Low-light complement to EL32? (1 Viewer)

[Dr. K]

Hello birders! I am looking for a complement to my EL 8x32 for low light. I am especially interested in finding a 7x42 but 8x42 would be alright if exceptionally bright.

I have been considering porros, but I haven't read about one yet that's convinced me. I am also very interested in the AK prisms - I think I'd pounce on a well-priced victory ht 8x42 but cannot find one anywhere. I am aware of the Leica uv 7x42, but between it being described as slightly less bright than the zeiss HT (and FL) and the closed bridge design, I am not sold. I'm not prepared to pay for a NL, unfortunately.

I've appreciated reading all the experiences and expert analysis of optics here and I think by virtue of searching these forums I may have found all the modern options available to consider, but I'm posting now to solicit any suggestions or insights that might drive my decision. Thanks very much in advance.

 

[Dr. K]

Also, is this amazing or what!? Black-capped Chickadee

 

[Chosun Juan]

Dr. K, the Zeiss HT 8x42 would indeed be a great choice - wonderful.A-K 'clarity' !

Considering the role of magnification in counteracting the drop in visual acuity in low light, then another great bin to consider is the Swarovski 10x50 SV. Better again is the bigger and heavier A-K prism 10x56 SLC. You owe it to yourself to give these a try to see what you think.


Chosun 🙅‍♀️

 

[Conndomat]

I am especially interested in finding a 7x42

Hi,

Zeiss FL 7x42, but unfortunately not to be found that often anymore.

Andreas

 

[GrampaTom]

Considering the role of magnification in counteracting the drop in visual acuity in low light, then another great bin to consider is the Swarovski 10x50 SV. Better again is the bigger and heavier A-K prism 10x56 SLC. You owe it to yourself to give these a try to see what you think.


Chosun 🙅‍♀️

1. "Considering the role of magnification in counteracting the drop in visual acuity..." Aha! Is this the answer to the question Ive asked a couple places? I think I notice visual acuity fall off with 825 Pockets peering into shadows of dense forest, or overhanging marsh grasses, even on bright sunny days and have worried that say a 1032, (similar EP) would do the same and lose what I enjoy from my larger 1042s?

2. Would be interesting to see somebody's comparison of NL 1042, SV 1050 and SLC 1056? Maybe even more interesting NL 1242 vs 1556 SLC?

 

[leonardo_simon]

It’s 16:30 and getting dark here in Oxfordshire! I’m sitting in the garden comparing my EL 8x32 with EL 8.5x42. I can’t discern any difference in brightness or clarity between the two binoculars.

My guess is that you’ll need some kind of “bigger step” in another pair of binoculars to notice a difference that is actually any use to you in the field. I certainly would.

 

[Dr. K]

It’s 16:30 and getting dark here in Oxfordshire! I’m sitting in the garden comparing my EL 8x32 with EL 8.5x42. I can’t discern any difference in brightness or clarity between the two binoculars.

My guess is that you’ll need some kind of “bigger step” in another pair of binoculars to notice a difference that is actually any use to you in the field. I certainly would.

Thank you that is very helpful. I haven’t read the most positive reviews of the zeiss ht 8x54, do maybe I should stick with 7x42 options, few as they are - I’m not really interested in exploring higher magnification than 8, so the big ELs don’t appeal to me. I might look at the Leica again, if I can find a comparison of brightness between the EL 8x32 and the 7x42 uv+

 

[Chosun Juan]

@Dr. K

"Considering the role of magnification in counteracting the drop in visual acuity..." Aha! Is this the answer to ....

Actually the drop in "visual acuity" in low light, is with 'your' eyes.

It's then a balancing act between magnification and objective size (hence exit pupil), and size and weight, to counteract that.

So the next steps up the ladder from 8x32 generally go 8x42 (5.2mm EP, 18.3 TWF), 10x50 (5mm EP, 22.4 TWF), 10x56 (5.6mm EP, 23.7 TWF), 12x63 (5.2mm EP, 27.5 TWF), 15x70 (5mm EP, 32.4 TWF), 20x80 (4mm EP, 40 TWF). For reference, the 7x42 is 6mm EP, and 17.1 TWF.

Twilight Factor (TWF) is just one metric, and only applicable over a certain range of brightness. Other factors come into play such as, the Exit Pupil (EP) of the viewer at the time(s), the quality of vision of the viewer (acuity, aberrations, etc), the conditions (light spectrum, intensity, atmospheric turbulence/clarity, etc), and the transmission profile, AR coatings, etc of the viewing instrument, etc.

There are other models, such as this one for astronomy, discussed here:

A new Performance Index for Binoculars - Articles

A new Performance Index for Binoculars Closing a gap in the technical literature on the topic of the visually accessible stellar limiting magnitude. by Beat Ch. Fankhauser ...

www.cloudynights.com

Or, more importantly, the best recommendations coming from the excellent work of Dr. Holger Merlitz:
Performance of binoculars: target detection

Performance of binoculars: target detection

Here is figure 6 from
Performance of binoculars: Berek’s model of target detection
Holger Merlitz
compiled: June 20, 2015
Showing results for Night, Twilight, and Daylight lighting levels, for a 60 year old person.



You can see that for someone of that age, that 8x42 (particularly HT) is superior to 7x42, and even that 10x50 is superior to the widely regarded 8x56.

Much of the choice then, will come down to what Dr. K means by "low light", and what will be the usage purpose, pattern, and conditions/environment, and will the binoculars be used freehand, or supported ? and what age is Dr. K ? (giving a rough guide to dilated pupil size, and hence EP requirements) ......




Chosun 🙅‍♀️

 

[Dr. K]

Much of the choice then, will come down to what Dr. K means by "low light", and what will be the usage purpose, pattern, and conditions/environment, and will the binoculars be used freehand, or supported ? and what age is Dr. K ? (giving a rough guide to dilated pupil size, and hence EP requirements) ......

Alrighty, well, By low light I mean after sunset and into the night ideally, interested in watching birds and other wildlife - I’d love to go owling. I would use them freehand and I am 40. I’m looking forward to your analysis!

 

[tenex]

Hello birders! I am looking for a complement to my EL 8x32 for low light.

My own experience matches Holger's account above. 42 is not really a noticeable improvement on 32 for me; 50-54-56mm is needed. I have and love the 10x56 SLC, which has given fine views of owls... and is beautiful in daylight also, giving incredibly sharp views at long distances.

 

[Chosun Juan]

Alrighty, well, By low light I mean after sunset and into the night ideally, interested in watching birds and other wildlife - I’d love to go owling. I would use them freehand and I am 40. I’m looking forward to your analysis!

Ok, in that case, have a look at figure 5 from Holger Merlitz's paper (I suggest reading the whole thing - very informative) -
Performance of binoculars: Berek’s model of target detection
Holger Merlitz
compiled: June 20, 2015

Performance of binoculars: target detection

Showing results for Night, Twilight, and Daylight lighting levels, for a 30 year old person.



You can see that 8x42 is still superior to the 7x42 up until halfway through twilight, and that 10x50 is superior to them both right into night. The 10x56 starts to show gains over the 10x50 beginning at twilight, and is then clearly superior for 80% of it and into deepest darkest night.

Getting specific, I think your choices (in increasing order of performance) are:
Zeiss 8x42 HT
Maven 10x50 B6
Leica 10x50 UVHD+
Swarovski 10x50 SV
Zeiss 10x56 FL
Swarovski 10x56 SLC (A-K model)

Have a look at the Maven here:

New Maven B.6 10x50: A brief comparative review

1. US company Maven is by now a well-known player in the market for outdoor gear and sports optics such as riflescopes and binoculars. Looking at their website, brochures and marketing material, the target markets seem clearly to be hunting and wildlife observation. Now, Maven has come out with...

www.birdforum.net

10x56 is your best no compromise optical choice, it's just a matter of whether the weight etc is acceptable to you.



Chosun 🙅‍♀️

 

[GrampaTom]

OK, helpful, maybe a bit wide of my question. Maybe. Im 77. My optometrist didnt get the mission, so dont have a real grasp of what pupil dilation I can still perform. I'm not asking about low light at ends of the day, but rather low light in places where direct sunlight is not able to penetrate, in the middle of the day. What I think of as acuity.

One example, Ill try again. There is a mud bank along a tidal pool that gets aggressive incoming/outgoing water. Couple hours fore or aft of high tide that wet mud bank is exposed but overhung with marsh grasses. They look rather like the curl of a breaking ocean wave. My birder friends and I hope to to catch the Ridgway Rail walking that mud bank under the grasses. Their markings, shape, coloration, the mud, the grass, the crab holes all compete. When the sun is not cooperating, things are darker just there, my little 825s with their 3.125 EP lose detail. My 1042/4.2 EP do not or do less.

Intrigued by Chosun's "Considering the role of magnification in counteracting the drop in visual acuity in low light,......." having been under the impression what I was observing, was mostly a pupil/EP thing, this suggests MAYBE what Im seeing is related to magnification? I am under the impression, (cant remember where I read it), twilight factor, once a published thing by bino makers, is now a discredited idea and no longer used??? Holger's charts infer what I believe Chosun was maybe saying. 1056 seems better than 856, even though EP would favor the 8. How come?

 

[dries1]

The chart represents results for a 30 year old individual, so the assumption is that for someone over 50 the larger EP of 7 (8X56) is useless, there are exceptions of course.

 

[GrampaTom]

Ah yes, assumptions.....

 

[Dr. K]

Well, I can’t believe it. I woke up 1.5hrs before my alarm this morning, found an adorable raccoon on my back porch, that would not leave, and then found a like-new Zeiss Victory 8x42 ht for sale online, just posted. I’d talked myself out of that one but with the buy button right there I gave in. I’ll be sure to share my experiences as I consider whether it would replace my EL32, which would be easier to swallow if my wife will accept it as a replacement for her beloved CL30… we shall see. Crazy morning!

 

[dries1]

I saw that one myself, the seller bought it for his wife, (yeah right) and it was not used much.

 

[Chosun Juan]

Ah yes, assumptions.....

??

 

[GrampaTom]

Dries’ #13, sorry for confusion.

 

[Chosun Juan]

Dries’ #13, sorry for confusion.

Gramps - I think your apology is misguided !

Those figures and recommendations are built on scientific models - based on a lot of fact and empirical evidence - and yes some assumptions (or parameters set) within those mathematical models. A seemingly pithy "assumptions" 'dismissal?' could be seen to display a level of ignorance and disrespect for the high level work. The limits of the work (quite relevant to your question) are clearly outlined in the conclusions and summary.

Figure 5 is for a 30 year old.

Figure 6 is for a 60 year old.

All of this was made quite clear.

Looking at Figure 6 you can actually trace and track exactly what you are seeing in practice - even in the daylight region as light levels drop (such as looking into shadows).


Chosun 🙅‍♀️

 

[dries1]

GrampaTom,

Perhaps contacting Holger directly would be better way to get his information.