• Welcome to BirdForum, the internet's largest birding community with thousands of members from all over the world. The forums are dedicated to wild birds, birding, binoculars and equipment and all that goes with it.

    Please register for an account to take part in the discussions in the forum, post your pictures in the gallery and more.
ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

Kowa's new 50 mm scope (1 Viewer)

donno about the review,but saw a unit on Ebay ,from japan..2200 plus dollars!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Whatever you buy from Japan on eBay will not be eligible for a US warranty from any of the major manufacturers. And why would you spend an extra $400 and not get a US warranty?
 
Sorry I did not post more before guys. This summer has been crazy busy. I do plan on writing something up. Until then I will post a link to my Flickr page. I took quite a few pics of the scope especially in comparison to the two MM4 models. I also Phonescoped several pics through the 553 and the MM4 60 mm.

It was a bright, sunny day and the distance to my feeders is about 20 yards(meters). iPhone 6S and Phoneskope Universal adapter/Bluetooth shutter release.

I didn't specifically label each pic but to my eye you can see the difference between the two easily enough. The Kowa has a smaller apparent field of view and the Opticron has a slightly out of focus field stop in the 1- 2 o'clock position. All pics were taken at maximum magnification on both scopes. The pics are unedited in any way. Zoom in to see the difference in detail.

First pic is with the Opticron at the link below. Scroll through all of them for the comparison.

https://flic.kr/p/WnxB5E
 
The images through the Kowa look very unimpressive compared with the modestly priced MM4..the MM4 is nailing more detail ,with a clear sweet spot right in the center,and shows better contrast and less lateral color ...anyway ,thanks for the pictures...Looked through your pictures a bit, loved the American Redstart shots..very cool
 
No store is allowed to sell them yet. Official release is 8/18 to coincide with the British Bird Fair. We can, do, and have taken pre-orders at Optics4Birding. They are not a scam. They are a fabulous little scope with a couple of cons that don't come close to outweighing the pros.

I was raving a bit, but around here the 553 is apparently more expensive than a Swaro ATS65. (Kowa is more expensive here than in the US, due to exchange rates I guess)

I noted though that the cost per/mm objective lens for the 553 is almost the same as for it's bigger siblings 773 and 883 (inc 25-60x EP).

Considering what scopes I see in the field around here (883's or Swaro 80mm+, Zeiss 85mm), 553 will not sell to any "normal" birders, but perhaps as a travel scope.
 
Last edited:
Henry,

I have some questions about performing these tests. I have never done either, so I did some reading about them.

All the star test articles say that the eyepiece magnification must be 1.6 times the objective diameter, but that is impossible on this scope. Is the test still valid?

We have resolution charts and have used them to test relative resolution between two optics. But if we're going to get an absolute resolution for a single optic, there would have to be a standard distance between the optic and the chart. In all my reading, I have not been able to find this distance. Can you tell me what that distance is? Or do I just specify the distance I use and give the smallest line-pair number I can resolve?

Steve,

Don't worry, 45x will be plenty for a star-test of a 55mm spotting scope. No less an authority than Richard Suiter (the guy who wrote the book on star-testing) recommends a magnification that matches the objective diameter and a bit less for low focal ratio scopes like the 553.

Do you have the USAF 1951 resolution target? I can post a formula and a chart that will allow you to derive resolution in arc seconds measured at any distance with that. Unfortunately, 45x may be on the low side for easily seeing the smallest resolvable line pairs with a diffraction limited 55mm scope, unless you know someone with 20/10 eyesight acuity. Do you have access to the Opticron doubler, Zeiss Tripler or something similar?

Henry
 
Piergiovanni just published his impressions on his website, and he seems to have got a better specimen of the small Kowa. He also offers an explanation why some of the early reviews came to different conclusions, namely that these scopes were pre-production samples that were still below the standard of the version that will go into production: http://www.binomania.it/recensione-dello-spotting-scope-kowa-tsn-553-prominar/

I must admit, I think that scope is an interesting product, even at the high price.

Hermann
 
Considering what scopes I see in the field around here (883's or Swaro 80mm+, Zeiss 85mm), 553 will not sell to any "normal" birders, but perhaps as a travel scope.

Or a scope for long trips in "difficult" terrain. I know Scandinavian birders are a hardy lot, but how many would want to carry, say, an 85mm scope+tripod for 15 kilometres or more in the Norwegian mountains?

Hermann
 
Steve,

Don't worry, 45x will be plenty for a star-test of a 55mm spotting scope. No less an authority than Richard Suiter (the guy who wrote the book on star-testing) recommends a magnification that matches the objective diameter and a bit less for low focal ratio scopes like the 553.

Do you have the USAF 1951 resolution target? I can post a formula and a chart that will allow you to derive resolution in arc seconds measured at any distance with that. Unfortunately, 45x may be on the low side for easily seeing the smallest resolvable line pairs with a diffraction limited 55mm scope, unless you know someone with 20/10 eyesight acuity. Do you have access to the Opticron doubler, Zeiss Tripler or something similar?

Henry

Henry,

I have some resolution charts from Swarovski that look exactly like the USAF 1951 targets. They are about 4" square. I also have a Vortex doubler. Please post the formula and the chart. That will be good to have.

FYI, our review writer just came in and refused to write a review on the scope we have. If we can't give a good review, we don't give one. He had too much trouble focusing over 30x in any weather condition, to give the scope a recommendation. After reading Hermann's post, but being unable to read or get a translation of the Italian review, we're going to ask Kowa for a production sample to see if there is any improvement.
 
FYI, our review writer just came in and refused to write a review on the scope we have. If we can't give a good review, we don't give one. He had too much trouble focusing over 30x in any weather condition, to give the scope a recommendation. After reading Hermann's post, but being unable to read or get a translation of the Italian review, we're going to ask Kowa for a production sample to see if there is any improvement.

Steve,

Google Translator is your friend: https://translate.google.de/transla...-spotting-scope-kowa-tsn-553-prominar/&edit-t

Hermann
 
Henry,

I have some resolution charts from Swarovski that look exactly like the USAF 1951 targets. They are about 4" square. I also have a Vortex doubler. Please post the formula and the chart. That will be good to have.

FYI, our review writer just came in and refused to write a review on the scope we have. If we can't give a good review, we don't give one. He had too much trouble focusing over 30x in any weather condition, to give the scope a recommendation. After reading Hermann's post, but being unable to read or get a translation of the Italian review, we're going to ask Kowa for a production sample to see if there is any improvement.

The Binomania site now has a 'Language' option.
This translate link is on the left side of the opening page, about half way down.

Thank you, Piergiovanni!
It makes it much easier to take advantage of your experienced evaluations.
 
Hello from Italy.
I have tried a specimen of Kowa TSN-553 which showed only a slight 45X sharpness drop. I used it often to those great enlargements without problems. I read about your complaints and contacted the Kowa Europe manager who confirmed to me that " some demos had this problem". I hope Kowa will solve the final version. I also hope to have more information about this.
I like this japanese spotting scope, but i love also Opticron MM4 that has a great price for his performance.
Piergiovanni
 
Henry,

I have some resolution charts from Swarovski that look exactly like the USAF 1951 targets. They are about 4" square. I also have a Vortex doubler. Please post the formula and the chart. That will be good to have.

FYI, our review writer just came in and refused to write a review on the scope we have. If we can't give a good review, we don't give one. He had too much trouble focusing over 30x in any weather condition, to give the scope a recommendation. After reading Hermann's post, but being unable to read or get a translation of the Italian review, we're going to ask Kowa for a production sample to see if there is any improvement.

Steve,

Sorry for the late reply. The first thing you need to do is to determine if the Swarovski chart is sized properly. Group 0, Element 1 should be made of bars and spaces that are each exactly 0.5mm wide, so that the 3 bars will align perfectly with the millimeter marks on a ruler. The print quality of paper charts can be so poor that reliable measurements may only be possible down to Group 2 or even Group 1. Resolved with this chart means the smallest Group/Element that still allows the direction of the lines to be detected. The next smaller Element will look like a gray square.

The Edmund Optics table below converts Groups and Elements to line pairs per mm. Edmund used to supply an odd formula for converting LP/mm to arc seconds of resolution, which I still use. It works like this: Measure the distance from the scope objective to the chart in inches. Determine the smallest Group/Element resolvable on the chart and convert to LP/mm. Multiply the distance to the chart in inches by the LP/mm resolution. Divide 8121 by that number. The result is the resolution in arc seconds.

Here's an example; distance to chart = 1000 inches, smallest resolvable Group/Element = 2/1, 1000 x 4.00 = 4000, 8121/4000 = 2.03 arc seconds

Edit: If you want to stay in the metric system just measure the distance in centimeters and use 20,627 instead of 8121.

The experiences of Binomania, Frank and your reviewer are perfect examples of why resolution measurements and star-tests are so essential for reviewing scopes. Subjective impressions of sharpness are not reliable since every telescope eventually loses sharpness at some magnification. Whether that magnification is lower than it should be for a given aperture can only be determined by measuring the resolution and comparing it to the diffraction limit for the aperture. If the Kowa scopes had been star-tested we would know exactly which ones were defective and what was wrong with them.

Henry
 

Attachments

  • DSC_0013.jpg
    DSC_0013.jpg
    64.5 KB · Views: 414
Last edited:
Steve,

Sorry for the late reply. The first thing you need to do is to determine if the Swarovski chart is sized properly. Group 0, Element 1 should be made of bars and spaces that are each exactly 0.5mm wide, so that the 3 bars will align perfectly with the millimeter marks on a ruler. The print quality of paper charts can be so poor that reliable measurements may only be possible down to Group 2 or even Group 1. Resolved with this chart means the smallest Group/Element that still allows the direction of the lines to be detected. The next smaller Element will look like a gray square.

The Edmund Optics table below converts Groups and Elements to line pairs per mm. Edmund used to supply an odd formula for converting LP/mm to arc seconds of resolution, which I still use. It works like this: Measure the distance from the scope objective to the chart in inches. Determine the smallest Group/Element resolvable on the chart and convert to LP/mm. Multiply the distance to the chart in inches by the LP/mm resolution. Divide 8121 by that number. The result is the resolution in arc seconds.

Here's an example; distance to chart = 1000 inches, smallest resolvable Group/Element = 2/1, 1000 x 4.00 = 4000, 8121/4000 = 2.03 arc seconds

Edit: If you want to stay in the metric system just measure the distance in centimeters and use 20,627 instead of 8121.

The experiences of Binomania, Frank and your reviewer are perfect examples of why resolution measurements and star-tests are so essential for reviewing scopes. Subjective impressions of sharpness are not reliable since every telescope eventually loses sharpness at some magnification. Whether that magnification is lower than it should be for a given aperture can only be determined by measuring the resolution and comparing it to the diffraction limit for the aperture. If the Kowa scopes had been star-tested we would know exactly which ones were defective and what was wrong with them.

Henry

Thanks, Henry,

On the chart that we have, in Group 0, the top line is marked "2", not "1", and the black bars line up exactly with the millimeter lines on a ruler. The paper is glossy and there is no bleed to the lines.

Testing will have to wait for a bit. I've spoken with Paul Kardos of Kowa and we are getting a new sample. He said Frank's sample was from the same batch as ours, so it makes sense that we saw the same results.
 
If 0/2 is on the upper left corner of your chart then 0/1 should be on the lower right corner. 0/1 is the only one that should align perfectly with the ruler, but 0/2 is only 12% smaller so it could look close. Try using a magnifier and line up the centers of the bars with the centers of the ruler marks.

I think it would be a good idea to measure the resolution and star-test the defective sample as well as the new one, so you will know how much improvement there is and what's wrong with the defective one.

Henry
 
If 0/2 is on the upper left corner of your chart then 0/1 should be on the lower right corner. 0/1 is the only one that should align perfectly with the ruler, but 0/2 is only 12% smaller so it could look close. Try using a magnifier and line up the centers of the bars with the centers of the ruler marks.

I think it would be a good idea to measure the resolution and star-test the defective sample as well as the new one, so you will know how much improvement there is and what's wrong with the defective one.

Henry

Group 0/1 on this chart has lines a bit farther apart than 1 mm. 0/2 is exact. Unfortunately, the defective scope is already packed and ready for pickup by UPS. I should have the new one, this time a TSN-554, tomorrow.

Star testing with stars also seems a bit difficult these days, as we have a lot of marine layer clouds from dusk through well past dawn. It saves on the A/C bills, though.
 
Since you now know that the Swarovski chart is off by one Element it will be easy enough to compensate on the conversion table by substituting the value of the next larger Element for the smallest one you can actually resolve.

I seldom use real stars for star-tests. I have a 10 meter indoor set-up using a pinhole over a halogen bulb, which is mainly useful for small apertures like binoculars. For scopes I set up a small round shiny object that catches a glitter point of sunlight at 30-50 meters (Christmas tree ornament, ball bearing, etc.).

Henry
 
Since you now know that the Swarovski chart is off by one Element it will be easy enough to compensate on the conversion table by substituting the value of the next larger Element for the smallest one you can actually resolve.

I seldom use real stars for star-tests. I have a 10 meter indoor set-up using a pinhole over a halogen bulb, which is mainly useful for small apertures like binoculars. For scopes I set up a small round shiny object that catches a glitter point of sunlight at 30-50 meters (Christmas tree ornament, ball bearing, etc.).

Henry

I figured that using the 0/2 as a basis would work as a replacement for 0/1.

The Christmas tree ornament takes me back to BA-3 at Brooks Institute of Photography. We did a lot of different lighting situations with an ornament, a racquetball, and a tennis ball on an 18% gray stand.
 
We received a demo TSN-554 this afternoon. I only had a few minutes to do some testing. On this sample, I get a sharp image at 45x, even read license plates easily at 250 yards, through heat shimmer. Granted, this is not a thorough test, but I feel a lot better about the scope. I did notice that there was a drop in eye relief at high power that I was able to solve by shortening the eyecup. This may be a problem for eyeglass wearers, especially those with astigmatism.
 
Warning! This thread is more than 6 years ago old.
It's likely that no further discussion is required, in which case we recommend starting a new thread. If however you feel your response is required you can still do so.

Users who are viewing this thread

Back
Top