8x42 vs. 10x50 dawn/twilight (6 Viewers)

[Vespobuteo]

But yes, the gaps are getting closer with each generation of binocular, maybe why Zeiss has largely ditched the abbe konig's. Also albino's only had the ht's at 91% not sure what Gijs has found.

There's still a bunch of AK-prism bins in the low-light segment. HT, Conquest, Victory RF, SLC etc.

Abbe/Koenig Roof Prism Binoculars - Optics Trade

Abbe/Koenig Roof Prism Binoculars

www.optics-trade.eu

 

[tenex]

Can you explain that? I do not understand why that is. Does it have something to do with the do with the resolution as well? Bigger EP gives better resolution/sharpness?

It's not about the exit pupil. Light is hitting the outer portions of an objective at a more acute angle than near the axis, so aberrations are greater, and resolution improves when stopped down (in this case by your daylight pupil). This has been discussed in some detail in previous threads, and if you have further questions you'll want more of an expert.

 

[William Lewis]

There's still a bunch of AK-prism bins in the low-light segment. HT, Conquest, Victory RF, SLC etc.

Abbe/Koenig Roof Prism Binoculars - Optics Trade

Abbe/Koenig Roof Prism Binoculars

www.optics-trade.eu

Yes but they used to have them in there '42's as well. I had a thought a while back that some of it may be to do with there long focal length / weight at the eye piece concept as well. Abbe konig's tend to be slightly longer than Schmidt pechan's so maybe they would have made the bins even longer, who knows...

 

[Gijs van Ginkel]

William Lewis, post 40,
We found the following transmission values for the Zeiss HT's: (the test reports are on the WEB-site of House of Outdoor)
HT 8x42: 500nm=92,6% 550nm= 94%
HT 8x54: 500nm=93,9% 550 nm=94,9%

Gijs van Ginkel

 

[Vespobuteo]

Yes but they used to have them in there '42's as well. I had a thought a while back that some of it may be to do with there long focal length / weight at the eye piece concept as well. Abbe konig's tend to be slightly longer than Schmidt pechan's so maybe they would have made them even longer, who knows...

Yes, I don't think they fitted in an optimal way in the SF ergobalance-concept etc.

My 7x42 FL:s with AK-prism are lighter and feels balanced as well though...so I don't really know what the main reason would be.

 

[William Lewis]

Cheers Gijs. I was amazed how good the kite ibis you posted about the other day were too, excellent!

 

[William Lewis]

Yes, I don't think they fitted in an optimal way in the SF ergobalance-concept etc.

My 7x42 FL:s with AK-prism are lighter and feels balanced as well though...so I don't really know what the main reason would be.

I wish they still made them.

 

[Conndomat]

Most have less 6mm or less by the age of 40. If you download this study you'll see just how lucky you are! Factors affecting light-adapted pupil size in normal human subjects. | IOVS | ARVO Journals

Most yes, but many not!

An EP of over 6mm is also worthwhile for many over 30 years old. Here's a more extensive study.

https://homepages.uni-tuebingen.de/martin.adler/pup_age.html

Andreas

 

[Richard D]

Most yes, but many not!

An EP of over 6mm is also worthwhile for many over 30 years old. Here's a more extensive study.

https://homepages.uni-tuebingen.de/martin.adler/pup_age.html

Andreas

That's a huge range - fascinating.

 

[William Lewis]

Most yes, but many not!

An EP of over 6mm is also worthwhile for many over 30 years old. Here's a more extensive study.

https://homepages.uni-tuebingen.de/martin.adler/pup_age.html

Andreas

That is a good one! I did a bit of research when I was looking into the habicht and slc but obviously didn't dig deep enough!

 

[Conndomat]

That is a good one! I did a bit of research when I was looking into the habicht and slc but obviously didn't dig deep enough!

You are right that the pupil tends to get smaller with age, if in doubt you should consult an ophthalmologist, or carry out @henry link method, which has been described here many times, independently.

Dark-adapted pupil diameter as a function of age medical study

Is this a good set of data to help a 54 year old buy his next set of Bino's? Generally speaking, I see I might benefit from a 10x56 with an exit pupil of 5.6, but an 8x56 with an exit pupil of 7 is for the younger guys. Dark-adapted pupil diameter as a function of age measured with the...

www.birdforum.net

Andreas

 

[William Lewis]

I back to backed the habichts and slc's when the light faded one evening and couldn't perceive a difference but it would be interesting to know definitively - such a simple test too.

I would consider changing the slc's for a 7x42, I tried the regular suspects (Leica ultravids) and want one in current production ideally- the habichts are good but the compromises are - yeah - there.

Not sure what's about with comparable transmission to the habichts but without the drawbacks? A modern day FL if you like but with a flatter field, did a bit if digging into the kite ibis, quite FL like with the composite (don't say plastic!) body but the FOV is narrower than the SLC and the transmission is still down a bit. For me I like to be able to see as best I can whatever the light levels....

 

[Gijs van Ginkel]

William Lewis, post 46,
Yes the 7x42 Kite Ibis 7x42EDwas a pleasant surprise for us too and, considering its price, it is a very good choice for 7x lovers.
Gijs van Ginkel

 

[dries1]

One reason I have so many Leica had initially to do with the excellence+compactness combination but if I end up getting some larger binoculars there's a good chance I may end up with whatever offers the best view, regardless of size, within reason that is.
Hard to believe I'm even talking about 50-56x when just a few months ago I was adamant about never even having anything over 32x, but now have 7x35 on the way.

Slowly those objectives grow in size along with the collection. Binocularitis.

 

[ReinierB]

One thing I also do not understand completely. which one will be better during twilight? A 8x42 or a 10x42 of the same type, lets say the SLC?
The 8x42 has a bigger exit pupil. The 10x42 has more power, but a smaller exit pupil.
I would the 8x42 is better in that case, but I am not sure.

 

[ReinierB]

Binocularitis... I understand what it is now. As soon as you know what's on the market, it is quite addictive...

 

[Gijs van Ginkel]

Reinier Bos, post 55,
When both binoculars have the same transmission spectrum the 8x42 will be brighter.
Gijs van Ginkel

 

[Trinovid]

When both binoculars have the same transmission spectrum the 8x42 will be brighter.

I'm assuming that's simply because 5.25 vs 5, right?

 

[ReinierB]

5.25 vs 4.2

 

[Trinovid]

5.25 vs 4.2

At least we agree that 42 ÷ 8 = 5.25 and you might want to look at 50 ÷ 10 again; it's 5.

I just saw what happened; I wasn't following your posts but rather the title of the thread. Depending on which one we're focused on, I guess we're both right.

At any rate, with both being 42mm, the 8x is definitely the hands down winner for brightness and shouldn't even be close.