Binocular advice

johnalison said:
doug748 said:
Just one proviso.

On another bino thread someone said that old gits can only dilate their eyes a little bit, so 7 * 50 would be a waste, 7 * 30 would do the job just as well.
QUOTE]

Not really.

Although 7x30 would give an exit pupil of 30/7 which is 4 point something. You would get less overall light (by a factor of 30 squared/50 squared).

The point of 7x50s is that the eye viewing can accommodate, so that the full light-gathering power is only apparent at lower light levels and is not dazzled in bright light. It may be that old fogeys like me have smaller dilated pupils, but going into the Dovetief channel last year when it was almost dark, with a mixture of lit and unlit buoys, I was extremely grateful for my trusty old 7x50s
Click to expand...
But if your pupils can only dilate to 4mm then you would have seen just as well with 7x30 bins because your eye is only passing the central 4/7ths of the light from the bins anyway ?

Boo2
Click to expand...
 
Seajet said:
When one considers the actual use & hard knocks,water - salt & condensation - etc seagoing bino's take, only a previously rich idiot will use something more exotic with a famous name.

7 X 50 seems ideal for a magnification -7- one can hold still, and max' normal light gathering - 50-.

I find an inbuilt compass invaluable, then I'm the sort of dinosaur who values hand bearing fixes to keep in touch should the GPS fail and for crew training.

When I worked at a chandlery briefly we were selling completely functional Tasco binoculars, when a total prat came in, " 'aven't you got any quality, Leica's ? "

My reply was he clearly hadn't been sailing...
Click to expand...
I have been sailing, in fact full time, for the last 5 years. I must be a Prat or rich idiot, because I do own a pair of Leica binoculars.
I compared them before purchase with Steiner etc and they were much superior The optical quality in low light is amazing.
If I ever drop them overboard there will be serious MOB drill, but they will probably outlive me.
The cost is high, but no more than say a chart plotter, arguably more useful and certainly more durable and future proof.
If you are in the market for binoculars, at any price level, have a look through some high end binoculars, at least you will know what us rich idiot prats can see.:)
 
Get your credit card on red alert

Aren't the imagination and ego wonderful things !

I notice my experience with ' money no object' military systems is swept aside...

If taking photo's - and that's something I forgot to mention, as well as compass equipped yacht standard bino's ( which normally incorporate a rangefinder for at least rough fixes when the GPS is down ) , might offer image stabilisation, night vision and now digital camera ability - if that isn't enough to bankrupt one, GPS in the viewfinder and position printed on the image ( anyone else here a fan of NCIS ? ! ) is now a reality...

Call me old fashioned, I thought bino's were to see things a way off, and a compass added was spiffing !
 
Last edited:
Steiner vs Steiner

One for Sailorman, poss, please.

Is there any reason that I should consider Navigators rather than Commanders, 'when the time comes' ?

Ignoring the seemingly horrific price difference.

I have always tried to buy the best quality tools , or at least starting with' show me the best and lets see if its worth downgrading from that benchmark....' and of course in the long run they are usually cheaper, quieter and superior in performance.

BUT, not clever enough to understand the difference with binos, despite Googling. Currently have Fujinon 7x50 with compass but the old eyes, ya know...
 
Rigger Mortice said:
That doesn't make sense to me. I would have thought that if the binoculars are getting more light to your eyes then you will get a better image however much your eyes are dilated.

I'm happy to be shown to be wrong......:)
Click to expand...

It is true that the more light that binoculars pass, the brighter the image, though the magnification will affect this. However, in normal use on a bright day, the image from 7x50s is too bright for comfort and the pupils will contract just as in non-binocular use and the image may appear less bright than a pair of 8x40s.

If you compare the two at dusk, then only with the 7x50s can the eyes get more light by dilating, when light from the full aperture of 50mm becomes available.
 
johnalison said:
It is true that the more light that binoculars pass, the brighter the image, though the magnification will affect this. However, in normal use on a bright day, the image from 7x50s is too bright for comfort and the pupils will contract just as in non-binocular use and the image may appear less bright than a pair of 8x40s.

If you compare the two at dusk, then only with the 7x50s can the eyes get more light by dilating, when light from the full aperture of 50mm becomes available.
Click to expand...

I am afraid the theory is not quite right.
BTW The eye varies pupil size more to optimize the image quality for the brightness level. The adaptation to different light levels is due mainly to changes in the retina. Pupil size plays only a very small role.
Probably more than you wanted to know in a sailing forum.:)
 
It can take minutes for the retina to adapt, so for the few seconds that I use binoculars I suspect that my pupils do most of the work. The larger exit pupil of 7x50s no doubt allows the pupils to carry out their normal image function as well.
 
It takes the retina a long time to adapt to the enormous illumination differences between daylight and starlight, but the much smaller differences when you look through binoculars or come in doors happen rapidly, otherwise we would bump into things.

Get someone to measure your pupil size outside and then inside. You will find the difference in pupil area is much too small to adapt to the change in illumination levels The retina does most of the illumination adaptation..

The larger exit pupil of 7x50s is a help, however, in low illumination because it allows the most light to get to the retina.
You have be young to get enough dilation to have a 7mm diameter pupil (The exit pupil size of 7X50), but the larger exit pupil size allows for some misalignment and 7X50 is a good choice on board a yacht where the size and weight of binoculars is not a great problem.
 
noelex said:
You have be young to get enough dilation to have a 7mm diameter pupil (The exit pupil size of 7X50), but the larger exit pupil size allows for some misalignment and 7X50 is a good choice on board a yacht where the size and weight of binoculars is not a great problem.
Click to expand...


Could a pair of 7 * 40 be a better compromise for the old boy seeking a more compact, general use pair? What do you think?
 
doug748 said:
Could a pair of 7 * 40 be a better compromise for the old boy seeking a more compact, general use pair? What do you think?
Click to expand...

7X50 will let in more than 50% more light than 7x40, but your eye also has have to have a wide enough pupil to let in this extra light.
Try measuring your pupil size under dim conditions. The easiest way is take a digital photo. If your maximum pupil diameter is under 6mm you are unlikely to notice much difference.
Binocular quality also makes a big difference in the low light capabilities so comparing the models is often more helpful than just predicting their theoretical performance.

I use an 8X50 pair.
 
I won a pair of Steiner Commander Vs in one of Cunliffe's YM competitions. They are very very good though there are a few drawbacks - The lens protectors are a bit of a fiddle, re-focussing for other users is awkward because of the separate-eyepiece adjustments. The 'auto focus' (actually fixed-focus with good depth of field) works well beyond about 20 yds so not too good for bird watching. Also the compass is difficult to see and means a lot of peering around to bring it into the field of view.

I originally bought a pair of Canon 10x30 IS. They are brilliant on land but I find them useless at sea as the large movements are beyond the mechanism's ability to compensate. Some people find they are good but maybe my boat moves too rapidly for them. The biggest snag with them is that if they are laid down on there backs or anything is put on top of them, the activation button will be held down and the batteries flattened very quickly.
 
Snowleopard, thanks for the info ESP re ( lack of) image stabilisation range on Canon and D of F on Steiner. I could live with 20yds but do use the bearing compass most.
 
doug748 said:
Could a pair of 7 * 40 be a better compromise for the old boy seeking a more compact, general use pair? What do you think?
Click to expand...

I actually prefer 7x35 or 40 or 8x40 on board, but I tend to cycle binos through house (we see the harbour from 2 rooms, so 2 pairs), then when the boat ones get bashed or otherwise wrecked I get another pair for the house and move one onto the boat.

Despite my preference for lighter 7x35 or 40 on board the boat the next pair going to the boat will be a ridiculously heavy but ultra-sharp pair of Russian 7x50s - bought them (couldn't not do so) for £10 at a car boot sale.
 
Boring answer: I have a pair of Bushmaster 7x50 binoculars with a built-in compass which cost approx £100. They work pretty well.
 
I have Tasco 7x50's with compass and like them very much.

Pulling two things already said together (a) lens coatings make a huge difference - they are not a gimmick (b) go to the shop at twilight to try the binos - you'll see the difference between them far better.

Pompous bit --->

The myth that pupil dilation is a major contributor to light gathering.

It's true that you might as well have your pupils wide open in dim light, but their effect is a tiny fraction of what's needed.

You can work it out from photography.

You can see in situations where you'd shoot 1 minute at F2 on ISO100 (ok not much colour, but rod vision).

You can see when you shoot 1/2000 at F32 (actually probably brighter)

That's a difference of 19 stops! i.e. a change in brightness by a factor of 2 to the power 19. (If I did my sums right.) The change in the pupil is a infinitesimally small fraction of this. The change in aperture does however produce a noticeable change in depth of field.

When you are in a bright light the retinal pigments bleach out meaning that the retina is not as sensitive to light. It takes them some time in dimmer light to recover. The recovery gets slower as you get older.

---end of pompous bit.
 
Bosun Higgs said:
I bought myself a set of the Canon image stabilised . Not the answer to a maidens prayer but a definite advantage over non stabilised. The image difference is between being able to read a big ship name and not doing so, ditto buoy topmarks, buoy names and the ubiquitous " is that big bugger anchored or under weigh?" And the other advantage is that they make using a higher magnification practical - so mine are 10x not 7x.

That said they do not iron out all boat movement by any means.

No compass of course but then I prefer the Personal compass for Autohelm.

I suppose the acid test is would I buy the same again and the answer is yes. Though I might go a bit more up the price bracket for even more stabilisation. Bought at SBS - the something camera company. London I think.
Click to expand...

I bought a pair of Bushnells with a compass - see this
http://www.bushnell.com/products/binoculars/marine/137500/

The optics are very good, but the compass is a complete waste of time, in anything of a seaway the compass is unreadable. Like others I have gone back to using my old flat digital Autohelm compass. I don't know weather or not the digital version is any better at sea but was very difficult to read.

I have often wished that I had paid a little more and got an image stabliser pair - that illusive ship name that I can see but not read....
 
You must log in or register to reply here.

Share this page

Top