Anyone had the opportunity to compare these side by side ? Ideally, someone independent of both brands 
Iray Finder FH25R v Pulsar XQ38lfr
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phillips321
Well-Known Member
I have just picked up the FH25R and must say I'm pleased with it. The picture resolution is 640x512 so significantly more than the Pulsar. The unit is very small as well. The biggest drawback is the battery life which is about 4hours. However it can be charged whilst in use.
I'll try and upload a video shortly for you.
I'll try and upload a video shortly for you.
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phillips321
Well-Known Member
Matthew,
Thanks. I appreciate the FH25R appears to have a higher spec' on paper, but no offence, it doesn't answer my question, unless, you actually spent some time with the Axion XQ38, and had the opportunity to compare the two.
I find most video from "all" brands, average to say the least, often out of focus, and not the ideal brightness, and contrast settings for the conditions.
I hoped the new Axion would meet my requirements, but it's a lot bulkier than the original Axion, isn't 640x512, and the base mag, is still too high. The Iray seems to meet the the sensor spec', but the base mag is a little lower than I would choose, so I need to know what it's like when the digital mag is used. This is an area the Iray's seem to suffer. And I'm not keen on built in batteries, but would work with it, if everything else was good.
So, looking for something the same size of the earlier Axion, Finder, LRF, base optical 2-2.5, 640x512 sensor, 12um, 38mm lens, and a slice of cake !
That said, I loved seeing the "pushme-pullyou", in your video, not seen one for years
Thanks. I appreciate the FH25R appears to have a higher spec' on paper, but no offence, it doesn't answer my question, unless, you actually spent some time with the Axion XQ38, and had the opportunity to compare the two.
I find most video from "all" brands, average to say the least, often out of focus, and not the ideal brightness, and contrast settings for the conditions.
I hoped the new Axion would meet my requirements, but it's a lot bulkier than the original Axion, isn't 640x512, and the base mag, is still too high. The Iray seems to meet the the sensor spec', but the base mag is a little lower than I would choose, so I need to know what it's like when the digital mag is used. This is an area the Iray's seem to suffer. And I'm not keen on built in batteries, but would work with it, if everything else was good.
So, looking for something the same size of the earlier Axion, Finder, LRF, base optical 2-2.5, 640x512 sensor, 12um, 38mm lens, and a slice of cake !
That said, I loved seeing the "pushme-pullyou", in your video, not seen one for years
The Axion XQ38 will produce a slightly more detailed image than the FH25R
When it comes to thermals, the word "resolution" is very frequently misused (and misunderstood)
Resolution has nothing to do with the number of pixels in the sensor
Resolution is a measure of the smallest angle (or area) that the thermal can "see"
The smaller the angle (or area) the more detailed the image will be.
There is a very simple calculation that can be made to ascertain the resolution
Simply divide the pixel size (at present 12 microns or 17 microns) by the focal length of the objective lens in mm
The answer is an angle in mrad (milliradians) and that angle can be converted to an area at a given distance simply by multiplying the angle by the distance in metres.
The answer to that simple calculation will be the length of the side of the square "seen" by a single sensor pixel at the specified distance
Using the 2 thermals in question as examples:
The FH25R has a sensor with 12 micron pixels and a 25mm lens
12/25 = 0.48mrad. At 100m, the side of the square seen by 1 pixel is 100*0,48 =48mm
So each pixel can "see" a box 48x48mm at a distance of 100m
The Axion XQ38 has a sensor with 17 micron pixels and a 38mm lens
17/38= 0.447mrad. At 100m the side of the square "seen" by 1 pixel is 100*0.447 = 44.7mm
So, each pixel can "see" a box 44.7x 44.7mm at a distance of 100m
How well a target can be seen depends on how many of these boxes it is covered by.
A target of a given size at a given distance will be covered by more XQ38 boxes than FH25R boxes and therefore the XQ38 will give a more detailed image
Note that the number of pixels in the sensor does not come into any of these calculations.
The principal effect of the number of pixels in the sensor relates to the field of view, and therefore the magnification of the thermal
For example, any Pulsar XQ50 will have the same resolution (and detection range) as any Pulsar XP50 because the pixels sizes and the focal lengths are the same.
However, the XP sensor has more pixels making it a physically larger sensor.
That increase in physical size results in the XP50 having a lower magnification, but wider field of view than the XQ50.
Cheers
Bruce
When it comes to thermals, the word "resolution" is very frequently misused (and misunderstood)
Resolution has nothing to do with the number of pixels in the sensor
Resolution is a measure of the smallest angle (or area) that the thermal can "see"
The smaller the angle (or area) the more detailed the image will be.
There is a very simple calculation that can be made to ascertain the resolution
Simply divide the pixel size (at present 12 microns or 17 microns) by the focal length of the objective lens in mm
The answer is an angle in mrad (milliradians) and that angle can be converted to an area at a given distance simply by multiplying the angle by the distance in metres.
The answer to that simple calculation will be the length of the side of the square "seen" by a single sensor pixel at the specified distance
Using the 2 thermals in question as examples:
The FH25R has a sensor with 12 micron pixels and a 25mm lens
12/25 = 0.48mrad. At 100m, the side of the square seen by 1 pixel is 100*0,48 =48mm
So each pixel can "see" a box 48x48mm at a distance of 100m
The Axion XQ38 has a sensor with 17 micron pixels and a 38mm lens
17/38= 0.447mrad. At 100m the side of the square "seen" by 1 pixel is 100*0.447 = 44.7mm
So, each pixel can "see" a box 44.7x 44.7mm at a distance of 100m
How well a target can be seen depends on how many of these boxes it is covered by.
A target of a given size at a given distance will be covered by more XQ38 boxes than FH25R boxes and therefore the XQ38 will give a more detailed image
Note that the number of pixels in the sensor does not come into any of these calculations.
The principal effect of the number of pixels in the sensor relates to the field of view, and therefore the magnification of the thermal
For example, any Pulsar XQ50 will have the same resolution (and detection range) as any Pulsar XP50 because the pixels sizes and the focal lengths are the same.
However, the XP sensor has more pixels making it a physically larger sensor.
That increase in physical size results in the XP50 having a lower magnification, but wider field of view than the XQ50.
Cheers
Bruce
Bruce,
Thanks for the explanation. It looks like I'm either going to have to wait, and see if Pulsar bring out a "XP" version, with a lower mag, higher FOV, or compromise, with the FH25R, to get the lower mag I want
Thanks for the explanation. It looks like I'm either going to have to wait, and see if Pulsar bring out a "XP" version, with a lower mag, higher FOV, or compromise, with the FH25R, to get the lower mag I want
There is a Helion 2 xq38f coming out next month, might be worth a look. Similar money.
I ran the two side by side for an evening and came to a conclusion pretty quickly. In an ideal world I would take features from both, but on balance the Pulsar is a more complete unit than the FH25R. The battery system is far better, the display feels bigger and the mag more useful. The LRF is much superior. As they are quite different units , it's hard to make direct comparisons, but even with the Pulsar being a decidedly right handed unit I much preferred it. I did use them both for the whole evening (well battery life) through different atmospheric conditions and looked for reasons to like and dislike on both parts, so feel able to comment fairly on both. It wouldn't be the end of the world for me to have the FH25R - it's by no means a bad unit - but it's not as good as it could be and left me feeling a little bit 'meh' about it.
phillips321
Well-Known Member
Thanks for the explanation. It looks like I'm either going to have to wait, and see if Pulsar bring out a "XP" version, with a lower mag, higher FOV, or compromise, with the FH25R, to get the lower mag I want
[/QUOTE]
The field of view of the Infiray helps with walking and stalking. It’s very difficult to scan and walk with a higher magnification sensor.
Bruce is completely correct in his calculations above, but completely ignores in the calculations that the resolution is that much more on the Infiray so gives you a much bigger FoV for more or less similar detection size 44.7 vs 48
I’d like to see them side by side with the same picture just to see the difference.
[/QUOTE]
The field of view of the Infiray helps with walking and stalking. It’s very difficult to scan and walk with a higher magnification sensor.
Bruce is completely correct in his calculations above, but completely ignores in the calculations that the resolution is that much more on the Infiray so gives you a much bigger FoV for more or less similar detection size 44.7 vs 48
I’d like to see them side by side with the same picture just to see the difference.
phillips321
Well-Known Member
The Pulsar also does not have the recording/video or WiFi options.
When acting as a spotter the ability to record can be worth its weight in gold trying to recover a wounded animal as you can review the footage slowtime.
The wifi also means you can put the thermal outside the car pointing at your watch zone while you sit in the car viewing the streamed footage on your phone. Might be pointless in the warm months but during the wet and cold months it’s useful.
Everyone with have their own criteria, regarding the features units have. Personally, video is of no interest on a spotter. I think I've had around 8 different versions of the Pulsar spotters, and not once used the video. where they had one.
A sight is different for me. When I had an Apex XQ50, I bought one of the small external recorders, so I could look, and see if the shot on the sight, matched where I actually hit the boar, and to have the experience again.
Maybe I'll just swap my Trail XP50, for the later LRF Version 2, and get standard non LRF spotter
Thank you, just the type of post I was hoping for. The Axion LFR was a concern, I always spot with my left eye, and hold left handed, so it looks like it will be a pain.
Nothing's simple !
A sight is different for me. When I had an Apex XQ50, I bought one of the small external recorders, so I could look, and see if the shot on the sight, matched where I actually hit the boar, and to have the experience again.
Maybe I'll just swap my Trail XP50, for the later LRF Version 2, and get standard non LRF spotter
Thank you, just the type of post I was hoping for. The Axion LFR was a concern, I always spot with my left eye, and hold left handed, so it looks like it will be a pain.
Nothing's simple !
The field of view of the Infiray helps with walking and stalking. It’s very difficult to scan and walk with a higher magnification sensor.
Bruce is completely correct in his calculations above, but completely ignores in the calculations that the resolution is that much more on the Infiray so gives you a much bigger FoV for more or less similar detection size 44.7 vs 48
I’d like to see them side by side with the same picture just to see the difference.
[/QUOTE]
There you go misusing and/or misunderstanding the meaning of the word "resolution"
The Infiray does not have a higher resolution than the XQ38 - it's the other way round, the XQ38 has a higher resolution than the infiray, because, in simple terms it can see smaller objects
The infiray has more pixels in it's sensor than the XQ38, but that doesn't give it a higher resolution - it gives it a wider field of view.
I agree that a wider field of view is beneficial in a spotter, but the XQ38 will provide a more detailed image.
Cheers
Bruce
phillips321
Well-Known Member
Sorry but we’ll have to disagree. You’re talking more about DPI.
By you’re argument you’re saying my iPhone XS Max screen with a resolution of 2688 x 1242 has a better image than my 60” 4K TV with a resolution of 3840 x 2160. It doesn’t, it just has a better density of pixels.
By you’re argument you’re saying my iPhone XS Max screen with a resolution of 2688 x 1242 has a better image than my 60” 4K TV with a resolution of 3840 x 2160. It doesn’t, it just has a better density of pixels.
What is resolution?
Allan Mitchell (Microscopy Otago) talks about the meaning of the term ‘resolution’ in microscopy. Using real-world examples, Allan explains that resolution is the ability to distinguish two points as separate structures rather a single fuzzy dot. In practice, resolution is a measure of the level...
www.sciencelearn.org.nz
A Pulsar XQ50 has the same resolution as a Pulsar XP 50 - check the Pulsar specs for detection distance.
They have the same resolution because they both have the same focal length lens and the same pixel size
In your comparison between an I Phone and a 60" TV you do not state the viewing distance (focal length) or the size of the pixels in each display
The number of pixels is irrelevant
Cheers
Bruce
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Thankyou, Bruce, for a most informative post. For the sake of the simple, could I ask you to elucidate on the relation between FOB and magnification encapsulated by the "therefore" in the snippet quoted above?
FWIW, I'd take the image of the Axion over that of the Finder. But there are pros and cons. I found the image from the Finder more contrasty, but rather "blobby", and thus better for revealing heat sources but less good for picking up detail at a given distance. As a left hander, however, the position of the rangefinder on the Axion is a real hindrance, although the unit itself is more reliable; whereas the Finder's rangefinder doesn't affect its ergonomics, but can require repeated pinging to obtain a reading. Overall, I'm more "at home" in the Pulsar interface, but still appreciate the comparatively intuitive controls of the Iray. (How I wish this fence were more comfortable to sit on... or easier to slip off onto one side or other!)
It's a shame, I found the FH25R for about £2350.00, from a dealer in Europe, but even then, it's way more expensive than the Axion, by the time you take the available discount, into account.
I'm actually disappointed with the opinions, I was really hoping the Finder would be as good in reality, as it is on paper
I'm actually disappointed with the opinions, I was really hoping the Finder would be as good in reality, as it is on paper
In a typical digital NV device or thermal device, the magnification of the device depends on 4 things.
These are:
The focal length of the objective lens in mm (lets call it A)
The diagonal size of the sensor in mm (lets call it B)
The diagonal size of the display in mm (lets call it C)
The focal length of the eyepiece lens in mm (lets call it D)
Lets call the magnification of the device M
The mathematical relationship which gives the magnification is M= (A/B)*(C/D)
From that equation it can be seen that magnification can be increased by:
Increasing the focal length of the objective lens
Reducing the diagonal size of the sensor
Increasing the size of the display
Reducing the focal length of the eyepiece lens
A good example of the magnification being reduced by increasing the focal length of the eyepiece lens are some of the Pulsar thermal scopes.
A Pulsar Trail XQ50 thermal riflescope has a base magnification of x2.7 while a Pulsar Helion XQ50 thermal spotter has a base magnification of x4.1.
Both devices have the same sensor, objective lens and display, but as a riflescope, the Trail needs much more eye relief than the Helion, and to get that, the focal length of the eyepiece lens has to be increased - and that reduces the magnification
Field of view depends only on the size of the sensor and the focal length of the objective lens
Because the sensor is normally rectangular, the horizontal field of view (HFOV) will typically be larger than the vertical field of view(VFOV)
A well specified device will give both horizontal and vertical field of view.
These values are usually given as angles and/or as widths and heights at a specific distance
For example, the field of view of Pulsar Helion XP50 is (HxV) 12.4x9.3 degrees or 21.8x16.3m at 100m
The equation used to calculate the field of view angle is FOV= 2*arctan (h/2A)
Where h is the length of a side of the sensor and A is the focal length of the objective lens
From this equation it can be seen that the field of view will increase as sensor size increases and also as focal length shortens.
Cheers
Bruce
These are:
The focal length of the objective lens in mm (lets call it A)
The diagonal size of the sensor in mm (lets call it B)
The diagonal size of the display in mm (lets call it C)
The focal length of the eyepiece lens in mm (lets call it D)
Lets call the magnification of the device M
The mathematical relationship which gives the magnification is M= (A/B)*(C/D)
From that equation it can be seen that magnification can be increased by:
Increasing the focal length of the objective lens
Reducing the diagonal size of the sensor
Increasing the size of the display
Reducing the focal length of the eyepiece lens
A good example of the magnification being reduced by increasing the focal length of the eyepiece lens are some of the Pulsar thermal scopes.
A Pulsar Trail XQ50 thermal riflescope has a base magnification of x2.7 while a Pulsar Helion XQ50 thermal spotter has a base magnification of x4.1.
Both devices have the same sensor, objective lens and display, but as a riflescope, the Trail needs much more eye relief than the Helion, and to get that, the focal length of the eyepiece lens has to be increased - and that reduces the magnification
Field of view depends only on the size of the sensor and the focal length of the objective lens
Because the sensor is normally rectangular, the horizontal field of view (HFOV) will typically be larger than the vertical field of view(VFOV)
A well specified device will give both horizontal and vertical field of view.
These values are usually given as angles and/or as widths and heights at a specific distance
For example, the field of view of Pulsar Helion XP50 is (HxV) 12.4x9.3 degrees or 21.8x16.3m at 100m
The equation used to calculate the field of view angle is FOV= 2*arctan (h/2A)
Where h is the length of a side of the sensor and A is the focal length of the objective lens
From this equation it can be seen that the field of view will increase as sensor size increases and also as focal length shortens.
Cheers
Bruce
Bruce, thankyou for this clear, concise and valuable breakdown.
Jeff8861
Well-Known Member
Rather than becoming more confused after reading these posts can you not have a look at these units in the flesh. Try them out then decide on which suits your needs. There is some great info on here but alot of it is very confusing. I'm sure we all have purchased something based on the specs on paper however when it arrives and you use it you find that it doesnt meet your expectations. I'm sure there will be someone near to you that is willing to let you have a look.
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