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Tsn-773 Vs Tsn-823m (1 Viewer)

Tonbit

Member
Hello,

First step first question:

I have the possibility to buy a telescope kowa tsn-773, but for the same price they offer a tsn-823M. Can somebody give me at least 3 arguments for chose the new model?

Thanks
 
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Here we go:

1. The TSN-773 is much lighter
2. it is much more compact
3. its has a very good dual-focus mechanism
4. there is a state-of-the-art zoom-ep available.

Steve
 
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1. The TSN-773 is much lighter
2. it is much more compact
3. its has a very good dual-focus mechanism
4. there is a state-of-the-art zoom-ep available.

I'd agree with all four of those...

Personally I think the 773 has a slight edge optically over the 823, when I tested one it seemed to be a bit sharper (though I didn't do any scientific tests). The focus on the new Kowa scopes is wonderful, smooth and acurate, I reckon this will be a real advantage for digisoping. I think the only way you could get a better Kowa scope would be to break the bank and go for the 883!
 
I'd agree with all four of those...

I think the only way you could get a better Kowa scope would be to break the bank and go for the 883!

Absolutely correct there Postcard...I use the 823 and got chance to try an 883 last month. The zoom on the 883 is pure magic, knocks spots of the 823. I'm currently trying to work out some method of syphoning the necessary dosh out of the bank account without a certain little lady noticing it.
 
Tonbit,

I agree with most of the above assessments when it comes to 883 over 823, but 773/823 I'm not at all so sure. All the arguments Steve gave in post #2 are valid (although I would say that the focus mechanism of the 823 is just fine too), but a good specimen of an 823 will resolve better and, for the samples I have seen, have less chromatic aberration and to my eyes slightly truer colors than the 773. The 823's zoom has a narrower field of view, somewhat less good edge performance and significantly less eye-relief, but if you don't need the eye-relief, it gives a very fine image. 5mm of extra aperture gives enough resolution advantage to be of practical significance.

But, the 773 is much more compact, and a metal body certainly feels and probably also is more durable.

If you want to look up more detail, Jan Meijerink has a test of the new as well as the old Kowas (in Dutch, but with resolution photos taken as well as lots of data on a table form) on www.tvwg.nl

Kimmo
 
The 823's zoom has a narrower field of view, somewhat less good edge performance and significantly less eye-relief, but if you don't need the eye-relief, it gives a very fine image.
Kimmo,

Have you had a chance to compare the old and newer 823 zooms? The older long & narrow zoom with rubber-eyecup used to have very poor eye-relief, but didn't the newer (which looks shorter and wider + with screw-in/out eyecup) eyepiece also get a couple of millimeters more eye-relief. Even the 883 zoom does not seem to have as good ER as eg. Leica & Swaro zooms (at 20x).

Am I right concluding that in spite of slower f-ratio the 773's XD-objective does not offer quite as good colour correction as the 883 (or even 823) with a "real" fluorite objective?

Ilkka
 
773 - 823 AND now 883

See the previous threads regarding the glass used in the 883 objective lens elements against that used in the 773.....they are not the same formulae. The 883 uses a higher ratio of "fluorine/fluorite/whatever" in the OG than that in the 773 as a bf member kindly brought to my attention. The 773 is very good overall but the 883 offers a brighter/sharper viewing, I believe, regardless of the larger light gathering capability due to this difference in glass.

I agree with the endorsements of the 773 being "better" than the 823 for a variety of reasons, some ergonomic, some optical.....comparing either of these against the 883 is another matter imo.
 
I am very grateful for your excellents contributions. I'm more confused than at the begin !!!!.
If the budget will be open, logically i haven't any doubt and the 883 will be the choose. But this is not possible (reply my wife). My doubts are one step below: it is difficult to refuse that the news product are not so good but, seems that the optics of the 823m is something better ("real objective fluirite") and the 773M have a better construction and more compact, is it really ?

With an photoadapter ( i have a EOS350D), 823M model gives 850mm and the 773M is (650-1000mm), if the diameter is less, why the focal distance is better for the new model ?

Thanks again,

Toni.
 
IWith an photoadapter ( i have a EOS350D), 823M model gives 850mm and the 773M is (650-1000mm), if the diameter is less, why the focal distance is better for the new model ?

The focal length that a photoadapter gives is dependant on the focal length of the scope and the adapter it is not affected by the size of the objective.

I've not heard that the 823 has a "real objective fluirite", as far as I know the 883/4 are the only big Kowa big scopes that have this (I think the 663/4 may also have it).
 
I've not heard that the 823 has a "real objective fluirite", as far as I know the 883/4 are the only big Kowa big scopes that have this
Peter,

I am pretty sure that the TSN-823 has an objective with a CaF2-element. -Not that the same performance couldn't be achieved with some other ED material... :t:

http://www.kowa-usa.com/frontend/proddetail.asp?pn=TSN-823M&co=10000378

"High-end Prominar with Fluorite Crystal Lens
For those seeking higher optical performance, there are the Prominar models with a fluorite crystal objective lens"

Ilkka
 
Having owning the 884 I would recommend the 773 for its smooth focus mechanism and it compactness is a real bonus, saying that if you can stretch for the 883 plus zoom you won't regret it.

The 823 has its focus wheel on one side of the body so in effect it is a right handed scope, were as the new models have it in the centre in the body, which makes it much easier to use both hands.
 
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Hello,
You are as the good friends that give good advice: yesterday I had the opportunity to test a 883M with the photoadaptador 650-1000 mm installed in my camera eos 350D, and it was exceptional. In BCN until July there are not disponibility, but it is not a problem, if I save every day 8 Eurus during 2 month, I will have the difference with the 773M. !!!

There is a sentence that says: A better world exists.. but it is more expensive

Any contribution it will be well received, but for my part the question is close.
Thanks to Hinnark,Postcardcv,Kabsetz, Iporali,Paul,Pyrtle and Keithal for your good and disinterested information.

Best regards

Toni
 
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