Daytime benefit of large objectives? (1 Viewer)

denco@comcast.n · Apr 10, 2018

Tenex really summarized the advantages of large apertures well. This is my subjective list of the things I observed using a big aperture binocular based on comparing them to binoculars of different apertures. I am not saying you will find these same things to be true. These are just what I noticed.

1) Clean, transparent aberration free image.

2) Very good control of flare.

3) Very good control of CA.

4) Comfortable to use because of big exit pupil.

5) Very good low light performance.

chill6x6 · Apr 10, 2018

tenex said:
No, of course it's not included. The SLC attaches to the accessory wagon's built-in tripod by the center hinge, you just pry off the little hawk cover tab and push it into the slot on the wagon for safekeeping. Neat, but pricey.

Yes, this is not only the reason I don't mind a 10 ft or so close focus, but also why I use the 6 ft on my 32mm fairly seldom (though it's cool when I do), and part of why I prefer 10x to 8. I suppose if I traveled to Costa Rica it might be a different story...

HAHA! I really did LOL!!!

chill6x6 · Apr 10, 2018

[email protected] said:
Tenex really summarized the advantages of large apertures well. This is my subjective list of the things I observed using a big aperture binocular based on comparing them to binoculars of different apertures. I am not saying you will find these same things to be true. These are just what I noticed.

1) Clean, transparent aberration free image.

2) Very good control of flare.

3) Very good control of CA.

4) Comfortable to use because of big exit pupil.

5) Very good low light performance.

So here's my question...

So suppose you have a SV 8.5X42 Field Pro at hand. Latest model. BTW the focus adjustment on mine is pretty dang good!

Ok.... So you think the view is worth the 13.7 ounces increased weight and bulkier dimensions over a SV 8.5? OR 15 ounces better than a SLC 8X42?

denco@comcast.n · Apr 10, 2018

chill6x6 said:
So here's my question...

So suppose you have a SV 8.5X42 Field Pro at hand. Latest model. BTW the focus adjustment on mine is pretty dang good! Ok.... So you think the view is worth the 13.7 ounces increased weight and bulkier dimensions over a SV 8.5? OR 15 ounces better than a SLC 8X42?

That is a very good question. IMO it would depend if you are hiking a good distance or not. From a static position and especially in low light say observing shore birds it might be worth it to carry the big glass but if you are hiking all day in the mountains it probably wouldn't be. That is why I just picked up an SLC 8x42 on Ebay. For hiking all day especially uphill in the mountains. I get it on Thursday. I will let you know what I think of it and how it compares to the SLC 8x56. The SLC 8x56 is not as good of an all around glass as the SV 8.5X42 obviously because not too many birders want to carry the weight but optically I feel the bigger glass would have the edge.

denco@comcast.n · Apr 10, 2018

"Yes, this is not only the reason I don't mind a 10 ft or so close focus, but also why I use the 6 ft on my 32mm fairly seldom (though it's cool when I do), and part of why I prefer 10x to 8. I suppose if I traveled to Costa Rica it might be a different story."

I have been to Costa Rica, Monteverde Rain Forest and I never needed that close of a focus. Most of the birds were at a good distance or high in the canopy. Always at least 20 feet away or more. In fact you need a spotter a lot of the time.

chill6x6 · Apr 10, 2018

[email protected] said:
That is a very good question. IMO it would depend if you are hiking a good distance or not. From a static position and especially in low light say observing shore birds it might be worth it to carry the big glass but if you are hiking all day in the mountains it probably wouldn't be. That is why I just picked up an SLC 8x42 on Ebay. For hiking all day especially uphill in the mountains. I get it on Thursday. I will let you know what I think of it and how it compares to the SLC 8x56.

You'll like it!

I'm gonna head to Dauphin Island this weekend....migration is about maxed out right now. The new model SLC 8X42 will be my main binocular.

chill6x6 · Apr 10, 2018

[email protected] said:
"Yes, this is not only the reason I don't mind a 10 ft or so close focus, but also why I use the 6 ft on my 32mm fairly seldom (though it's cool when I do), and part of why I prefer 10x to 8. I suppose if I traveled to Costa Rica it might be a different story."

I have been to Costa Rica, Monteverde Rain Forest and I never needed that close of a focus. Most of the birds were at a good distance or high in the canopy. Always at least 20 feet away or more. In fact you need a spotter a lot of the time.

I agree. 10 feet is plenty for me. ALL 42mm Leica UVHD+ have CF of about 10ft. SLCs are the same. I've never had a problem birding with any of them.

Troubador · Apr 10, 2018

tenex said:
Comfort of a bigger exit pupil? Definitely. Probably even more important with shaky hands.

Brighter view? It depends; thicker lenses don't help. With mirrorless prisms, maybe. And perhaps more as a peripheral effect than on axis, thanks to the larger EP minimizing vignetting. Then again, there's Nagler's reasoning about the brightest possible image even if your pupil doesn't accommodate all of it... I'm still confused about this. In any case, any difference is nowhere near as obvious as in lower light.

Better view of shadow areas? Maybe, if those areas occupy the whole visible field allowing the pupil to dilate further. In more mixed light, probably not.

Better resolution? Maybe, but not due to diffraction limits (that's your own pupil). More likely because you're stopping down a large objective to its central portion where aberrations are better controlled.

Better color detail? Some claim that this is an even more obvious advantage than greater resolution, but I haven't heard a plausible explanation for it yet given the limit of one's own pupil. (Or does this get back to Nagler's argument?) I'm not sure I've seen it myself.

Is that a good summary so far? This isn't exactly rocket science, so the degree of confusion surprises me.

Great summary and good timing to post it.

A few years back after a period when Henry had been posting about the qualities of his FL 8x56 I made a point of trying them out at Bird Fair and there was something about the view that was so nice but I couldn't put my finger on just what this quality was. I picked them up 3-4 times over the Bird Fair weekend and the only thing that kept on suggesting itself was the photographic concept of bokeh or texture.

So I would like to pose the question: do large aperture binos above a certain minimum optical quality have a 'texture' to the view that is more visually pleasing than binos with smaller objectives?

Lee

denco@comcast.n · Apr 10, 2018

chill6x6 said:
You'll like it!

I'm gonna head to Dauphin Island this weekend....migration is about maxed out right now. The new model SLC 8X42 will be my main binocular.

Thanks! Dauphin Island looks like a really interesting place to visit and bird. Have a good time.

Theo98 · Apr 10, 2018

Troubador said:
Great summary and good timing to post it.

A few years back after a period when Henry had been posting about the qualities of his FL 8x56 I made a point of trying them out at Bird Fair and there was something about the view that was so nice but I couldn't put my finger on just what this quality was. I picked them up 3-4 times over the Bird Fair weekend and the only thing that kept on suggesting itself was the photographic concept of bokeh or texture.

So I would like to pose the question: do large aperture binos above a certain minimum optical quality have a 'texture' to the view that is more visually pleasing than binos with smaller objectives?

Lee

BOKEH is at times the term I'm "focused on" in photographic composition. IMO, to obtain the most pleasing and satisfying bokeh you need two main ingredients...a large f-stop aperture and really good SLR lenses!

With binoculars, most of us want to See not only a very in-focused sharp and clear POI, but also "as deep" an in-focus foreground and background DOF. Birding virtually demands it, general terrestrial viewing, not so much.

I've glassed with some 8X and 10X optics whose on-axis and DOF looked real nice, but the foreground\background OOF fields looked\felt atrocious, actually creating for me a tense, nervous, uncomfortable view! Then there's some instruments that although your in-focus DOF may be shallower (higher powers), the OOF regions in both foreground and background are easy on the eye, not irritating and overall...pleasing!

In photographic optics, premium glass, large aperture Rules in creating a most desirable Bokeh! I can see it and usually unconsciously, quickly pick the quality of a complete binocular field that not only gets the "subject right, but also has an overall pleasing sense, a relaxed, easy-on-the-eyes view. In other words, the qualities of a superior Bokeh!

Even though you may not consciously see it...It's there, good or bad. The effects no doubt are individualized, and for some, may be the best description between an individuals optical viewing comfort, or lack of?!

YES...Believe you've "hit the nail on the head", Lee!! :t:

henry link · Apr 10, 2018

My understanding of the term "bokeh" in photography is that it refers to the appearance of out-of-focus objects in the background of a photo. A smooth appearance is desirable and that is accomplished by using a low focal ratio to limit depth of field and over-correcting the lens for spherical aberration so that the out-of-focus diffraction patterns of point sources beyond the focused subject appear as soft discs with a fuzzy bright center rather than as hard discs with dark centers and bright rings on the edge of the disc as in under-corrected lenses.

There is nothing desirable about spherical over-correction in a telescope or binocular. What is wanted is the high resolution that comes from exact correction, but since most binoculars are considerably under-corrected the bokeh of background objects in a well corrected or at least less under-corrected binocular should look smoother than a more severely under-corrected one, whether the aperture is large or small.

Troubador · Apr 10, 2018

henry link said:
My understanding of the term "bokeh" in photography is that it refers to the appearance of out-of-focus objects in the background of a photo. A smooth appearance is desirable and that is accomplished by using a low focal ratio lens and over-correcting the lens for spherical aberration so that the out-of-focus diffraction patterns of point sources beyond the focused subject appear as soft discs with a fuzzy bright center rather than as hard discs with dark centers and bright rings on the outside edge.

There is nothing desirable about spherical over-correction in a telescope or binocular. What is wanted is the high resolution that comes from exact correction, but since most binoculars are considerably under-corrected the bokeh of background objects in a well corrected or at least less under-corrected binocular should look smoother than a more severely under-corrected one, whether the aperture is large or small.

So thats a 'no' then Henry...:t:

Lee

Kammerdiner · Apr 10, 2018

henry link said:
My understanding of the term "bokeh" in photography is that it refers to the appearance of out-of-focus objects in the background of a photo. A smooth appearance is desirable and that is accomplished by using a low focal ratio lens and over-correcting the lens for spherical aberration so that the out-of-focus diffraction patterns of point sources beyond the focused subject appear as soft discs with a fuzzy bright center rather than as hard discs with dark centers and bright rings on the outside edge.

There is nothing desirable about spherical over-correction in a telescope or binocular. What is wanted is the high resolution that comes from exact correction, but since most binoculars are considerably under-corrected the bokeh of background objects in a well corrected or at least less under-corrected binocular should look smoother than a more severely under-corrected one, whether the aperture is large or small.

That's the first explanation of bokeh I sort of halfway understand. Thanks Henry! :t: Thanks to Theo as well. I learn stuff around here every day.

I draw the line at 42mm. I ain't carrying anything bigger unless it's a scope.

Pileatus · Apr 10, 2018

Dennis,
Are these big enough?
https://www.dreamstime.com/stock-ph...up-bald-against-gray-background-image31841883

denco@comcast.n · Apr 10, 2018

Pileatus said:
Dennis,
Are these big enough?
https://www.dreamstime.com/stock-ph...up-bald-against-gray-background-image31841883

Now THAT'S a binocular!:eek!:

tenex · Apr 10, 2018

Troubador said:
So I would like to pose the question: do large aperture binos above a certain minimum optical quality have a 'texture' to the view that is more visually pleasing than binos with smaller objectives?

Bokeh I understand, but not so much "texture". Does that have a specific meaning in photography?

b3rd · Apr 11, 2018

[email protected] said:
I have been to Costa Rica, Monteverde Rain Forest and I never needed that close of a focus. Most of the birds were at a good distance or high in the canopy. Always at least 20 feet away or more. In fact you need a spotter a lot of the time.

Wow. I had a completely different experience in the cloud forest. We saw plenty of stuff very up close, although not the Resplendent Quetzal. He was a good 20' away. But we were up close on some warblers and other cool birds. I wouldn't want to be without something with at least 6' focus or so.

b3rd · Apr 11, 2018

Theo98 said:
IMO, to obtain the most pleasing and satisfying bokeh you need two main ingredients...a large f-stop aperture and really good SLR lenses!

Much of the reason high quality SLR lenses have better bokeh is because of the aperture blades. Cheaper lenses tend to have less blades, and create a more choppy bokeh that looks like a bunch of overlapping transparent polygons. The more expensive lens has more blades, creating smooth circles. They'll also round the blades to more closely approximate a circle.

With binoculars, I don't think this is a consideration in the design--I'd guess the analogue component is perfectly circular--

The other impact on DOF is aperture, which I am also not sure what the analogue for binoculars would be. Would a larger objective relate to a lower f/stop (e.g. wider aperture and lower DOF?)

denco@comcast.n · Apr 11, 2018

b3rd said:
Wow. I had a completely different experience in the cloud forest. We saw plenty of stuff very up close, although not the Resplendent Quetzal. He was a good 20' away. But we were up close on some warblers and other cool birds. I wouldn't want to be without something with at least 6' focus or so.

We did see Resplendent Quetzal's and they were probably about 30 feet away. In fact we used a spotter to get closer to them. Even the hummingbirds were over 10 feet away. The tarantula's were close. I guess you could have used a close focus on them if you wanted to get that close.

Troubador · Apr 11, 2018

tenex said:
Bokeh I understand, but not so much "texture". Does that have a specific meaning in photography?

AFAIK 'texture' doesn't have a meaning in photography and I put the word inside apostrophes because texture is really something you detect by touch but I wanted to come up with a word that categorised the kind the effect that different bokehs have and perhaps 'visual texture' might have been a better choice. I was grasping at straws really, trying to come up with a word that might capture the nature of the quality of the view through the FL 8x56s.

Lee

Daytime benefit of large objectives? (1 Viewer)

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