Binoc's - individual v. center focus - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Gear & Maintenance
 Not a Member? 
  #1  
Old 09-01-2009
mstern's Avatar
Senior Member
 
Join Date: May 2002
Posts: 659
Thanks: 6
Thanked 7 Times in 6 Posts
Rep Power: 13
mstern is on a distinguished road
Binoc's - individual v. center focus

I was using my binoculars last night on a lovely after work sail, and I got frustrated enough to finally ask for some advice. I have a pair of waterproof West Marine binocs. Nothing fancy, no built in compass or anything, just your standard, rubber housed binocs. I got them as a gift, but find that I rarely use them. Why? Because focussing them is such a pain in the ass. Each eyepiece focusses independently, and it is such an effort to do so that I can't believe I'm doing it correctly.

For example, if I am using my small center focus binocs, I must focus on the object I want to view. This is easy to do by spinning the center control. However, I find doing this same thing with the individually focussed eyepieces is almost a never ending effort; it seems that every change on one side leads to the need for changes on the other, which again leads to changes back on the first, etc. I never get it right. When I try to roll both eyepieces simultaneously, it never leads to a focussed view.

Am I doing something wrong, or does everyone else have the same issues as me? If this is really just my inability to do a simple task that others have mastered, I am ready to use my non-waterproof binocs on the boat until I get a new pair of centerfocus waterproof binocs. But before I throw in the towel, I'd like to hear from the collective group. Any help?
Reply With Quote Share with Facebook
  #2  
Old 09-01-2009
CalypsoP35's Avatar
Senior Member
 
Join Date: Jul 2006
Location: Cape Cod
Posts: 321
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 9
CalypsoP35 is on a distinguished road
I have a similar pair binocs and have the same issue. I was under the impression that independent focus was supposed to be the better method, but I agree I think its more of nuisance than an advantage.

I'll probably get a new pair of binocs this winter. Anybody have any suggestions? Nothing too extravagant, maybe in the $200 range.

Last edited by CalypsoP35; 09-01-2009 at 02:39 PM.
Reply With Quote Share with Facebook
  #3  
Old 09-01-2009
TaylorC's Avatar
S/V Loon
 
Join Date: May 2008
Location: Seattle & Whidbey Island
Posts: 61
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 7
TaylorC is on a distinguished road
sport focus

My understanding was that the individually focused eye pieces make binoculars easier to waterproof and has fewer moving parts for higher reliability.

I have a pair with individual focus, and I never need to refocus them, unless I'm looking at a object that is less than about 30 feet away (or a child resets them.) I sometimes see binoculars like this called 'sports focus', and apparently they are good for marine use because they are good for about 30 feet and beyond, but not so good for things closer.

I think it comes down to depth of field, which is the range from far to near that things are in focus. More depth of field means you don't need to refocus as often. You want to pick up and be in focus from infinity and foward to some distance closer too you. In cameras (and thus I assume binocs) depth of field is related to your f-stop, which is the relationship between the size of the exit and focal length of the lens- basically larger f stops numbers (smaller appature) gives you greater depth of field. I'm not exactly sure how to calculate depth of field in binoculars.

For what's its worth, I've had it with cheapo binocs, I bought good ones and I'm sticking with them, they are a joy to use every time I pick them up. I use Fujinon FMTRC-SX, pretty much their top of the line 7x50.

In your case, you might try messing with the focus to get a general focus from infinity down and see if that reduces the number of times you need to refocus.
Reply With Quote Share with Facebook
  #4  
Old 09-02-2009
Member
 
Join Date: Jan 2008
Location: West Chester, PA
Posts: 42
Thanks: 1
Thanked 0 Times in 0 Posts
Rep Power: 0
davmarwood is on a distinguished road
Binocs

Two years ago I bought 7/50 Celestron binocs with integral illuminated compass. They have individual focus, and, for my money, this is the way to go. As long as the captain and only the captain uses them, they are fast, and clear. Individual focus is actually an advantage as long as you don't have other people using the binocs. Once they are focused, you don't need to fuss around with them, just bring them up to your eyes and you are instantly focussed. Additionlally, as suggested in earlier posts, the lack of center focus makes sealing and waterproofing of the binocs more effective.
Reply With Quote Share with Facebook
  #5  
Old 09-02-2009
Senior Member
 
Join Date: Mar 2006
Location: VA
Posts: 2,008
Thanks: 1
Thanked 2 Times in 2 Posts
Rep Power: 9
PalmettoSailor will become famous soon enough
Quote:
Originally Posted by davmarwood View Post
snip... They have individual focus, and, for my money, this is the way to go. As long as the captain and only the captain uses them, they are fast, and clear. Individual focus is actually an advantage as long as you don't have other people using the binocs. Once they are focused, you don't need to fuss around with them, just bring them up to your eyes and you are instantly focussed. snip
That's only partially true, but does apply at longer distances. However, if you want to look at something closer, you'll have to refocus.

I have a pair or Steiner Military 8x30's with individual focus that I've had for 20+ years including 10 years use in the military. They are fine on land, but since focusing them takes both hands, even if just for a second, I decided center focus was a must have for use on the boat.
__________________
PalmettoSailor
s/v Palmetto Moon
1991 Catalina 36
Reply With Quote Share with Facebook
  #6  
Old 09-02-2009
October Moon B43
 
Join Date: Mar 2009
Location: SE Pennsylvania
Posts: 400
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 6
MJBrown is on a distinguished road
I have a pair of Tasco 56's that I bought at the Annapolis show a number of years ago. At the time they cost somewhere in the $230 range. Ruby coated lenses for better low light and haze penetration as well as a built in compass. They're center focus and their depth of field is so great that there's no need to focus unless the subject is in close. In that case I generally don't need to use them. Not sure if they still market them as I haven't seen them for sale recently. They also had a cheaper pair for around $200.
Reply With Quote Share with Facebook
  #7  
Old 09-03-2009
mstern's Avatar
Senior Member
 
Join Date: May 2002
Posts: 659
Thanks: 6
Thanked 7 Times in 6 Posts
Rep Power: 13
mstern is on a distinguished road
Thanks to all for the input. I am going to make one more attempt to focus my binocs along the lines of the advice I have been given here and on another site. After that, I go with the centerfocus model, and the kids have something to buy me come holiday season.
Reply With Quote Share with Facebook
  #8  
Old 09-04-2009
hellosailor's Avatar
Plausible Deniability
 
Join Date: Apr 2006
Posts: 10,415
Thanks: 1
Thanked 74 Times in 72 Posts
Rep Power: 10
hellosailor has a spectacular aura about hellosailor has a spectacular aura about
As Taylor said. The only reason for individual focus is that it makes the binocs significantly cheaper, and part of that cost is cheaper to waterproof them.

With *most* "marine" binocs you focus them once at 100 yards or so, then adjust one eyepiece for any diopter difference between your eyes, if you have one. Now mark that eye ring and tape it down so it doesn't move, if you're the only one using it. Or put a spot of white-out on it.

The binocs should have enough depth of field so you don't need to refocus them at all in normal use. If you're busy changing the focus to check out things on your own bow...that's another matter. For "at sea" you should rarely need to refocus.

And if you can afford better glass...it can be pricey but worth it.
Reply With Quote Share with Facebook
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
What can you tell from the numbers? brazilnut Boat Review and Purchase Forum 10 07-01-2009 04:09 PM


All times are GMT -4. The time now is 11:37 AM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012