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Are porro prisms actually a better value? (1 Viewer)

Bedankt Ries!

"1- The Fujinon 10x50 FMTR-SX.
Among other things, there are strong stories on the Internet about this viewer. It has long been claimed that
The viewer has a light transmission of 95%. Our measurements could not confirm this.
This is a door that uses light as the day of light
The maximum wavelength (550-560 nm) is 85% and the maximum wavelength is 85%.
85% of the market was turned into a light emitter
less than with a light transmission of 95%."

Andreas
 
Dennis, post 20,
Is the graph shown in post 21 convincing enough to show that extremely high transmission values for the Fujinon are internet nonsense?
Transmission is hampered by two main factors:
-1- absorption of light in the optical glass components and the extent of absorption depends very much on the quality of the optical glass and
-2- light losses due to reflection, which can be diminished by using appropriate coatings.
Even the recent excellent flagship of Nikon hardly reaches 90% light transmission and in that binocular the best optical glass components and top-of-the-line coatings are applied.
Gijs van Ginkel
 
As you can see by their own description in Dennis post #20 Albinos' earlier method of measuring light transmission was really nothing more than a rough guess.

When they began to use a spectrophotometer around the beginning of 2010 there followed a period of what might be called teething problems. There were a number of suspiciously high transmission values, but it was the Docter 8x56 Nobilem measurement from Dennis post #5 that most clearly demonstrated that something was wrong, since it shows an obviously impossible 100% transmission between about 570 and 590 nm.

My impression is that Albinos' measurements after around 2012/13 became more reliable and have tended to fall more in line with the measurements using ISO protocols followed in Gijs reviews.
 
Gijs van Ginkel said:
Dennis, post 20,
Is the graph shown in post 21 convincing enough to show that extremely high transmission values for the Fujinon are internet nonsense?
Transmission is hampered by two main factors:
-1- absorption of light in the optical glass components and the extent of absorption depends very much on the quality of the optical glass and
-2- light losses due to reflection, which can be diminished by using appropriate coatings.
Even the recent excellent flagship of Nikon hardly reaches 90% light transmission and in that binocular the best optical glass components and top-of-the-line coatings are applied.
Gijs van Ginkel
Click to expand...
i guess that is why the Habicht's have such high transmission. A simpler porro prism design with less air to glass surfaces combined with Swarovski EL glass and EL coatings.
 
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Hi, CO West. I worked on this question for my satisfaction in use with binoculars. I have come across a few Porro that I thought were good enough to be usable as a high quality binoculars to my eyes.

reverse Porro, Pentax Papilio , 8.5x21, a Minolta 10x25 , a Bushnell Elite 7x28.

Porros mid size: Swift Audubon 8x42, Fujinon Sxfmt 8x30 as well as the 6x30 Marine Ark, and the Nikon 10x35 E2.

Porros Larger, Oberwerk Ultra 10x50 as well as the Deluxe model. Minox BP 10x42, Orion Ultraview 10x42, Eschenbach Trophy 8x56, Captains Nautical 7x50 a Kamakura offering.

Astronomical Porros 15x70 Oberwerk, and 16x70 Fujinon SXFmt. Williams Optics 22x70, Pentax 20x60, And an older Oberwerk BT100.

All of these are good to my eyes. Some have gone out of fashion. , (not function.)

People are calling on science tests. If your eyes seem to show they are good, then they are good. Sure, my eyes aren't as good as they were when I was young....
 
Dennis, post 27,
Our method of measuring transmissions was checked by:
-1- an independent German institute for calibrating and checking optical instruments and
-2- by one of the large binocular companies in Germany-Austria.
Our results were spot on correct and with exactly the same results within experimental error as found by these two institutions. So our method is very reliable it is even used to measure small absorption changes on a molecular level in biological samples.
Gijs van Ginkel
 
CO_west said:
I understand the differences between porro and roof prism binoculars, and I read again and again that you can get equivalent performance out of porro prisms for less money. What I don't know is how specific porro prisms compare to roof prism binoculars.

For example, I see the Nikon Monarch 5 recommended as a good set of binoculars in their price range (about $270). How would the porro prism Nikon Action Extreme binoculars ($130) compare? I would go to the store and try them, but I hardly trust my judgment when it comes to these things - I don't really know how to judge binoculars other than what feels nice.

I'm in the market for 8x42 binoculars (or something similar), and I am willing to spend up to $300. If I can get the same performance for less, and end up saving money, that would be great. I'd just like to know how current porro prism offerings compare to the popular roof prisms.
Click to expand...

Does size, weight, and bulk figure into your performance equation?
 
Gijs van Ginkel said:
Dennis, post 27,
Our method of measuring transmissions was checked by:
-1- an independent German institute for calibrating and checking optical instruments and
-2- by one of the large binocular companies in Germany-Austria.
Our results were spot on correct and with exactly the same results within experimental error as found by these two institutions. So our method is very reliable it is even used to measure small absorption changes on a molecular level in biological samples.
Gijs van Ginkel
Click to expand...
Gijs van Ginkel. Thanks. There is so much variation between the transmission testing it makes you wonder who is correct. Even Fujinon uses a 95% transmission figure in their advertising for the 10x50 FMT-SX. How could they do that without some valid testing? Wouldn't that be false advertising?

" FUJINON’S unique EBC coating allows 95% of light to pass through the binocular great for low-light performance."
 
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Hello,

sometimes the own review helps!
I tested the Fujinon 10x50 for a whole day, evening and night against a Swarovski 10x50, that Swarovski is measured at allbino's "only" with about 85% transmission, but I could not see any brightness differences between the two glasses, on the contrary, in some situations in the dusk, I even had the feeling that Swarovski was a touch brighter!
The Fujinon should have been a bit brighter here with 10% more reflection, even then I realized that allbinos neither the fujinon nor the Swarovski had measured correctly, I estimated both glasses on about 90% transmission.

Andreas
 
Conndomat said:
The Fujinon should have been a bit brighter here with 10% more reflection, even then I realized that allbinos neither the fujinon nor the Swarovski had measured correctly, I estimated both glasses on about 90% transmission.

Andreas
Click to expand...

How could you "estimate" the light throughput more accurately than people who have measured it, can you enlighten us? I have recently looked thru a pair of vintage extra-wide angle French 8x30 binos (a side note: with a true FoV of 200m/1000m, AFoV=91*!). They seemed to be quite bright to me, but the light transmission certainly was no more than 50-60%.
 
Foss said:
Does size, weight, and bulk figure into your performance equation?
Click to expand...
Another more subtle aspect that has not been mentioned on this thread is the fact that objects (such as birds) look significantly smaller thru porros than when viewed thru roofs of the same magnification. I would think that for many people, certainly for me, that is a deal killer. Besides a number of roofs I own two porros, Nikon SE 8x32 and 10x42, but they do not see a lot of use. How do people who frequently use porros cope with the above "size scaling issue"?
 
PeterPS said:
Another more subtle aspect that has not been mentioned on this thread is the fact that objects (such as birds) look significantly smaller thru porros than when viewed thru roofs of the same magnification. I would think that for many people, certainly for me, that is a deal killer. Besides a number of roofs I own two porros, Nikon SE 8x32 and 10x42, but they do not see a lot of use. How do people who frequently use porros cope with the above "size scaling issue"?
Click to expand...

You can avoid this problem by comparing instruments with not only the same magnification, but also the same field of view.
 
Mark9473 said:
You can avoid this problem by comparing instruments with not only the same magnification, but also the same field of view.
Click to expand...

Unfortunately that's not true: the image size scaling in porros is insignificantly affected by the FOV, if at all.
 
PeterPS said:
How could you "estimate" the light throughput more accurately than people who have measured it, can you enlighten us?
Click to expand...

I did not say that so, Mr. van Ginkel's measurements will be a lot more accurate!
But, swarovski is an absolutely serious manufacturer by the way, as the only one in his binoculars the correct AFOV indicates, I trust the measurements of this company much more than the measurements of allbino's and they give 90% transmission on the Swarovski 10x50!

If I take this as a basis and compare it to the Fujinon, that even in some situations I found it a bit darker, my estimate is not so far from the measured 85% that was measured for the fujinon!
However, it was clear that the Fujinon never has 10% more transmission than the Swarovski.

Andreas
 
PeterPS said:
Another more subtle aspect that has not been mentioned on this thread is the fact that objects (such as birds) look significantly smaller thru porros than when viewed thru roofs of the same magnification. I would think that for many people, certainly for me, that is a deal killer. Besides a number of roofs I own two porros, Nikon SE 8x32 and 10x42, but they do not see a lot of use. How do people who frequently use porros cope with the above "size scaling issue"?
Click to expand...

Hi,

I know that it is an illusion caused by the larger stereo basis of normal porro binoculars and ignore it - our brain is used to a stereo basis of our interpupilary distance and gets confused by the effects of a larger one and believes the object is closer and thus appears smaller.

Instead I enjoy the 3d view which is directly connected to that illusion.

Joachim
 
CO_west said:
I understand the differences between porro and roof prism binoculars, and I read again and again that you can get equivalent performance out of porro prisms for less money. What I don't know is how specific porro prisms compare to roof prism binoculars.
Click to expand...

In theory yes - but in practice, for binoculars to be used for birding, roofs tend to be more suitable. Porros are hard to make sealed/waterproof and there are fewer options so your opportunities to test one "in the hand" (very very important, in my opinion) may be limited. Most of the porros mentioned in this thread (eg. the Habichts, Nobilems and even the EIIs) are well beyond of the US$300 class, and the Nobilems and Fujinons are much bigger/bulkier than an 8x42. The Nikon SEs are the best of those mentioned for birding (longish eye relief, very important if you wear spectacles/glasses, and reasonably weatherproof), but are no longer in production and sought after by collectors. I would try to test something like the Swift 820 Audubon (8.5x44) or maybe the Vixen Foresta 8x42 porro which I've seen some good comments about. In the UK Opticron's HR WP series (not sure how available these are) seemed really good for their price, albeit with a somewhat restricted field of view. But none of these will be as weatherproof as the Monarch 5. This isn't an issue if you are stargazing or backyard/urban birding, but it's very different if you're trekking about and the binoculars may get rained on or exposed to dust etc...

I recently tried the 8x30 Kowa YF porro and was very impressed. It ticked most of the boxes - bright enough, sufficiently sharp, competitive field of view despite having enough eye relief to be used with glasses. There was a bit of distortion and build quality was what you'd expect of a $100 binocular, but you've got to remember this is a $100 binocular! And it's waterproof (at least in theory)! If someone invested in a higher quality development of this it could be very good indeed. But, alas, no one will...
 
"In theory yes - but in practice, for binoculars to be used for birding, roofs tend to be more suitable."

I don't know about that. Have you ever actually used a porro in the field much? I sure like the way porro's with their 3D stereoscopic view pop the birds out from the backround and how bright they are with their high transmission and how light they are with out all that glass inside them that a roof has like in the Nikon porro's and Swarovski porro's. Porro's and roof's have their disadvantages and advantages. A porro can be ever bit as good of a birding binocular as a roof and with better optics and higher quality for less money. I am having a hard time deciding what binoculars I am taking to Yellowstone National Park next week my $2500.00 Swarovski SV 12x50's or my $700.00 Swarovski 10x40 Habicht's because the Habicht's pop the grizzly bears out of the deep woods with their 3D like you wouldn't believe. You get that same advantage birding with a porro also. I would take a Nikon 8x30 EII porro over a lower end roof any day for birding.
 
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