a rise fall are apparent. Go a bit easy on the screws if the shell and eyepiece underpart are plastic- way too easy to overtorque a fine brass thread in a softer threaded hole, stripping it. Mebbe you can  have inscribed on the binos "triple tested- shades of bushnell" now as the makers checked them, Obie and Kevin checked em, now you did  as well!

Now here is something unusual.  The ittsy-bitsy set screw, being re-inserted by me, has the effect of locking the eyecap in place and not allowing it to go up or down by twisting at all.

 

I was getting the ratchet-like issue because it had come out of the tiny bolt hole and was catching on each of the plastic ridges in turn.  With the set screw removed from the picture completely, the eyecup has a smooth and normal up and down motion.  Go figure...

 

Rick

[pat in los angeles basin]

you going to leave well enough alone? Done that myself  on a couple of binos..

[revans]

you going to leave well enough alone? Done that myself  on a couple of binos..

Yes, this comes in the category of "if it's working don't mess it up" or maybe it's "if it ain't broke don't fix it." 

 

Rick

[pat in los angeles basin]

I have a good performing  orion 20x70 that has a prism that shifts out of position, compromising  alignment. A soft tap in the right place into the palm of the hand straightens it out. Been that way for 5 years. Sure, I could take out that cluster and take another hour or so to correct the situation, but it is SO predictable... ergo

 

if it's working don't mess it up

[revans]

At long last the rain has gone away and a cloudy but bright and fog free morning as dawned.  I took the 20x80 ES mounted on a photo tripod onto the deck and spent some time just using them to look at the landscape around me. I quibbled a bit with the micro-collimation I did yesterday and took another few minutes to correct the really subtle residual collimation error.  To do this it was necessary to minimally tweak the objective in the right sided barrel I had not previously adjusted. 

 

Weather conditions, free of fog, gave me crisp views of my favorite 2 mile distant tree lined ridge of hills and a look down into the valley below me.  I noticed that correct eye placement is not as easy in the 20x80 ES as in lower powered binos I use.  Even though collimation is perfect, incorrect eye placement can create a subtle ghost image that is annoying and which isn't real to the extent that it is independent of having perfect collimation.  I wonder if this is because, during the day, my pupil size is likely somewhat smaller than the exit pupil of the binoculars.  I'm not quite sure, but I suspect something like this could be going on. 

 

If you close one eye at a time you can see that collimation is right on, but with both eyes open, if your eyes are not positioned just so, you can see a faint ghost image at least in daylight views.  

 

I tried to take another look at the optical quality of these binoculars now that the weather is much improved and I have excellent collimation that I cannot further improve upon.  The center of the field is sharp and bright, color rich and contrasty... and this extends out to at least 2/3 and perhaps 3/4 of the FOV from the center outwardly.

 

Beyond this there is slight dimming and slight loss of contrast although the image does remain pretty sharp in this outer area.  I don't notice this using the binoculars handheld, but you do notice it using them mounted. The FOV is not claustrophobic and the apparent FOV seems comfortable to me. There is no feeling of tunnel vision.

 

The focus mechanism is smooth but just a tiny bit stiffer than I'd like.  The diopter adjustment is great.  The weight of the binoculars is very good... I'd seen early reports on CN that they weigh 5.25 lbs but the specs say 4.7 lbs and that would be my guess as well.  The eyecups gave me trouble yesterday because of a set screw issue, but since addressing that, the twistable eyecups are fine again and are a pleasure to use.  

 

The binocular fit and finish is good.  There is a little more plastic than I'd like, but at their price point there is really nothing to complain about.  The flexible fabric case is semi-rigid and very nice as well.  I hope I have a chance to use them a bit more tonight in my ZGC.

 

To sum up, one of the nicest things about these binoculars is that they are no so expensive that you are afraid to work on them yourself.  And so they can be used to teach you a lot of binoculars and their maintenance.  I think I've learned more from using this pair over the past week or so than I have with any of my other pairs except maybe my BT-82.

 

Rick

[Mark Y.]

Nice looking instrument there! 

[revans]

I've been working on improving the collimation and at long last could say it was upgraded from an A- to an A today.  Although cloudy, Capella and neighboring stars could be viewed and collimation was spot on.  Many overhead planes as well passed by and were sharply seen with no double vision.  I'm glad that problem is over, at least for now.  I'm now ready for a double star session with this pair of binoculars.

 

Rick