Megadensity of lens ?

Discussion in 'General Dash Cam Discussion' started by Lola, Sep 24, 2017.

  1. c4rc4m

    c4rc4m Active Member

    Messages:
    356
    Likes Received:
    78
    Country:
    United Kingdom
    Not aware of any legal implication in the UK from a car cam.

    In the UK some privacy restrictions apply to CCTV cameras and how they are directed.
     
    Lola likes this.
  2. TonyM

    TonyM Well-Known Member

    Messages:
    681
    Likes Received:
    423
    Location:
    York, England
    Country:
    United Kingdom
    Dash Cam:
    SG9665GC, Mobius1 x3, Mobius2, Aukey DR01
    Thanks guys that's all good news, as I'm planning to get one of these telephoto lenses on my spare mobius
     
    Lola likes this.
  3. Dashmellow

    Dashmellow Well-Known Member

    Messages:
    9,320
    Likes Received:
    9,493
    Location:
    Uncanny Valley (●_●)
    Country:
    United States
    Dash Cam:
    SG9665GC, Mobius/M2 (x7), GT680W (modded), DR32, others
    Really?....Earlier you claimed that using an 8-10mm lens is "more suited to drone use" and then went on to advise, "60 degrees minimum, and even then some might say that was too much." So now, suddenly, you are "fully aware of the implications and the benefits". ;)

    I find it rather interesting that you have nothing whatsoever to say about the excellent 8-12 mm focal length examples posted recently by three different DCT members on the forum. In each and every case, all of us have stated and demonstrated right from the start that our telephoto dash cams are intended for use as a companion to a traditional wide angle camera and have presented examples, yet for some odd reason you feel the need to argue that "wider than 30 degrees is better....to ensure you capture front side impacts". Again, your comments seem based on speculation and theorizing rather than personal experience with lenses like this. And, as is self evident to everyone but you, side impact is not the purpose or motivation for anyone interested in telephoto lens dash cams. Nevertheless, while posted examples demonstrate the ability to capture extreme detail at closer range these longer focal lengths also demonstrate an ability to capture a fairly wide swath of traffic out farther ahead from the vehicle which will include at least two lanes of traffic or more, even at 12mm. But side impact capture is not the point of this exercise anyway, so why drag it into the discussion? I'm guessing you are trying to ignite another one of these tedious circular arguments you are so fond of.

    You repeatedly advise others to go out and purchase specialized high end Back-Bone lenses. It doesn't seem from anything you've ever indicated that you personally own any of those. Even if you do, do you think @Lola or most of us others are willing or able to purchase individual high end lenses that cost in most cases as much or far more than the dash cameras they would be installed on like a Mobius in this instance or the fact that some of these expensive high resolving power lenses exceed the capabilities of the sensors they would be mounted on? While I do advocate buying good quality lenses perhaps like the one kamkar1 invested in, selecting these 90 dollar and up lenses would be a waste of money, not only because the resolution isn't needed but also because longer lenses have virtually no issues with barrel distortion and don't need the level of optical correction you advocate.

    Anyway, thanks for the lecture on resolving power. It sounds like you must have watched the presentation about the "debunking the megapixel myth" I linked to before you decided to explain this to all of us. Pixel density is all well and good if you have the correct sensor to make use of the capability but it is really a different subject than the use of longer lenses. Granted, this thread started out on that topic before Lola inquired about the 8-10mm purchasing, but we're talking apples and "meatballs"here. o_O

    FYI, @Lola,
    has been talking about her requirements and interests in a dash cam and has been slowly zoning in on accomplishing her objectives since her very first posts here on DCT and so asking about longer 8-10 mm lenses has been part of that process as far as I can tell.
     
  4. kamkar1

    kamkar1 Well-Known Member

    Messages:
    14,282
    Likes Received:
    7,275
    Country:
    Denmark
    Dash Cam:
    Lukas LK-7500G / Innovv C3 / mobius / G1W / SG9665GC & more
    I / We have experimented with lenses on a quadcopter in relation to the FPV camera, and we found a 6 mm to be the best of both worlds in regard to feel for distance to objects and FOV in general.

    Sure you can fly your race quadcopter in a confined environment using a wide angle lens too as it like so many other things are just a matter of getting used to it, but we never race and only fly once in a while / just about never now, so we agreed the 6 mm was the best for the view camera, and the recording camera well those was always the regular action camera lenses.

    I think i would go for a 4 - 6 mm lens too for a action camera, around 80 - 90 degrees FOV are fine as long as you dont get too close to the target.
    A M.O.D ( Minimum Optical Distance ) of a few feet / 0.5 M sound fine to me.
     
    c4rc4m and Lola like this.
  5. Lola

    Lola Well-Known Member

    Messages:
    575
    Likes Received:
    306
    Location:
    Maryland
    Country:
    United States
    Dash Cam:
    Mobius
    This is not a case of one over the other meaning wide angle vs narrow angle, it's very easy to make a case for the wide angle camera up front, however it just isn't enough! When I saw the footage of dashmellow and kamkar1 I decided right then on having both, a 12mm narrow FOV and a wide angle view, both have their strengths and weaknesses but together their is not one single dash/camera available that comes close to comparing regardless of cost, at least to the general public!
    My first thoughts were on a 8 or 10 mm and that would probably be OK but I wasn't sure, I still might try another wide angle lens on the associated camera for view and definition, but the second Mobius will definitely be a narrow FOV 12mm as it's companion. Like the old saying A picture is like a 1000 words and seeing kamkar1' presentation of this is proof in any sane persons book.
    The original idea was we are not getting enough from a wide angle dash cam, if you think I'm wrong take a long look at the footage these two guys have put together and tell me what you want to go into court with :D:cool:!
     
    SawMaster and c4rc4m like this.
  6. c4rc4m

    c4rc4m Active Member

    Messages:
    356
    Likes Received:
    78
    Country:
    United Kingdom
    Exactly. Best of both worlds running both wide angle and narrow cams.
     
    Lola likes this.
Loading...

Share This Page