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Bushnell Rangemaster: Vintage Binocular vs. Modern Birds (2 Viewers)

John Dracon

John Dracon
Another piece of information to give you some perspective. When I damaged the top lens of one of the oculars of the IF Fuji, I sent the whole package to Cory to see if he had a lens in his collection which would fit. Meanwhile the Fuji monocular arrived, and although the housing was in rough condition, the lens were OK. After a period of time elapsed, it appeared Cory would be unable to come up with the lens replacement (hardly a surprise with a half century old piece) I decided to "cannibalize" the monocular and use the ocular with the IF binocular. So Cory returned the ocular piece. Does this make sense?

Another piece of esoteria for you "do it yourself" folks. As you know dissimilar metals will result in galvanic action and break down the threads of screwed in pieces over time, particularly in salt air environments. My experience with many old Japanese binoculars where aluminum and magnesium (not really sure what alloys they are) will make assembly and re-assembly difficult in screwed in components. This was true of the ocular housing from the Fuji monocular, but I managed to screw it in with some care, gritty feeling all the way.

Remember, I'm an old man who has been playing with this old stuff for over 60 years.

John
 

henry link

Well-known member
John,

The eyepiece you describe is a bit of a mystery to me. Is it the very same 70º one used in the CF Rangemaster? Where is the cemented doublet placed in the order of elements?

Also, how are your Fuji binoculars labeled as to coatings, "Coated Optics" or "Fully Coated".

Henry
 

Grimnir

Well-known member
In a 1952 ad Bushnell claim for the Rangemaster that "All air-to-glass surfaces hard coated"

As the ad was placed in 1952 I imagine this applies to the earlier BK7 model, rather than the later high-index models under discussion.

Nevertheless it seems to me unlikely that Fuji having fully coated an earlier model Rangemaster would only partially coat a later model Rangemaster especially when David Bushnell told Fuji "that they should make the best they could produce".

I therefore suspect that all Rangemasters were fully coated.

Graham
 

Steve C

Well-known member
In a 1952 ad Bushnell claim for the Rangemaster that "All air-to-glass surfaces hard coated"

As the ad was placed in 1952 I imagine this applies to the earlier BK7 model, rather than the later high-index models under discussion.

Nevertheless it seems to me unlikely that Fuji having fully coated an earlier model Rangemaster would only partially coat a later model Rangemaster especially when David Bushnell told Fuji "that they should make the best they could produce".

I therefore suspect that all Rangemasters were fully coated.

Graham

Somewhere I saw that ad, or a similar one with the same information. But couldn't confirm that, so thanks for that information. The surfaces I can see in my Fuji specimen certainly look like they are all coated. The coatings in the Fuji specimen are lighter in a blue hue than the ones on the Tamron model I have.

I wonder some about the Bk-7 vs BaK-4 prisms. I see where, for example Simon Spiers in his flicker stream shows an early FPO Bushnell Rangemaster that looks just like mine, but his comment is one concerning low indexing prisms. However, the one I have is quite clearly Bak-4 as evidenced by perfect, and quite distinct, sharp edged, round exit pupils. There was another comment in a Cloudy Nights thread as well, about low Bindexing prisms in the early Fuji Rangemaster. I can see it likely that they used Bk-7 early on until they could get their hands on some Bak-4.

This sets off some speculation that maybe Fuji decided to do a little early experimentation, and kept quiet about it until they saw what happened. There is a statement from David Bushnell, in the interview with him I linked above (referenced by Grimnir), that his request to FPO was just to build him the best binocular they could, and he'd buy it. If they decided he was good for his word, they would take an opportunity to produce a better product for a customer in hand, where they had a ready sale for their binocular. Seems like they could easily have decided to use some Bak-4 and fully coat all surfaces in that circumstance. I do not have any idea when Bak-4 glass was first available either.

So I find myself in full agreement with Grimnir in his above post.
 
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Grimnir

Well-known member
Steve

Actually the Bk7 and Bak4 FPO Rangemasters are readily distinguishable by the screws - or lack of them - on the prism cover plates. The Bk7 doesn't have them but the Bak4 does.

Graham
 

Steve C

Well-known member
Steve

Actually the Bk7 and Bak4 FPO Rangemasters are readily distinguishable by the screws - or lack of them - on the prism cover plates. The Bk7 doesn't have them but the Bak4 does.

Graham
Thanks, I did not know that!
 

Grimnir

Well-known member
I think that there were at least nine distinct Rangemaster models:

FPO Bk7 IF
FPO Bk7 CF
FPO BaK4 IF
FPO Bak4 CF
FPO Bak4 silver trim IF
FPO BaK4 silver trim CF
Tamron conventional-style version
Tamron custom-style version, strap lugs attached to prism covers
Tamron custom-style version, strap lugs attached to barrels

Also at least one monocular and a booster.

Graham
 

Steve C

Well-known member
I think that there were at least nine distinct Rangemaster models:

FPO Bk7 IF
FPO Bk7 CF
FPO BaK4 IF
FPO Bak4 CF
FPO Bak4 silver trim IF
FPO BaK4 silver trim CF
Tamron conventional-style version
Tamron custom-style version, strap lugs attached to prism covers
Tamron custom-style version, strap lugs attached to barrels

Also at least one monocular and a booster.

Graham

Thanks again. I'd like to see that booster!

Edit: Just went back to Simon's stuff and looked again at his early Fuji Rangemaster photo, obviously has no prism plate screws. You learn something every day!
 
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henry link

Well-known member
Graham,

Was that the booster that was placed up front, ahead of the objective? I'd like to know more about that one.

Henry
 

John Dracon

John Dracon
Henry - The Fuji(s) I have just state, "coated optics." Regarding the order of the lens, I'm sorry but I didn't mark or write that down. I should have. And I should have saved the broken lens, but I didn't. This I do remember, the exterior part of the lens was flat, and the back side was convex.

I can easily send you the monocular and all its parts for you to examine. The cost is not an issue with me (maybe $6 bucks) I'll spring for the sending and you can pay for the return. If that is what you want, send me your mailing address via my email address ([email protected]), and I'll mail it out to you. I'm sincerely interested in your analysis of what kind of lens system the Fuji has because I don't know.

John
 

Grimnir

Well-known member
Henry,

Yes, the booster slides over the objective ring. They are 2.5x so yield 17.5x when attached to a Rangemaster.

There appear to be at least two variants depending on the method of attachment: one is a push fit held in place by three small rubber buffers, the other is clamped in place by a single screw. The screw type seems to be the more common of the two.

John Dracon has several Rangemaster boosters and is very fulsome in his praise for them.

I too would like to know more about them, in particular who manufactured them and whether the variants are optically identical.

John, can you help out here?

Graham
 

henry link

Well-known member
John,

Thanks for the offer. I'll send you an email.

Graham or John,

Do you know what optical design the booster uses? The only thing I can imagine working ahead of the objective is some sort of 2.5x Galilean telescope.

Henry
 

Grimnir

Well-known member
Henry,

Yes I feel sure that's what it must be but I have no idea how many elements it has.

Unfortunately, I can't inspect one as I don't have one here at the moment. However, I do have one incoming which should be with me in about 3 weeks.

Graham
 

John Dracon

John Dracon
Henry - My technical knowledge of optics is limited, but I believe the Booster is a Galilean hybrid. The image coming out of the end is straight up. Interestingly, when I place my little Zeiss 3x behind the Booster (there is a round groove which helps center it), it becomes an excellent 7.5x monocular.

John
 

Steve C

Well-known member
John and Henry

I hope you can work out the lens shipment. I have taken some more pictures, but they are not what I need. I have no real desire to take the oculars off again, so I hope John can get his to Henry. I'd like to know about the coatings too. Although just looking at them they appear coated on all surfaces.

After using these for awhile, they are both going to stay. In a response here earlier to Pompadour, I said that if the house was on fire and if I could only save one binocular as I dived out the fire escape, it would be my Leupold Gold Ring HD 8x42. I think I'd modify that a bit and say I'd have the GR in a gear bag by the exit. In the bag with the GR would be the Rangemasters, my Audubon 8.5 and the Nighthawk. There would be a couple of others, but I would grab all of these on the way out.

It is hard, if not impossible for me to state which of these is best. The Fuji has better depth and edges (the last of no real concern to me). The Tamron is a little brighter (and that might be a figment of the imagination) and seems to resolve a little better at distance. I was watching some deer about 1.75 miles from the house (according to Google Earth) in a little burn on the Klamath Hills. The Tamron did show them just a bit sharper than the Fuji.

I enjoy the looks I have gotten from people seeing the Tamron..."just what is that thing anyway!?" I like the Fuji comments too..."It's HOW old!?"
 

Simon S

Well-known member
i think you will find the Rangemaster has coatings on all the lenses in the ocular.
Mine does indeed appear to have low index prisms, however that is not necessarily a bad thing. Just as a digital camera with a high count pixel sensor sounds good, there are disadvantages.
Bk7 prisms are less likely to show CA in high contrast areas of an image.I would also like to bring to you attention some excellent performing Swift models in the 7x50 range Holiday, Panoramic, Sports King etc... that can perform as well as my FPO model.
 

Simon S

Well-known member
Well I have just bought an FPO with Bak4 prisms, will be interesting to compare the other side by side.
 

Steve C

Well-known member
Well I have just bought an FPO with Bak4 prisms, will be interesting to compare the other side by side.

I just passed on an early model with Bk-7 prisms ;). Sold pretty low, but as I have my eye on another sort of binocular right now, I let that one pass. I was interested in seeing how the Bk-7 and Bak-4 models compared. I am interested in your take on the two.

I suspect the differences will be less than what many would expect. I have a few Bk-7 binoculars and a lot of them are very good.
 

Grimnir

Well-known member
Simon,

I will also be very interested to read your comparison. I have an FPO Bk7 here but my FPO Bak4 is out on loan for another few weeks. I should have it back sometime in January when I'll do a comparison.

Graham
 

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