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.

8X32 FL vs 8X42 FL

Reply
 
Thread Tools Rating: Thread Rating: 1 votes, 5.00 average.
Old Saturday 19th February 2005, 13:50   #1
henry link
Registered User

 
Join Date: Feb 2004
Location: north carolina
Posts: 4,383
8X32 FL vs 8X42 FL

I had the opportunity yesterday to briefly compare a new Zeiss 8X32 FL to my 8X42 FL. My time at the store was limited so I confined the comparision to the two areas of optical performance that interested me the most between these two binoculars. I felt I could make reasonably accurate judgements about relative light transmission and off-axis sharpness in the 20 minutes I had available. Most of the observations were made in bright sunlight, a few in subdued light inside the store.

Since Zeiss claims that there is less than a 2% difference in light transmission between these two binoculars even though the 32mm uses a Schmidt-Pechan prism and the 42mm an Abbe-Koenig, I was curious to see if I could detect any difference in image brightness in sunlight, where the difference in exit pupil sizes would not be a factor. I know from comparing eyepieces with measured transmission figures that my threshhold for being able to detect any difference at all in light transmission is about 3%. The binoculars were extremely close, but the 8X42 was consistently slightly brighter in sunlight. In a low light area of the store it was substantially brighter. Color transmission appeared to be identical between the two. Contrast in the 32mm was extremely good, roughly equal to the 42mm in sunlight.

From looking at internal views of the FLs' optics on Zeiss websites I suspected that the objective focal ratio of the 32mm might be higher than the 42mm. I wondered whether this could produce better off-axis behaviour in the 32mm. Sure enough, I did observe an improvement in sharpness at the edge of the field in the 32mm (even though it's apparent field is actually a little wider than the 42mm), and more importantly for actual use in the field (provided this aspect of performance matters to you at all) there is clearly some improvement in the area about 10-15 degrees of AFOV away from the center. I would say the off-axis loss of sharpness in the 32mm closely resembles the behavior of the Swarovski 8.5X42 EL, not in the same class as binoculars with field flatteners, but quite good.

The store had a Nikon 8X32 SE and a Swarovski 8X32 EL in stock so I very briefly compared the 8X32 FL to those. The FL was obviously brighter and had better off-axis sharpness than the EL. It appeared about equal to the SE in brightness, but as usual the SE field flattener produced superior off-axis sharpness. I didn't have time or the resolution chart, magnification booster and tripod I would have needed to judge center of the field sharpness, but hand held the 32 FL appeared to have no obvious problems even compared to the 42mm FL.

One curious observation; I noticed that magnification in the 32mm FL appeared a little higher at close distances compared to the 42mm FL. I remembered that AK prisms have a slight off-set like porros, only much less. When I compared the objective spacing of the two I could see that the centers of the 32mm objectives were around 5-10mm closer together than 42mm's at the same IPD setting. A good indication of just how sensitive the eye/brain is to this particular illusion.

Last edited by henry link : Saturday 19th February 2005 at 19:32.
henry link is online now  
Reply With Quote
Old Saturday 19th February 2005, 19:06   #2
Richard Scott
Registered User

 
Join Date: Nov 2004
Location: South Yorkshire
Posts: 347
I'm really pleased that someone has got around to comparing these two models. The other day I compared the Zeiss 10x32FL, 8x42FL and Leica 8x32 Ultravid. Unfortunately, there were no Zeiss 8x32 in stock.

I'm unable to see CA, so can't comment on that. I looked for the reported lack of off-axis sharpness in the 8x42, but couldn't see that either. In fact to my eyes they all looked superb, and at that price they should be!

What I can comment on is how they felt in the hands.

The 10x32FL was extremely comfortable to hold, a pleasure to use. Almost as comfortable as the suprememely comfortable Swaro 8x32EL.

The 8x42FL, I thought was comfortable, well-balanced, but very bulky - they dwarfed my Leica 10x42BAs.

As for the 8x32 Ultravids, they look the business, feel superbly engineered (better than the Zeiss), but in my hands they are far too small. I found them uncomfortable - no space to put the thumbs. Even my wife, with her relatively small hands, came to the same conclusion. No doubt they are optically superior to the model they replace, but ergonomically they are a backward step.

Incidentally, they all worked well with my glasses, but I had to twist up the eyecups a notch on the Zeiss 8x42 to avoid getting black-outs when panning.

Rich
(still can't make up my mind what to buy)
Richard Scott is offline  
Reply With Quote
Old Saturday 19th February 2005, 21:36   #3
Swissboy
Registered User
BF Supporter 2019
 
Swissboy's Avatar

 
Join Date: Dec 2003
Location: Sempach, Switzerland
Posts: 3,612
Quote:
Originally Posted by Richard Scott
(still can't make up my mind what to buy)
Rich, same with me, I am still undecided. I did not have the x32 Ultravids to compare, but other than that, I fully agree with your findings. I also felt the x42 FLs were rather bulky. But what bothered me most were the ribs. They are not as bad as on the (Leica) Trinovids, but definitely irritating as long as one does not wear gloves.

I did have the x32FLs to compare, however. They a rather smallish, too. But I gave little attention to them as I don't have a need in that size now. They were a bit brighter than the x32 ELs, but the ELs had a more comfortable feel in the hand. (Unlike the x42 ELs which are too large for my hands.)
__________________
Robert
--PS: That's a Sooty Falcon on the avatar, photo taken near Sharm el Sheik, Egypt. My highest priority raptor at the time.
What's your species on the avatar? I often have no clue
!
Swissboy is offline  
Reply With Quote

BF Supporter 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 Support BirdForum With A Donation

Old Sunday 20th February 2005, 06:22   #4
Curtis Croulet
Registered User
 
Curtis Croulet's Avatar

 
Join Date: Apr 2004
Location: Temecula, California
Posts: 1,294
Swissboy: Some users in the (in)famous Living Bird article agree with you -- they don't like the "ribs." For me, the FL is very comfortable. I have small hands.
Curtis Croulet is offline  
Reply With Quote
Old Monday 21st February 2005, 13:54   #5
Swissboy
Registered User
BF Supporter 2019
 
Swissboy's Avatar

 
Join Date: Dec 2003
Location: Sempach, Switzerland
Posts: 3,612
Quote:
Originally Posted by Curtis Croulet
Swissboy: Some users in the (in)famous Living Bird article agree with you -- they don't like the "ribs." For me, the FL is very comfortable. I have small hands.
Thanks Curtis, I think I could get used to the ribs; it's just not optimal for me. But definitely better than on the Trinovids. There, I had tried to file off the ribs to some extent. With unsatisfactory results I should add, as they now have a rough texture. So I actually made things worse in a way.

But the ribs on the FLs do increase the circumference to some extent.
__________________
Robert
--PS: That's a Sooty Falcon on the avatar, photo taken near Sharm el Sheik, Egypt. My highest priority raptor at the time.
What's your species on the avatar? I often have no clue
!
Swissboy is offline  
Reply With Quote

BF Supporter 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 Support BirdForum With A Donation

Old Monday 21st February 2005, 16:35   #6
Curtis Croulet
Registered User
 
Curtis Croulet's Avatar

 
Join Date: Apr 2004
Location: Temecula, California
Posts: 1,294
My Eagle Optics bin has a smooth exterior, like the Ultravid, so I immediately liked the Ultravid (that aspect of it, anyway) when I picked it up. It's all a matter of individual preference. One man's, "It should have ribs, to make it easier to hold when I'm wearing heavy gloves in Antarctica" becomes another man's, "Why the @#$% did they put those ribs on there -- it's so uncomfortable to hold!"
Curtis Croulet is offline  
Reply With Quote
Old Monday 21st February 2005, 17:34   #7
Bill Atwood
Registered User
BF Supporter 2019

 
Join Date: Feb 2004
Location: Central Illinois
Posts: 836
I like ribs, but the doc says there bad for me.
Bill Atwood is offline  
Reply With Quote

BF Supporter 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 Support BirdForum With A Donation

Old Monday 21st February 2005, 18:57   #8
Curtis Croulet
Registered User
 
Curtis Croulet's Avatar

 
Join Date: Apr 2004
Location: Temecula, California
Posts: 1,294
I do, too. Mmm!
Curtis Croulet is offline  
Reply With Quote
Old Monday 21st February 2005, 19:19   #9
michaelboustead
Registered User
 
michaelboustead's Avatar

 
Join Date: Dec 2003
Location: York, PA USA
Posts: 363
I have owned a pair of 8x42fl for about 6 months and like them very much. I bought my wife a pair of 8x32 fl so I have had an opportunity to look through both extensively.

The biggest difference is that the 8x42fl appears brighter. Because they appear brighter, the resolution appears to me to be slightly better in the 8x42fl. I am not sure that if someone did a scientific test, I would be right. But this is what I see.

The "ribs" do not bother me. I frankly find the 8x42 easier to hold steady than the 8x32-maybe balance or mass of the 8x42. I am not sure Both are comfortable.

Mike
michaelboustead is offline  
Reply With Quote

BF Supporter 2005 2011 Support BirdForum With A Donation

Old Thursday 3rd March 2005, 21:36   #10
Eric F
Registered User
 
Eric F's Avatar

 
Join Date: Jul 2004
Location: Warrington, Cheshire, UK
Posts: 84
Although I hate to admit it, I feel myself being drawn into looking into a new pair of bins & I'm particularly taken with the FLs - although I've not had the opportunity to extensively look at them.

My only chance, in fact, was at the Rutland Water Birdfair 2004 - hardly ideal testing conditions I know. My impression was that theses - both 8x32 & 8x42 were the first Zeiss bins in a long while that I'd looked through & thought - wow these really do deliver "the business". Previous views with the Victories were lacklustre, with massive CA being visible to me - this seemed to have been banished with the FLs and resolution & brightness seemed to have been upped a notch to boot.

My dilema therefore is, should I consider upgrading my Leica 8x42 BNs.

I find them comfortable and they provide fantastic, relaxing images. However, I guess I just have that nagging feeling that there's something better out there. Can I justify this feeling???!!! Can anyone help sway me one way or the other.

Recent binocular coverage is also hinting at the pros of 7x magnifications bins - this appeals too. Shame nobody's thought of a hi-spec 7x32 bin as I'm sure this would have great potential.
Eric F is offline  
Reply With Quote
Old Friday 4th March 2005, 01:44   #11
Pileatus
Registered User

 
Join Date: May 2004
Location: USA
Posts: 2,580
Quote:
Originally Posted by Eric F
Although I hate to admit it, I feel myself being drawn into looking into a new pair of bins & I'm particularly taken with the FLs - although I've not had the opportunity to extensively look at them.

My only chance, in fact, was at the Rutland Water Birdfair 2004 - hardly ideal testing conditions I know. My impression was that theses - both 8x32 & 8x42 were the first Zeiss bins in a long while that I'd looked through & thought - wow these really do deliver "the business". Previous views with the Victories were lacklustre, with massive CA being visible to me - this seemed to have been banished with the FLs and resolution & brightness seemed to have been upped a notch to boot.

My dilema therefore is, should I consider upgrading my Leica 8x42 BNs.

I find them comfortable and they provide fantastic, relaxing images. However, I guess I just have that nagging feeling that there's something better out there. Can I justify this feeling???!!! Can anyone help sway me one way or the other.

Recent binocular coverage is also hinting at the pros of 7x magnifications bins - this appeals too. Shame nobody's thought of a hi-spec 7x32 bin as I'm sure this would have great potential.
Eric,

Since you already own a nice bin, my suggestion would be to comparison shop. Always use your BN for direct comparison and, if you find something more appealing, buy it. If you compare across magnifications, you will be surprised to find that 7X42's are very comfortable on the eyes and that, in some instances, you might actually see more due to increased stability. The truth is, however, that during the initial moments of an observation an 8X, IMO, always shows more detail than a 7X due to the increased magnification. The same is true for 10X versus 8X/7X. As soon as handshake kicks in, and it always does, lower powers become VERY appealing.

I strongly urge anyone who owns a nice bin to make direct comparisons under different lighting conditions. It's amazing how similar the best of the best are.

John
Pileatus is offline  
Reply With Quote
Old Friday 4th March 2005, 02:54   #12
Jonathan B.
Registered User

 
Join Date: Nov 2003
Location: United States
Posts: 363
Quote:
Originally Posted by Eric F
Recent binocular coverage is also hinting at the pros of 7x magnifications bins - this appeals too. Shame nobody's thought of a hi-spec 7x32 bin as I'm sure this would have great potential.
Swarovski had a 7x30 and discontinued it, so I assume it did not sell very well. The 7x30 SLC is a fine binocular whose exterior is identical to the 8x30. The FOV is slightly disappointing at 378' and the image has a subtle but noticeable amber cast. Nevertheless the image has great depth of focus and has a wonderful, natural feel, in addition to being very sharp.
Jonathan B. is offline  
Reply With Quote

BF Supporter 2004 2005 Support BirdForum With A Donation

Old Thursday 7th April 2005, 06:31   #13
Rich N
Registered User

 
Join Date: Sep 2004
Location: California
Posts: 237
Quote:
Originally Posted by Eric F
Although I hate to admit it, I feel myself being drawn into looking into a new pair of bins & I'm particularly taken with the FLs - although I've not had the opportunity to extensively look at them.

My only chance, in fact, was at the Rutland Water Birdfair 2004 - hardly ideal testing conditions I know. My impression was that theses - both 8x32 & 8x42 were the first Zeiss bins in a long while that I'd looked through & thought - wow these really do deliver "the business". Previous views with the Victories were lacklustre, with massive CA being visible to me - this seemed to have been banished with the FLs and resolution & brightness seemed to have been upped a notch to boot.

My dilema therefore is, should I consider upgrading my Leica 8x42 BNs.

I find them comfortable and they provide fantastic, relaxing images. However, I guess I just have that nagging feeling that there's something better out there. Can I justify this feeling???!!! Can anyone help sway me one way or the other.

Recent binocular coverage is also hinting at the pros of 7x magnifications bins - this appeals too. Shame nobody's thought of a hi-spec 7x32 bin as I'm sure this would have great potential.
Hi Eric,

The Leica 8x42BN is a great binocular. I love mine. I plan to keep it even if I add a Zeiss 8x32FL. I have a Zeiss 10x42FL and love it. It may be very rugged but it doesn't look as rugged as the Leica BN.

My Swarovski 8.5x42 EL I like a little better than my Leica 8x42BN.

Rich
Rich N is offline  
Reply With Quote
Old Friday 8th April 2005, 17:53   #14
tlb
Registered User

 
Join Date: Jan 2004
Location: Atlanta, Georgia
Posts: 50
Field Flatteners

Quote:
Originally Posted by henry link
I would say the off-axis loss of sharpness in the 32mm closely resembles the behavior of the Swarovski 8.5X42 EL, not in the same class as binoculars with field flatteners, but quite good.
Henry,

With respect to your comment about field flatteners, what are the tradeoffs that preclude designers from incorporating field flatteners in all binoculars?

Thanks very much for your insights,

Tony
tlb is offline  
Reply With Quote
Old Friday 8th April 2005, 20:03   #15
Leif
Registered Member

 
Join Date: Mar 2003
Posts: 2,959
Quote:
Originally Posted by tlb
Henry,

With respect to your comment about field flatteners, what are the tradeoffs that preclude designers from incorporating field flatteners in all binoculars?

Thanks very much for your insights,

Tony
I'm sure Henry can give you a better answer, but I would guess that the reason is simply cost. Manufacturers decide what features they think are most important and which can fit into the design budget. A field flattener as used in the 8x32 HG makes the eyepieces more expensive. Zeiss do not use field flatteners in the 8x32 FL, but unlike Nikon, they use use dielectric coatings on the prisms rather than silver. These are more expensive but give improved transmission and contrast. Zeiss also use flouride glass in the objectives, increasing the cost still further. I can only guess that Zeiss thought that improved coatings and improved objectives were more important than using field flatteners. Whether that is a correct call will no doubt be decided by sales. I happen to think that in 10 years time we will have binoculars with all the advantages of the FL series plus better edge to edge sharpness as per the Nikon HG and SE series. They will be more expensive, but the last few decades show that we all willing to pay ever more for better quality.

Leif
Leif is offline  
Reply With Quote

BF Supporter 2004 2005 2006 Support BirdForum With A Donation

Old Saturday 9th April 2005, 10:03   #16
Eric F
Registered User
 
Eric F's Avatar

 
Join Date: Jul 2004
Location: Warrington, Cheshire, UK
Posts: 84
Hi guys,

Thanks for all your messages - I'm surprised that at current top-end binocular prices the big names feel they have to compromise somewhere - i.e. field-flatteners or coating - I guess profit creeps in to the Q as well.

I'm off to Portugal next week and will be taking my trusted BNs. I may be tempted to have a closer look at the 7x42FLs - trouble is in an ideal world I'd also like a decent camera adapter, a new lightweight large scope and a carbon fibre tripod!

I think I might have to compromise on the bins & scope as I already have decent kit & look at a set-up for my digi-scoping. :-)
Eric F is offline  
Reply With Quote
Old Tuesday 12th April 2005, 00:49   #17
henry link
Registered User

 
Join Date: Feb 2004
Location: north carolina
Posts: 4,383
Quote:
Originally Posted by tlb
Henry,

With respect to your comment about field flatteners, what are the tradeoffs that preclude designers from incorporating field flatteners in all binoculars?

Thanks very much for your insights,

Tony
Tony,

Sorry for the late reply. I just saw your question, to which I don't really have much of an answer. I don't see any apparent optical tradeoff that I can attribute to field flatteners in the binoculars I own that use them. There has to be a very small light loss from the extra glass to air surfaces and it has been suggested here that the central sharpness may suffer, but I haven't been able to measure or see that. However, as usual with binoculars there is no way to know how a completely identical instrument except without a field flattener would compare.

I'm sure Leif is right about cost being a factor in low to medium priced binoculars, but some field flatteners like the ones in the Fujinon FMT-SX and the Nikon HG/LX are just simple singlet eyepiece elements. I would think the cost of manufacturing them must be less than $10 each, probably less than $5.

Henry
henry link is online now  
Reply With Quote
Old Tuesday 12th April 2005, 01:30   #18
Pinewood
New York correspondent
 
Pinewood's Avatar

 
Join Date: Jun 2004
Location: New York, USA
Posts: 3,806
May I suggest that effective field flatteners preclude a wide field of view and that they may have an adverse affect on edge distortions. Then again field flatteners may be used with narrow fields of view to prevent edge distortions.

Happy bird watching,
Arthur Pinewood
Pinewood is online now  
Reply With Quote
Old Tuesday 12th April 2005, 12:22   #19
Leif
Registered Member

 
Join Date: Mar 2003
Posts: 2,959
Quote:
Originally Posted by henry link
I'm sure Leif is right about cost being a factor in low to medium priced binoculars, but some field flatteners like the ones in the Fujinon FMT-SX and the Nikon HG/LX are just simple singlet eyepiece elements. I would think the cost of manufacturing them must be less than $10 each, probably less than $5.

Henry
Henry: Although there is only one extra element, I suspect that other elements in the eyepiece also have to change, leading to a greater increase in cost than might otherwise be expected. To my eyes the issue with the Zeiss FL (and Swarovski 8.5x42 EL) is not primarily field curvature, though there is some, but off axis softness. In other words, simply flattening the field would provide minimal benefit though it might still be worthwhile. To get a signficant improvement the entire eyepiece design would have to change.

I suspect the field flattener element is just the one component of the design that the marketing wonks have focussed on (no pun intended) as it sounds good ("we've got something Leica haven't got [from Nikon HQ comes the sound of a raspberry being blown]") and highlights the fact that there is an almost flat field and almost perfect edge to edge sharpness.

Perhaps there are also patent issues? I wonder if companies such as TMB and Televue patent eyepiece designs such as the Naglers ...

Leif
Leif is offline  
Reply With Quote

BF Supporter 2004 2005 2006 Support BirdForum With A Donation

Old Tuesday 12th April 2005, 15:46   #20
Curtis Croulet
Registered User
 
Curtis Croulet's Avatar

 
Join Date: Apr 2004
Location: Temecula, California
Posts: 1,294
Quote:
Originally Posted by Leif
Perhaps there are also patent issues? I wonder if companies such as TMB and Televue patent eyepiece designs such as the Naglers ...
The Nagler eyepiece design is patented: U.S. Patent #4,286,844, issued Sep 1, 1981.
Curtis Croulet is offline  
Reply With Quote
Old Tuesday 12th April 2005, 15:47   #21
henry link
Registered User

 
Join Date: Feb 2004
Location: north carolina
Posts: 4,383
Arthur and Leif,

Probably "field flatteners " is a misnomer for these things since the binoculars that use them still have some field curvature. A diagram in an old Fujinon FMT-SX brochure shows a reduction in "distortion" and edge "astigmatism". I think most of the edge softness that can't be corrected by refocusing is astigmatism. It turns star points near the edge into lines, parallel to the edge of the field on one side of focus, perpendicular on the other side and little crosses at best focus. That's what I see near the edge of the field in the Zeiss 8X42 FL.

As to distortion, I can't see much in the flat field binoculars I use, and it varies from some pincushion in a Pentax 10X50 PIF to very slight barrel in a Fujinon 8X30 FMT-SX. It's true I haven't noticed any flat field binoculars with AFOV's above 65 degrees, but it seems that almost all "wide field" binoculars now have fields that fall between 60 and 65 degrees. Binoculars with 70 degree fields like the Nikon EII and Swift Audubon (and Arthur's beloved Leitz Binuxit) have unfortunately become rarities.

Henry
henry link is online now  
Reply With Quote
Old Tuesday 12th April 2005, 17:22   #22
kabsetz
Registered User

 
Join Date: Jun 2004
Location: Finland
Posts: 1,495
Yep,

The Nikon SE, with "field flatteners", has much less astigmatism towards the edges than do binoculars without them, such as all the Ultravids, Zeiss FLs, Swaros etc., and like Leif, I also don't think it is just because of an element which reduces curvature.

The flattest field I have seen in binoculars, with the least amount of both curvature and astigmatism, is in the Canon 15x50 IS UD, which also has a "field flattener".

Kimmo
kabsetz is offline  
Reply With Quote
Old Tuesday 12th April 2005, 21:18   #23
Rich N
Registered User

 
Join Date: Sep 2004
Location: California
Posts: 237
Unhappy

Quote:
Originally Posted by kabsetz
Yep,

The Nikon SE, with "field flatteners", has much less astigmatism towards the edges than do binoculars without them, such as all the Ultravids, Zeiss FLs, Swaros etc., and like Leif, I also don't think it is just because of an element which reduces curvature.

The flattest field I have seen in binoculars, with the least amount of both curvature and astigmatism, is in the Canon 15x50 IS UD, which also has a "field flattener".

Kimmo
When comparing the Nikon SE to Ultravids, FLs, and ELs you need to consider the size of the true field. The image quality in the Ultravids, FLs, and ELs have better image quality at the point where the EL stops than at the edge of the field in the Ultravids, FLs and ELs.

The true field of the 10x42 SE is 314 feet at 1000 yards
The true field of the 10x42 Ultravid, FL and EL, is 330 feet at 1000 yards.

If you look at an object 157 feet (1/2 of the field of the SE) from the center of the field in the Ultravid, FL and EL it will look better than the same object at 165 (1/2 of the field of the Ultravid, FL and EL) from the center of the field in the Ultravid, FL and EL.

Rich

Last edited by Rich N : Tuesday 12th April 2005 at 21:39.
Rich N is offline  
Reply With Quote
Old Saturday 21st May 2005, 21:59   #24
henry link
Registered User

 
Join Date: Feb 2004
Location: north carolina
Posts: 4,383
Recently I borrowed a friends new Zeiss 8X32 FL with the idea of doing a detailed comparison of it, the Nikon 8X32 SE and the Zeiss 8X42 FL. Unfortunately it became apparent after resolution and star testing with the magnification boosted to 40X that this particular 8X32 FL was not a very strong sample. The defects were not severe, but the left side had some astigmatism and the right side had slightly decentered optics. It would have been at a clear disadvantage in an overall comparision to defect free samples of the other two. So what I am posting now are just the observations I an pretty confident are not affected by the sample defects.

The eyecups on the 32mm FL have been changed compared to the early 42mm FL cups. The rim is now wider and IMO more comfortable. Zeiss-USA says the new cups fit the 42mm models, but are not yet available as a separate part in the US. Ill be getting a pair as soon as they are available. If any other 42mm FL owners are interested you will need to get a new larger rainguard at the same time. I suppose the newest 42mms are already supplied with these.

The 32mm FL has more elaborate internal baffling between the focusing element and the prism housing compared to the 42mm. I dont know if this reflects different baffling requirements for the 32mm or if it is an improvement designed to increase contrast that will be incorporated in the 42mms. A little flare can be seen under difficult lighting conditions. In the 8X32mm this occurs at close focus when the focusing element has been moved far enough back to expose reflections from the edge of the objective cell to the eye. Oddly enough it happens for exactly the opposite reason in the 8X42mm FL. At longer focusing distances in the 8X42 the focusing element moves far enough forward from the prism housing for reflections from the edge of its cell to become exposed to the eye. Flare is really not much of a problem in either and is highly dependent on the eyecup length chosen.

Light transmission is very high in the 8X32 FL, only very slightly below the 8X42. I find Zeiss claim of about 92% transmission quite credible. This is a considerable achievement given the disadvantage of the Schmidt-Pechan prism. Sometimes I could see no difference at all in brightness between the two (or the Nikon SE), however after switching back and forth quickly many times I found the majority of the time the 8X42 FL and 8X32 SE looked slightly brighter in bright sunlight. Of course in dim light the 8X42 was much brighter than the other two. I could detect no difference in color transmission between the two Zeiss.

Correction for longitudinal chromatic aberration appears to be just as good in the 32mm FL as in the 42mm. Even with the magnification boosted to 40X the center of the field is remarkably free of color friinging, with fringes about 1/4 the width of those in the Nikon 8X32 SE.

I measured center of the field resolution of the left (astigmatic) side of this pair of 8X32 FLs at 5.2. The right side measured about 4.2 which is certainly closer to what could be expected from a defect free pair. Under the same test conditions the Nikon SE measured about 3.8 and the 8X42 FL about 3.2. All of these figures when multiplied by 8X are better than eyesight resolution, but worse than expected measured resolution, even if it is still better than eyesight usually means something is wrong that may be visible. In this case star testing revealed astigmatism in the left barrel, and in use that side looked slightly soft. I've found that the the 8X42 FL looks a tiny bit sharper than the SE in the center of the field. I doubt that this is related to actual resolution, but more likely is a benefit of lower longitudinal chromatic aberration. Off axis sharpness in the 8X32 FL holds up a bit better than the 8X42 FL. It falls about midway between the 8X42 FL and the Nikon SE. Toward the edge of the field star points in both Zeiss become astigmatic changing from points into lines running parallel to the field edge, but the length of the line is about half as long in the 8X32. In the Nikon SE stars at the edge of the field remain mostly points with only slight elongation.

One interesting thing I noticed is that the apparent or subjective field of the 8X32 FL is actually no larger at all than the apparent field of the 8X42FL even though the Zeiss spec for real field is 5m wider for the 8X32. I checked this by holding one eyepiece of each binocular to each eye simultaneously and comparing the fieldstop sizes. The left side field stop of the 8X32 matched the 8X42 exactly and the right side was actually slightly smaller (different sized field stops in the same binocular is something I don't like to see since it can indicate different magnifications). At first I assumed the spec for the 8X32 real field must be wrong, but when I measured real field with a measuring tape placed at 10m I found the 8X32 did have a slightly wider real field. The explanation is pin-cushion distortion. There is more of it in the 8X42. That causes an increase in magnification at the edge of the field which reduces real field compared to a more distortion free eyepiece of the same apparent field. The Nikon SE has less distortion than either of the Zeiss, barely any at all.

One last thing, which I mentioned earlier in my quick store impressions. The objective spacing of the 8X32 FL is 7mm narrower than the 8X42FL at the same IPD. Believe it or not that small difference creates a noticeable illusion of higher magnification in the 8X32 compared to the 8X42 at close distances.

I suspect my household will be acquiring a pair of 8X32 FLs. My birder wife usually considers binoculars a necessary (or not so necessary) evil. She found herself so smitten with these that she didnt even flinch very much when I told her the price and actually mulled over buying a pair herself, a first in twenty years of marrage.

Last edited by henry link : Sunday 22nd May 2005 at 16:08.
henry link is online now  
Reply With Quote
Old Monday 30th May 2005, 16:11   #25
Alexis Powell
Registered User

 
Join Date: Dec 2003
Location: LY+DG counties, Kansas, USA
Posts: 3,126
Zeiss 8x32 FL "sweet spot"

Henry,
As I mentioned in my comments on another thread, I find the "sweet spot" of the Zeiss 8x32 FL to be small compared to my preferences and to the Leica 8x32 BN and Leica 8x32 Ultravid. This finding is disappointing to me, because these are otherwise, optically, the most outstanding of midsize roofs. Yet if not for their exceptional close focus, excellent eye relief, and exceptionally low (52mm) minimum interpupillary setting, I would probably opt for the Leica 8x32 Ultravid over the FL because I so much enjoy how well the Ultravid retains its sharpness outside the center of the field (and I'm not bothered by CA unless I am actively looking for it).

At the risk of reinitiating the whole Zeiss FL sweet spot controversy, I would really appreciate yours or others' careful description of field sharpness in the 8x32 FL. I've been using the Zeiss 8x32 FL for several hours a day, every day, for the past several weeks in the course of doing fieldwork for a grassland bird study and can testify that they are optically outstanding and very comfortable to use (even one-handed). In the heat of such work, the size of the sweet spot is not at all bothersome--in fact, I find nothing wanting with regard to optical performance, in contrast to most other binoculars of similar size and weight. One nice feature of the FL that I have not seen others mention, is that the diameter of the ocular housing/eyecups is fairly large, so they do a good job of blocking lateral light when used with eyeglasses.

On the other hand, I've looked at two 8x32 FL units and found them to be essentially identical with regard to having considerably more resolution-robbing distortions (mainly astigmatism I think) outside the center of the field than the Leicas and others. As a consequence, I am completely baffled by some reviews I have seen extolling the edge-of-field sharpness of the 8x32 FL (much as I was baffled by some early reviews of the Leica 8x42 Ultravid proclaiming that it has very low chromatic abberation and exceptional edge of field sharpness, neither claim of which I find to be true). The Zeiss seem to be a bit more finicky than some others with regard to centering one's eyes on the exit pupil to get the best quality view, and the optics of my glasses does not seem inteface with them as well as with other binoculars when it comes to off-axis viewing, but I do not think these factors account for my perception that the Zeiss 8x32 FL sweet spot is on the small side.

--AP
Alexis Powell 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
8x32 v 8x42? amh2029 Binoculars 23 Sunday 30th December 2007 12:37
FYI Bino Article Bill Atwood Binoculars 75 Saturday 18th August 2007 11:38
Leica 8x32 Ultravid vs. Zeiss 8x32 FL Justin Binoculars 3 Sunday 29th August 2004 17:02
Nikon 8x32 SE vs. Nikon Venturer 8x32 LX - Please advise - Newbie oathkeeper Nikon 37 Wednesday 14th July 2004 11:08
Leica BR 8x42 vs Swar EL 8x32 mike60 Leica 13 Monday 24th May 2004 09:53

{googleads}

Fatbirder's Top 1000 Birding Websites

Help support BirdForum

Page generated in 0.26213193 seconds with 37 queries
All times are GMT. The time now is 01:41.