Konus Spotting Scope--80mm or 100mm?

[Cuc Tu]

I've read some reviews around here and this seems like a good brand. Much better than what Big 5 has anyway.

I was wondering if there would be any benifit to having the 100mm and if it is really worth an additional $70?

Thanks

Oh, I also found out that the 100mm is weatherproofed, but the 80mm is not. The 80mm comes with a tripod.

Here are some specs from the mfg:

code: 7122
model: KONUSPOT-100
type: zoom prismatic spotting scope
magnification/diameter: 20-60x100
field of view at 1000 m (1000 yd.): 33.2 m (100 ft.) at 20x
exit pupil: 5 mm/0.2" at 20x
weight: 2400 g (84.7 oz.)
lenght: 480 mm/19.2"


code: 7120
model: KONUSPOT-80
type: zoom prismatic spotting scope with tripod
magnifications/diameter: 20-60x80
field of view at 1000 m (1000 yd.):
52,4 m (157,2 ft.) at 20x
exit pupil: 2.9 mm/0.12" at 20x
weight: 1550 g (54.7 oz.)
lenght: 420 mm/16.8"

Each scope has the same eye relief of 18-12mm

I found one complaint on the 100mm and that was that the body was weak--a cast metal ring that holds it together broke.

[FirstFreedom]

I was wondering if there would be any benifit to having the 100mm and if it is really worth an additional $70?

Absolutely, yes.

The bigger the objective lens, the higher the resolution (clarity) possible, ceteris paribus. Using Pi*R^2 for surface area, a 100mm scope has a 56.25% greater surface area to let light in than an 80mm (over "half again as much"), to allow for more resolution (7,853.98 sq. mm for 100, versus 5,026.54 for the 80mm). Bigger exit pupil too, which helps on high power.

[Cuc Tu]

I love math...56% more surface area for 39% more money.

I was confused as to why the field of view was so much lower for the bigger scope. That is 36% lower.

So, if I had both scopes side x side, the bigger one would be brighter, or more clear, or have a higher resolution, but I would have a smaller FOV at the same power?

[FirstFreedom]

No at the same power, IINM, the field of view is the same, regardless of obj size. Look at this recent thread which devolved into a discusssion of re: reflectors & mat-cas scopes:

http://www.thefiringline.com/forums/...d.php?t=216908

[Cuc Tu]

at the same power, 20x:

the 80mm says FOV = 152 feet
the 100mm says FOV = 100 feet

i don't know how this can be?

I do expect the rest to be true.

I'm still confused as to how the objective and exit pupil can both be larger, yet end up with a smaller FOV at the same power?

I might get the 100mm anyway because I'm sure I'd like to use it at higher powers and in marginal lighting conditions, even for some light sky viewing.

I already have a 6.5" newtonian, so astronomy is well enough covered.

Thanks,

[Jim Watson]

I have seen very few 100 mm spotting scopes where I shoot. That is getting to be a BIG scope to hump around. Not just bigger objective, bigger and heavier overall. An 80 (or even a good 60) is enough to see a 500 metre ram fall (or not, with the dirt flying off his tail) or a spotting disk on a bullseye at 1000; and read the mirage. What I don't know is whether a bigger scope will have enough better actual resolution to pick out bullet holes in the black at longer ranges for solo shooting.

[Mute]

You should get a slightly brighter image with better resolution at the expense of size and weight. It's all a matter of what your needs are. I drag alot of gear with me to the range especially when I do long range shooting. Every bit of weight saving helps.

[Cuc Tu]

Well, I decided to go for the Konuspot-100.

I was interested in having the greatest performance and versatility in a scope that was within my limited budget...the Konuspot-100 streatched that a bit as it was. Otherwise, I might have picked the Kowa 82mm.

I can overcome a bulkier, heavier scope and hopefuly this one will be a good performing general purpose scope that allows good image quality in moderate light, convenient astronomical views (in addition to my telescope), good for the family, and photography.

I also caught a decent looking deal at cheaper than dirt for a BSA 20-60x60mm that comes with tripod, door mount, and hard case for around $60. That might be a good throw around range scope.

I'll try to post a couple of pictures through the lense after it comes in. Unfortunatley, I will have nothing to compare it against.

[FirstFreedom]

at the same power, 20x:

the 80mm says FOV = 152 feet
the 100mm says FOV = 100 feet

Now that is a conundrum - I don't believe that that is possible, and is probably an error, but I could be wrong. I think you'll be glad you got the bigger objective, definitely.

[Cuc Tu]

OK, well I read that the general rule is that the bigger objective will have a smaller FOV. It does go along with my experience as larger telescopes have smaller FOV, especially when compared to binoculars. I the think the naked eye has the largest FOV.

Anyway, as it so happens, UPS delivered right on time. I had a really good experience with their tracking and delivery. Nice blow-by-blow updates there.

Now, how do I upload my rather crude, stick the point-and-shoot digital camera to the eyepiece images?

I think I got it! These are taken at about 50 feet. The day is rather dim and it looks like it might rain. I know I'm not very good at this photograhy stuff, but at least I now have more tools to practice with.

First impression is decent construction--about what I would expect in this price range and I found no defects. Good image quality for an average user.

[raymond-]

C-
which vendor did you go with on this scope? tnx

[Cuc Tu]

I went with OpticsPlanet...I saw them on ebay too.

I also seen it in a mail order catalog for a bit less, but I forget the name of the place. I think it is a relatively large place and I've seen it mentioned on here before. They were about $20 cheaper.

[ocabj]

I don't think the 100mm is worth the extra money.

It's not like you're going to be able to see bullet holes any better than the 80mm.

All you should expect from any spotting scope is to be able to see 22cal holes in paper at 200 yards in decent conditions.

After that, all you care about is being able to see the scoring disc, spotting disc, and mirage.

At a recent match, I had no problems with image clarity in a Kowa 661 (66mm objective) at dusk on a 600 yard target.

[raymond-]

ahhh, but the point to larger objective isn't just to resolve better, it's to gather light.
so if the additional glass serves this purpose...when incliment wx conditions prevail
(eg at dusk) helps increase contrast, etc. then it's done the job. not as if you must
use this for spotting bullet holes, but also non-shooting chores as well. the eyepiece
is also crucial as it brings it all to focus for you to see....in your eyeball.

you boast of the resolving power of your 66mm obj. are you saying that (given
your example) that anything larger is also not worth the money? i owned a
66mm Kowa and it sucked....when compared to an 80mm Kowa. same grade
optics, same eyepiece power, just larger objective. so I sold the smaller and
purchased the 80mm unit. if mirage is an issue, i dial back to lower power
eyepiece. most of my need is bullet holes at 500 meters. where the 66mm
failed the 80mm succeeded. when the light was poor at the range, i've played
with an 8" obj lens and the light gathering was super....though vibration and
mirage became an issue.

the additional obj size may not be worth the money to you, but it can be for
others. it comes down to the task at hand and others may not be shooting
in conditions you prefer and benefit from with a 66mm unit.

[Jim Watson]

I have often spotted targets through a friend's Kowa 82mm.
Please tell me how to reliably spot bullet holes at 500 metres.
I can see bullet splash on steel, for metallic silhouette (with my 60mm, too); but a hole in paper is a sometimes thing even with some really strange colored targets that the NRA does not approve.

[Cuc Tu]

I think in the context of spotting bullet holes at any range that I'm going to be at (100 yards is the longest range), that 20-60x50mm BSA scope would do the job just fine. I'll probably buy that one since it is only $60 and comes with a tripod, window mount, and hard case. Perfect for the range.

The Konuspot-100 is a bit larger than I was expecting, too large for any ranges around here, but it has been performing exceptionally well for everything else so far. I'm hoping to take it up into the hills this weekend.

If I had the money, I would have been looking at the more expensive scopes, but over a grand is a grand too much, so I though I could compensate with a larger optic.

[FirstFreedom]

ok, top right image of $2 bill

vs.

bottom right image

Which is taken in which way? Since one is clearer than other - One with Konus and one with other brand or what?

Raymond is correct - the 100 may *just be* the difference in being able to, or not being able to make out, small holes (.17 or .22) at 200 yards at dawn, dusk, or on a very cloudy day, and may be the difference between seeing and not seeing the holes at all at 300 on sunny day. Bigger objective gathers more light. Although I haven't done it (don't have access to a 1,000 range), my understanding is that some 1,000 yard shooters use the same Celestron C130 mat-cas scope which I have (130 mm) to actually see their holes at that range. I fully expect it to work at 400 yards for spotting .22 and bigger holes. We'll see. It sure looks like it could, as I can make out small features of tree leaves at 380 yards plus out the back window.

The fact is that large objectives *DO* in fact (to a certain extent), make up for glass grind quality (smoothness, symmetry, coatings). A $300 100mm Konus will outperform a $1000 60mm Zeiss about any day, IINM. Dunno about 65mm and up - the glass quality CAN make up a large difference as well in resolution, depending on how large the difference, but Konus ain't no slouch in glass quality either. In any event, glass quality can make up for resolution, but not light-concentration, compared to a larger objective.

[Cuc Tu]

There is not really much value in the image I posted.

The upper left is at 20x, the lower left is at 60x--same scope.
The right side is the same image that was blown up with software. The difference in clarity most likely results because there a whole lot more pixels in the original area for the lower image. The upper right was magnified much more just to make them the same overall size.

What I learned is that the difference between 20x and 60x is not as much as I was expecting. If I had thought about it, I would have realized it is only 3x difference. The funny thing is that it looks to be only 2x in the comparison. That just might be the way that I had the camera held to the eyepiece. I don't have a complete mount yet.

[FirstFreedom]

ok, got it. Right side is digital after-zoom. Hmm, you're right; it's only twice as big (if that), not 3 times - weird.

[Cuc Tu]

Arg...never mind. I'm being stupid. Remember it was me just holding the camera to the eyepiece with a point and shoot...

I blew up the 20x shot a bit to make the views the same size...

Now I've gotten OT...I took the thing out to have a look at Saturn. Nice view of Saturns rings and I could even just start to imagine that I was seeing the Cassini division. I found the CloudyNight forum and after a couple days browsing, I'm hooked on building a 20" dobsonian. There is a 17.5" mirror on ebay, I might go for it. Then the Konus could be my finder scope...Hmmm, I think I'm starting to come back down from the clouds now.

[raymond-]

LOL ...same sequence for me and now i have my nice 8" Schmidt Cass since that
is easy for me to move around. Even used at the range a couple of times. Love
the motorized skewing control, making me feel as though I was in the movie, The
Jackel