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Kowa's new 50 mm scope (2 Viewers)

henry link said:
Fluorite can't possibly justify an $1800 price tag for such a small scope. A few years ago I did a little research on how much more Fluorite costs than the usual ED types found in scopes. See the post below:

http://www.birdforum.net/showpost.php?p=2998255&postcount=2
Click to expand...


There is surely good potential demand for a top quality small scope, but the pricing Kowa proposes seems hard to justify.

The Celestron Hummingbird 9-27x56 MicroED presumably uses ED glass.
It also sports a less than 10' close focus and sells for $359 at Optics4Birding.
 
Steve O4B said:
FOV at 132' at 1000 yards at 15x.
Click to expand...

Resulting in a 2.5 deg true field or a whopping 38 deg apparent field of view aka soda straw :-(

With the big body zoom this thing would have 15-37x magnification and 4 deg or 210'/1000y at 15x or 60 deg afov and even more afov at higher mags.

Regarding price the question remains, if fluorite is really necessary for such a small aperture instrument to be reasonably colour free.
Yes, it's fairly fast at f5.5 but on the other hand it's only 55mm aperture...

Joachim
 
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Hi.
I also saw the narrow field.
But a 55m aperture isn't bad. :)
Bigger than the OWL telescope.

Maybe they break a lot of the crystal elements, so they charge for the broken ones.
 
etudiant said:
There is surely good potential demand for a top quality small scope, but the pricing Kowa proposes seems hard to justify.

The Celestron Hummingbird 9-27x56 MicroED presumably uses ED glass.
It also sports a less than 10' close focus and sells for $359 at Optics4Birding.
Click to expand...

All ED glass is not created equal. There are many different versions of ED glass. many of the lower cost optics with ED glass don't have fluoride in any of its several versions. Compare a Nikon Monarch 5 with a Zeiss Victory SF. That said, the Kowa TSN-550 series scopes don't have ED glass. They have pure fluorite crystal objectives. This is not glass that is melted into blanks and then ground, it is crystal that is grown, then ground. The Celestron Hummingbird ED is at the low end of ED glass. The Kowa TSN-553/554 are at the extreme top. You're comparing Yugos with Ferraris
 
Steve O4B, post 25
Pure fluorite crystal is very vulnerable and can in fact not be used on surfaces exposed to open air, so the producer has to take precations to avoid that.
Gijs van Ginkel
 
Gijs,

What you say about the maker needing to know what they are doing is true. However, Kowa has been making scopes with pure fluorite crystal since the TSN3/4 introduced in the 1980s, and their track record is excellent. They certainly know how to make the fluorite last. I have not heard of any problems with Kowa fluorite scopes that would be resulting from the choice of lens material.

Kimmo
 
The Kowa 553 (inc the zoom eyepiece..not inchangeable) will be slightly more expensive than the ATS 65+25-50x around here.
Weight 810 grams (vs 1400g for the ATS), but Kowa body made of polycarbonate. FOV 44-23 (15-45x).
Just wonder why Kowa choose to put the cheapo zoom on it, as the Prominar series is know for their huge AFOV EP:s...a bit sad.
 
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Hi,

Kowa fluorite lenses are made by Canon-Optron, the same division of Canon which does the fluorite work for Takahashi - and unlike Kowa they even have refractors with fluorite in the front element (FS series) - not a problem with the right coatings.

The real question is if fluorite is needed in this instruments and at the magnifications offered by the fixed EP or if visually perfect CA control could be reached too with sth like FPL-53, FCD-100 or OK4.
My guess is no due to the small aperture, without having fired up OSLO...

Joachim
 
kabsetz said:
Gijs,

What you say about the maker needing to know what they are doing is true. However, Kowa has been making scopes with pure fluorite crystal since the TSN3/4 introduced in the 1980s, and their track record is excellent. They certainly know how to make the fluorite last. I have not heard of any problems with Kowa fluorite scopes that would be resulting from the choice of lens material.

Kimmo
Click to expand...

Kimmo, The first scopes to ever have pure fluorite crystal are the TSN-883/884. The TSN-3/4 and the TSN-823/824 had some variety of calcium fluoride doped glass.

OTOH, the TSN-883/884 have been around for 10 years without the crystal being an issue. So, you're right in that respect.
 
Steve O4B said:
All ED glass is not created equal. There are many different versions of ED glass. many of the lower cost optics with ED glass don't have fluoride in any of its several versions. Compare a Nikon Monarch 5 with a Zeiss Victory SF. That said, the Kowa TSN-550 series scopes don't have ED glass. They have pure fluorite crystal objectives. This is not glass that is melted into blanks and then ground, it is crystal that is grown, then ground. The Celestron Hummingbird ED is at the low end of ED glass. The Kowa TSN-553/554 are at the extreme top. You're comparing Yugos with Ferraris
Click to expand...

I agree with all your points except that based on the quoted specs, the Celestron is fully competitive in FoV and eye relief.
It is at least a high performance Yugo versus a detuned Ferrari Dino for 5x the price.
 
Steve O4B said:
Kimmo, The first scopes to ever have pure fluorite crystal are the TSN-883/884. The TSN-3/4 and the TSN-823/824 had some variety of calcium fluoride doped glass.
Click to expand...

I beg to disagree - the first spotting scopes with with fluorite crystal were the TSN-3/4 introduced in 1986. Takahashi first produced an astro scope with fluorite in 1972 - the TS 80.

They certainly didn't use some variety of calcium fluorite doped glass aka ED glass as these were not available back then. They were developed later to replace the expensive and difficult to work with CaF2 crystal (although FPL-53 is not a lot better to work with).

You can easily check if a scope uses fluorite crystal or ED glass by shining a green laser through it. With a fluorite element, you will see reflections where the beam enters and exits the crystal and nothing in between, while with glass you see a distinct line between the entry and exit point. This line is caused by the light being scattered by bubbles in the glass, which are absent in crystal.

Joachim
 
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It is disappointing that KOWA has cut corners by using plastic body and poor quality zoom lens, yet the priced in premium range. I own Takahashi refractors with Fluroite, some of their 4inch scopes FC series with back fluorite element can be purchased for less than $2k.
 
We received both the TSN-501 and TSN-553 samples today. I didn't spend much time with the 501, but did a fair amount of comparison between the 553 and other scopes.

Our first test pitched the Opticron MM3 50mm with SDL v2 eyepiece. The difference was beyond astounding. Since UPS got here around noon, long distance viewing was fraught with heat shimmer. We concentrated on holes in the hedge across the parking lot. The Opticron could barely see into the hole, but the 553 saw nearly to the far side of the hedge. The 553 also had significantly better contrast. Cell phone photos bore this out.

Later in the day, I compared the 553 with the original version of the Vortex Razor 16-48x65. Again, the 553 was brighter, sharper, and had better contrast. I didn't take any photos of this comparison due to time constraints.

These are preliminary observations. I'll have more to post next week. I plan on taking the 553 birding on Saturday morning.
 
Dear Steve.

How does the Kowa 553 compare to the well regarded Nikon 50mm?

I don't have the Nikon, but have thought of getting one.

Are the weights similar?
 
Binastro said:
Dear Steve.

How does the Kowa 553 compare to the well regarded Nikon 50mm?

I don't have the Nikon, but have thought of getting one.

Are the weights similar?
Click to expand...

The Opticron MM3 and MM4 are better than the Nikon. If you want something in the $800 range, get the Opticron. But, neither come close to the Kowa TSN-553.
 
Steve O4B said:
The Opticron MM3 and MM4 are better than the Nikon. If you want something in the $800 range, get the Opticron. But, neither come close to the Kowa TSN-553.
Click to expand...

No way is the MM3 50 better than the Nikon ED50 good samples of both. Come to think of it I haven't star tested a really good MM3 yet. Each to their own though.
 
What I want is a good Canon 50mm image stabilized scope that is steady at 50x hand held. Maybe a straight through design not angled.

If anyone says this isn't possible, I would say that Canon has the necessary technology now to make it.
 
Steve O4B said:
We received both the TSN-501 and TSN-553 samples today. I didn't spend much time with the 501, but did a fair amount of comparison between the 553 and other scopes.

Our first test pitched the Opticron MM3 50mm with SDL v2 eyepiece. The difference was beyond astounding. Since UPS got here around noon, long distance viewing was fraught with heat shimmer. We concentrated on holes in the hedge across the parking lot. The Opticron could barely see into the hole, but the 553 saw nearly to the far side of the hedge. The 553 also had significantly better contrast. Cell phone photos bore this out.

Later in the day, I compared the 553 with the original version of the Vortex Razor 16-48x65. Again, the 553 was brighter, sharper, and had better contrast. I didn't take any photos of this comparison due to time constraints.

These are preliminary observations. I'll have more to post next week. I plan on taking the 553 birding on Saturday morning.
Click to expand...
How's the FOV and eye relief?
 
jring said:
.
Yes, it's fairly fast at f5.5 but on the other hand it's only 55mm aperture...

Joachim
Click to expand...

If my calculations are good the scope is actually f/6.5..grants 15x-45x ,like most 60-65 scopes, thus having 360mm FL ..divided between 55mm aperture..6.54....makes even less necessary to use fluorite..and perhaps the celestron uses low grade ed glass,but if its performance is good,then it was well designed..I dont know what glass the Nikon ED50 uses,but works great correcting CA in a quite fast F/5.7 scope.(I dont think the MM3 is better than the Nikon either,to me feels flimpsy and Image quality is on par at best.).
So the Nikon does not come even close to the Kowa 553?..Is it better then than the 883..?..because the Nikon comes close to that level of performance,at least reasonably for its size and price pooint---.in any case,It,the kowa, seems extravagant for what we are used in THIS forum ...perhaps the market is totally different and the lil kowa becomes a hot item..If it would have used the big wide zoom,then perhaps,even at a hig price it would have appealed to 88 users as a travel companion..as it is, I dont have any interest personally,and I think people wanting a really expensive travel scope would find the Swaro ATX 65 a more interesting option..That is if Swaro does not release a 55 module and makes the kowa look even worst
 
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