Individual focusing, why? (1 Viewer)

[jzmtl]

Just wondering, why are some brand still use individual focusing predominately on some models with all the advances in central focusing?

I was looking at steiner binoculars and pretty much all their big porros, marine, military, police, all use individual focusing.

 

[gulf1263]

It works to seal better.
Military binoculars are required to remain water proof under more stringent conditions as to depth, contaminates in the water and conditions of vibrations.
Looking at the US Navy specs it is evident that they are much more stringent than for the Japanese Class 7.
The bino's are much more durable than the troops in many situations.
Take the binocular up to 45,000 feet at minus 40 degrees F and then move it to plus 120 degrees F and then submerge it to 33 feet.
Those are some of the specs along with being immune to a chemical cocktail that the bino is submerged in while being vibrated at a certain frequency and speed.
Tough to water proof center focus to those specks.
Art

 

[Dennis Mau]

It works to seal better.
Military binoculars are required to remain water proof under more stringent conditions as to depth, contaminates in the water and conditions of vibrations.
Looking at the US Navy specs it is evident that they are much more stringent than for the Japanese Class 7.
The bino's are much more durable than the troops in many situations.
Take the binocular up to 45,000 feet at minus 40 degrees F and then move it to plus 120 degrees F and then submerge it to 33 feet.
Those are some of the specs along with being immune to a chemical cocktail that the bino is submerged in while being vibrated at a certain frequency and speed.
Tough to water proof center focus to those specks.
Art

Also, for Astronomy IF binoculars hold focus better, they have more diopter range(for people who don't want to wear glasses) and they are more precise.

 

[dalat]

Some binocular uses that mainly require looking at things far to very far away, (military, marine, astronomy, some type of hunting) don't require focussing a lot, so centre focus is not really needed, IF is enough. And IF is simpler, cheaper to make, more rugged.

Central focus is mainly needed for birding and all-round use binoculars.

 

[typo]

Some binocular uses that mainly require looking at things far to very far away, (military, marine, astronomy, some type of hunting) don't require focussing a lot, so centre focus is not really needed, IF is enough. And IF is simpler, cheaper to make, more rugged.

I can't say I've tried many, but I'd also suggest sharper and brighter than comparatively priced roofs.

David

 

[Pinewood]

I can't say I've tried many, but I'd also suggest sharper and brighter than comparatively priced roofs.

David

David,

I think you are writing more about the differences between Porro and roof glasses. Both Nikon and Zeiss made IF roof glasses, called the Trailblazer and the Safari, respectively. They looked rather alike and by today's standards would be dim and lacking in contrast.
Incidentally, internal center focussing binoculars, practically standard in today's roof binoculars, have a slightly higher tendency towards chromatic aberration.

Happy bird watching,
Arthur Pinewood :hi:

 

[typo]

Arthur,

Of course you are right the IF shouldn't make a difference vs. a c.f. porro but two I tried recently, the Opticron M-3 Marine 8x30, the Steiner Commander 7x30, and the Chinese 12x50 I own have particularly impressed compared to mid range roofs and the cf porros I've managed to try. (There are still a few I hope to track down though.) For non-birders I feel they are worth considering. Now you mention it the CA control did seem very good for non-ED binos.

David

 

[steve@37n84w]

Arthur,

Of course you are right the IF shouldn't make a difference vs. a c.f. porro but two I tried recently, the Opticron M-3 Marine 8x30, the Steiner Commander 7x30, and the Chinese 12x50 I own have particularly impressed compared to mid range roofs and the cf porros I've managed to try. (There are still a few I hope to track down though.) For non-birders I feel they are worth considering. Now you mention it the CA control did seem very good for non-ED binos.

David

David

What did you think of the Opticron Marine 8x30? Also was it manufactured in Japan?

Steve

 

[typo]

David

What did you think of the Opticron Marine 8x30? Also was it manufactured in Japan?

Steve

Steve,

I was very impressed. Huge sweet spot, with a gentle field curvature and only a mild softening at the edges. CA control was very good 'till the last 10%. Colour was good with the whites looking white, but maybe a slight dip in the green. Couldn't find any glare problems. Winding in the eyepieces got me to around 12ft. I thought it very sharp. It is Chinese but very well built as far as I could judge, though there was an uncomfortable ridge in the armour that I think I'd want to trim. My guess it's essentially the same as the General Hi-T Holger reviewed in 2006 but there could have been updates in the meantime.
http://www.holgermerlitz.de/ares8x30.html

David

 

[jzmtl]

Some interesting points, I thought about ruggedness but didn't think they'd need more waterproofness, and not needing refocus often.

 

[berryns]

My take on IF binoculars

I often use IF binoculars for birding and viewing wildlife. Currently I own two IF binoculars: Steiner 8x30 predator and the Zeiss 8x30 Safaris.

Mostly, I use the IF binoculars for hunting and birding in the fall and winter when 95% of wildlife is 50m or more. I like the set and forget function of IF binoculars and in general I find the depth of field and ease of viewing to be exceptional. For example, my 8x30 Olive B/GA safaris are much easier to use than my Zeiss 8x30 B/GA T*P Classics, even though the 8x30 T*P Classics have sharper image and wider FOV.

 

[OPTIC_NUT]

From a reliability and aging point of view, cleaning up old waterproof common-focus
binocs can a be a real pain. So many wiping parts to clean and re-lube, for
balanced torque on the focuser. Separate sets of o-rings, silicone, and
direct fine threads are so much smoother and crisper over time.

 

[Simon S]

Rugged, waterproof and on good models once set not easy to knock.

 

[chartwell99]

Rugged, waterproof and on good models once set not easy to knock.

Wow - that's an astounding collection of genuinely interesting binoculars. My wife has been fussing about my meager by comparison assortment of binoculars for years and your collection should be a real help establishing perspective.

 

[OPTIC_NUT]

The earliest Occupied-Japan binocs were frequently independent focus.
7x50s and 6x30s are very common. They both vary from maker to maker in
view quality. The Kendon 6x30s I got are super, but that could have been
the product of slumbering in the back of a dark dry closet for 60 years.

 

[Simon S]

Wow - that's an astounding collection of genuinely interesting binoculars. My wife has been fussing about my meager by comparison assortment of binoculars for years and your collection should be a real help establishing perspective.

Thanks, a lot of people have used my collection to assure their partners they are sane.