extenders (1 Viewer)

Hi Bob, That would be the Nikon 8x30 Trailblazer.
http://www.adorama.com/NK830RC.html
I fell asleep on the couch for a while. I thought I had posted the link before.

Ooooh, an IF roof! I looked through one of the Docters like that recently, also not phase coated I think, and it seemed pretty good, image wise. Certainly not obviously anything wrong. And way macho.
Ron

This is the IF roof Docter I'm talking about:

http://www.browe-inc.com/products/DOCTER-7x40-B{47}GA-%2d-The-Adventures-.html

Ron

Ron I don't think this Nikon Trailblazer would compare to the IF Docter roof.

ronh said:

Ooooh, an IF roof! I looked through one of the Docters like that recently, also not phase coated I think, and it seemed pretty good, image wise. Certainly not obviously anything wrong. And way macho.
Ron

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I tried Steve's 20-year-old, non-phase coated 7x30 SLC and was surprised that the images didn't seem a bit soft like the 8x36 Sporter I I had.

However, the resolution for the Docter (also listed as "Jena Analytic" 7x42 B/GA) is 7 arc seconds, far behind the 7x42 FL. If you did an A/B with the FL, I'm sure you'd notice the difference in image sharpness.

Too bad Docter didn't update Jena's old NVA EDF 7x40 with phase coatings. They appear to be built to last, and there's plenty of "real estate" to hold on to for a closed bridge roof.

They would be good for hunting or wildlife observation if they had p-coatings.

Brock

John Dracon said:

The 2x of the Swarovski is too costly, but it is more useful if one owns the appropriate model since the optical path is always in alignment and the binocular only suffers a 50% reduction in the exit pupil. But it requires more fiddling around removing the eye piece cover and screwing in the adaptor. I adhere to the belief that more individual pieces results in more dropping and fumbling around.

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I agree that the price of the Swarovski booster is incredible (especially considering that they used to sell for less than half as much, and with coupon from Swarovski that came with new bins, could be had for just a bit over $100), but I want to point out that it can be used without screwing the booster into the bin. I sometimes use mine with my Leica and Zeiss bins. In fact, an enterprising person could machine an adapter that would thread into the booster on one side and have a big rubber cup on the other to hold it onto the ocular.

--AP

Alexis - Some where in your syntax you have me confused, "... an adapter that would thread into the booster on one side and have a big rubber cup on the other..." Henry Link talks about the advantages the Zeiss 3x extender has over the other extenders (simply more versatile), and of course as usual he is correct. My point is that a doubler is plenty with its severe reduction in FOV and exit pupil. 3x only makes its worse. I have passed on all my Swarovskis to relatives, friends, etc., but I still have the Swarovski doubler LNIB with all the attachments. If there is anyone in birdland panting for one, contact me by email and I'll send it to them for a very reasonable price.

John

John

Friday and Saturday when it was sunny and unusually mild (near 50* and almost no wind), I tried an EO 2.5x13 booster. It fit perfectly on my SE and EII eyecups, but not on my 9x63 roof or 804 Audubon.

I used it free hand and mounted, and blimey if the eye placement isn't fussier than any optics I've ever used! It took a lot of patience to line up my eyes just right (slightly to the left of center) to keep the image from blacking out.

I first used it with the 10x42 SE. Given the SE's image blackout issues, I switched to the 10x35 EII and then 8x30 EII to see if EP design or FOV made a difference, but the results were the same -- the slightest movement of my hand or head, and half the image blacked out.

I also found the image quality degrades slightly with the booster, and at 25x, the increase in CA was quite noticeable.

The upside of using a booster on bins is that I could spot the bird and center it at lower power with the unboosted EP and then find it in the boosted EP. Trying to find the bird directly with the booster's narrow FOV was much harder.

I tried the booster by itself to see if it would work as a 2.5x monocular, but to achieve sharp focus at the center, I had to move my eye back from the EP about 2". Need more diopter adjustment. The FOV was a lot less claustrophobic at 2.5x and eye placement much less fussy.

Using the booster as a monocular gave me the impression that I might like using a good quality monocular since it would be very convenient to carry anywhere.

The booster is good for resolution tests, but for birding, I found it too difficult to work with.

Brock

I'd like to try a Zen-Ray 8x42 ZRS HD-M monocular and a really well-made front-end teleconverter.

Brock, I just tried this Bushnell 2 1/2 extender and as far as ER both the EO and Bushnell were the same for me. I do have to tilt using the technique some, but had no problem with either the 8SE or 8EII. No problem lining up at all, must be your deep set eyes I guess. That would be 20x not 25x. I don't think you would get on with most spotters, most have short ER and claustrophobic views.

I had the EO booster. It's biggest problem was that it would not seat itself solidly on the eyecups and I was using it on an EO 6 x 32 Platinum Ranger. If it was going to work well on any binocular it should have been that one. The 6x32 became what? A 15x32. You still had a 2.13 exit pupil to work with. I sent it back for a refund, which I got without any problem. I discussed my experience with it and shortly thereafter EO discontinued it.

Bob

mooreorless said:

Brock, I just tried this Bushnell 2 1/2 extender and as far as ER both the EO and Bushnell were the same for me. I do have to tilt using the technique some, but had no problem with either the 8SE or 8EII. No problem lining up at all, must be your deep set eyes I guess. That would be 20x not 25x. I don't think you would get on with most spotters, most have short ER and claustrophobic views.

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Was the sun out when you used the "extender"? From the pix you posted, it looked like the image was half blacked out in the first photo.

I used the booster with the eyecups up and down, so my facial features weren't a factor, but the 1.6 mm exit pupil was (with the 10x SE). In sunlight, the iris contracts to about 2mm. That doesn't leave much margin for error.

Not sure how you manage to keep your eye perfectly placed with a 1.5mm exit pupil (8x EII) during daylight with no problems, but then, we usually see things differently even through the same bins.

As far as spotting scopes, I tried the Zeiss Diascope 85 FL at 30x, and no eye placement problems. Rather the problem was keeping out stray light since the EP and eyecup are HUGE. I also tried a Swaro ATM/STM 65mm, and had no problems with image blackouts though I don't remember if I pushed the zoom all the way.

The third spotting scope I tried was a Nikon 60mm Spotter XL II. That was trickier because it had no eyecup and had a straight through body rather than angled like the other two scopes.

If I use the EO booster when its cloudy, I'll probably have less problems with eye placement since my entrance pupils will be larger, but then the image will be dim with the small exit pupil. Catch 22.

Captain Brock Yossarian

"Was the sun out when you used the "extender"? From the pix you posted, it looked like the image was half blacked out in the first photo."

Brock, Post #11 That first picture is of the EO extender showing it is not phase-coated, that is why it is half blacked out. This was using the computer screen like Henry did. Later on post #19 I show the same thing with the Nikon Trailblazer 8x30 and the Swarovski 8x30 SLC neu. Picture from the objective side with computer monitor in background.\

"Not sure how you manage to keep your eye perfectly placed with a 1.5mm exit pupil (8x EII) during daylight with no problems, but then, we usually see things differently even through the same bins."

I will tell you again, I had no problem at all. I try to adapt to what ever I am using, find a way to make it work and just use it, I don't get caught up in over analyzing stuff and just use it. Well most of the time.

mooreorless said:

"Was the sun out when you used the "extender"? From the pix you posted, it looked like the image was half blacked out in the first photo."

Brock, Post #11 That first picture is of the EO extender showing it is not phase-coated, that is why it is half blacked out. This was using the computer screen like Henry did. Later on post #19 I show the same thing with the Nikon Trailblazer 8x30 and the Swarovski 8x30 SLC neu. Picture from the objective side with computer monitor in background.\

"Not sure how you manage to keep your eye perfectly placed with a 1.5mm exit pupil (8x EII) during daylight with no problems, but then, we usually see things differently even through the same bins."

I will tell you again, I had no problem at all. I try to adapt to what ever I am using, find a way to make it work and just use it, I don't get caught up in over analyzing stuff and just use it. Well most of the time.

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You have the malleability of Mr. Fantastic. I bet if you were one of the chickens in the experiment where they made them wear image inverters, you'd be the first to adjust to an upside down world.

I'll say it again, a 2mm entrance pupil in front of a 1.5-1.6mm doesn't leave much wiggle room. I think I'm probably the rule rather than the exception on this one.

Brock

An interesting "extended" discussion. I still have both extenders, the Eagle Optics one now being in backup mode. I too have found the Bushnell model of use, though I have not been doing exhaustive testing of it either

It resides in my 3-season "lite kit" small bag; with my 8x SE, and a Nikon tripod adapter. Attached to the foot of that adapter is a Bogen quick-release plate that matches the small bogen adapter that is on the top of my hiking pole. If extended study at a distance is necessary I can do so with some stability at 20x, with a good quality image. :t:

brocknroller said:

You have the malleability of Mr. Fantastic. I bet if you were one of the chickens in the experiment where they made them wear image inverters, you'd be the first to adjust to an upside down world.

I'll say it again, a 2mm entrance pupil in front of a 1.5-1.6mm doesn't leave much wiggle room. I think I'm probably the rule rather than the exception on this one.

Brock

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Ok so I guess what I see is not possible according to you, have a nice life.

brocknroller said:

Was the sun out when you used the "extender"? From the pix you posted, it looked like the image was half blacked out in the first photo.

I used the booster with the eyecups up and down, so my facial features weren't a factor, but the 1.6 mm exit pupil was (with the 10x SE). In sunlight, the iris contracts to about 2mm. That doesn't leave much margin for error.

Not sure how you manage to keep your eye perfectly placed with a 1.5mm exit pupil (8x EII) during daylight with no problems, but then, we usually see things differently even through the same bins.

As far as spotting scopes, I tried the Zeiss Diascope 85 FL at 30x, and no eye placement problems. Rather the problem was keeping out stray light since the EP and eyecup are HUGE. I also tried a Swaro ATM/STM 65mm, and had no problems with image blackouts though I don't remember if I pushed the zoom all the way.

The third spotting scope I tried was a Nikon 60mm Spotter XL II. That was trickier because it had no eyecup and had a straight through body rather than angled like the other two scopes.

If I use the EO booster when its cloudy, I'll probably have less problems with eye placement since my entrance pupils will be larger, but then the image will be dim with the small exit pupil. Catch 22.

Captain Brock Yossarian

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Brock,

I doubt that exit pupil size has anything to do with the eye placement problems you're reporting. Certainly, pupil placement with the Zeiss Tripler is quite unfinicky at these exit pupil sizes, no matter what binocular it's matched with. I've looked through a lot of telescopes in daylight and never found any special pupil placement problems associated with exit pupils close to the size of the eye pupil.

You mentioned in an earlier post that you had to place your eye to the left of center to avoid blackouts. That suggests a possible defective unit to me. Try rotating the extender and see if the off-center pupil position moves with it.


Henry

Hello Brock,

I agree with Henry. Try this simple experiment.

Take a business card or larger piece of thick paper and punch a small hole in the middle of it. While looking through the eyepiece, move the whole around in front of the objective lens. I doubt you will notice any difference in the exit pupil, except when the edge of the whole vignettes the exit pupil.

The point being that regardless of where light enters the objective, it will exit at the same relation to the optical axis.

John Dracon said:

Alexis - Some where in your syntax you have me confused, "... an adapter that would thread into the booster on one side and have a big rubber cup on the other..." Henry Link talks about the advantages the Zeiss 3x extender has over the other extenders (simply more versatile), and of course as usual he is correct. My point is that a doubler is plenty with its severe reduction in FOV and exit pupil. 3x only makes its worse. I have passed on all my Swarovskis to relatives, friends, etc., but I still have the Swarovski doubler LNIB with all the attachments. If there is anyone in birdland panting for one, contact me by email and I'll send it to them for a very reasonable price.

John

John

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My point was that the Swarovski booster, which I own, and which I agree is more practical in the field (because hand holding can still be possible at ~16x), can be used without screwing it into a dedicated Swarovski binocular. It need only be held up to and centered on the ocular. I don't like fiddling with eyecup removal etc, so that is the way that I use mine w/my Swaro bins most of the time, and it is the only way to use it with other branded bins. I have a way of wrapping my neckstrap such that it forms a brace and allows relatively stable viewing despite the fact that the booster is not fixed to the ocular. But someone could make an adapter for the Swaro booster that would allow it to be pressed onto the ocular in similar fashion to the Zeiss and other generic models.

--AP

Steve, Remember when you point your finger, there are three pointing back at you. Me, over analyzing? Pshaw!

It is amazing how we never agree on what we see through the same optics! After every, and I mean every, post I make about optics we've both used, if I say potato, you say pa-tah-toe (though hopefully you don't spell it with an "e" like Dan Quayle

I don't deny what you see, if there's any advocate of the subjective view, it's me. However, given the numerous reports by compact bin owners about finicky eye placement, and the fact that those bins have at least a mm more exit pupil than the 2.5x booster mounted on a bin, I thought critical eye placement would be a common issue with a 1.5mm exit pupil used during the day when one's entrance pupils are only about 2mm.

Eye placement is a bit fussier with my 8x23 Venturers than my other bins, though it's not critical like the EO booster.

I think part of the difficulty with compacts is due to the small eyecups, which can slide around in your eye orbits more easily.

Henry, I tried what you suggested and it didn't make a difference. No matter how I rotated the booster, eye placement was critical, and I still got blackouts.

However, if I used a modified MOLCET by anchoring the left side of the eyecup against the bridge of my nose and the top of my eyelid so I could maintain that left of center position, I could pan w/out too much trouble, but I had to keep this position perfectly. A slight deviation and the image would blackout.

Also, unlike Jay's unit, the image is soft through the booster compared to the unboosted image.

I examined the booster by itself, and the "zone of critical sharpness" is fairly small. Not far off axis, the image starts souring (field curvature and coma). If I keep my eye perfectly aligned, the overall image is usable, however, I see "rolling ball" while panning with it, though this isn't present when used with a bin.

Ron, I tried your "card trick" and it works. I can move the pinhole in the card back and forth across the EP and still maintain the exit pupil (better than I can w/out the card, in fact) as long as I move my head along with the card.

The exit pupil looks egg shaped, flattened at the 11 o'clock and 5 o'clock positions. That's also where the image blacks out for me.

The other thing I noticed is that although the booster fits snugly over the SE and EII eyecups, I have to make sure it's lined up vertically with the EP. If I'm not careful, the booster will tilt at a slight angle to the EP. Perhaps when I'm pushing my eye into the eyecup, I'm tilting the booster. I looked at the alignment once and it had moved.

Well, I don't want to over analyze this or Steve is going to rib me again. Suffice it to say that the EO 2.5x booster does not work well for my eyes.

Brock