CLOUDY NIGHTS FORUM ARCHIVES
"Live Forums" can be found here: Live Forums


Equipment Discussions >> Binoculars

Pages: 1
charen
Pooh-Bah


Reged: 05/28/05
Posts: 1446
Loc: New Zealand
9x63 and exit pupils size new
      #901134 - 04/05/06 11:58 PM

Hi - I was going to buy the Meade 9x63's - however I the read the excellent article on CN's reviews by Bill Greer on 'Binoculars, Astronomy and Exit Pupils' - the summary being that at at 7mm exit pupil for the Meades, I would be wasting some of the light as I am 50 years old [but with still reasonable good eyesight]. I have the option of instead of buying some cream colored 'Sportmaster' 20x80's [Japanese,FMC,3.7 F.O.V.,central bracket - excellent optics - almost clear to edge from a brief view] but they are about 3x what I was going to pay for the meades. Exit pupil would be a better 4mm - but obviously they need a tripod. I want some larger binoculars to complement my excellent Ashai Pentax 10x50s. My skys are reasonably dark. Any suggestions ? Thx.

--------------------
30 binos.
Celestron C8
Skywatcher Equinox ED120 / Goto HEQ5.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Rich N
Post Laureate


Reged: 09/22/04
Posts: 5618
Loc: San Francisco Bay Area, Calif...
Re: 9x63 and exit pupils size new [Re: charen]
      #901232 - 04/06/06 01:53 AM

Hi charen,

Hebditch, in 1947, came out with a table that seems to have made everyone
think that when you hit 50 your eyes will only open to 5mm. There is a later study that
I believe is much closer to reality... see below.

1972
----------------
F.S. Said & W.S. Sawires, Age Dependence of Changes in Pupil
Diameter in the Dark, Opitca Acta, 1972, Vol. 19, #5, pp. 359-61.

Mean Scotopic Pupil for European 30-year-old: 7.19 mm.
Mean Scotopic Pupil for European 70-year-old: 5.40 mm.
-----------------

The finding above is interesting because the mean pupil size for a 70 year old is
greater than the pupil size for a 50 year old in the 1947 study, and it shows that
some 70 year olds will have greater 5.4mm dark adapted pupils. Also, the mean 5.4mm
is hardly the 3.2 mm mentioned for a 70 year old in Mr Hebditch's table.

Try the 9x63. They may work very well for you.

All the best,
Rich


Post Extras: Print Post   Remind Me!   Notify Moderator  
EdZ
Professor EdZ


Reged: 02/15/02
Posts: 18806
Loc: Cumberland, R I , USA42N71.4W
Re: 9x63 and exit pupils size new [Re: Rich N]
      #901342 - 04/06/06 05:40 AM

OR, measure your own eye pupils so you'll have a better idea where you fit in the scheme of things. But setting eye pupil diameter aside, I would almost never recommend a binocular with a 7mm exit pupil to anyone unless it is going to be used under very dark skys it will have a tendency to produce washed out images, regardless of you eye pupil size.

From my backyard, skies generally 4.8 to 5.4, I never see more with a Fujinon 10x70 than I can with a Fujinon 16x70. I never see more with an 8x56 than I can with a 10x50. I can never see more with a 7x50 than I can with an 8x42. You may not see any more with a 9x63 than with your 10x50, and if your skies are bright, say mag 4.8 to 4.5, you are going to see less with the 9x63.

You already have a selection of 7x50s. You must be able to tell the difference in the view between several of your binoculars? Do you see the 7x50s as washed out compared to your 10x50? If so, Consider a 12x60 or 15x70 or go for the 20x80.

edz


Post Extras: Print Post   Remind Me!   Notify Moderator  
Rich N
Post Laureate


Reged: 09/22/04
Posts: 5618
Loc: San Francisco Bay Area, Calif...
Re: 9x63 and exit pupils size new [Re: EdZ]
      #901348 - 04/06/06 05:59 AM

Hi Ed,

You're right.

The reason I suggested going for the 9x63 was because for a few years I thought a binocular with a 5mm exit pupil was all I could make use of. One night at our "dark sky" site I had my Celestron Pro 10x50 binocular and was having a hard time seeing a small comet. A fellow let me try his Celestron Pro 9x63 and I was really surprised that it made a difference. I could see the comet quite easily in his binocular. The next day I bought a Celestron Pro 9x63 and later bought a Celestron Ultima 9x63. :-)

Rich


Post Extras: Print Post   Remind Me!   Notify Moderator  
brocknroller
Carpal Tunnel


Reged: 10/16/03
Posts: 1983
Loc: Bedford Falls, Pa.
Re: 9x63 and exit pupils size new [Re: Rich N]
      #901664 - 04/06/06 12:07 PM

I have a 9x63 roof bin. From my moderately light polluted skies, the views are "white washed" except on those two or three exceptional nights of the year where conditions improve dramatically, there is no moon in the sky, and humidity is below 40%.

However, at Cherry Springs State Park where Mag 7+ skies are possible on a low humidity, dark night, this same mid-priced binocular turns into a "Zeiss", yielding excellent contrast (even though it is not FMC), fairly sharp stars (even though it is not P-coated), and bright views of DSOs. I've passed the bins around and have gotten a lot of ooohs and aaahs from big Dob owners.

I've always assumed that my entrance pupils were about 5mm, based on the "old" scale, but they might be larger, though I rarely observe under dark sky conditions enough to take advantage of it.

The other thing that I've read is that one's pupil size can vary. Some medications, caffeine and alcohol consumption, your emotional state, etc. can affect your pupil size. So your pupil size as measured at home may be different than under dark skies unless all other factors are equal, though by taking several readings at different times, you should be able to find your "average". Sky conditions vary too, so you might consider your typical sky conditions rather than the best.

If you can try before you buy (borrow someone's 9x63 or 8x56 bin) and compare it to a 10x50 or 8x42, that might be the best way to assess whether or not this configuration works for your eyes and your sky conditions.

--------------------
Press: Are you a mod or a rocker?
Ringo: I'm a mocker


Post Extras: Print Post   Remind Me!   Notify Moderator  
Rich N
Post Laureate


Reged: 09/22/04
Posts: 5618
Loc: San Francisco Bay Area, Calif...
Re: 9x63 and exit pupils size new [Re: Rich N]
      #901818 - 04/06/06 01:58 PM

That night when I found out that I could benefit from the 9x63 I was happy but I also mad and felt cheated that I'd believed the garbage from that old 1947 Hebditch study that says when you hit 50 years old 5mm of exit pupil is all you can use.

Rich


Post Extras: Print Post   Remind Me!   Notify Moderator  
EdZ
Professor EdZ


Reged: 02/15/02
Posts: 18806
Loc: Cumberland, R I , USA42N71.4W
Re: 9x63 and exit pupils size new [Re: Rich N]
      #901877 - 04/06/06 02:51 PM

I don't think of this as an age issue as much as a dark sky issue. I don't think anybody has believed in the age thing for years. But without a real dark sky, that large exit pupil is under-utilizing magnification, wasting a lot of aperture, and not providing you with as good a view as you could otherwise get.

edz

--------------------
Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21


Post Extras: Print Post   Remind Me!   Notify Moderator  
Rich N
Post Laureate


Reged: 09/22/04
Posts: 5618
Loc: San Francisco Bay Area, Calif...
Re: 9x63 and exit pupils size new [Re: EdZ]
      #901900 - 04/06/06 03:23 PM

It seems as if there have been quite a few posts here on CN by people who believe (or wonder if it is true) that at 50 years of age 5mm is the max size of your dark adapted pupil.

I don't think the skies were all that dark the night I saw the comet in the 9x63, but I didn't do a sky check.

Unfortunately I don't have a Celestron Ultimaa 10x50 right now to compare with my Ultima 9x63.

Rich


Post Extras: Print Post   Remind Me!   Notify Moderator  
Rich N
Post Laureate


Reged: 09/22/04
Posts: 5618
Loc: San Francisco Bay Area, Calif...
Re: 9x63 and exit pupils size new [Re: Rich N]
      #901946 - 04/06/06 04:02 PM

Ok, I just ordered a Celestron Ultima DX 10x50. It should be here in a few days. Even though it's a Celestro Ultima it is a little different than my older 9x63. This new Ultima is waterproof and has twist up eyecups. Not sure what other change have been made.

Rich


Post Extras: Print Post   Remind Me!   Notify Moderator  
Swedpat
Pooh-Bah


Reged: 02/18/05
Posts: 1144
Loc: Boden, Sweden, Scandinavia
Re: 9x63 and exit pupils size new [Re: Rich N]
      #902029 - 04/06/06 05:04 PM

To really find out the ability of using large exit pupils I think the best way is to compare different binoculars with equal light transmission, and preferably same magnification. If you are doubtful about your ability to make use of a 7mm exit pupil you just have to compare a 7x42 to a 7x50. A proposal is Swarovski SLC 7x42 and SLC 7x50.

You don't need to know your exact eye pupil size, but just decide if the image under dark condition in the 7x50 is brighter enough than the image in the 7x42. And if the gain of brightness justifies a purchase of the model with 7mm exit pupil is a decision only you can make.

Regards, Patric

--------------------
*2,3x40 Constellation View Wide-Bino
*Leupold Katmai 6x32
*Nikon Sporter I 8x36
*Swarovski SLCNew 7x42B
*Bresser (Lidl) 10x50
*Oberwerk 11x70
*Stellarvue SV50 spottingscope
*Meade 5000 26mm Plössl, Vixen LV 10/5mm

Psalm 19:2


Post Extras: Print Post   Remind Me!   Notify Moderator  
dynamite
member


Reged: 03/15/06
Posts: 71
Loc: Switzerland
Re: 9x63 and exit pupils size new [Re: Rich N]
      #902035 - 04/06/06 05:07 PM

Always these exit pupils... :-)

As you know I prefer large ones, day and night.

One thing to consider: higher than 10x is difficult to hold steady freehand.

--------------------
Gruss aus der Schweiz,
dynamite
Leica 8x20, Swarovski SLCnew 8x56, Nikon 20x120 Mark III


Post Extras: Print Post   Remind Me!   Notify Moderator  
Rich N
Post Laureate


Reged: 09/22/04
Posts: 5618
Loc: San Francisco Bay Area, Calif...
Re: 9x63 and exit pupils size new [Re: Swedpat]
      #902072 - 04/06/06 05:31 PM

Quote:

To really find out the ability of using large exit pupils I think the best way is to compare different binoculars with equal light transmission, and preferably same magnification. If you are doubtful about your ability to make use of a 7mm exit pupil you just have to compare a 7x42 to a 7x50. A proposal is Swarovski SLC 7x42 and SLC 7x50.

You don't need to know your exact eye pupil size, but just decide if the image under dark condition in the 7x50 is brighter enough than the image in the 7x42. And if the gain of brightness justifies a purchase of the model with 7mm exit pupil is a decision only you can make.

Regards, Patric




Go for it, Patric!

Rich


Post Extras: Print Post   Remind Me!   Notify Moderator  
Swedpat
Pooh-Bah


Reged: 02/18/05
Posts: 1144
Loc: Boden, Sweden, Scandinavia
Re: 9x63 and exit pupils size new [Re: Rich N]
      #902116 - 04/06/06 06:09 PM

Rich,

I have thought about this long time. The problem is to either collect enough money for ordering both the SLC 7x42 and 7x50 under "satisfied or send back-warranty" and send back one of them, OR find a dealer which (have both of them in stock) and can provide me the service to compare them under dark condition before buying. This isn't normally possible in the most stores.

Patric

--------------------
*2,3x40 Constellation View Wide-Bino
*Leupold Katmai 6x32
*Nikon Sporter I 8x36
*Swarovski SLCNew 7x42B
*Bresser (Lidl) 10x50
*Oberwerk 11x70
*Stellarvue SV50 spottingscope
*Meade 5000 26mm Plössl, Vixen LV 10/5mm

Psalm 19:2


Post Extras: Print Post   Remind Me!   Notify Moderator  
Rich N
Post Laureate


Reged: 09/22/04
Posts: 5618
Loc: San Francisco Bay Area, Calif...
Re: 9x63 and exit pupils size new [Re: Swedpat]
      #902346 - 04/06/06 09:20 PM

I was thinking if some store had them, the test could be done in the store. Maybe they would let you sit in a darkened room for an hour or two.

It's really frustrating that so few walk in stores have a good selection of high end binoculars.

Rich


Post Extras: Print Post   Remind Me!   Notify Moderator  
EdZ
Professor EdZ


Reged: 02/15/02
Posts: 18806
Loc: Cumberland, R I , USA42N71.4W
Re: 9x63 and exit pupils size new [Re: Swedpat]
      #902361 - 04/06/06 09:29 PM

Patric,

testing a 7x42 vs a 7x50 is an important comparison. But equally telling would be to compare a 7x50 vs 8x50 vs 9x50 vs 10x50. of course not all sizes are available.

In the first test you maintain brightness, but not only do you change the exit pupil from 6mm to 7mm, you also you change the total light gathering, so the end result difference seen is dependant on two changed factors.

In the second test, you maintain a constant aperture, the total light gathering is fixed, but you vary magnification and therefore exit pupil and brightness.

Both tests rely in being able to decifer the influence of two varialbes in the result. Each test modifies two different variables.

I'm inclined to think the first test that modifies the aperture would show easier the changes in low contrast brightness such as in extended objects because light gathering is increased. The second test which modifies magnification never gathers more light but brightness changes and would show the changes easier in high contrast light gathering such as point sources or faintest stars.

edz

--------------------
Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21


Post Extras: Print Post   Remind Me!   Notify Moderator  
HfxObserver
Pooh-Bah


Reged: 11/12/04
Posts: 1150
Loc: Regina, SK, Canada
Re: 9x63 and exit pupils size new [Re: EdZ]
      #902398 - 04/06/06 10:00 PM

I think the 9X63 are too close to your 10X50's, I'd go with something substantially larger and incease both power and aperature or go image stabilized if you are looking for hand held. Those Pentax are pretty nice binos, I'd be rather surprised if the Meade was a noticable difference.

-Chris

--------------------
Chris
7X50 Vixen, 10X70 Nikon "Astroluxe",22X100 Antares
80mm William Optics Megrez II ED
Santel MK6
Borg 125SD f6 (Pentax/Oasis version)
Tak-Lapides, Micro-Star
Pentax XW's 40,20,14,10,7,3.5, 5mm XO,3.8XP, Speers 5-8, 30mm Widescan III


Post Extras: Print Post   Remind Me!   Notify Moderator  
Mark9473
Postmaster


Reged: 07/21/05
Posts: 6459
Loc: 51°N 4°E
Re: 9x63 and exit pupils size new [Re: HfxObserver]
      #902641 - 04/07/06 04:22 AM

Patrick if you have a 7x50 you could always apply an objective mask to make it 7x42...

--------------------
Mark
Leica 8x20; Nikon 7x35; Vixen 8x42; Orion 15x63; Docter 15x60
WO Megrez II 80 FD / APM 107mm f/6.5 / Mewlon 210 on DM-6 + Berlebach Planet


Post Extras: Print Post   Remind Me!   Notify Moderator  
Swedpat
Pooh-Bah


Reged: 02/18/05
Posts: 1144
Loc: Boden, Sweden, Scandinavia
Re: 9x63 and exit pupils size new [Re: Mark9473]
      #902714 - 04/07/06 07:36 AM

Yes I understand a complete investigation would be to do as you mention EdZ.
The reason I prefer same magnification is because I think the same image scale gives the most relevant comparison when comparing ability to make use of a large exit pupil. And of course I can actually do like you Mark propose, and mask the objective.

Patric

--------------------
*2,3x40 Constellation View Wide-Bino
*Leupold Katmai 6x32
*Nikon Sporter I 8x36
*Swarovski SLCNew 7x42B
*Bresser (Lidl) 10x50
*Oberwerk 11x70
*Stellarvue SV50 spottingscope
*Meade 5000 26mm Plössl, Vixen LV 10/5mm

Psalm 19:2


Post Extras: Print Post   Remind Me!   Notify Moderator  
brocknroller
Carpal Tunnel


Reged: 10/16/03
Posts: 1983
Loc: Bedford Falls, Pa.
Re: 9x63 and exit pupils size new [Re: EdZ]
      #902909 - 04/07/06 11:04 AM

Quote:

Patric, testing a 7x42 vs a 7x50 is an important comparison. But equally telling would be to compare a 7x50 vs 8x50 vs 9x50 vs 10x50. of course not all sizes are available. edz


There are some 8x50s around, Steiner, Swarovski, B & L, Leica, and Doctor 8x50s occasional pop up on eBay. But much to my surprise there is at least one 9x50 configuration: http://www.opticsplanet.net/barska-9x50-matrix-binoculars-digital-timer-ab10600.html It's not FMC and has BK-7 prisms so it won't be an "apples to apples" comparison with a 10x50 unless you can find one with the same coatings and prisms. The Barska Matrix 9x50mm Binocular comes with built-in digital timer, watch, and calendar, and is "focus free". Rumor has it that Barska is planning to introduce a WP/FP model that will include a built-in outdoor thermometer, barometer, and weather vane. :-)

--------------------
Press: Are you a mod or a rocker?
Ringo: I'm a mocker


Post Extras: Print Post   Remind Me!   Notify Moderator  
Rich N
Post Laureate


Reged: 09/22/04
Posts: 5618
Loc: San Francisco Bay Area, Calif...
Re: 9x63 and exit pupils size [Re: Rich N]
      #907026 - 04/10/06 07:36 PM

Quote:

Ok, I just ordered a Celestron Ultima DX 10x50. It should be here in a few days. Even though it's a Celestro Ultima it is a little different than my older 9x63. This new Ultima is waterproof and has twist up eyecups. Not sure what other change have been made.

Rich




The new Celestron Ultima 10x50 arrived today. At first I thought it would be useful to buy two Ultimas because they would be similar in construction other than objective size and magnification. The new Celestron Ultima is a completely different binocular.

The views through the new Ultima 10x50 aren't bad. You get a lot of binocular for the money. The old Ultima has a little better resolution and contrast and so does the Zeiss 10x42FL.

I think I have yet another 10x50 that just doesn't crank my tractor. (Doesn't hold my interest)

The view of the exit pupils in the new Ultima show a little cut off of the view at the upper inside edge of each image.

Maybe I'll keep this new 10x50 for public star parties. If some kid drops it or sticks his finger on the lens it won't bother me quite as much as it would if let him use my Swarovski 10x42EL. Although the EL would likely survive.

Rich


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1


Extra information
0 registered and 43 anonymous users are browsing this forum.

Moderator:  EdZ 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 1001

Jump to

CN Forums Home



Cloudy Nights Sponsor: Astronomics