Thermal Sensitivity

[Dan Bowers, CMI]

Anybody know if all other things are equal, what will a camera with .08 do compared to one with .1

[Barry Adair]

here's some info not sure it's what you're looking for

[Kevin A. Richardson]

I don't think you will see much of a difference. However, it depends on other factors such as IR resolution, image frequency, etc.

Here is a good article to help you decide and compare different imagers:
http://www.infraspection.com/IRINFO_...ial_offer.html

Kevin

[kweiss]

Kevin,

Could you repost the link, that did not go to an article (at least I did not see one.)

Dan,
While I think there is a difference, and I have always been one to think that if big is good - bigger is better as applicable to the question. I am beginning to think that in MOST cases for Hi, a good solid mid range camera will work fine. As I said in your other post, I recently had to oppertunity to compare side by side in real houses my .05 with a .07. I do not think that there was a noticeable difference that day. At least in that I didn't see things that he did not.

Honestly, that has really made me think about what all these specs really mean. I think a better question would be - how do the factors of thermal sensitivity, IR resolution, temp range, image frequency(which I don't know about) interact? What is the most important factor or how do they rank? What is the best combination or compramise for use in the home inspection industry? Seems that the manufacturers are vague on this - obviously they want you to buy as much as you can.

I am beginning to think that in some way (not all so people don't get up in arms) for MOST HI applications it is like saying which is better - 300 HP or 350 HP in a car. I had a professor in school that used to laugh at that one as we would talk about ecking the last little bit of HP out of our cars. He would say who cares - you hardly ever really use those last HP, so many other things come into play.

I think maybe we get too hung up in the "specs." The answer will probably ultimately be that any camera will work MOST of the time. But in the rare case where there is some very slight anomally - and I have had some of these like finding a small roof leak after 3.5 weeks from last rain, it was just a slight shadow but enough to make me check it - the better your camera is that better your chances - but I cannot say for sure as I did not get to compare it with a different camera. What you have to decide is simply going above and beyond to use IR enough. Or do you have to go all the way possible? And then how is all the way possible going to be defined?

[John Snell]

Originally Posted by badair

here's some info not sure it's what you're looking for

This link is about the efficiency with which the surface emits energy rather than the sensitivity of the detector in the camera. Sensitivity IS critical to what you see. It is certainly not the only factor, but all else being equal (or nearly so!), a camera with a 0.08 sensitivity will yield better images nearly all the time and will allow you to work on more days and for more hours on any given day.

A visual analogy, though it is somewhat of a mixed metaphor, would be seeing 20/20 versus something less than that. You WILL see more—and more often see more—with increased sensitivity.

What would I pay for this increase? Where I live (Vermont) I often have plenty of temperature difference and so can get by with a lessor sensitivity. Pretty much anywhere else, I'd just do a back-of-the-envelope calculation, and look at my finances, and figure how fast could I make back the difference by being able to work 15% more often, which is about the difference between an .080 and a 1.00mK camera.

By the way, I do NOT recommend buying only by "spec." This spec, however, is one that is crucial to pay attention to. My paid webinar on buying a camera (we are 100% neutral to brands) gives lots more information and I'm happy to answer any questions you might have after you view it. See https://www.thesnellgroup.com/CourseDetails.aspx?id=30 for details. There is also a FREE white paper (Breakthroughs in Infrared Camera Prices and Performance Performance - Building Applications) on buying cameras that I wrote for Home Energy magazine available for download at https://www.thesnellgroup.com/WhitePapers.aspx.

Thermally yours,

John Snell
ASNT NDT Thermal/Infrared Level III #48166
Snell Infrared
800-636-9820
802-229-9820
http://www.thesnellgroup.com
http://www.IRTalk.com
http://www.learnnewsolutions.com/

[Kevin A. Richardson]

Kevin,

Could you repost the link, that did not go to an article (at least I did not see one.)

Sorry, that was the wrong link (different thread)

Here is the right one: http://www.irinfo.org/Articles/artic...3_seffrin.html

Kevin

[David Sorge]

I received my B60 today. Here are 2 identical images of an area in my house that I know to be missing insulation. Area is above a fireplace. 1st image is from the BCAM, 2nd from the B60.

[Dan Bowers, CMI]

Damn David -

Aren't you worried about showing the pics of ex-wifes over your mantle on a national site like this. What will the FBI's most wanted think??

Seriously - The pic on the right was a tidge bit clearer BUT not enough that I could see a major difference. What did you think of the images.

[David Sorge]

Originally Posted by dbowers

Damn David -

Aren't you worried about showing the pics of ex-wifes over your mantle on a national site like this. What will the FBI's most wanted think??

Seriously - The pic on the right was a tidge bit clearer BUT not enough that I could see a major difference. What did you think of the images.

The X's are buried in the yard

The difference is really apparent if you enlarge the photos...you can't enlarge the BCAM photos at all before they blur. That said, I havent had much time to play with it. The B60 photo was right out of the box without adjusting anything. I'll have a better feel for any difference when I use it in the field this week. Overall, I think the small details are quite a bit clearer.

For moisture, insulation, and air infiltration I would think that the B60 isn't necessary...the BCAM was fine for that. It will likely shine for electrical and mechanical applications though.

[kweiss]

So, sensitivity means ability to work in lessor differentials - knew that - and resolution means the ability to work from farther away or blow up the images to larger sizes - knew that too. I would agree that sensitivity does appear to be more important.

The question that isn't answered is what is enough sensitivity? Enough for HI work? Enough for other IR applications? In most HI applications it seems you can "help" set your differential - by adjusting the interior temperature to achieve some differential. In my area, in the last 18 months of using IR for HI, I see that there are a few weeks in the spring and fall that are "difficult" when the temperatures outside are near 70 and have been for a while - from there you can only raise or lower the temps inside so much and the differential sucks.

Another question or thought. My camera shows a "sensitivity" on the screen. I have only ever seen it go down to 0.4, yet my specs say my sensitivity is .05. Am I misunderstanding something?

Mr Snell,

No offense, but while I might chose to take a certification class from your company, I for one am getting kind of tired of vendors constantly half answering these kinds of questions then posting links to "paid Webinars" that may or may not be of any use. Either answer these kinds of questions out of good will and to encourage people to perhaps do real training with your company or not.

[David Sorge]

Originally Posted by kweiss

The question that isn't answered is what is enough sensitivity? Enough for HI work? Enough for other IR applications? In most HI applications it seems you can "help" set your differential - by adjusting the interior temperature to achieve some differential. In my area, in the last 18 months of using IR for HI, I see that there are a few weeks in the spring and fall that are "difficult" when the temperatures outside are near 70 and have been for a while - from there you can only raise or lower the temps inside so much and the differential sucks.

Kevin,

I think the short answer to your question is that a sensitivity of 0.1 is "enough" for HI's. Having used a BCAM in the field for 1 year now there are several important considerations regardless of camera choice.

Thermography is limited by many factors that are beyond the HI's control. Sure, we can manipulate certain parameters but at the end of the day, the limitations imposed on the thermographer by the environment(both interior and exterior), will usually always overshadow the limitations placed on us by our equipment...at least today.

As thermography grows in popularity, prices for equipment will drop and the capabilities of the equipment will increase...we're already beginning to see this. Having the "latest and greatest" comes at a price and I'm certain that today's mid-grade, and even high end cameras will be tomorrows junk.

[John Snell]

Originally Posted by kweiss

Mr Snell,

No offense, but while I might chose to take a certification class from your company, I for one am getting kind of tired of vendors constantly half answering these kinds of questions then posting links to "paid Webinars" that may or may not be of any use. Either answer these kinds of questions out of good will and to encourage people to perhaps do real training with your company or not.

I'm not offended but am surprised as I try my best to always post accurate, useful information. In the 25 years I've been in business, I've had one person tell me our products had no value to them, and I gladly refunded that person's money. BTW, the free article I offered delivers TONS of good, solid info that could save someone literally thousands when buying a camera by helping the by the right system for their needs.

I, for one, not yet found a way to run our business giving everything away free. If you have, I'd be interested in talking! Meanwhile we try to price things fairly and deliver the best information we know. I hope you'll give us a try one day soon.

Thermally yours,

John Snell
ASNT NDT Thermal/Infrared Level III #48166
Snell Infrared
800-636-9820
802-229-9820
http://www.thesnellgroup.com
http://www.IRTalk.com
http://www.learnnewsolutions.com/

[Ron C. Bibler]

Originally Posted by John Snell

I'm not offended but am surprised as I try my best to always post accurate, useful information. In the 25 years I've been in business, I've had one person tell me our products had no value to them, and I gladly refunded that person's money. BTW, the free article I offered delivers TONS of good, solid info that could save someone literally thousands when buying a camera by helping the by the right system for their needs.

I, for one, not yet found a way to run our business giving everything away free. If you have, I'd be interested in talking! Meanwhile we try to price things fairly and deliver the best information we know. I hope you'll give us a try one day soon.

Thermally yours,

John Snell
ASNT NDT Thermal/Infrared Level III #48166
Snell Infrared
800-636-9820
802-229-9820
http://www.thesnellgroup.com
http://www.IRTalk.com
http://www.learnnewsolutions.com/

Say John thanks for all your Hard work. your post have been a big help to me and my company.\ and the people we serve.

Please keep up the good work

Thermally yours,

Ron

[Dan Bowers, CMI]

John -

Same here. I appreciate your contributions and don't take them as anything else but opinions. Although I've seen vendors be peddling their stuff big-time on here, I don't find that to be the case with yours.

[kweiss]

John,

I apoligize for my post. I was having a bad day and took it out unfairly on you. You did offer advice on the subject at hand and my comments were out of line.