Help settle a debate

[Robert Ellis]

A Milwaukee birding pal and I have been having an "arguement" about our bins. It is not about whose make is better, but about the configurations.

Our forest/general bins are in the same price range, but I use 8x32 and 7x42, both of which work great for general birding. The debate comes when I am visiting and we wander to the edge of the reserve and find ourselves on the shore of Lake Michigan. I rarely have luggage space to drag my scope with so we use what we have on the migrating waterfowl and shorebirds.

Here is the debate. I contend that his 7x42s are the better of the two when presented with distant birds seen when at the shore for sake of the larger aperture giving more detail over distance. He would prefer to use my 8x32s because of the slight magnification advantage.

It is not important if I am right or he is, but we thought we would invite others into the debate. Thoughts?

[dwalton]

A Milwaukee birding pal and I have been having an "arguement" about our bins. It is not about whose make is better, but about the configurations.

Our forest/general bins are in the same price range, but I use 8x32 and 7x42, both of which work great for general birding. The debate comes when I am visiting and we wander to the edge of the reserve and find ourselves on the shore of Lake Michigan. I rarely have luggage space to drag my scope with so we use what we have on the migrating waterfowl and shorebirds.

Here is the debate. I contend that his 7x42s are the better of the two when presented with distant birds seen when at the shore for sake of the larger aperture giving more detail over distance. He would prefer to use my 8x32s because of the slight magnification advantage.

It is not important if I am right or he is, but we thought we would invite others into the debate. Thoughts?
IMO, in daylight I'd prefer the 8x and the additional magnification.

Doug

[RAH]

Although they claim that more magnification doesn't matter as far as resolving fine detail (the quality of the optics is the most critical thing), given the choice, I'd take the higher magnification over the larger aperture. I'm not even sure if "larger aperture giving more detail over distance" is true. I've always thought that the advantage of a larger aperture was in light-gathering, useful for low-light conditions.

However, having said that, viewing over long distances has so many other problems (bad "seeing" being the main one), I doubt that either binoc would have much advantage over the other.

[henry link]

Consider that in bright daylight the eye will be closed to 3mm or less, so any 7X bin will effectively be a 7X21 and any 8X will be an 8X24. Given "perfect" optics the 7X will have resolution of 5.5 arc seconds and the 8X will actually be better at 4.8 arc seconds. Multiply those figures by the magnifications and you get 37.5 and 38.4 arc seconds; the resolution of the two bins as seen by the eye. The human eye's resolution in bright light is usually given as 60 arc seconds, so the image in both binoculars will contain more detail than the eye can see. More of that detail should be visible in the 8X than the 7X simply because the image size is larger. The situation is then complicated by the tremors of hand holding which might give the 7X a little advantage and slightly close the gap. The stopped down 7X42 also has a possible optical advantage from effectively becoming a slower optical system than the stopped down 8X32 (about f/8 vs about f/5.3 if both have f/4 objectives), so it's aberrations should be lower producing a bit cleaner image. Ask a simple question and you open a Pandora's Box of unwanted complications. Finally you'll just have to try them and see, but my money is on the 8X32.

[Robert Ellis]

Well stated Henry. What would you say for cloudy/rainy days. I can't control the weather when I travel.

[henry link]

Well stated Henry. What would you say for cloudy/rainy days. I can't control the weather when I travel.

Robert,

We just happen to have such a day here today, so I did a quick comparison between a Nikon 8X32 SE and a Nikon 7X50 Prostar, two bins of approximately equal optical quality and close to your configurations. I focused on tree branch details in a dark area of woods about 500 ft away, the longest distance I could manage.

Hand held I could make out slightly more detail with the 8X32. With the binoculars tripod mounted there was considerably more more detail visible in the 8X32. Given equal quality optics I doubt that a 7X of any aperture will show as much detail as a 8X30-32, even under quite dark daylight conditions.

Henry

[Robert Ellis]

Gracias Henri.

[marcus]

Do you see several species of shorebirds by Lake Michagan? You may want the stronger one to determine the differences in them.
You know, what RAH said up there is true, that over long distances neither one of them would likely be better than the other.

[kabsetz]

Marcus,

There is no reason why higher magnification would not be an advantage over long distances also.

Kimmo

[marcus]

Hello Kimmo,
Higher magnification an advantage over long distances? I thought that what I was saying!
I guess I need to check out what RAH really said.
Wait a minute. Now let me get this right.
'There is NO reason why higher magnification would NOT be an advantage over long distances...' 'also.'
I don't recall saying that higher magnification would not be an advantage over long distances. What I meant to express in my first message is that over long distances higher magnification would be better. I apologize if you got something else out of the message.

[marcus]

Oh, I see. I just read my first message again and saw what I wrote about over long distances probably neither magnification would be better. I guess I just should not have written that.

[Grousemore]

The English language from Finland seens eminently more understandable than that emanating from the USA ;)

[Atomic Chicken]

The English language from Finland seens eminently more understandable than that emanating from the USA ;)


Precision in the use of language implies precision in thinking. Perhaps many Americans are forgetting how to think? ;)

Best wishes,
Bawko

[marcus]

OK, Trevor, Bawko. I'm sorry.

[Swissboy]

Precision in the use of language implies precision in thinking. Perhaps many Americans are forgetting how to think? ;)

Best wishes,
Bawko

The problem is that you are FORCED to be more precise in your thinking when you try to say something in a foreign language. This is often apparent in German speaking parts of Switzerland. Our dialects are so different from standard German that they are basically another language. And sure enough, it is often easier for us to understand what another German speaking Swiss person really wants to say when that person explains it in standard German rather than using his/her actual mother-tongue dialect.