jkevn
sage
Reged: 03/02/06
Posts: 213
Loc: Tucson, Arizona
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Why is it that people interested in birding prefer roof prism over porro prism binoculars? Is there a disadvantage in using roof prism binoculars with phase-corrected coatings for amateur astronomy?
If the two types of binoculars share the same manufacturer, magnification, objective lens size and field of view, what is the difference in what you see?
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Rich N
Post Laureate
Reged: 09/22/04
Posts: 5618
Loc: San Francisco Bay Area, Calif...
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I find the roof prism binocular a little easier to hold steady because my hands are closer together.
I think the birders go where the better optics are. The high end binocular makers mostly make roof prism binoculars.
I'm not sure which came first, birders wanting high end roof prism binoculars or that's what was being made, so birders buy them.
Rich
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Some Guy
member
Reged: 11/03/06
Posts: 17
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I want to assume birders use roof prisms because they are smaller and apeture is not very important for day time.
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BillC
on a new path
Reged: 06/04/04
Posts: 4391
Loc: Lake Stevens, WA, USA
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Convenience, and to be stylish. A GOOD roof prism bino costs more to make than a Porro of equal quality. Also, Porro binos provide better depth perception.
Cheers,
Bill
--------------------
William J. Cook, Chief Opticalman, USNR-Ret.
Ophthalmic Tech, Naval Station, Everett, WA
Optical Mechanic, Puget Sound Naval Shipyard
Founder, Amateur Telescope Making Journal
21-year Mgr., Optics Dept., Captain's Nautical Supplies
Optics Mechanic, Ft. Lewis, WA.
Contributing Editor for Numerous Magazines
It's better to be a "has been" than a "never was." But only barely; the pay is about the same!
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Jon Isaacs
Postmaster
Reged: 06/16/04
Posts: 32442
Loc: San Diego, California
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>>>I want to assume birders use roof prisms because they are smaller and apeture is not very important for day time.
-----
I am something of a birder and I like roof prism binos for both star gazing and birding...
These are some of the reasons I like roof prism binos...
- Comfortable to hold, hands are closer together.
- Good eye relief... Roof prism binos tend to have 16-20mm eye relief, I don't wear glasses but I like the easy view provided by a long eye relief.
- Nitrogen purged and waterproof. The Roof design is easier to seal. Nice if it rains when birding, I think it helps prevent eyepiece fogging at night.
- Close focus. (Extremely important for astronomy. :-) ) Many mid range ($150-$400)and up roof prism binos will focus well under 10 feet. A small bird at 8 feet is a real find and binos can make spotting elusive details a lot easier. It can be frustrating to be in a position to catch a glimpse only to discover that you can't get your binos to focus.
- My experience is that roofs seem to have a slightly narrower field of view but are better corrected across the field of view, nice for viewing star fields.
Of course, you are right in that these are smaller hand held binos, 8x42s and 10x42s are popular birding sizes, there are quite a few 10x50's and a few larger ones but for big killer binos, I think its pretty much porroprisms.
And too, I know there are porro prism binos that have many of the features I described but in general, when one adds in the compactness of the roofs, they provide a good show.
Jon
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geoffrey
sage
Reged: 01/05/04
Posts: 362
Loc: North West England
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Not having a view one way or another, and ignoring the optics of my new bins and reasons for the change, I changed from porro to roof 10 days ago.
For the first hour I hated them, and then when I learned how to hold them properly, I love them.
I find them easier to hand hold, and to hold steady because my hands are closer together, and they cause your elbows to come closer to the body.
Geoffrey
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Celestron Nextstar 8SE
6.25" F7.6 Dob
Skywatcher ST80
Opticron imagic BGA PC ASF T 8x42
Zeiss Victory T FL 8x32
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KennyJ
The British Flash
Reged: 04/27/03
Posts: 20139
Loc: Lancashire UK
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Some good points made above , although I'm not sure about the accuracy of SOME of them ! :-)
For exaample , a year ago , prior to selecting a centre - focus 10x binocular for multi - purposes , I tried every one of the current top of the range roof prism offerings from Leica , Nikon , Swarovski and Zeiss .
Only the Nikon 10 x 42 HGL had comfortable eye - relief for me .
I also prefered the colour rendition and " quiet view " of the Nikon over the others , and the fact that the right diopter is adjusted in the " conventional way " -- i.e by adjusting the right eyepiece , as opposed to overly complex , awkward to use , central locking systems .
In the event , after careful consideration , in spite of the lack of waterproofing and twist - up eyecups ( another feature which most birders seem to prefer and which is more often found on roofs ) although I thought that all in all , the Nikon HGL was in fact superior to the namesake , I just couldn't justify the 40% increased price difference between the Nikon HGL and the Superior E Porro , so I settled for the Nikon 10 x 42 SE .
Apart from the much longer closest focus capability , and it's obviously narrower TFOV , I still can't decide which binocular I like the best between the 10 x 42 SE or my Zeiss 7 x 42 BGAT Classic !
For astronomy , the Nikon SE is probably superior due to it's better edge performance , and in fact , in spite of it's considerably narrower TFOV ( 7.2 * v 8.6 * ) and larger exit pupil , for star gazing , I prefer the clunky Captain's Helmsman 7 x 50 IF Porro to the Zeiss .
The Zeiss shows some small internal reflections from the roof prism which just takes the edge off it when compared to the well baffled Helmsman .
Once , when carefully comparing the two whilst mounted , looking at horizon Venus in twilight , I could JUST make out the crescent phase through the Helmsman but not through the Zeiss , although part of the reason for that could have been the finer adjustment of focus for my eyes with the individual focus of the Helmsman .
Because their barrels are closer together , roof prism do tend to have closer focussing than Porros , which can be a HUGE advantage for birders , but by virtue of the same physical trait , it is almost impossible to make a roof prism binocular any larger than around 65mm without the oculars ending up too far apart for human eyes .
Anyone in any doubt about how well roof prism binoculars can perform for hand - held astronomy need look no further than the observing reports from Fiske in the mini - reviews section of the Nikon 8 x 42 HG .
Regards , Kenny
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Milton Wilcox R.I.P
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Claudio
sage
Reged: 07/26/04
Posts: 277
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My experience is that roof prism binoculars with good phase correction can be as sharp as the Porro prism glasses. However, binoculars with roof prisms are generally designed in order to be compact instruments, therefore they are often fast optics and their longitudinal chromatic aberration is not well controlled.
Regarding some effects of the different stereoscopic vision in Porro glasses and roof glasses, read some contributions in the following thread:
http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/221933/page/0/view/collapsed/sb/5/o/all/fpart/all/vc/1
Regards
Claudio
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edcannon
professor emeritus
Reged: 11/19/03
Posts: 693
Loc: Austin, Texas
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This was probably implied above, but for a given size, e.g., 8x42, 10x42), I'm pretty sure that roof-prism models are almost always significantly lighter in weight. That's very good for hiking, especially if they are hanging on a strap around your neck.
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Ed Cannon - Austin, Texas, USA
Bushnell H2O 8x42, Celestron Skymaster 12x60
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moynihan
Carpal Tunnel
Reged: 07/22/03
Posts: 2039
Loc: Lake Michigan Watershed
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If i am not mistaken, i think it may not be possible, or without great expense, to make porroprism binoculars truly waterproof (i.e., extended immersion), unless they have individual focus eyepieces.
My Swift Audubon porros are advertised as WP, but it is hard to believe they would not leak during an extended full immersion.
The WP factor is important to many birders. That combined with compactness (exspecially the narrower grip), I think account for quite abit of popularity.
The close focus champions are often porros (reverse porro design actually, i.e. Bushnell 7x26 custom, Pentac Papilio).
Optically, there few center focus porros made to very high quality, compared to roofs, now days, (Swift Audubon series, Nikon SE series to name the two i am familiar with). That is not an optical characteristic though, it is more a market characteristic. For example, the Nikon SE series matches (in my viewing experience) anything in the roof world on the high end.
The advent of the phase coating for roofs by Zeiss in late 1980's)is what allowed them to conquer the high end consumer and middle level market. It allowed them to match the better porros.
The market dominance of roofs in the high end i think pretty much precludes the more high quality center focus porros from entering, due to the consumer preference. Personally, i use both porros and roofs.
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"May I have the ability to reduce the uncertainties I can; the willingness to work with the uncertainties I cannot; and the scientific knowledge to know the difference."
Based upon an adaptation from Reinhold Niebuhr's Serenity Prayer, by J. Barsugli, C. Anderson, J. Smith and J. Vogel.
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Rich N
Post Laureate
Reged: 09/22/04
Posts: 5618
Loc: San Francisco Bay Area, Calif...
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Hi Kenny,
Have tried diopter adjustment on one of the mid or full sized Leicas? It's very user friendly.
Thanks,
Rich
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hallelujah
Post Laureate
Reged: 07/14/06
Posts: 3980
Loc: Colorado Rocky Mountains
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moynihan,
As far as making porro prism binoculars truly waterproof(extended immersion) I don't see what, if anything, that has to do with bird watching. 
Only JIS 7 and JIS 8 (Japanese Industrial Standards) are designed for immersion/submersion. Unless a birder drops their binoculars into a lake or pond or stream, the "highest" classifications can also be an unnecessary cost factor. 
The Pentax PCF WP II's are rated JIS 6 (Watertight - Having no ingress of water into inside by receiving direct jet of water from any direction). These have internal focus and are $250 and under.
Leupold also make an internal focus porro prism in their Cascades series for around $300.
Fujinon also makes the BFL waterproof porro prism binocular for around $300.
I would be willing to speculate that the majority of consumers, who purchase roof prism binoculars because they are rated as waterproof, have NO idea of the water-proofness classification.
Also, just because a roof prism is "advertised" as waterproof does not mean anything, 'unless' you are aware of its classification. 
http://www.opticstalk.com/forum_posts.asp?TID=784&PN=1
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Nikon7x35GoldSentinel 9.3*(2)+Pentax8x40PCFWPII+MinoxBD10x44BP+FujinonFMTRSX7x50
Nikon10x50GoldSentinel+Pentax12x50 5.5*Japan+Pentax12x50PCFWPII+Vixen8x56Geoma
Fujinon12x60HB+Pentax16x60PCFWP+Pentax20x60PCFWP+Pentax20x60PCFWPII
Tento20x60USSR+Orion12x63MiniGiant+Spectrum I 20x65+Orion15x70LittleGiant II
Orion20x70LittleGiant II+Orion16x80Giant+Orion30x80MEGAView+Barska30x80X-Trail
BurgessOptical20x90SeriesII
Edited by hallelujah (05/26/07 03:02 PM)
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BillC
on a new path
Reged: 06/04/04
Posts: 4391
Loc: Lake Stevens, WA, USA
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>>>If i am not mistaken, i think it may not be possible, or without great expense, to make porroprism binoculars truly waterproof (i.e., extended immersion), unless they have individual focus eyepieces.
My Swift Audubon porros are advertised as WP, but it is hard to believe they would not leak during an extended full immersion.<<<
#3 Write it in stone and remember it.
Cheers,
Bill
--------------------
William J. Cook, Chief Opticalman, USNR-Ret.
Ophthalmic Tech, Naval Station, Everett, WA
Optical Mechanic, Puget Sound Naval Shipyard
Founder, Amateur Telescope Making Journal
21-year Mgr., Optics Dept., Captain's Nautical Supplies
Optics Mechanic, Ft. Lewis, WA.
Contributing Editor for Numerous Magazines
It's better to be a "has been" than a "never was." But only barely; the pay is about the same!
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moynihan
Carpal Tunnel
Reged: 07/22/03
Posts: 2039
Loc: Lake Michigan Watershed
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Quote:
...I would be willing to speculate that the majority of consumers, who purchase roof prism binoculars because they are rated as waterproof, have NO idea of the water-proofness classification.
I would certainly agree with that
jay
--------------------
"May I have the ability to reduce the uncertainties I can; the willingness to work with the uncertainties I cannot; and the scientific knowledge to know the difference."
Based upon an adaptation from Reinhold Niebuhr's Serenity Prayer, by J. Barsugli, C. Anderson, J. Smith and J. Vogel.
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Rich N
Post Laureate
Reged: 09/22/04
Posts: 5618
Loc: San Francisco Bay Area, Calif...
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A friend and very active birder would find water inside his old non-waterproof porro prism binocular when he and the rest of the local Audubon group would be birding in a light rain. He now has a Zeiss 8x42 FL and has had no more problems with water getting into his binocular.
Rich
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KennyJ
The British Flash
Reged: 04/27/03
Posts: 20139
Loc: Lancashire UK
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< Hi Kenny,
Have tried diopter adjustment on one of the mid or full sized Leicas? It's very user friendly. >
Hi Rich ,
Yes , as I mentioned above , I tried a couple of 42mm Leica Ultravids .
The pull - push system DID work for me -- but the pessimist in me envisaged the possibility of something going wrong with that system ( as it has with several Zeiss FL models I've read about ) and call me old fashioned -- but I just prefer dipoter adjustments to be on the RIGHT ocular , and non - locking ! :-)
I've never have any trouble either setting the diopter or with the diopter " adjusting itself " on any of the better binoculars I've had , so personally , I'm of the opinion --
-- " if it ain't broke -- why fix it ? " :-)
Regards , Kenny
--------------------
Milton Wilcox R.I.P
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Rich N
Post Laureate
Reged: 09/22/04
Posts: 5618
Loc: San Francisco Bay Area, Calif...
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Thanks Kenny. Nothing wrong with the old way.
What I like about the Leica system, you can adjust both sides at the same time before you lock the wheels (knobs?).
I don't use my Zeiss FLs every day but so far there have been no problems with the focuser diopter adjustment. The same for my Leicas.
Back to the roof vs. porro question, the Nikon SEs are very comfortable to hold.
All the best,
Rich
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hallelujah
Post Laureate
Reged: 07/14/06
Posts: 3980
Loc: Colorado Rocky Mountains
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jkevn,
Another company that I forgot to mention is Minox. They have the BD 8x44 (10x44) BP porro-prism binoculars with internal focusing which is waterproof down to 5m, for around $500.
Birders may gain in terms of slightly lighter weight.
For example, a Leupold Cascades 8x or 10x porro prism is only 2 ozs & 2.3 ozs. heavier than the equivalent roof prism binocular.
Minox 8x44 porro weighs 24.3 ozs. while the Minox HG roof 8.5x43 weighs 22.9 ozs., for a total weight difference of 1.4 ozs.
The roof prism may offer slightly less weight and a smaller size, but, it is a trade-off in terms of less light transmission (Minox roofs 92%) and a loss of 3D-effect, etc.
Speaking for myself, as a birder, I appreciate the heavier weight of porros when using 10x, and higher magnifications, becuase I notice better dampening/less handshake.
Minox readily states in their literature, "The Porro prism offers clear advantages over roof prisms, especially in the higher light transmission (94.5%), as less light is lost in the optical path through reflection, on the way to the eye".
"Only binoculars fitted with Porro prisms are able to provide the user with an enhanced three-dimensional shape or 3D-effect of the object in view, this being based on the increased objective lens spacing. With this almost three-dimensional imaging it is a lot easier to exactly estimate the position and distance of the objects in the field of view".......
Not all birders "prefer" roof prism binoculars, I surely do not.
Edited by hallelujah (05/26/07 05:14 PM)
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JHollJr
sage
Reged: 06/10/06
Posts: 204
Loc: Quantico, Virginia
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Kenny,
Remember that there is a lifetime guarantee with the Leicas so if something goes wrong with diopter adjustment Leica will fix it ro replace, as the situation dictates.
--------------------
Justin
Northern Virginia
Celestron Nexstar 8i SE
Questar 3.5 purchased 1980
Leica Ultravid 10x50's
Oberwerk 20x80 Ultra Lights
UA UniMount Light Deluxe
Horrible Eyes
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Swedpat
Pooh-Bah
Reged: 02/18/05
Posts: 1144
Loc: Boden, Sweden, Scandinavia
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Quote:
Why is it that people interested in birding prefer roof prism over porro prism binoculars? Is there a disadvantage in using roof prism binoculars with phase-corrected coatings for amateur astronomy?
Hi jkevn!
I have some opinions in this matter:
A roof prism binocular is more durable than a porro model which often is more important for birders.
Yes, there may during some circumstances be a disadvantage in using roof binos for astronomy: against strong light sources the roof construction reproduces "spikes" across the light source, who resemble the effect of a star filter.
This page shows how it looks like:
http://www.tiffen.com/star_filters.htm
The star filter effect may be striking at astronomical photos, but surely not desirable at live views...
Quote:
If the two types of binoculars share the same manufacturer, magnification, objective lens size and field of view, what is the difference in what you see?
I will say that besides a sometimes (mostly seldom) noticable star filter effect you will not se any difference, if the optical quality is equal. But this will result in a much higher price for the roof prism model.
About the stated 3D-effect, or depth perception, of the porro model I highly object to that this will have any importance at astronomical distances...
Regards, Patric
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*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
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