Spotting scope question.

[Kilboars]

I have a Vortex Razor HD 65mm

I got to use it for the first time in the field early morning glassing for Elk and noticed it was well lit at low power but when I zoomed in it got very dark and grainy.

Is that normal for spotting scopes?

I was very disappointed for all the cost and trouble trekking the scope and tripod out in the field.


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[flyinsquirel]

Normal for all spotters to lose some quality and brightness as you zoom in. The degree to which this happens is directly tied to how much $$ you spent on the scope. I haven't looked through a 65mm Razor, but my guess is what you're experiencing may be normal for that scope.

 

[chutinlead]

That happened to me even on a friend's 20-60x65 Swarovski. I was a little shocked, but doing the math on exit pupil of Obj size/magnification, it makes a little more sense. So a 65mm/60x means your exit pupil is barely over 1mm. At 15x it's over 4mm. You eye can dilate to over 8mm in darkness and averages 5mm in low light.

 

[Dalen88]

yeah my 65mm swaro will do that in low light as well

 

[chutinlead]

I couldn't believe it and had to look thru my 85mm razor with the 30x fixed ranging eyepiece to see at last light.

It's not a problem as in bright daylight your pupil constricts to that 1-2mm size and makes any scope look bright.

 

[WCB]

That is normal for any adjustable magnification optic. The exit pupil shrinks the higher the magnification (less light is allowed through). Do the same thing with your rifle scope at last/first light.

 

[338weatherby]

I know the size of exit pupil is everything and the larger scopes will be best. Surprised to hear that a 65mm Swaro is grainy still at dusk. I am not well versed in spotters and am needing to pick one up. Looking at the 553 Kowa. Being only 55mm, will this be a huge disappointment? Wanting a smaller unit for packing and to bring with to the range .

 

[chutinlead]

I know the size of exit pupil is everything and the larger scopes will be best. Surprised to hear that a 65mm Swaro is grainy still at dusk. I am not well versed in spotters and am needing to pick one up. Looking at the 553 Kowa. Being only 55mm, will this be a huge disappointment? Wanting a smaller unit for packing and to bring with to the range .

Not if you don't set your expectations too high lol. At dawn/dusk 45x will be unusable, but 15x should be ok. 45x will work just fine during the bright sunshine. Exit pupil is most of it, light transmission % is the other half. By the time the light goes thru a scope, you might only be getting 70-90% of the light. Higher end glass gets you closer to 90% and top tier might get you to 95%.

 

[Newtosavage]

This is a big reason I switched to a fixed power eyepiece. I just stopped using the zoom eventually and then realized I was giving up field of view and brightness for a zoom feature I didn't use anyway. Figure out what power you normally use at dawn and dusk, then just get a fixed eyepiece that power. You'll be glad you did and probably wonder why you didn't do it sooner. Something around 20-24x seems to be a nice compromise to me although I lean toward 20x.

That said, I don't use my spotter nearly as much as I use my binoculars on a tripod mount. Probably 10:1 if not 20:1. I'm not a trophy hunter and I can tell pretty much all I need to know with my bins on a tripod mount, with less eye strain and less weight in the pack. My spotter stays in my truck nowdays. In fact, I upsized from an ED50 to an ED60 and from an angled to a straight spotter this year for that reason.

 

[338weatherby]

Not if you don't set your expectations too high lol. At dawn/dusk 45x will be unusable, but 15x should be ok. 45x will work just fine during the bright sunshine. Exit pupil is most of it, light transmission % is the other half. By the time the light goes thru a scope, you might only be getting 70-90% of the light. Higher end glass gets you closer to 90% and top tier might get you to 95%.

Would you say the Kowa 553 is on the upper end of glass as far as light transmission goes?

 

[chutinlead]

Would you say the Kowa 553 is on the upper end of glass as far as light transmission goes?

Yeah I bet that Kowa is probably one of if not the best 50mm class spotting scopes.

 

[AZ_Hunter_2000]

Would you say the Kowa 553 is on the upper end of glass as far as light transmission goes?

Yes.

This Kowa competes very favorably with the Kowa 773/774 and the Swaro STX 65 when in the field.

The Kowa 553/544 has an exit pupil of 3.7-1.2.

The Swarovski STX has an exit pupil of:
65: 2.6-1.1 mm
85: 3.4-1.4 mm
95: 3.2-1.4 mm
115: 3.9-1.6 mm

I have the STX 65/95 and Kowa 554. This Kowa is awesome and has earned a permanent place in my optics arsenal. The Kowa is not enough for me to sell the STX but it’d be good enough (for most things) if I did not already own the STX.

 

[338weatherby]

@chutinlead and azhunter,

Thanks for your input. That was enough to push me. Just ordered a 553 from Cameraland along with the stay on case, ARCA plate, and phone adapter. I feel a little lighter now for some reason

 

[AZ_Hunter_2000]

@chutinlead and azhunter,

Thanks for your input. That was enough to push me. Just ordered a 553 from Cameraland along with the stay on case, ARCA plate, and phone adapter. I feel a little lighter now for some reason

It'll be worth it. Wallet may be lighter but the Kowa is light (mine is about 32 ounces with neoprene cover) and much nicer to carry than my STX (about twice the weight).

Did order "ULBTER 5 Pack Elastic Lens Cap Keeper" from Amazon to tether the front and rear caps. Works well.

Depending on which case you went with, the front has a strap to hold the lens cap (at least on the neoprene). Nice touch.

 

[Blue72]

This is a big reason I switched to a fixed power eyepiece. I just stopped using the zoom eventually and then realized I was giving up field of view and brightness for a zoom feature I didn't use anyway. Figure out what power you normally use at dawn and dusk, then just get a fixed eyepiece that power. You'll be glad you did and probably wonder why you didn't do it sooner. Something around 20-24x seems to be a nice compromise to me although I lean toward 20x.

That said, I don't use my spotter nearly as much as I use my binoculars on a tripod mount. Probably 10:1 if not 20:1. I'm not a trophy hunter and I can tell pretty much all I need to know with my bins on a tripod mount, with less eye strain and less weight in the pack. My spotter stays in my truck nowdays. In fact, I upsized from an ED50 to an ED60 and from an angled to a straight spotter this year for that reason.

^^^^^this!!!

I switched to fixed magnification eyepiece as well for better image quality and wider field of view. Which is the way to go if using a scope.

I too eventually switched to high power bino's

 

[eric1115]

This is a big reason I switched to a fixed power eyepiece. I just stopped using the zoom eventually and then realized I was giving up field of view and brightness for a zoom feature I didn't use anyway. Figure out what power you normally use at dawn and dusk, then just get a fixed eyepiece that power. You'll be glad you did and probably wonder why you didn't do it sooner. Something around 20-24x seems to be a nice compromise to me although I lean toward 20x.

That said, I don't use my spotter nearly as much as I use my binoculars on a tripod mount. Probably 10:1 if not 20:1. I'm not a trophy hunter and I can tell pretty much all I need to know with my bins on a tripod mount, with less eye strain and less weight in the pack. My spotter stays in my truck nowdays. In fact, I upsized from an ED50 to an ED60 and from an angled to a straight spotter this year for that reason.

Yes! I love the 30x wide angle on my Kowa 66. Wider FOV than the 20-60 at 20x, and I think it's enough brighter and sharper that the variable doesn't show more detail until around 45x in good light (assuming mirage is mild enough to allow the use of higher magnification), and probably doesn't ever beat it at dawn/dusk.

 

[Kilboars]

This is a big reason I switched to a fixed power eyepiece. I just stopped using the zoom eventually and then realized I was giving up field of view and brightness for a zoom feature I didn't use anyway. Figure out what power you normally use at dawn and dusk, then just get a fixed eyepiece that power. You'll be glad you did and probably wonder why you didn't do it sooner. Something around 20-24x seems to be a nice compromise to me although I lean toward 20x.

That said, I don't use my spotter nearly as much as I use my binoculars on a tripod mount. Probably 10:1 if not 20:1. I'm not a trophy hunter and I can tell pretty much all I need to know with my bins on a tripod mount, with less eye strain and less weight in the pack. My spotter stays in my truck nowdays. In fact, I upsized from an ED50 to an ED60 and from an angled to a straight spotter this year for that reason.

I was thinking of selling the Razor for a larger pair of Binos.

 

[Kilboars]

Thank you all. I thought that was the case. I have a pair os swaro EL 10x42 that really do a great job overall.