Join for FREE
It only takes a minute!
Zeiss - Always on the lookout for something special – Shop now

Welcome to BirdForum.
BirdForum is the net's largest birding community, dedicated to wild birds and birding, and is absolutely FREE! You are most welcome to register for an account, which allows you to take part in lively discussions in the forum, post your pictures in the gallery and more.

Death by sharpness (8x30 W Habicht)

Reply
 
Thread Tools Rate Thread
Old Monday 15th April 2019, 09:20   #1
yarrellii
Registered User
 
yarrellii's Avatar

 
Join Date: May 2016
Location: Spain
Posts: 166
Death by sharpness (8x30 W Habicht)

I thought of placing this in the Swarovski sub-forum, but I think it actually relates to common issues with binoculars, and not a particular brand.

After experiencing “the revelation” of sharpness and brightness with a 7x42 Zeiss Victory FL, I finally gave in and got myself a 8x30 w Habicht, having read that sharpness is one of its strengths. 8x30/32 is my favourite format and I love porros. I have an 8x30 EII which I adore, but its lack of water (or should I say weather) proofness is a real concern. I live in a very wet environment, so I’ve already have the EII all fogged up internally: not nice. So I got the Habicht.

I’ve been using the 8x30 W Habicht extensively over the last weeks and every praise I read about it is certainly right: so, so, so, so sharp and bright that it becomes really addictive, somehow like having a superpower in your eyesight, so to speak. But, as has already been said many times in the forum, the ease of view of the EII is (to my eyes anyway) far superior. And here comes my question/rambling: Can there be such a thing as “too much sharpness”?

Let me explain. I’m aware that DOF is related the format: say, 7x35 will have a different DOF than 10x42, and (correct me if I’m wrong), the DOF of two 8x30 binoculars will be mainly determined by the fact that both are 8x30, not by the work of the manufacturer in terms of glass, coatings, etc. (I might be mistaken here). However, the “perceived” DOF of the Habicht is way bigger (well, deeper) than the EII. It seems that there is less need to refocus, because everything is in focus. Actually, I have read that the focus wheel on the Habicht is very stiff, and this is true, but I don't find it particularly annoying given the fact that I simply have to play with the focus way less than with the EII (in a way, the 8x30 Habicht remind me of the DOF of the 7x binoculars I’ve used).

And here comes the “weird” feeling: I am under the (absolutely and very personal) impression that, because of the great DOF (to my eyes related to the sharpness of the binos), I tend to focus less, so my eyes end up doing a lot of accommodation to get everything in focus (and they do, and the result is mindblowingly sharp and bright), maybe the same way your eyes have to work using a IF binocular. The result is that, at the end of the day, my eyes feel much more tired than if I was using the 8x30 EII: death by sharpness, I call it. Hence the question whether too much sharpness can lead to unease and tiredness.

Excuse me for the longish post, I hope it makes sense, and do let me know your thoughts on “death by sharpness” (I would not like to make this another Habicht vs EII thread, but rather a debate on optical properties and subjective impressions).

Last edited by yarrellii : Monday 15th April 2019 at 09:23.
yarrellii is offline  
Reply With Quote
Old Monday 15th April 2019, 10:28   #2
aengus4h
Registered User

 
Join Date: Jan 2019
Location: UK
Posts: 33
is the aperture in the Habicht smaller than the EII's?

DOF is affected by both magnification and iris aperture, higher mag and/or larger aperture result in shallower DOF, hence the 5x & 6x bino's I have exhibit a much deeper DOF and more relaxed view than the 10x+ ones. Not sure how much by, but I expect the brighter image will maybe close your pupils a shade more too, which will improve DOF a little further, perhaps?

The problem though is that within the DOF presented, your eyes do need to accommodate the variance in focus between the extremes of that field (front-back edge focal planes). May seem unnoticeable as your eyes naturally adjust their focus but I guess after long-time viewing sessions they would feel more tired, compared to if you were bringing the optics into sharper focus to the plane you wanted to examine each time. The latter would mean your eyes are at a more relaxed state compared to pushing focus to accommodate.
aengus4h is offline  
Reply With Quote
Old Monday 15th April 2019, 10:44   #3
Gilmore Girl
Beth
 
Gilmore Girl's Avatar

 
Join Date: Feb 2012
Location: Northeast
Posts: 2,653
I think I know what you mean when you say it's just too sharp.

I had this with my very first pair of eyeglasses and it was so bothersome I decided I didn't need glasses for a few years (weak prescription anyway). It was biting sharp to the point of being bothersome and tiring my eyes quickly; very uncomfortable. The prescription was just stronger than necessary I guess. Fast forward a few years later (around 6 yrs ago) I felt my vision got worse to the point I had to wear glasses, so off to the optometrist again. I went to a new place close by in town and told the doctor about my bad first experience and he said he'd get it right so that it's comfortable and clear. I only go to this guy now. My first pair with his prescription was comfortable right away; sharp and clear enough but easy on the eyes and brain.

I find my ultravid+ plenty sharp and certainly don't think I need anything to be sharper . My Swaro CL (original recipe) noticeably less sharp right away (compared to the Leica) , but sharp enough (it's comfortable). Both binoculars are easy on the eyes.

Last edited by Gilmore Girl : Monday 15th April 2019 at 10:50.
Gilmore Girl is offline  
Reply With Quote

BF Supporter 2013 Support BirdForum With A Donation

Old Monday 15th April 2019, 10:59   #4
yarrellii
Registered User
 
yarrellii's Avatar

 
Join Date: May 2016
Location: Spain
Posts: 166
Quote:
Originally Posted by aengus4h View Post
is the aperture in the Habicht smaller than the EII's?
In this case, both are 8x30, but the results could not be different.
Habicht is much sharper and brighter. The image is just so "sparkling" and the "perceived/subjective" DOF is greater than the Nikon.
Nikon is very sharp indeed (but less so than the Habicht), but most noticeabley, the "perceived/subjective" DOF seems to be less, hence my feeling that this difference in perceived DOF has to do with the stunning sharpness of the Habicht, and the fact that I don't need to focus that much with it, as I do with the Nikon, both being very sharp 8x30 offering an extremely pleasant image
yarrellii is offline  
Reply With Quote
Old Monday 15th April 2019, 13:26   #5
wllmspd
Registered User

 
Join Date: Feb 2008
Location: Hampton
Posts: 217
For no focus adjust usage the Bushnell Rangemaster 7x35 are excellent, though they have huge eye lenses and are really heavy. The 8x30E2 is so light in comparison, if a little narrow field of view.
I have come across a “too sharp” image, looking at the moon in my 30x70APM, the craters are so crisply defined they almost look artificial. I really need to up the magnification. I also find moving from these binoculars ultrawide and sharp field to the 8x30E2 a bit of a let down with less field of view and edge sharpness.
wllmspd is online now  
Reply With Quote
Old Monday 15th April 2019, 14:10   #6
Binastro
Registered User

 
Join Date: Aug 2012
Location: S.England
Posts: 4,263
It may be that someone with very fine eyesight has too much information for the brain to easily process, when actually looking for fine detail.
When the eyes are relaxed and basically doing nothing, or not very much, I presume the brain has an easier time.

This may also apply to very fine optics.

This is probably more in the realm of a neuroscientist to answer. It may be a more difficult question than one might think.
Binastro is online now  
Reply With Quote
Old Monday 15th April 2019, 14:45   #7
ceasar
Registered User

 
Join Date: Aug 2005
Location: NE Pennsylvania
Posts: 11,645
The 8x30 EII with its very wide 8.8 FOV has a huge amount of pincushioning at the edge of its view. It can be dialed into sharpness. That might affect the perception of depth of field.

Bob
ceasar is online now  
Reply With Quote

BF Supporter 2010 Support BirdForum With A Donation

Old Monday 15th April 2019, 18:21   #8
jring
Registered User

 
Join Date: Aug 2015
Location: Germany
Posts: 1,851
Quote:
Originally Posted by ceasar View Post
The 8x30 EII with its very wide 8.8 FOV has a huge amount of pincushioning at the edge of its view. It can be dialed into sharpness. That might affect the perception of depth of field.

Bob
Hi,

first of all, while the 8x30 E2 indeed has some pincushion distortion, that cannot be dialed out with the focus. What can be dialed out is field curvature (edge of field not sharp but can be brought to focus). This is normal for short focal length refracting telescopes (like binoculars) and can only be corrected with additional optics - see Smyth lens.

Pincushion distortion means that a square is imaged in pincushion form, that is with the middle of the sides closer to each other than adjacent corners. This is often introduced on purpose by eyepiece designers for terrestial optics in order to combat the so called globe effect when panning.

As for the symptoms described by the original poster - I would strongly recommend to test for a light decollimation as the brain can adapt for this and merge the slightly wrong images but it will be strained and you get a headache after prolonged use.

You can watch a star and either keep one eye closed and then open it and see two stars rapidly merge into one as the brain adapts.
Or keep one barrel in focus and defocus the other maximally using the diopter - in that case you see a star in the in-focus barrel and a diffraction circle in the out-of-focus one - the brain does not adapt as the two images are quite different. The star should be in the middle of the diffraction circle, if the pair is collimated well (or at least ok for your IPD).

PS: You can calculate the depth of field - try this handy online calculator and use 0.2mm for CoC of the eye, focal length = 150mm and f-stop = f/5 and maybe 10m observation distance. The E2 is a bit shorter, it's probably more like f=120mm and f/4 - you will see that the depth of field is quite a bit slimmer due to that.

https://www.dofmaster.com/dofjs.html

Joachim

Last edited by jring : Monday 15th April 2019 at 18:37. Reason: speling and added postscriptum
jring is offline  
Reply With Quote
Old Monday 15th April 2019, 19:35   #9
Tringa45
Registered User

 
Join Date: Dec 2017
Location: Cologne, Germany
Posts: 221
I don't think we can apply calculations of depth of field for cameras to binoculars or telescopes, which are afocal devices in which the ocular or focussing lens is adjusted so that for normal or corrected vision the "rays" emerging from the eyepiece are parallel.

There are several factors which can affect the perceived depth of field, such as one's ability to accommodate, the light intensity and field curvature, but for binoculars and telescopes dof is defined by the magnification and is inversely proportional to its square. Under similar conditions a 7x binocular would have twice the dof of a 10x binocular.

John
Tringa45 is online now  
Reply With Quote
Old Monday 15th April 2019, 19:54   #10
yarrellii
Registered User
 
yarrellii's Avatar

 
Join Date: May 2016
Location: Spain
Posts: 166
Quote:
Originally Posted by Tringa45 View Post
... for binoculars and telescopes dof is defined by the magnification and is inversely proportional to its square. Under similar conditions a 7x binocular would have twice the dof of a 10x binocular.
This is the most puzzling thing of it all: comparing directly the 8x30 EII and the 8x30W Habicht, the latter seems to have way more DOF (which is impossible, by the mentioned fact). That's the thing that got me wondering, after extensive use of the Habicht, where I find my eyes more tired than after an equivalent use of the EII. My impression is that, because of this "perceived" greater DOF, I tend to focus way less with the Habicht, and probably leave my eyes to do more work accommodating to get things in focus than what I do with the EII. It's quite a curious phenomenon.
yarrellii is offline  
Reply With Quote
Old Monday 15th April 2019, 20:52   #11
jring
Registered User

 
Join Date: Aug 2015
Location: Germany
Posts: 1,851
Quote:
Originally Posted by Tringa45 View Post
I don't think we can apply calculations of depth of field for cameras to binoculars or telescopes, which are afocal devices in which the ocular or focussing lens is adjusted so that for normal or corrected vision the "rays" emerging from the eyepiece are parallel.

There are several factors which can affect the perceived depth of field, such as one's ability to accommodate, the light intensity and field curvature, but for binoculars and telescopes dof is defined by the magnification and is inversely proportional to its square. Under similar conditions a 7x binocular would have twice the dof of a 10x binocular.

John
Hi John,

you might be right that the calculator is not correct here... but certainly telescope depth of field does not only depend on magnification.

Just use a slow fraunhofer astro scope (f13 or so) and compare to a fast APO at the same magnification. In the former, it's easy to focus with a single speed focusser, with the fast APO you certainly need a 1:10 slow focus drive.

Joachim
jring is offline  
Reply With Quote
Old Monday 15th April 2019, 22:28   #12
james holdsworth
Consulting Biologist
 
james holdsworth's Avatar

 
Join Date: Oct 2009
Location: ontario
Posts: 3,265
I find a bin that ''snaps'' into sharpness quickly and easily to be less tiring to use, by far, than a less sharp unit that requires hunting to hit the spot.
__________________
''serenity now....insanity later.'' - Lloyd Brawn
james holdsworth is offline  
Reply With Quote
Old Monday 15th April 2019, 22:34   #13
Tringa45
Registered User

 
Join Date: Dec 2017
Location: Cologne, Germany
Posts: 221
Hi Joachim,

Yes indeed. In the example you mention the depth of focus of the "slow" Fraunhofer is so much greater that it needs a correspondingly longer focus travel to attain optimum focus with the (longer focal length) eyepiece.
At the same magnification though, the depth of field as seen through the eyepiece would be the same as with the "fast" APO.

John
Tringa45 is online now  
Reply With Quote
Old Tuesday 16th April 2019, 06:19   #14
typo
Registered User

 
Join Date: Feb 2010
Location: Hertfordshire
Posts: 3,731
Yarrellii,

There have been occasions when I've noted that a higher effective resolution binocular had a greater apparent depth of field than a low one, but the difference was considerably larger than between the Habicht and the E2. I think it's a rather unlikely explaination in this case.

For a given magnification, the pupil of the eye is the principle determinant of the apparent depth of field. (Providing the EP isn't limiting of course.) The question is would the two binoculars induce different pupil diameters. Possibly!

The control of pupil diameter is rather complex. Psychological factors play a major role as do physical ones like the FoV. Both here are wide fields so probably not relevant either. 'Brightness' obviously plays a role, but perhaps not in the way I was taught at school. I'm sure most are aware that peak daylight sensitivity is around 555nm and night around 505nm due to the physiology of the cones and rods respectively, but pupil diameter is controlled by the non-visual but photosensitive retinal ganglion cells. These are most responsive to light in the blue around 470 to 480nm. Is the transmission of the Habicht at these wavelengths sufficiently greater than the E2 to increase the apparent depth of field? I don't know to be sure, but it certainly seemed to me that blue content of the Habicht view was higher than the E2 when I compared them. Just another possibility to think about.

I've only used the Habicht and E2 for short periods as birding shows and stores so not long enough to give me eye strain. However I did find the Habicht view harsh for my eyes in bright conditions, where the E2 seemed a more comfortable option. I'm sure opinions will differ.

David
typo is offline  
Reply With Quote
Advertisement
Reply


Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Habicht 8x30 vs new CL companon 8x30 B cfranchi Swarovski 59 Wednesday 10th April 2019 13:18
Tried the Habicht 8x30 james holdsworth Swarovski 24 Friday 9th March 2018 19:25
Habicht SLC 8x30 WB mak17 Swarovski 5 Monday 6th March 2017 04:48
Classic Porro Comparision: Swarovski Habicht 8x30 vs. Nikon 8x30 E2? Dantanamo Binoculars 31 Sunday 4th September 2016 22:47
Habicht 8x30 solium Swarovski 4 Wednesday 30th December 2015 16:51

{googleads}

Fatbirder's Top 1000 Birding Websites

Help support BirdForum

Page generated in 0.20547295 seconds with 27 queries
All times are GMT. The time now is 20:59.