Is The Zoom The Problem?

[David Buffington]

Hi Folks!

For a decade, maybe two, my primary spotting scope has been an ancient Bausch & Lomb “BALScope Sr.” You know it. They’re a 60 mm scope with a lumpy, green body. You see them all over the place at yard sales and auctions. This one came with a 30-power, fixed eyepiece and a Freeland stand. If I recall correctly, I paid $100 for it.

But then, this fall, I stumbled into a great buy on a 65 mm Swarovski ATS with a 25-60-power, zoom eyepiece. It is really nice. After all, it’s a Swarovski with modern lens designs and modern coatings and all of that.

Yet, when I tried it on the various resolution targets I routinely use around my house – some screws on a house 200 yards or so away, some wiring on a transformer maybe 300 yards away, a hilltop a half-mile away – I found it was no better, probably inferior in resolution to the Bausch & Lomb, not just in the center, but edge-to-edge.

So I sold it and tried another, a Leica Televid 62 with a 16-48-power eyepiece.

Ugh. I flipped that one immediately. The lack of eye relief made it miserable, and again, it’s resolution was inferior to the B&L.

Then I tried a friend’s Pentax PF, the one with the 65 mm objective and a factory 20-60-power zoom. It was close to the B&L but still not there, until …

I swapped out the factory zoom eyepiece with an 1.25-inch astronomical eyepiece. You can do that with the Pentax spotting scopes, and yes, that made a difference. With the astronomical eyepiece, an 18mm Televue Radian, the resolution was equal to the B&L.

So, I went out an bought a new (yes, new! I rarely buy new anything) Pentax PF 80A without an eyepiece, and with the Televue, I finally have a package that’s clearly superior to the B&L. Yes, I know that’s due in large part to the larger objective, and still, it’s superior.

And for someone who is target shooting – presumably, at known ranges – the loss of the zoom function is no loss at all.

Am I off base? Or should we be ditching our zooms? Or buying 60-year-old B&Ls?

Enjoy!
Dave

 

[David Buffington]

For those of you under 50, this is a B&L BALScope Sr. =)

 

[Kittitas George]

I've used a B & L Discoverer 15 to 60 power for many years. We did an unscientific and rather crude comparison with my friends expensive multi lens Pentax, we couldn't determine any difference. I see The B & L Discoverer on various websites for $200, that's what I paid for mine 50 years ago. I can see .17 caliber holes at 300 yds. with decent light. Too big for sheep hunting, but very good at the range.

 

[Schutzen2]

Are they made in Japan ?

 

[stork]

Are they made in Japan ?

Yes they are Japanese. Excellent glass. I bought an extra one just in case something ever happened to my primary.

 

[David Buffington]

I've used a B & L Discoverer 15 to 60 power for many years. We did an unscientific and rather crude comparison with my friends expensive multi lens Pentax, we couldn't determine any difference. I see The B & L Discoverer on various websites for $200, that's what I paid for mine 50 years ago. I can see .17 caliber holes at 300 yds. with decent light. Too big for sheep hunting, but very good at the range.

Perhaps I've just discounted -- or just plain forgotten -- the fact that Bausch & Lomb made fantastic optics back in the day ... and believe me, I'm not a back-in-the-day kinda guy.

Again, a note for anyone under 50 … The Bausch & Lomb of the past is very different than the Bausch & Lomb of today. Today, it's primarily a maker of contact lens products. Decades ago, its products were made in the U.S. and were seen as the equal of premium makers like Zeiss. Then, it sold its consumer optics operations to Bushnell, which gradually cheapened the brand and moved its production overseas.

Thanks!
Dave

 

[6ShotsOr5?]

Add it to the list of things to watch for at estate sales: old Colts, primers, old B&L spotters, primers, ...

 

[Kittitas George]

Perhaps I've just discounted -- or just plain forgotten -- the fact that Bausch & Lomb made fantastic optics back in the day ... and believe me, I'm not a back-in-the-day kinda guy.

Again, a note for anyone under 50 … The Bausch & Lomb of the past is very different the the Bausch & Lomb of today. Today, it's primarily a maker of contact lens products. Decades ago, its products were made in the U.S. and were seen as the equal of premium makers like Zeiss. Then, iit sold its consumer optics operations to Bushnell, which gradually cheapened the brand and moved its production overseas.

Thanks!
Dave

pib hunting west of Red BluI'm kinda a back in the day guy. All my 'modern' gopher and prairie dog guns have Leupolds on them fixed 10X to the 8.5 X25 Long range. But when headed into the Bob Marshal that pre 64 Win Mag was wearing the B & L 2.5 to 8 that I put on it that summer of '64. I use a pre '64 win 270 Win with the same scope when not in big bear country and I just changed a pre war Mod 70 25-06 form B&L 2.5 to 8 to a Leupold, gophers, prairie dogs, rock chucks and antelope. A few years back I was pig hunting west of Red Bluff, Calif. it rained and snowed all morning, I'd forgotten my scope covers. It didn't hurt that B &L one bit, dead pig. An extremely long shot 30 feet. The B & L scopes work, no reason to change. Over the years I've shot quite a few gophers and rock chucks with the 25-06 and 2.5 to 8, I just wanted more power to reach out for the prairie dogs, longest shot, so far 508 on a western Mt. gopher.

 

[David Buffington]

By the way ... In the process of reading up on this subject, I stumbled onto this website with the key to the B&L date codes:

http://www.binoculars-cinecollectors.com/html/body_bausch_lomb_prod_list.html

I now know that the BALScope Sr. above was made in 1958. Not bad for a 60-plus year old optic.

Enjoy!
Dave

 

[smoooth]

Very Interesting!

I bought a used Vortex Razor HD 27-60x85 and have been rather disappointed in the lack of resolution, especially considering the cost. Admittedly, this is my first spotter, but there is room for improvement. Pretty disappointing to hear this seems to be normal for today's spotting scopes, regardless of price.

 

[Turbulent Turtle]

Very Interesting!

I bought a used Vortex Razor HD 27-60x85 and have been rather disappointed in the lack of resolution, especially considering the cost. Admittedly, this is my first spotter, but there is room for improvement. Pretty disappointing to hear this seems to be normal for today's spotting scopes, regardless of price.

Yeah, I don't think that's reality.

 

[smoooth]

Yeah, I don't think that's reality.

Sir, would you please explain what part of my comment is not "reality"?

 

[Turbulent Turtle]

Sir, would you please explain what part of my comment is not "reality"?

I'm happy to do that.

This thread was started by the OP reporting that new spotting scopes did not seem to have the resolution that his 60 years old B&L spotting scope has.

You reported "I bought a used Vortex Razor HD 27-60x85 and have been rather disappointed in the lack of resolution, especially considering the cost." I have no issues with that, because that's YOUR impression and Vortex is not something I would ever consider using.

Then you made this sweeping statement: "Pretty disappointing to hear this seems to be normal for today's spotting scopes, regardless of price."

This is the statement that is not based on reality. Let me explain what led me to that conclusion, in the spirit of this thread. Remember the OP is talking about a 60 year old scope and that's what you replied to.

Since the dawn of optics, there has been a penalty with respect to loss of brightness at each air to glass surface. This loss is in the form of about 4-5% of the incoming light being reflected (and thus not transmitted any further) every time there is a change in medium. By this, I mean going into glass, or going into air. Usually a lens has two sides and so the light loss is almost double for each lens. In another thread, I explained how to calculate the overall light transmission using the number of faces. Up until the late 1960s, that was the way of the world.

Around 1969, Nikon invented lens coating. A lens coat is a very thin film of material deposited on the surface of the glass that prevents light from reflecting off that surface. The issue is that a specific lens coat reduces the reflectivity of the light but only for a specific wavelength; in other words, a color. Applying one coating would enhance that wavelength to the sensor (your mark 1 eyeball, for instance) and thus give the impression of a tint. This has the effect of messing with the true colors of the object, plus it only reduces the reflection a very small amount since all the other colors would be getting 5% reflected.

To compensate for that, manufacturers apply multiple coatings to the glass, to cut down the reflection loss for as many colors as possible. I do not know the size of bandwidth addressed by each coating and I do not know exactly how many coats are required to reduce the overall reflectivity loss and bring up the transmission rate to about 99.5% for each surface, which I understand is about the best possible.

The lens coating process hit the photography world early on in the 1970s and 1980s. In those days, I was a camera fiend and I read every magazine that I could get my hands on dealing with the subject. The coatings were the rage. You had: coated lens, which meant one coat on one side; multi-coated lens, which meant multiple coats on one side or one lens; fully coated lens, which meant all faces in the optics had one coat; and finally, fully multi-coated, all lenses with multiple coats. Even with that, we had some brands that tended warm, or cold, of greenish tints and so on and so forth. Lots of competition and fast-paced innovation. This coating technology was also used in sports optics, which is in what we are interested.

Optics prior to fully multi-coated lens seem dull, with washed out color and low contrast. The light loss is in the order of 50% or more. One way manufacturers made up for that was to have genormous objective lenses.

Another innovation, again by Nikon, around the same timeframe was ED glass, Extra-low Dispersion glass. This ED glass approaches the quality of Fluorite crystal glass to refract all wavelengths together instead of spreading them out a little creating what we call chromatic aberration, a fancy term that means "spraying the colors around." This type of glass was first used in riflescopes about 12 years ago by March. I do not know for sure when it started being used in spotting scopes, but it was before that, albeit not so many years before that.

Camera lenses and spotting scopes are not subject to the same continuous pounding that is experienced by riflescopes, so the use of pure fluorite crystals is not rare in their construction. Indeed Kowa has a brand called the Prominar that makes us of fluorite crystals lenses. It's price is breathtaking, just like its IQ. Several other manufacturers offer spotting scopes with Fluorite crystal, ED or even Super-ED glass in them. Names like Leica and Zeiss offer Fluorite glass spotting scopes. Nikon has some with ED glass, as you would expect. The benefits of this type of glass is better color rendition, better contrast and yes, better resolution.

The advances in optics, with regard to glass material, coatings, and yes, manufacturing methods, have provided us with spotting scopes that are so far and beyond where the state of the art was even just 10 or 20 years ago, let alone 50 or 60 years ago.

Optics is a competitive field and I seriously doubt manufacturers are willing to go backwards in optical development. Now, if you get optics from the bottom of the barrel, all bets are off, and simply disregard what I just wrote.

 

[gdbleb]

Very nice write up. Thank you Denys.

 

[msinc]

................"Up until the late 1960s, that was the way of the world."..............."Around 1969, Nikon invented lens coating............."

Yeah, I don't just think this is not reality, I know it is not!!!! Seriously???? Nikon invented lens coating in 1969???? You are joking right???? Nevermind, just have a look at lens coatings in Wikipedia.
This thread will explode in 3,2,1.........

 

[Turbulent Turtle]

Yeah, I don't just think this is not reality, I know it is not!!!! Seriously???? Nikon invented lens coating in 1969???? You are joking right???? Nevermind, just have a look at lens coatings in Wikipedia.
This thread will explode in 3,2,1.........

I broke rule #2, writing that long post in between conference calls, meetings, piecemeal over 9 hours. I didn't even proofread it before hitting Post Reply. So, I conflated things. Yeah, Nikon didn't invent coatings in 69, that was ED glass. However Nikon has long been a leader and innovator in optics. I'm a big fan of their cameras and have been ahooting with Nikon for ages. By shooting here, I mean taking pictures, photography.

 

[msinc]

I broke rule #2, writing that long post in between conference calls, meetings, piecemeal over 9 hours. I didn't even proofread it before hitting Post Reply. So, I conflated things. Yeah, Nikon didn't invent coatings in 69, that was ED glass. However Nikon has long been a leader and innovator in optics. I'm a big fan of their cameras and have been ahooting with Nikon for ages. By shooting here, I mean taking pictures, photography.

I understand. I also admire a man that is man enough to admit when he makes a mistake.

 

[PA.Frank]

I too am a fan of the Balscope Sr made in Rochester NY I buy them every time I see one available for a reasonable price and have owned at least 5 of then of various vintages. I still have one with a 30X eyepiece and its my go-to scope for the range.. The only other scope I have seen that exceeds the resolution of the Balscope is a Kowa. I have one of them too 27X eyepiece on a TNS721