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Kowa TSN-501 - a brief review (1 Viewer)

dwatsonbirder

Well-known member
Disclaimer: I should preface the following by stating that I am likely planning on selling the scope for reasons which will be covered in detail in the review - I don't want to be accused of drumming up a sale, but hope that this review may assist others who are looking at options for a compact scope.

Introduction

Having previously owned several Nikon ED50 scopes, I decided to abandon the travelscope format on updating/upgrading from the tried and tested Nikon fieldscope series to an 80mm HD Swarovski scope. Earlier in the year I obtained an old Opticron MM2 ED travelscope which proved suitable enough during a trip to the Philippines, though the draw design and lack of waterproofing were concerns in such a humid and occasionally very wet environment.
Fast forward to the present, and I found a good deal on an ex-demo Kowa TSN-501. The scope ticked a lot of boxes (waterproof, compact, very lightweight) however there appear to be limited reviews of the scope in the field available.

Body

Kowa updated the 500 series in March 2017 following on from the previous TS-501/502/504. Like its predecessor, the TSN-501 is a compact, non-ED (the TS-504 had ED glass) travelscope with a fixed eyepiece. The key differences appear to be that the newer model is only available with a zoom (the TS 500 was offered with either a 20x fixed or a zoom), fully multi-coated optics, and a different body shape. The original model retailed at +/- £120 with the fixed lens and +/- £150 with the zoom, where as the RRP on the new model is £319 - a fairly significant increase in price, even considering the increase in inflation.
The scope itself is either a reinforced composite or plastic body, with a metal eyepiece. The focus knob, eyecup and zoom grip have a pleasant soft rubber covering. Interestingly, the body of the scope has a pleasant grippy and slightly coarse texture - one could be forgiven for expecting a smooth textured finish from stock photographs. There is a peep line along the right-hand side of the body, and interestingly the focus knob is also oriented on the right. There is a standard tripod mount with reinforced 1/4" insert on the mounting base.
Despite the slightly quirky appearance, I like the aesthetics of the design, and although it feels tiny, there is a solidity and feel of decent build quality without any heft.
The weight with eyepiece comes in at 412g on my scale - half of that of my Zeiss 7x42 binoculars!

Mechanical operation

Build quality follows through into the mechanical aspects of the scope.
The focus wheel is just roughly one and a quarter fingers width, and turns remarkably smoothly with just the right amount of resistance for my tastes (fairly low). The positioning of the wheel on the right feels a bit odd after years of using helical wheels, and my preference would probably have been for this to be central rather than off to one side - again down to personal choice.
The zoom mechanism has a higher level of resistance though is still easy to turn, with the rubber grip providing some assistance in wet weather or with gloves. Once the desired magnification is set, it is unlikely that it could accidently be knocked out of position or subject to drift.
The eyecup is of the twist out variety, with a single intermediary position - this does not click, and could therefore theoretically be moved if careless - applying some gentle downward pressure, I was quite easily able to depress the eyecup to the fully retracted position. As this is very much a budget scope, the expectation that some areas will suffer as a result of costs is inevitable, however, that the only mechanical issue relates to the eyecup is praise indeed on such an instrument.
The one area which requires some consideration and for me is a deal-breaker with this scope is the eye-relief which varies between 12.5 -14mm across the zoom range. I would advise to try before purchasing if you wear glasses, as for me there was some difficulty in getting the right position with glasses, and comparing the view with and without glasses I was surprised to lose about 25% of the field of view.
There is no extendable hood on the front end of the scope, though the objective lens is recessed about 1.5cm. There is a partial thread on the inside edge which could potentially support a third party screw in hood if needed - I did not test this.

Optics

To keep this brief, I'll summarise these broadly into pros and cons. I will post some images showing IQ across the zoom range later.

Pros
  • Very sharp image, with genuinely impressive resolving detail. Viewing a flock of winter thrushes at a distance of 160m I was clearly able to distinguish the flank streaking and extent and shape of the supercilium on a Redwing. At around 800m it was quite easy to age and follow individual Common Gull feeding in a field at 20x. Increasing the zoom, the image is still excellent at 30x, and even at 40x a good level of detail is evident, though there is a negligible softening on fine detail.
  • Colour rendering seems natural, with whites appearing white, and no obvious colour cast.
  • Excellent focus "snap". This is most likely as a result of the image sharpness, but impressive to get this with a standard glass optic.
  • Colour fringing (CA) isn't too bothersome, and is almost absent in the centre of the field of view at all magnifications - really impressive for standard glass. It doesn't really appear in the view at 20x, kicking in at around 25x though only to a minor degree.
  • Quite a bright view given the 50mm objective up to 25x.
  • Excellent close focus - perfect sharpness at 2m.

Cons
  • Eye relief is short, check if you wear glasses.
  • Field of view is quite narrow across the entire field, though the flipside of this is that the sharpness and other aspects are better corrected as a result.
  • Colour fringing is apparent in certain circumstances (e.g. viewing bare branches against the sky, dark bird against pale background), becoming more obvious at magnifications of 30x and above.
  • Some softness of the image in the outer 25% of the field
  • Drop off in brightness at magnifications above 30x.
Summary

The Kowa TSN-501 is a great low budget option for anyone looking for a travelscope, first scope, or back-up which could be left in a bag/car/window. The combination of solid build quality, and a good image (considering the small objective lens and standard glass) make this a worthy consideration when space and weight are at a premium.
The primary concerns relate to the short eye-relief and narrow field of view which won't work for everyone - most likely not an issue if you do not wear glasses, but worth checking beforehand if you do.
I would suggest the the TSN-501 is a worthy update of the previous TS-500 series, and optically the equal of the ED version of the Opticron MM2 fieldscope, even with standard glass.
The scope doesn't perform optically at the same level as the Nikon ED50 or newer Opticron MM3 or MM4 ED scopes, however the additional cost of all these, along with the scarcity of obtaining eyepieces for the Nikon, and the added weight of the Opticron scopes mean that Kowa have filled a niche in the market, and provided what is probably the best value travelscope currently available.
 

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Here are some comparative images taken at 20x and 40x using my mobile through the scope, it isn't a terribly good phone but hopefully show some of the optical characteristics discussed.
 

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Hi Dan.

I've had a look at these scopes to chuck in a bag with a monopod, like I used to do with my ctc 30/75 but the lack of a decent case for them had put me off. I see the Kowa stay on case that you can get with them but it doesn't seem to offer a way to protect either the eye piece or the objective- what did you use? Are the supplied caps likely to stay on when it's rattling round in the bottom of a rucksack?
 
Hi Will, thanks for your comment. Unfortunately the ex-demo version I purchased didn't come with a stay on case, but I suspect one of the cases which fits the smaller Opticron scopes (for example) would work, and offer some additional protection. The eyecups are actually quite good, though I never consider them - they are press on, and stay quite firmly in place, so would definitely offer some protection.
 
Daniel:

Great review! A shame Kowa didn't use an eyepiece with a bit more eye relief. And a slightly wider field of view. I personally think a smallish fixed WA might well work better with such small scopes, say a 25x WA.

I'm actually not surprised CA is quite well-controlled. Kowa made several small scopes over the years, and they all had resonable CA correction. I've got two different small Kowas, still with metal bodies, and although modern scopes with their better coatings have higher contrast, they're still quite useable. Kowa knows how to build scopes, that's for sure.

I switched to using glasses last summer, after more than 40 years with contact lenses, so the small Kowa isn't really suitable for me. I'll stick to my ED50s (I've got two of them) for the time being. But then I've got plenty of different eyepieces ...

Hermann
 
Daniel:

Great review! A shame Kowa didn't use an eyepiece with a bit more eye relief. And a slightly wider field of view. I personally think a smallish fixed WA might well work better with such small scopes, say a 25x WA.

I'm actually not surprised CA is quite well-controlled. Kowa made several small scopes over the years, and they all had resonable CA correction. I've got two different small Kowas, still with metal bodies, and although modern scopes with their better coatings have higher contrast, they're still quite useable. Kowa knows how to build scopes, that's for sure.

I switched to using glasses last summer, after more than 40 years with contact lenses, so the small Kowa isn't really suitable for me. I'll stick to my ED50s (I've got two of them) for the time being. But then I've got plenty of different eyepieces ...

Hermann
Thanks for your kind comments Herman.
I agree completely, if Kowa had released this with the option of a C.24x wide angle, they would've been onto a sure fire winner. I think for those that don't need glasses it is still an attractive budget option though. I've had an old TSN 611 with a 20x kicking around for a while, and that is also a well corrected scope - remarkably so considering it has standard glass and is probably getting on for 30 years old!

The ED50's cannot be beaten in terms of a lightweight, high quality optic - I've owned three since their release, and all were excellent samples which accompanied me on some fantastic overseas trips. Enjoy!
 
I bought a Kowa TSN-501 several months back and used it outside only 4 times. I bought it to have the experience of using a spotting scope as I possessed no spotting scope before. I didn't have a bigger budget to go for a higher quality scope or had no will to buy a bigger one.

During the first 3 times, it didn't surprise me with the image quality it produced and I thought it showed more or less the same details as the Curio or Monarch 7 8x30 I had. Only one time did it help to confirm the ID of one bird.

However, yesterday, I took it again to a different place, to a marshland closer to my new place of stay. It was a gloomy and cold day. However, this time I brought a better tripod with me. Even though the SFL 10x40 disappointed me again with its unacceptable level of CA, the little Kowa didn't disappoint me at all. I watched big flocks of black-headed gulls, mallards, gray herons, and Canada geese as well as a tree creeper nearly a hundred meters away. At 20x power it was bright and sharp in the center field. It showed much more detail compared to the SFL 10x40 I had. Maybe the shaky hand of me in the cold condition was the reason for that. Anyway, it has proven the little Kowa TSN-501 is still a worthy addition to keep. I am planning to take it for my next outings as well.
 
During the first 3 times, it didn't surprise me with the image quality it produced and I thought it showed more or less the same details as the Curio or Monarch 7 8x30 I had. Only one time did it help to confirm the ID of one bird.
That's highly surprising. Something must be wrong. You did use a tripod, right? Most likely is IMO probably a combination of user error and a total lack of experience with scopes.
However, yesterday, I took it again to a different place, to a marshland closer to my new place of stay. It was a gloomy and cold day. However, this time I brought a better tripod with me. Even though the SFL 10x40 disappointed me again with its unacceptable level of CA, the little Kowa didn't disappoint me at all. I watched big flocks of black-headed gulls, mallards, gray herons, and Canada geese as well as a tree creeper nearly a hundred meters away. At 20x power it was bright and sharp in the center field. It showed much more detail compared to the SFL 10x40 I had. Maybe the shaky hand of me in the cold condition was the reason for that.
Any half-way decent scope on a decent tripod at 20x will show A LOT more detail than ANY handheld 10x binocular. Even than a high-quality stabilised 10x binocular. A muggle binocular won't stand a chance.

What I'd recommend you to do is use the Kowa a lot. In all sorts of habitats. You need to get used to it to become really proficient. A scope has a steeper learning curve than a binocular.

Hermann
 
That's highly surprising. Something must be wrong. You did use a tripod, right? Most likely is IMO probably a combination of user error and a total lack of experience with scopes.
Yes, I suspect the wrong thing I did was trying to use higher magnifications and using an unstable tripod. Also, I am inexperienced as this is my first spotting scope.

You need to get used to it to become really proficient. A scope has a steeper learning curve than a binocular.
Yesterday, I used a stable tripod and stuck into the lowest mag. It made a real difference. I was seriously thinking about buying a Swaro or Kowa 56mm spotting scope to replace this. After the pleasant experience I had with it, I am going to stick to this for a little longer.

However, not to be offended, I don’t realize why spotting scopes have steeper learning curves compared to binoculars. Binoculars like NL pure need careful IPD, eyepiece (and diopter) adjustments to avoid blackouts and glare problems.
 
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I often use my Opticron with a lower power fixed magnification wide angle eyepiece. Higher magnifications can show a little more, but sometimes the higher brightness at lower magnifications makes things easier to see or just provides a more pleasant view. A zoom can allow you to find that “sweet spot” in different conditions or as the sun drops in the late afternoon.
A stable scope can show so much more than just binos, similar to goi g from naked eye to binos again. Dots become birds, gain feather detail and personality. I am always surprised how few scopes I see at birding sites…. They’re missing so much.

Peter
 
However, not to be offended, I don’t realize why spotting scopes have steeper learning curves compared to binoculars. Binoculars like NL pure need careful IPD, eyepiece (and diopter) adjustments to avoid blackouts and glare problems.
Well, with a new pair of binoculars you need to find the right IPD, the right diopter adjustment and the right setting for the eyecups (which incidentally has gotten more difficult over the years). You also need to get used to the ergonomics.

I personally find I need a couple of hours to set up a binocular that is new to me and about a week in the field to get used to the ergonomics. (BTW, that's why I find "reviews" based on trying a binocular for half an hour in a shop quite hilarious ... :ROFLMAO: )

With a scope you need a few more steps:
  1. You need to find the right setting for the eyecup.
  2. You need to get used to the ergonomics, especially the focuser.
  3. You need to get used to handling the whole setup, especially how to set up the scope+tripod quickly and efficiently in the field to make sure the whole contraption is stable. (BTW, that's one of the reasons why I tend to use tripods from the same manufacturer. They all handle the same.)
  4. You need to get used to holding the entrance pupil of your eye in the (small) exit pupil of the scope, especially at higher magnifications. That takes some practice, not just in windy conditions.
  5. You need to learn to find the bird quickly and efficiently in the scope, especially at higher magnifications and when the bird is in the air. That's not easy at all, especially if you use an angled scope, not even if you use a cable-tie sight (Make your own simple sight (aiming) device for telescopes: illustrated instructions) which is quite helpful.
Quite a bit more complex than using a pair of binoculars ... :cool:

Hermann
 
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