Mr Spock Posted September 13 Share Posted September 13 It just so happens I seem to have accumulated eyepieces around 4mm, not least because they are useful in the scopes I have. 4mm gives x185 in the 100mm, 250mm in the 120mm and x380 in the Dob. Each has their advantages and disadvantages, and like most eyepieces and other kit, it's down to which view you prefer. The review here isn't extensive, it's more a taster of each's individual value to observing and gives small idea of what they are like. Visual test done via a Takahashi FC-100 and a StellaLyra 12" Newtonian. I didn't notice any of these eyepieces struggling with the f5 Newt. Images taken through a Takahashi FS-60CB which is in between the two at f6. Nirvana 4mm FOV: 82° Sharpness: excellent in the centre and right to the edge - which you can't really see in the image. False colour: some towards the edge but not disturbing. Distortion: strong pincushion Contrast: excellent Colour balance: neutral Eye position and relief: Relief is good though eye positioning is quite critical to get the whole fov. There are no blackouts or kidney beaning effects, unless you let your eye wander. Much better than a T6 Nagler in this regard. Visual: a pleasing eyepiece for both stella and planetary objects. On the moon you can study craters right to the edge of the fov. Jupiter is nicely rendered with good contrast and fine detail. Svbony 3-8mm @ 4mm (in between the 3mm and 4mm settings) FOV: around 58° Sharpness: Very good for the price, you won't miss much with this. False colour: none Distortion: strong pincushion Contrast: excellent Colour balance: neutral Eye relief and positioning. Very little eye relief and not really comfortable to use. Positioning not critical. Visual: rapidly gaining a good reputation, it doesn't disappoint. Nice and crisp on the moon and Jupiter looks sharp and detailed. Vixen LVW 3.5mm. A bit more power than the others, but a useful comparison. FOV: 65° Sharpness: excellent False colour: yellow/blue colour fringing in the outer areas but doesn't distract too much. The blue 'ring of fire' you can see in some LVWs is absent here. Distortion: slight pincushion, hardly noticeable Contrast: Excellent Colour balance: neutral Eye relief and positioning. Excellent eye relief and like all LVWs very comfortable in use. Eye positioning a bit more critical than other LVWs - move your eye away too far and you get a black tunnel effect. Visual: Fantastic on the moon. There's just something special about the way it presents detail - I'm not sure I can describe it! It has the same, or more detail than the others here, but presents it in a way that's easy on the eye. Circle-T Orthoscopic. FOV: about 43° Sharpness: excellent edge to edge False colour: some colour noted - not typical of orthos Distortion: none. What you see here is the camera. Contrast: Let down by it's lack of modern coatings Colour balance: very slightly warm Eye relief and eye positioning: eye relief almost none existent. The volcano shape helps but if you wear glasses forget it! Visual: Compared to the others it's like looking down a narrow tunnel. Nice and sharp in use and presents star airy discs well. Excellent on planets where its small fov isn't relevant. The fact Circle-T orthos aren't par focal means it's difficult to use for double stars where its sharpness would otherwise be an asset. I find it difficult to focus on faint stars. Takahashi TOE 4mm. FOV: 52° Sharpness: excellent False colour: none Distortion: none Contrast excellent to 'biting' Colour balance: warm Eye relief and eye positioning: Eye relief isn't too bad and positioning is non critical Visual: excels with all targets. It's sharp, contrasty and reveals the finest details; it demands the best optics and diagonals. A very different presentation to the LVW though; more 'edgy' and less comfortable. Overall it's a very close second to the LVW and I do enjoy both of them Little and Large! Size comparisons always best done with an image! Conclusion: You would be happy using any of these for critical planetary observing. The tiny ortho is a way behind the others due to its age and lack of coatings. Still a fine eyepiece though. I terms of value for money the TOE is outrageously expensive. Get the Svbony for a third of the price. It can go toe to toe (excuse pun) with the TOE and has all the other focal lengths too! If you can find one, definitely put an LVW on your shopping list. It has the most relaxed viewing experience of them all. Edit*** Picture of the chart with just the camera (iPhone XR) so you can see what, if any, distortion / foibles it has. 15 6 Link to comment Share on other sites More sharing options...
Don Pensack Posted September 13 Share Posted September 13 Excellent comparison. Couple minor points: 1. If your camera adds pincushion as seen in the image, it likely exaggerates the pincushion seen in the other images. 2. The blue ring seen at the field stop in some eyepieces is not what the term "ring of fire" refers to. The "ring of fire" is a strong yellow/orange/brown tint to the field in the outer 5 to 10° of the field, as found in the 31mm Nagler, 30mm 82° ES, and KUO 28mm 82° and a few other eyepieces. It is also referred to as CAEP, or chromatic aberration of the exit pupil. 3 Link to comment Share on other sites More sharing options...
Ratlet Posted September 13 Share Posted September 13 Cracking review. Not sure how I feel about the ruler not being wood, but I guess times are moving on. I take a lot of images through my svbony and have noticed the pincushion, but only on the images. I've never found it massively intrusive at the eyepiece. The contrast is brilliant on it though, at least compared to a bst starguider. Makes pulling detail out on Jupiter easier. 3 2 Link to comment Share on other sites More sharing options...
John Posted September 13 Share Posted September 13 Good and useful report Mr Spock I seem to have accumulated quite a lot of eyepieces around 4mm in focal length as well. Some of them covered by your review ! 1 Link to comment Share on other sites More sharing options...
Paz Posted September 13 Share Posted September 13 Great review thanks for posting, it makes it easy to weigh up the pros and cons of each. When it comes to trade offs for me I like good eye relief and a flat field but I'm ok accepting things like pin cushion, angular magnification and edge of field CA, and I don't mind smaller fields of view (up to a point). I think I would like the LVW from this group. 1 Link to comment Share on other sites More sharing options...
Mr Spock Posted September 13 Author Share Posted September 13 28 minutes ago, Ratlet said: Not sure how I feel about the ruler not being wood, but I guess times are moving on. Indeed. Sadly the rulers, despite being modern, still have inches 2 Link to comment Share on other sites More sharing options...
CraigT82 Posted September 13 Share Posted September 13 What’s the cause of the dark centre donut in the Nirvana image? Also the LVW but there it’s more of a disc than donut. 1 Link to comment Share on other sites More sharing options...
Ratlet Posted September 13 Share Posted September 13 20 minutes ago, Mr Spock said: Indeed. Sadly the rulers, despite being modern, still have inches At least they're proper inches. With fractions. We quite frequently have to deal with decimal inches in the oilfield. 2 1 Link to comment Share on other sites More sharing options...
Hans Joakim Posted September 13 Share Posted September 13 Wonderful review, Michael! Thanks so much for sharing. My eyepiece in this short FL range is the 3.5 XW. I have not had the opportunity to try other options in this range yet. Curious to hear if anyone has compared the 3.5 XW to one or more of those in Michaels review? 1 Link to comment Share on other sites More sharing options...
Astronomist Posted September 13 Share Posted September 13 Very good write up, I use and enjoy the 4mm nirvana as my high power eyepiece, but this review is making me want to try out an LVW 3.5... 38 minutes ago, Ratlet said: decimal inches That's a thing??? An inch divided into 10ths instead of multiples of 2? 1 Link to comment Share on other sites More sharing options...
Louis D Posted September 13 Share Posted September 13 1 hour ago, CraigT82 said: What’s the cause of the dark centre donut in the Nirvana image? Also the LVW but there it’s more of a disc than donut. Generally they're caused by exit pupil aberrations such spherical aberration of the exit pupil (SAEP), also known as kidney beaning. Obviously, both have it very mildly. When a field of view is described as needing critical eye positioning to take in the entire field of view, it's generally due to SAEP. It's more critical in the daytime or with bright objects that cause your eye's iris to constrict. This can cut-off mid-field light rays. See the following post for some animations created by @Ruud: 1 Link to comment Share on other sites More sharing options...
John Posted September 13 Share Posted September 13 23 minutes ago, Hans Joakim said: Wonderful review, Michael! Thanks so much for sharing. My eyepiece in this short FL range is the 3.5 XW. I have not had the opportunity to try other options in this range yet. Curious to hear if anyone has compared the 3.5 XW to one or more of those in Michaels review? I have the 3.5mm XW and have compared it with the TOE 4mm, Nirvana 4mm, Ethos 3.7mm and a few others as well. The results were very close indeed but I've still got the 3.5mm XW and the others have found new homes now. I also still have the Nagler 2-4mm and 3-6mm zooms and the Svbony 3-8mm zooms as well. In the past I've owned the 3.5mm Nagler Type 6 and used a Vixen LVW 3.5mm but that was long ago so my memory can't be trusted on that one plus I didn't have the chance to compare the LVW with the XW at that focal length. At this level personal preferences play as much, if not more of a part in what "floats your boat" as outright optical performance in my humble opinion. The 4mm Nirvana and 3.5 LVW are pretty good I reckon. The TOE might be very slightly better than the others in pure optical terms, under excellent observing conditions, and even then it's a very subtle difference for me. Others will probably vary in their opinions though - often the case with eyepieces ! 6 1 Link to comment Share on other sites More sharing options...
Mr Spock Posted September 13 Author Share Posted September 13 1 hour ago, CraigT82 said: What’s the cause of the dark centre donut in the Nirvana image? Poor adjustment of the phone distance by me. 1 Link to comment Share on other sites More sharing options...
Ratlet Posted September 13 Share Posted September 13 30 minutes ago, Astronomist said: Very good write up, I use and enjoy the 4mm nirvana as my high power eyepiece, but this review is making me want to try out an LVW 3.5... That's a thing??? An inch divided into 10ths instead of multiples of 2? It's what happens when you have to input fractional inches into computers. Most of the time we stick to fractions but for data entry it's more common to make them decimal. The software we use will accept both though which is an oddity (and because we have clients in the EU, we've had complaints because they've been conditioned to decimals). An odd exception is for drilling but nozzles. Which are almost always specified in 32th of an inch, regardless of how many there are (16/32 nozzles, 8/32 nozzles, etc.). 1 1 Link to comment Share on other sites More sharing options...
Louis D Posted September 13 Share Posted September 13 2 hours ago, Ratlet said: Most of the time we stick to fractions but for data entry it's more common to make them decimal. Then they should be in powers of two fractions to avoid rounding errors when converting to binary. Link to comment Share on other sites More sharing options...
vlaiv Posted September 13 Share Posted September 13 Am I imaging things or is it LVW by far the sharpest in the center? Link to comment Share on other sites More sharing options...
Mr Spock Posted September 13 Author Share Posted September 13 20 minutes ago, vlaiv said: Am I imaging things or is it LVW by far the sharpest in the center? No, it's not your imagination. It is my favoured lunar eyepiece with the Tak for that reason. On these images if you look to the left of the '19', the small black dot and white lines are better defined in the LVW. It's not as even across the fov as the TOE, but for me the centre is where I'm concentrating on detail. 3 Link to comment Share on other sites More sharing options...
Bivanus Posted September 15 Share Posted September 15 I have the Lacerta 4mm that is practically the Nirvana 4mm down to the font used for the markings 😂 and it's a good piece of kit , the only thing being a propensity to a very small kidney-bean phenomenon , a tad interesting because it's a fine shape very thin and elongated like an upside down braket. It's not an EP killer for me , especially since I use it on planets and the central view remains clear with the blackness either below or above it. Link to comment Share on other sites More sharing options...
Mr Spock Posted September 15 Author Share Posted September 15 Now done some additional tests at 3.3/3.5mm with a different target. LVW 3.5mm Svbony 3-8mm @ 3mm (measures 3.5mm) TOE 3.3mm **Edit. Replaced the TOE image with a better one. I had half a dozen attempts with this eyepiece, the phone doesn't seem to like it. 1 Link to comment Share on other sites More sharing options...
vlaiv Posted September 15 Share Posted September 15 19 minutes ago, Mr Spock said: Now done some additional tests at 3.3/3.5mm with a different target. Any chance you can do comparison to Vixen SLV? I'm interested if the two give the same level of sharpness. Link to comment Share on other sites More sharing options...
Don Pensack Posted September 15 Share Posted September 15 26 minutes ago, Mr Spock said: Now done some additional tests at 3.3/3.5mm with a different target. LVW 3.5mm Svbony 3-8mm @ 3mm (measures 3.5mm) TOE 3.3mm Either the TOE was not as well focused or it lacks sharpness on axis. I suspect the former. The 3-8 zoom has either FC or astig. at the field edge, as does the LVW (less on the LVW). The TOE was uniform across the field--just a softer focus. Link to comment Share on other sites More sharing options...
Mr Spock Posted September 15 Author Share Posted September 15 16 minutes ago, Don Pensack said: Either the TOE was not as well focused or it lacks sharpness on axis. I had three attempts at getting it sharp. It just won't co-operate. I'll try some more but I'm not keen on fiddling too much. 26 minutes ago, vlaiv said: Any chance you can do comparison to Vixen SLV? I used to have a 4mm SLV and sold it. It was very sharp but the wider field and comfort of the LVW won. 1 Link to comment Share on other sites More sharing options...
F15Rules Posted September 15 Share Posted September 15 Interesting and useful comparison, Michael..👍. Sadly, I had to let my LVW 3.5mm go just last week. This wasn't due to any lacking on the part of the eyepiece, but due to deterioration in my eyes, especially my right eye 😏. I now see floaters regularly at anything much over 200x. The LVW 3.5mm delivered c 253x in my Vixen SD115S, and the floaters just became too distracting. I still have the rest of the set (5mm, 8mm,13mm,17mm, 22mm, 42mm), and will keep them all except possibly the 42mm (where I have a different UWA which is significantly better). The 5mm gives 177x native, and x283 with my 1.6x barlow, so I can still go above 200x if I need to. I find that I get less floaters in my binoviewers..and, using an excellent pair of Tak LE 12.5mm and Carton Japan/Megavista 10.5s and a Baader 1.7x OCS, I can get quite high powers with much reduced floaters..and the aforementioned eyepiece pairs are much lighter than LVWs, so better suited to binoviewing. Dave Link to comment Share on other sites More sharing options...
Mr Spock Posted September 15 Author Share Posted September 15 I've re-done the 3.3mm - several times. It's possible it's the lighting - the sun is out now but it was getting quite dark before. It's now consistent with the 4mm; very even over the fov and just a bit behind the LVW in central sharpness. That's what I find on real targets like the moon. The Svbony isn't bad, but like people are finding it deteriorates as you get towards the 3mm setting. Distortion is similar but it starts to loose the outer parts more. Link to comment Share on other sites More sharing options...
GordonD Posted September 15 Share Posted September 15 Really interesting and useful, Michael. It must take a lot of time and effort to do these comparisons and photos so thank you very much! 1 Link to comment Share on other sites More sharing options...
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