If you have two pulsar quantum hd units, one is an hd19a, and the other is an hd38a, is there any difference in the "quality" of the thermal image seen, OTHER than the difference in magnification? When looking on quantums web site at the technical properties of these two units, magnification is all I can see different. I was wondering if, in the real world of usage, this changed some other "quality" of the viewed image through the view finder? Thanks in advance!!
A thermal tech. question
- Thread starter mt-ed
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wigwamitus
LSB Active Member
The larger lens allows more "information" to enter the system. Hence as "thermal performance conditions" degrade, we would expect the larger lens to allow detection and identification at greater distances.
For example I would expect the hd38a (38mm lens) to be able to see cows at 2,200yds on some nights where the hd19a (19mm lens) would not be able to see those same cows.
Larger lens does not necessarily mean more magnification, but it often turns out that way.
All other things being equal, there is evidence that restricting FOV increases detection distance.
Note the relationships between FOV and detection distance in these charts:
Hence, since magnification restricts FOV, we can infer that all other things being equal, increasing magnification would increase detection distance (because increasing magnification restricts FOV).
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These things being said, I am not the "authority" on optics ... maybe some such folks will show up and provide more info !!!
I am interested in the answers!!!
For example I would expect the hd38a (38mm lens) to be able to see cows at 2,200yds on some nights where the hd19a (19mm lens) would not be able to see those same cows.
Larger lens does not necessarily mean more magnification, but it often turns out that way.
All other things being equal, there is evidence that restricting FOV increases detection distance.
Note the relationships between FOV and detection distance in these charts:
Hence, since magnification restricts FOV, we can infer that all other things being equal, increasing magnification would increase detection distance (because increasing magnification restricts FOV).
==
These things being said, I am not the "authority" on optics ... maybe some such folks will show up and provide more info !!!
I am interested in the answers!!!
I would suggest that the only benefit of higher magnification or reduced FOV vs. lower magnification or increased FOV in a spotter - assuming all other aspects equal, lens size, etc., is that with higher magnification some of the "white spots" when the unit is set to white hot, can be discerned to be critters, as opposed to just background. This seems to be especially true when the critter is partially obscured with brush, or when thermal conditions suck.
I have an HD 19 (1x) as well as a Patrol (native mag at about 1.45x, smaller FOV,) both with 19mm lens and the detection range of the Patrol is greater, primarily because of the magnification, though resolution is also a factor. Compared to either, my MK II 35mm (native magnification @ 2.45x) provides greater detection range, particularly when compared to the Patrol, almost exclusively because of magnification - BUT!, the loss of FOV makes it the least effective spotter of the three.
JPK
I have an HD 19 (1x) as well as a Patrol (native mag at about 1.45x, smaller FOV,) both with 19mm lens and the detection range of the Patrol is greater, primarily because of the magnification, though resolution is also a factor. Compared to either, my MK II 35mm (native magnification @ 2.45x) provides greater detection range, particularly when compared to the Patrol, almost exclusively because of magnification - BUT!, the loss of FOV makes it the least effective spotter of the three.
JPK
wigwamitus
LSB Active Member
One recent data point from my side is I took q-14 (19mm 1x 640(30)) and Zeus (75mm 3x 640(30)) out together. I went to top of my "Signal" hill. There were cows in a pasture at 2,200yds. The Zeus could see them. The q-14 could not see them at all. This was a fairly poor thermal performance night. On a scale of 1 to 5 (1 being worst and 5 being best) this was a 1.5.
All I need to see is white blobs and I know they are cows due to the distribution of the shapes ... and the fact that I know there were ~40 cows in that pasture at that time. And hence it could not be 40 giraffes !!!
The Zeus saw 40 ish white blobs ... the q-14 saw darkness.
So my theory is that the 75mm lens was the primary variable that made the Zeus able to see the cows, not the 3x. Of course my theory could be wrong !!!
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On a better thermal performance night ... both devices could see the cows (er blobs) at 2,200yds.
All I need to see is white blobs and I know they are cows due to the distribution of the shapes ... and the fact that I know there were ~40 cows in that pasture at that time. And hence it could not be 40 giraffes !!!
The Zeus saw 40 ish white blobs ... the q-14 saw darkness.
So my theory is that the 75mm lens was the primary variable that made the Zeus able to see the cows, not the 3x. Of course my theory could be wrong !!!
==
On a better thermal performance night ... both devices could see the cows (er blobs) at 2,200yds.
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I would agree 100 percent regarding the extra lens diameter, and so surface area, being the driver. And FOV, even with 3x, is not going to be an issue at that kind of range.
But cut the range in half and then I wonder if the Q14 might pick up the cows but the hot spots be lost in the view in the surrounding thermal variances. That is what seems to happen with the lower magnification thermals I have, with reduced probability the hot spots are "lost" in the background variances as magnification increases.
The better the thermal conditions the less hot objects seem to get lost in the surroundings and the more they "pop."
JPK
But cut the range in half and then I wonder if the Q14 might pick up the cows but the hot spots be lost in the view in the surrounding thermal variances. That is what seems to happen with the lower magnification thermals I have, with reduced probability the hot spots are "lost" in the background variances as magnification increases.
The better the thermal conditions the less hot objects seem to get lost in the surroundings and the more they "pop."
JPK
wigwamitus
LSB Active Member
I believe there is a range of cases where you are correct.
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This was my experience when using the MKII 35MM looked great in good conditions but could not see cows at 500 yards in poor consituons, while the zeus 75mm picked up those same cows. The zeus 100mm picked up those same cows at 500 yards and then many more across the road that the 75mm did not detect.
I've done several side by sides with both units here at the shop, and can pretty much confirm the above. In perfect conditions, they will both look fantastic, the 38 will have more magnification though obviously. In poor conditions (moisture in the air) the 38 will pull ahead due to the larger lens gathering more information. They are extremely impressive for the money. You won't be disappointed with either one. Personally, I'd make the decision primarily based on budget and terrain. If you have the distance to utilize the 38, and the budget will allow for it, then go that route. If not, you'll be happy with the 19a.
Following up on what Delta 4-3 is saying, where I do most of my predator hunting here in MD, the 19A is proving to be a great unit. We do not have vast, expansive fields or pastures and the range of the 19A and it's wide field of view are just right, especially when cost is considered.
Pulsar gives the detection range for the 19A as 500 meters for a man sized target, iirc. Using deer as targets, I have never encountered thermal conditions so poor that the Pulsar wouldn't detect deer at that range. I have encountered thermal conditions where looking through the Pulsar I saw something that made me look twice, and which I needed to confirm with the MK II, but up here those are proving to be rare conditions.
I do think you guys in TX have to deal with generally worse thermal conditions, and more often.
JPK
Pulsar gives the detection range for the 19A as 500 meters for a man sized target, iirc. Using deer as targets, I have never encountered thermal conditions so poor that the Pulsar wouldn't detect deer at that range. I have encountered thermal conditions where looking through the Pulsar I saw something that made me look twice, and which I needed to confirm with the MK II, but up here those are proving to be rare conditions.
I do think you guys in TX have to deal with generally worse thermal conditions, and more often.
JPK
WOW, such incredible help....thanks so very much guys. I know this is a hog hunting site, and although I live in MT where "if" there are any hogs, they are probably someone's pet, or on a family farm!! haha I will be hunting coyotes exclusively. Humidity here is typically very low, often in single digits in winter. Also, it will most likely be 20F and lower when hunting, so I think the thermal contrast b/t target and habitat will be significant. Since I am able, I prefer to make stands where I can see many hundreds of yards, and even a few miles away. If I pick up a potential target at such a distance that it cannot be identified with a spotting device, I'll either wait for it to come to the call, close the distance, or move to a new area for another stand. I have no need nor desire, to take such a risky shot at a suspect target. If a spotter will "locate" a potential target, I think I can use my more expensive and much better quality scope to track it inbound and make the shot. If I were hunting in closer quarters, and for such large "groups" as you often seem to find piggies, I can see why you often recommend a wide FOV. Even if I do manage to call in multiples, once that first shot is fired, the rest most often turn on the after burners and putting lots of distance between them and myself very very quickly......so.....follow shots, if taken, will be at high speed targets at quite far distances....so high magnification will come in handy then.
I really want to thank you all for you help. I know there are other coyote sites, and perhaps many of you visit them as well, but you guys seem to take this thermal topic with great professionalism, and don't make a nube feel bad through snarky and condescending comments! This site, as well as it's members are top shelf....a real class act! Thanks again.
I really want to thank you all for you help. I know there are other coyote sites, and perhaps many of you visit them as well, but you guys seem to take this thermal topic with great professionalism, and don't make a nube feel bad through snarky and condescending comments! This site, as well as it's members are top shelf....a real class act! Thanks again.
wigwamitus
LSB Active Member
To "identify" it will take the "more expensive and much better quality scope" ... to "spot" (i.e. detect) the "spotting device" will do fine.
If you use a suppressor, then after the first shot, the critters in question will turn on the afterburners. But they will not be trying to increase distance between themselves and YOU so much as between themselves and the SOUND THEY HEARD .. which will be the supersonic crack to their flank (these being the ones that were not hit). So most often they will run laterally ... on occasion directly away and on occasion directly towards you. But most often laterally. So keep that in mind. The suppressor will influence the behavior of the critters!
High magnification is a pro and a con. I'm in the 3x club ... and that includes shots out to 500yds. Too much magnification and you can't get oriented back to your right as quickly if you tracked a critter to your left. Like with 6x you would struggle more. 3x seems to be the best balance and others here have said the same. I just say I agree based on my limited experience. Target shooting with 3x thermal at 500yds I'm getting sub moa groups consistently and I am surprised.
If a great thermal clipon exists, then in theory that would be a great solution. You could start at 3x and then if tracking something father away increase the magnification. I'm just not sure a great thermal clipon exists.
If you use a suppressor, then after the first shot, the critters in question will turn on the afterburners. But they will not be trying to increase distance between themselves and YOU so much as between themselves and the SOUND THEY HEARD .. which will be the supersonic crack to their flank (these being the ones that were not hit). So most often they will run laterally ... on occasion directly away and on occasion directly towards you. But most often laterally. So keep that in mind. The suppressor will influence the behavior of the critters!
High magnification is a pro and a con. I'm in the 3x club ... and that includes shots out to 500yds. Too much magnification and you can't get oriented back to your right as quickly if you tracked a critter to your left. Like with 6x you would struggle more. 3x seems to be the best balance and others here have said the same. I just say I agree based on my limited experience. Target shooting with 3x thermal at 500yds I'm getting sub moa groups consistently and I am surprised.
If a great thermal clipon exists, then in theory that would be a great solution. You could start at 3x and then if tracking something father away increase the magnification. I'm just not sure a great thermal clipon exists.
mt-ed,
Fortunately or unfortunately, no hogs here in MD, I have to travel for those.
But I do hunt coyotes and foxes here, and it sounds like terrain couldn't be more different. We have a few farms around that offer perhaps a mile or more of open field, but they are not typical. Most areas I hunt have a limit of maybe 800yds of open ground.
For your purposes it sounds like the HD38 is the ticket with it's greater magnification and reduced FOV, as well as the bigger lens.
Also, take a look at the hunting video section, you will find a bunch of coyote kills on "film." It will give you a good idea of what a coyote looks like through various thermal sights. You may have read that it takes an intensified light NVD or scope to make a positive ID, but that is just not true with a good thermal, at least at ranges up to maybe 500-600yds.
I am with Wiggy and a lot of others and find around 3x to be the sweet spot for a thermal scope. Most of our shots here on both foxes and coyotes are well inside of 50yds, a surprising number right at the call or very close to it.
JPK
Fortunately or unfortunately, no hogs here in MD, I have to travel for those.
But I do hunt coyotes and foxes here, and it sounds like terrain couldn't be more different. We have a few farms around that offer perhaps a mile or more of open field, but they are not typical. Most areas I hunt have a limit of maybe 800yds of open ground.
For your purposes it sounds like the HD38 is the ticket with it's greater magnification and reduced FOV, as well as the bigger lens.
Also, take a look at the hunting video section, you will find a bunch of coyote kills on "film." It will give you a good idea of what a coyote looks like through various thermal sights. You may have read that it takes an intensified light NVD or scope to make a positive ID, but that is just not true with a good thermal, at least at ranges up to maybe 500-600yds.
I am with Wiggy and a lot of others and find around 3x to be the sweet spot for a thermal scope. Most of our shots here on both foxes and coyotes are well inside of 50yds, a surprising number right at the call or very close to it.
JPK
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That is a component I had not considered Wiggy. I just got suppressed and have not experienced animal behavior, after the shot, as you have described. I'm also wondering if coyotes behavior changes after dark, as opposed to daylight. I don't know how well they can see in the dark, but I might tend to think they may be even more cautious because I would hesitate to think that their vision would actually "improve" after dark. So many factors.....I tend to overthink things I think...(chuckle)
wigwamitus
LSB Active Member
Based on behavior, I believe coyote vision improves (almost) infinitely with respect to ours at night! I'd assume they have gen2+ NV and operate from roughly that point of view
In my experience most nocturnal critters behave as if they assume we cannot see them ... they haven't got the NV or Thermal chapters in their books yet. Give them another 50 years or so and they will adapt.
I've had coyotes "saunter" past me at night inside 60yds on a number of occasions ... several times between me and my targets while I was reloading or changing optics. I believe they knew I was there. I believe they assumed I could not see them. And before I had thermal I did not see them. But with thermal I do - many times!
Here is a video off my front porch at 5am last January ... I heard the coyotes hollering so I went out with the thermal + DVR ... after the first "dancing" episode (I think they had just killed a rabbit) I "hollered back" and they (well the one by then) heard me and looked at me. But then proceeds to yawn and lie down for a nap (I get no respect). But "he" is obviously behaving as if I am not a threat. This must indicate he assumes I cannot see him. For a long time coyotes have operated near humans at night and have not been (very) threatened. But for those of us with NV/thermal we break the pattern.
In my experience most nocturnal critters behave as if they assume we cannot see them ... they haven't got the NV or Thermal chapters in their books yet. Give them another 50 years or so and they will adapt.
I've had coyotes "saunter" past me at night inside 60yds on a number of occasions ... several times between me and my targets while I was reloading or changing optics. I believe they knew I was there. I believe they assumed I could not see them. And before I had thermal I did not see them. But with thermal I do - many times!
Here is a video off my front porch at 5am last January ... I heard the coyotes hollering so I went out with the thermal + DVR ... after the first "dancing" episode (I think they had just killed a rabbit) I "hollered back" and they (well the one by then) heard me and looked at me. But then proceeds to yawn and lie down for a nap (I get no respect). But "he" is obviously behaving as if I am not a threat. This must indicate he assumes I cannot see him. For a long time coyotes have operated near humans at night and have not been (very) threatened. But for those of us with NV/thermal we break the pattern.