Jen,
Thanks for frank and honest reply. I agree with a lot of what you said, really. After seeing fenderman's reply, and the "distance sensor" question from a new reader of the thread, I thought "maybe I shouldn't lead people down a path that might be time wasting, or get into other subjects, such as a distance detecting device".
This forum has many readers. My reply was meant for a) the wider audience (including future readers), and b) to maybe put this intellectual conversation on daylight sensors into perspective. For "Users Group" readers, my drill down reply on how the camera decides when to be in b/w or color might be something a little far afield for this forum. I respect this forum, and want to stay true to serving its members.
Like I said, I just wanna know how it works. Like "what's triggered by that button" and "what's that part". I don't feel like I'm drilling down and down.
Jen, I'm an engineer, cursed (or blessed) with a natural curiosity to always ask "Why?". It's a joke with my non-engineer friends, who tease me. And unfairly, IMHO, of too much thinking. "Analysis Paralysis". In this case, they'd say, "Dude, the camera works! Why do you need to know what each part behind the camera window is for?"
My reply today wasn't meant to dis you specifically.
you seem to be annoyed with my question, and to feel that I'm questioning your knowledge because I don't "accept" your explanation.
I didn't think you were "questioning my knowledge" which required a rebuttal or pushed me into pushing back on you. I'm confident in my knowledge, and questing me doesn't threaten me. Jen, no "annoyment" existed on on my end, directed towards you.
saying my curiosity is amusing seems to be a nicer way of saying that I'm a bit ridiculous.
My comment was directed to a)you and eeeees poster and b) other readers forum readers that might post questions like "explain this", "what electrical component is that?", "Explain how the software corrects images in this or that way".
I said I ran an engineering department that designed cameras. My rather long post showed I had technical insight. Maybe defensively, I said to the (possible) wider audience, some being non-technical, that if the camera works, isn't that good enough?
I spent time on that previous post of "daylight sensor" vs simple "light sensor". I wasn't looking to do long future posts on "Why this?", and "why that?".
you were the one coming up with the test I ran, thank you for that, and the cam just didn't behave the way it should have. Why is the cam turning the IR LEDs on when I'm not blocking the daylight sensor but only the image sensor ?
Jen, maybe my previous post wasn't worded clearly.
Entering b/w mode is based on two things: 1) daylight sensor voltage output and 2) image sensor light detection and contrast ratio. Disclaimer: I didn't work for Dahua, Hik or any other vendor on this forum.
My cameras would enter b/w mode even if the daylight sensor was bathed in light. (visible portion, not IR)
If you wanna talk about that, for fun and simply to help me, thank you.
I'm willing to help you, sorry if I seemed snotty. Or threatened by your questions. Like I said, my intellectual curiosity has been a cross to bear for many years. I just need to know how shit works!
Regards,
Fastb
Oh, re my comment on daylight sensor wavelength response:
If you have a camera with 940nm IR LEDs, I can make it go into daylight mode by shining 880nm IR light at it. Again, not to tout my experience. But if forum readers are intellectually curious, that's fine. I just would rather not be the tutor.
In my past, putting cameras in Dept of State armored vehicles for use overseas, the 880nm IR LEDs were NOT acceptable. The human eye sees them as a warm red glow. DoS insisted on 940nm IR illumination. Much, much less visible to the eye. But that requires a modified approach to "IR Cut Filters".
If a vehicle had our traditional 880nm cams and some newer 940nm cams, guess what? The daylight sensor for 940 cams, and the lens coating for 940nm cams didn't benefit from 880nm illumination.
As an extra wrinkle, we didn't use IR Cut filters, that physically move into and out of place. We did it all with lens coatings. And we had to deal with the coatings on car windows, which block IR. To keep your car cool in summer. And they unfortunately, they don't have a sharp "knee" between passing 880nm IR vs 940 nm IR in their wavelength response curves.
Most interestingly, when our cams had problems dealing with the "Sun" and "Dark" in the canyons of NYC while the Gov't Suburbans are ferrying diplomat's wives/girlfriends to 5th Ave shopping while their husbands are at the United Nations, we scrambled. How do you make a cam work for day/night behind a tinted window in the canyons of NYC? Should the suburban cams go into b/w mode at 2pm, due to limited light in the canyons of NYC and the tinting of the armored suburbans? eg: If that's a Fed Ex truck, I wanna see purple! Color at 2pm is expected!
Entering/Exiting color and b/w mode was a huge topic. And getting 940nm IR through Suburban windows, which have coatings to keep the vehicle cool.
Again, I've gone on too long. I could teach a class, or talk for hours.
Jen, I didn't intend to dis to you. Your curiosity strikes a chord with me, personally.
Anyone else: Don't ask me questions. Too time consuming, mainly. I participate to share tidbits of knowledge, if you have a spot-on question. And some of my techniques/knowledge/expertise probably shouldn't be shared.
At this point: I'll read replies, but won't do so such in a LONG AND WORDY AND DRAWN OUT Replies. Today, you caught me on a loquacious night.
If you're still reading, give a "Like". Please like
@nayr, not me, 'cuz he is a giant on this site. Nayr is awesome.
Fastb
