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#1 aa5te

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Posted 19 April 2011 - 11:32 PM

Posted Image
No, that's not sunspots...
Here's some of her clothing off, she should bathe more:
Posted Image
Another teaser:
Posted Image
She fell to pieces...
Posted Image
And now her identity is revealed:
Posted Image

So what's the story? Well, eBay... and I took one for the team...

There I was, surfing for more binoculars that I didn't really need. I noticed this Pentax 7x50 PCF advertised for the last several weeks, but no bids on it, same price. I remember it being listed for $49.99 buy it now, and looked at it, but it had dirt "between" the lenses according to the seller (a pawn shop, apparently). Well, the seller had hi-res pics of it and sure enough, there was a lot of dirt, but I new these objectives were cemented together, so I figured that it was just on the inner surface, even though some spots were visible on the eyepiece pics provided by the seller.

Well, after 3 weeks or so, the seller changed it to buy it now or make an offer, so I offered $25 plus $10 shipping and he accepted within 10 minutes. Binos arrived this Saturday via Fedex, wrapped in an almost 10' long piece of bubble wrap(!). Got them out and holy cow, there is dirt everywhere in them, water spots on the prisms, all over and in the thing. Took a sniff of it - hmmmm, I've smelled that before, lake water and fishing tackle! I'm certain these were submerged in a lake for a while, they at least took a dive.

So, I decided to look through them... not bad, actually at all. Spots in the view were only noticeable against bright backgrounds (the clouds during the day), but it bothered me enough to disassemble them and clean. Well, this was interesting...

You basically have to pull/pry off the rubber outer armoring as it is glued/fused in a few places. I felt bad about doing that, but, once complete, the screws are visible and came out easily. Lots of plastic is present, but the prism housing is metal. After a thorough rinse in the kitchen sink with hot water and soaking in Palmolive dish soap, the dirt disappears.

I cleaned the prisms with Windex (note that the objective side prism and the eyepiece side prism are different sizes). The only real damage that I noted is an area of about 2mm x 4mm where the coating came off of one of the prisms, but you can't tell it in actual use, even though it's in the light path.

One thing I should have done was remove the collimation screws (they push the prisms from the prism housing) when the glue on them was wet and soft. I bent a good hex wrench trying to get them loose after I reassembled everything. I had to put alcohol on them and let it soak to allow them to come out, but even though it was very difficult getting that glue out of those holes.

I cleaned everything thoroughly, reassembled, and what do you know, collimation is WAY off. I took them outside, after killing an hour and the hex wrench mentioned above in simply getting the collimation screws loose, and had them nicely aligned in about 10 minutes.

So, I compared them to my best 7x bino (Tasco 116 7x35) during the bright, broad daylight. FOV is no contest, Tasco wins by about 4 degrees or so. But that's all it wins at... Brightness is about the same, but the Tasco view is kind of washed out and gray compared to the Pentax. The Pentax view compared to the Tasco is like taking a digital picture and turning up the saturation and sharpness on it! It's quite noticeable and really quite nice.

Now, for the night time view...

Sirius - Tasco is dimmer and less colorful, slight flaring in a few directions.
Triangle of stars used to find M51/Whirlpool Galaxy - can only see the bottom star (mag 7.45; the other two are 7.05) with averted vision in the Tasco and then only sometimes; Pentax shows them all easily with direct vision.
Overall, the Pentax shows a LOT more stars and obviously provides a sharper and more colorful view, minus my beloved ultra wide FOV of the Tasco.

I'm questioning why I have an 8x40 bino. The 7x35 is wider, and the 10x50 I have has close to the same FOV (almost 8 degrees, compared to 9.1 degrees). The Pentax seems to show everything that the 8x40 Century Mark IV does, minus the FOV again. I have a hard time focusing these 8x40s - even though the focus it stiff, it seems to shift even with no apparent movement.

Up against the Sears 10x50... well, 10x makes the Beehive look a LOT better, but the Pentax seems to show almost as many stars - I couldn't hardly find any (a handful) that the 10x50 would show that the 7x50 wouldn't. The wide FOV and spacewalk feeling of the 10x50 is pretty sweet, though.

My only complaint about these Pentax 7x50s is that it seems you can't get a nice, single circular view out of them with both barrels, regardless of IPD or alignment. I always see two circles when looking through them, but that may be due to a 7mm exit pupil, I'm not sure.

But, I am happy with my purchase!
Link to Picasa album with more pics & zoom capability

#2 aa5te

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Posted 19 April 2011 - 11:51 PM

One more item - I did blacken the edge of the objectives with a Marks-A-Lot marker, as well as the prism clips. I don't know if it helped or not, but it couldn't hurt, and I already had it disassembled.

#3 RichD

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Posted 20 April 2011 - 03:29 AM

Nice story, glad you got them cleaned up. The two circles when viewing shows they are not aligned correctly. Either still mis collimated or the images from both barrels are overlapping. EdZ has written about that problem in the past - I believe even he struggled to fix it.

Enjoy them!

#4 aa5te

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Posted 20 April 2011 - 07:16 AM

The lineup from last night, the leaning tower of binos. From left to right:
Sears 2531 10x50, Tasco 116 7x35, Century Mark IV 8x40, Pentax 7x50 PCF

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#5 aa5te

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Posted 20 April 2011 - 07:17 AM

Eyepiece view, from L to R:
Sears 2531 10x50, Tasco 116 7x35, Century Mark IV 8x40, Pentax 7x50 PCF

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#6 aa5te

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Posted 20 April 2011 - 07:20 AM

Objectives & coating colors, from top to bottom, right to left:
Pentax 7x50 PCF (green/purple), Century Mark IV 8x40 (purple & blue), Tasco 116 7x35 (light blue), Sears 2531 10x50 (amber/yellow)

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#7 Mike Lynch

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Posted 20 April 2011 - 08:56 AM

You KNEW you'd get us to read the message, with that "Subject," didn't you?! ;)

But once I saw the shots of the "surgery," I had to agree! Pretty graphic. I'm not THAT brave, by ANY stretch of the imagination!

Glad it worked out pretty well!

Mike Lynch
Frankfort KY USA

#8 Jawaid I. Abbasi

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Posted 20 April 2011 - 08:58 AM

Nice work.

#9 aa5te

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Posted 20 April 2011 - 01:46 PM

Rich & Jawaid, thanks!

Mike, YES, and thanks too!

#10 Philip Levine

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Posted 20 April 2011 - 10:52 PM

Very interesting post.
I surf eBay as well, for binos I don't really need, but what the heck. Most are good finds. The most invasive disassembly I've done is to clean the inner objectives with Windex, and do the best prism cleaning short of removing them.
I think I'll post some pics of my bino eBay purchases in the near future, but I'll have to think hard on how to top your eye catching subject line.
Phil

#11 aa5te

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Posted 21 April 2011 - 03:20 PM

I'll have to think hard on how to top your eye catching subject line.
Phil


You could try this, and I'm seriously thinking about Photoshopping/GIMPing a pic of it:
"Pentax 20/30/40x110 PCF WP X 90° announced, 10 lbs., 4° TFOV @ 20x, 2° @ 40x, $999 shipped"






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