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Posted: 8/10/2019 2:59:11 PM EDT
[Last Edit: 8/10/2019 2:59:45 PM EDT by TheHorta]
Which would you take:

1) S/N: ~30 + 72 LP
2) S/N: ~35 + 64 LP

???
Link Posted: 8/10/2019 3:00:23 PM EDT
Link Posted: 8/10/2019 3:04:53 PM EDT
prices?
Link Posted: 8/10/2019 3:06:08 PM EDT
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Originally Posted By ar15joe:
prices?
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Same price. Other relevant specs practically similar.
Link Posted: 8/10/2019 3:06:42 PM EDT
Originally Posted By TNVC:
35...IMHO S/N rules.
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This
Originally Posted By ar15joe:
prices?
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exactly
Link Posted: 8/10/2019 3:06:59 PM EDT
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Originally Posted By TNVC:
35...IMHO S/N rules.
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I lean that way too, though I’d have to seriously consider an 80LP tube.
Link Posted: 8/10/2019 3:08:53 PM EDT
#2.

There was a thread a while back where they talked about the digital equivalent of lp/mm.

Iirc 64 would still be multiples better than even a 4k screen at that size.

It was a good thread, I'd say check that out.
Link Posted: 8/10/2019 3:14:18 PM EDT
Link Posted: 8/10/2019 4:25:05 PM EDT
As everyone knows, the S/N ratio changes drastically with even the slightest movement of the external gain pot. the S/N can also be changed by "tuning" or adjusting one of the pots on the tube itself. I think the lpmm on a tube is pretty much baked in. I would chose a tube with a lower S/N and really high PCR, low EBI, and higher resolution over one with slightly higher S/N.
Link Posted: 8/10/2019 4:32:10 PM EDT
[Last Edit: 8/10/2019 4:32:32 PM EDT by 1paintball]
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Originally Posted By 1paintball:
As everyone knows, the S/N ratio changes drastically with even the slightest movement of the external gain pot. the S/N can also be changed by "tuning" or adjusting one of the pots on the tube itself. I think the lpmm on a tube is pretty much baked in. I would chose a tube with a lower S/N and really high PCR, low EBI, and higher resolution over one with slightly higher S/N.
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Even in the darkest conditions I always turn the gain knob down a little to get rid of some of the ion strikes, and let my eye adjust to it, your eyeball has a gain control too! lol.
Link Posted: 8/10/2019 5:55:59 PM EDT
SNR of 35 no doubt.

Once the SNR is in the 30s (even high 20s), I start weighing tubes more on EBI. Then PCR. Very last is resolution. Would pick a 64lp/mm 0.5 EBI tube over a 72lp/mm 0.8 EBI tube without hesitation. Only situation where I might look at resolution twice is if the tube was intended to be solely used in a clip-on scope.
Link Posted: 8/10/2019 6:38:12 PM EDT
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Originally Posted By txdx:
SNR of 35 no doubt.

Once the SNR is in the 30s (even high 20s), I start weighing tubes more on EBI. Then PCR. Very last is resolution. Would pick a 64lp/mm 0.5 EBI tube over a 72lp/mm 0.8 EBI tube without hesitation. Only situation where I might look at resolution twice is if the tube was intended to be solely used in a clip-on scope.
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Interesting. What will the EBI difference do for you over the resolution difference?
Link Posted: 8/10/2019 7:09:23 PM EDT
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Originally Posted By TNVC:
Well if course, I was gonna caveat that at 80+ LP.
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Originally Posted By TNVC:
Originally Posted By TheHorta:
Originally Posted By TNVC:
35...IMHO S/N rules.
I lean that way too, though I’d have to seriously consider an 80LP tube.
Well if course, I was gonna caveat that at 80+ LP.
How noticible is the jump from 72 to 80+? You had a 82 or 83 that you use for astronomy if I remember correctly.
Link Posted: 8/10/2019 7:49:52 PM EDT
Link Posted: 8/10/2019 8:29:47 PM EDT
I've got a 0.2 EBI/30.3 SNR/64 lpmm filmless tube in my MOD3s and it certainly has made me appreciate specs beyond just SNR.

I do not buy on specs or consider them all that much for personal use, but it's fun to compare tubes for their different attributes.
Link Posted: 8/11/2019 10:00:48 AM EDT
Link Posted: 8/11/2019 10:15:45 AM EDT
The higher FOM unit
Link Posted: 8/11/2019 6:51:11 PM EDT
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Originally Posted By Shqype:

Interesting. What will the EBI difference do for you over the resolution difference?
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Any resolution improvement over 64lp/mm is a point of rapidly diminishing returns, unless in a clip-on configuration or some other system that has magnification downstream of the tube. Under extremely low light conditions, the resolution of the human eye drops even further and a tube with a resolution of say 57lp/mm would appear equally sharp, rather equally fuzzy. Under those same extremely low light conditions, EBI will be the dominant parameter that determines tube performance and how pleasing the image appears or even whether an image even appears. A 10-20% difference in EBI then becomes noticeable.
Link Posted: 8/11/2019 7:29:40 PM EDT
Link Posted: 8/14/2019 2:53:52 AM EDT
Application?

For Aviation, anything over 30 SNR and I prioritize EBI over extra SNR.

Ground use, I'd probably still pick the higher lp tube as long as both are over 30.
Link Posted: 8/14/2019 3:14:51 PM EDT
If your SNR is over 30...
If your Halo is under 1...
If your EBI is under 1...
If your lp/mm is 64 or higher...

IMO you would have to test back to back to tell which is which in normal, head mounted use and even then its not going to be very noticable.

I doubt you could throw one on in a blind test in a new location and say "This is the 31.9 SNR tube, this is the 34.6 SNR tube, or .8 vs .6 Halo, or .8 vs .5 EBI..." etc. if you just tried one random tube and didnt look at the other.

Perhaps if one is more than double the EBI or Halo of the other it would be immediately noticable in situations where those are much more obvious, but there would probably not be much practical difference, even then.

I tried a recently tried an L3 tube which was lower in ALL those stats vs mine and had to look for a blem or pull it away from my face to tell which was which. Halo size was probably the easiest to spot back to back and 72lp/mm vs 64lp/mm the hardest.
Link Posted: 8/14/2019 4:55:43 PM EDT
[Last Edit: 8/14/2019 4:57:10 PM EDT by DevL]
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Originally Posted By SpyHawk:
#2.

There was a thread a while back where they talked about the digital equivalent of lp/mm.

Iirc 64 would still be multiples better than even a 4k screen at that size.

It was a good thread, I'd say check that out.
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How does that conversion work exactly? Is the lp/mm based off the 26mm lens or 18mm tube? 64 x 2 lines x 18 or 64 x 2 x 26?

2304 pixels vs. 3328 pixels across.

A 60" TV at 6 feet is a 40 degree wide FOV, but not as tall. 3840 pixels wide is still better than a 64lp tube either way if that is yhe formula.

72lp/mm x 2 lines x 26mm with a 40 degree fov would be 3744 pixels. If based off the 18mm tube 2592 pixels wide. So 72 lp/mm might be under 4k in that case?
Link Posted: 8/14/2019 5:20:26 PM EDT
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