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Kowa's new 50 mm scope (1 Viewer)

I may eat my words, but totally agree with mayoayo.
As currently described, the scope seems an odd hybrid, a superior objective lens coupled with an ordinary zoom in a plastic body, priced at a huge premium.
Perhaps the expectation is that scope prices will increase dramatically, something that Nikon was earlier seeking to achieve with their EDG series.
If the 883 successor model is priced at $4000+, the 553 begins to appear reasonable. No idea whether the Chinese competition will allow that.
 
mayoayo said:
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....
Click to expand...

Hi,

if we assume that the zoom on the 553/4 is actually the small body zoom (which the image showing it labeled 60x linked by me somewhere above in this thread implies), the calculation is as follows:

The small body scopes (except for the odd 82SV) all have a focal length of 420mm and the small body zoom yields 20-60x on those - which makes it a 7-21mm zoom.

So if this zoom is used in the 553/4 and gives 15-45, we get 7x45 or 21x15 = 315mm as the focal length of the 550 bodies. So the focal ratio is 315mm/55mm = 5.7...

A 55m doublet with fluorite at that focal ratio should show very good CA control - maybe better than is needed for 45x...

But why oh why did they use that zoom... sure, the magnification range of 15-37x with the big body zoom would look a bit strange, but then they could have increased the focal length of the body a bit to 380mm and it would have been roughly 19-45x... that would have made the objective f6.9 and any FPL-51 clone ED glass would have given great results too to bring down the price.
I'm quite sure they could have kept this one below 1000g and a bit longer than it's now and it would have been quite a bit more attractive.

Joachim
 
Using the old zoom will keep development costs down. That it's not exchangeable is a bit annoying though, especially if you already own that zoom EP. Don't doubt that 553 will be the best small scope optically, but still it's just 55mm, limiting brightness and resolution, and raw light transmission have never been Kowas strength.

Cost/mm objective lens will be less than for the Kowa 88mm + EP though.

Wealthy travelers might buy this, but you still need to carry a tripod and head if you want the same versatility/stability as a larger scope.
 
There was a well regarded Vixen 55mm telescope, possibly fluorite objective.

The manufacturing cost of telescopes, at least astro telescopes, varies between the square and cube of the aperture, not linearly with aperture.
I don't know what the factor is nowadays, as giant scopes seem remarkably cheap, mainly due to computerisation, I suppose, and advanced altazimuth mounts.

P.S.
The Vixen 55mm fluorite is possibly the same as the Celestron C-55F. Made by Vixen?
Said to be the same as Takahashi FC-50.
But if from 1985 I would be wary, in case moisture has affected the fluorite.
Maybe f/8 440mm focal length.
 
Last edited:
jring said:
:

The small body scopes (except for the odd 82SV) all have a focal length of 420mm and the small body zoom yields 20-60x on those - which makes it a 7-21mm zoom.



Joachim
Click to expand...

I stand corrected..I didnt realize the small zoom true focal lenght,until you pointed to it..It grants 21-63X in the 82SV,and I assume that scope has 450mm,like the 823..in any case 315 mm seems right for a 55 mm scope of that size..
Couldn´t they have designed the scope with a removable eyepiece at least?
I guess they want you to buy their narrow view zoom at a very high price yes or yes..
 
Binastro said:
There was a well regarded Vixen 55mm telescope, possibly fluorite objective.

The manufacturing cost of telescopes, at least astro telescopes, varies between the square and cube of the aperture, not linearly with aperture.
I don't know what the factor is nowadays, as giant scopes seem remarkably cheap, mainly due to computerisation, I suppose, and advanced altazimuth mounts.

P.S.
The Vixen 55mm fluorite is possibly the same as the Celestron C-55F. Made by Vixen?
Said to be the same as Takahashi FC-50.
But if from 1985 I would be wary, in case moisture has affected the fluorite.
Maybe f/8 440mm focal length.
Click to expand...

Hi,

yes, the Vixen FL55S f8 - built until 1984... not quite the same as the FC-50 but close...

SInce all of these are in Steinheil configuration aka fluorite element to the back, I would not be too concerned - I have two old Kowa 77mm objectives which are probably from late 80s or early 90s and they're fine.

Joachim
 
The video contains a short animation which shows some blurry interior detains. My reading is that the prism system is a Porro followed by a semi-pentaprism with focusing accomplished by prism movement. The objective elements are not revealed, so it may be a triplet or more likely a simple doublet.

The last images in the video seem to suggest that this scope is a shrunken TSN-883. That is something of a misrepresentation, given how different the optical designs are. The 883 uses a 5 element objective (including a doublet focusing lens), a Schmidt erecting prism and a more sophisticated zoom eyepiece.. The design of the 553 looks to be much closer to a shrunken TSN-3 from 30 years ago.
 
I found this Japanese video review of the TSN-553.

https://www.youtube.com/watch?v=pJxMFAsyKII

The reviewer voices some of the same complaints that have been aired here, including the insupportably high price. He confirms that the prism configuration is Porro + semi-pentaprism and also mentions that Kowa has not specified what mirror coating material is used in the semi-pentaprism.
 
henry link said:
I found this Japanese video review of the TSN-553.

https://www.youtube.com/watch?v=pJxMFAsyKII

The reviewer voices some of the same complaints that have been aired here, including the insupportably high price. He confirms that the prism configuration is Porro + semi-pentaprism and also mentions that Kowa has not specified what mirror coating material is used in the semi-pentaprism.
Click to expand...

Good find there.

I just can't understand the pricing and why they didn't make it an interchangeable mount with the existing wide zoom for the 883/4 scopes.
 
The price is why I suggested a possible Canon IS scope.
For that money I would much prefer good image stabilization over a fluorite objective.
If such a scope had a fixed zoom or even a fixed magnification eyepiece I would still prefer that.
 
dipped said:
... and why they didn't make it an interchangeable mount with the existing wide zoom for the 883/4 scopes.
Click to expand...

Suspect that it is the 'weight' factor.
This scope was designed for the lightweight user.....biologist, hunter, backpacker.
If one could weigh the eyepiece that is permanently affixed as opposed to Kowa's existing zoom offerings the weigh difference would likely be dramatic.
Again, pure speculation here.

I for one, would welcome the fluorite 55mm with Kowa's TE-11 wide angle zoom. Justifying the cost involved for such a small objective is another story. I doubt it would deliver the optical quality of my Leica 65mm APO televid anyway.
 
the big gap in price and specifications between the 50 and 55 models doesnt makes sense either..I think if they had a 50 design already,they could have easily made it with ED glass and if you want the fixed zoom, as a less expensive ,more compromised option,and sell the 55 fluorite body only,leaving the owner to decide on the eyepiece..and with a realistic price,for gods sake,,I dont care if You can see through foliage or whatever,,for that price you should be able to have Xrays vision!
 
I'm quite sure KOWA as a company is not oblivious to how markets work and pricing strategy. Are they just riding the hype factor of TSN 883/4 and assume consumers will bear the the cost for no obvious feature differences compared to less expensive 50mm spotting scopes. I am tempted to put an order, but concerned to take a big hit if they drop the prices in future.
 
Sorry folks. I haven't been on the forums since back at the very beginning of June. I was given the opportunity to evaluate the little 55 mm Kowa. I have had it for a little over two weeks.

I have compared it directly with the Opticron MM4 50 and 60 mm scopes with the SDL V2 zooms.

I will post a much more extensive review with pics in the next couple of days.

My initial impressions from a week or so ago were contrary to what Steve OB4 posted but then I am comparing the MM4s instead of the MM3. Not a huge difference between those two versions but still worth noting.

Just a couple of quick points based on my observations....

- Yes, the zoom is definitely the limiting factor for this scope. The high end of the zoom range is not quite as good as I expected plus the narrow apparent field of view is definitely noticeable in comparison to the SDL V2 MM4s.

- It is nice compact, light scope which gives me the impression physically of a compromise between the MM series and the Nikon ED series.

- Mechanics are very good but different feel and focusing speed compared to the MM3s and MM4s.

All for now but I will answer any questions you folks have.
 
FrankD said:
- Yes, the zoom is definitely the limiting factor for this scope. The high end of the zoom range is not quite as good as I expected plus the narrow apparent field of view is definitely noticeable in comparison to the SDL V2 MM4s.
Click to expand...

Hi Frank,

I'm curious about the statement above. What's not quite as good as you expected at the high end of the zoom range? What makes you think the problem is the eyepiece?

Have you done a star-test?

Henry
 
No star test yet Henry so, yes, we could chalk up my experience with the scope as being unit specific. Will try do so tonight or tomorrow.

All of the usual optical characteristics I look for (apparent sharpness, apparent brightness, contrast, CA control, edge performance, etc...) are certainly agreeable up to a point in the magnification range. Then there is a drop off where I expect to see more detail than what is presented. Eye positioning also seems to be a bit more critical than what I am accustomed to with either of the Opticron models.

They eyepiece has 15x printed on one end of the zoom range and a 45x on the other end. There are three white "dots" at regular intervals between the two numbered settings. It is from the last dot up to 45x that I see the drop off in performance.

My initial opinion is that they attempted to do a little bit "too much" with just the one eyepiece. They went for a specific magnification range (more typical of 60-65 mm scopes) but wanted to keep a variety of optical characteristics at a certain performance level (thinking CA control, edge sharpness, etc...). The compromise is in how easy the eye placement is, the somewhat lower level of performance at the magnification level mentioned above and narrower apparent field of view.
 
Last edited:
FrankD said:
No star test yet Henry so, yes, we could chalk up my experience with the scope as being unit specific. Will try do so tonight or tomorrow.

All of the usual optical characteristics I look for (apparent sharpness, apparent brightness, contrast, CA control, edge performance, etc...) are certainly agreeable up to a point in the magnification range. Then there is a drop off where I expect to see more detail than what is presented. Eye positioning also seems to be a bit more critical than what I am accustomed to with either of the Opticron models.

They eyepiece has 15x printed on one end of the zoom range and a 45x on the other end. There are three white "dots" at regular intervals between the two numbered settings. It is from the last dot up to 45x that I see the drop off in performance.

My initial opinion is that they attempted to do a little bit "too much" with just the one eyepiece. They went for a specific magnification range (more typical of 60-65 mm scopes) but wanted to keep a variety of optical characteristics at a certain performance level (thinking CA control, edge sharpness, etc...). The compromise is in how easy the eye placement is, the somewhat lower level of performance at the magnification level mentioned above and narrower apparent field of view.
Click to expand...
Hi Frank,
There should be no drop off at all, except for those based on atmospherics. The aging ED50 stays pin sharp from 13-40, so much so it's always kind of amazing sitting next to a much larger scope (883). We're using both in NS and the only quality loss in either is due to heat.

I was hoping this was a mini-883 but it seems not to be. My wife loves the ED50 but I can't tolerate the narrow FOV or short eye relief for any length of time.
John
 
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