Welcome to PhantomPilots.com

Sign up for a weekly email of the latest drone news & information

P2V Raw files and speed of microSD Card

Discussion in 'Phantom 2 Vision Discussion' started by Frank;-), Feb 7, 2014.

  1. Frank;-)

    Joined:
    Feb 6, 2014
    Messages:
    4
    Likes Received:
    0
    Hi All,

    First of all I would like to thank all members of this forum for posting so many good answers and solutions. This forum is a great source for learning about P2V. I'm new to quadcopters so I'm learning every day.

    Last weekend I updated all my software of P2V, that was quite challenging, but I think I succeeded. Then I did a flight and took some raw photo's in DNG format.

    http://www.flickr.com/photos/83953651@N04/12271318125/

    After making a raw photo it took about 14 seconds before the display on the smartphone showed the live view again. At first I thought of a mallfunction but then I realised that the raw files would be much larger than JPG so it would take much longer to write the image to the MicroSD card. The JPG file is about 3-5 MB's and that takes about 3 secs, the RAW fies is 28 MB.

    I experimented a bit with another MicroSD card, a Class 4 8Gb MicroSD card from Transend. With that card it took about 9 secs to write the RAW image. What's strange here is that the size of the photo (L/M/S) doesn't seem to influence the duration.

    Next I did some research on the internet. A Class 10 card writes about 10 Mb/s so I guess it would take about 3,5 s to write the image, almost the same as the JPG. The fastest card I can find is a Sandisk Extreme PRO microSD kaart 16 GB UHS1 45MB/s € 79,99. I guess using this card it would take less then 1s to take a photo.

    Any advice or other findings?
     
  2. iResq

    Joined:
    Dec 23, 2013
    Messages:
    545
    Likes Received:
    2
    Location:
    Annapolis, Maryland
    Not exactly. Write speeds are based on several factors, not just card speed. My class 10 still takes about 10 seconds to write. Could you imagine if burst mode raw were enabled? LOL.
     
  3. FSJ Guy

    Joined:
    Feb 1, 2014
    Messages:
    174
    Likes Received:
    0
    You just have to wait.

    I have a Class 6 card and it takes a while, too. Good thing it's fairly stable in a hover!

    I haven't tried panos yet, but I guess you'll have to shoot those in the horrible JPG mode or it will take too long and the craft will drift too much. :- (
     
  4. Frank;-)

    Joined:
    Feb 6, 2014
    Messages:
    4
    Likes Received:
    0
    Wow, a digital camera that needs 10 secs to write an image of 28MB? Never heard of anything like that before. It's hard to believe that this is the best DJI can do. What is taking so long? Maybe the conversion from RAW to DNG?

    Any thoughts about the image quality? I didn't expect pixel perfect images with such a small sensor and small lens but at first I was a bit disappointed with the quality of the images. Not much detail and a lot of noise. After processing with NIK DFine it started to look much better.

    Does anybody know if it is possible to set shutter speed?
     
  5. Frank;-)

    Joined:
    Feb 6, 2014
    Messages:
    4
    Likes Received:
    0
    The JPG's are to much compressed I think: fine details are lost.

    Pano's are indeed challenging when taking RAW images. I think the way to go is to try keeping the P2V completely stable for 10 secs after taking a photo and wait for the the live view before moving to the next shot.
     
  6. Pull_Up

    Joined:
    Nov 5, 2013
    Messages:
    3,684
    Likes Received:
    48
    Location:
    South Oxfordshire, UK
    I don't believe so. If you get the lens filter kit, though, you can add ND filters to the front which as I understand it would bring the shutter speed down.
     
  7. jimre

    Joined:
    Nov 24, 2013
    Messages:
    371
    Likes Received:
    1
    Location:
    North Bend, WA
    It's also processing & saving the JPEG file every time, too - which normally takes 3-4 seconds. So the DNG file is taking the additional 5-6 seconds. It seems that unlike "real" cameras - this camera has no buffer space. It cannot take another image until the current one is done being processed. And I'm guessing it has a very primitive CPU - again unlike the latest "real" cameras that have the latest super-whizzy, dual-processor DIGIC or EXPEED chip.

    Several threads here already discussing image quality in depth. If you're talking about DNG/RAW images - they definitely need post-processing - as they are deliberately left very soft & unsharpened, with no noise-reduction applied. The idea is that with the RAW data, the photographer can do a better job at all these than the camera can, with its crude JPEG processing.

    Nope. You can set ISO (AUTO, 100, 200, 400) and you can set Exposure Compensation (-2 to +2, in 1/3-stop steps). But shutter speed is always set by the camera automatically. Please see the user manual, Page 40 for all of the camera settings:
    http://download.dji-innovations.com/dow ... .12_en.pdf
     
  8. alenic

    Joined:
    Apr 15, 2014
    Messages:
    7
    Likes Received:
    0
    Hi,

    I am new in this forum and I thank you in advance for any answers.

    What is the file size for Large jpg photos and for RAW photos.

    Thanks!

    Alexis
     
  9. BMEWS

    Joined:
    Mar 25, 2014
    Messages:
    368
    Likes Received:
    0
    Location:
    Cambridgeshire UK
    RAW (DNG) should be 28,187KB (approx. 28MB)
    JPG up to about 6,188KB (approx. 6MB), but this can vary dependent upon the size you select

    Hope this helps

    Bmews
     
  10. jimre

    Joined:
    Nov 24, 2013
    Messages:
    371
    Likes Received:
    1
    Location:
    North Bend, WA
    Just in case you have the wrong idea about the Small/Med/Large settings - unlike most cameras these are NOT for "JPEG Quality". There is only one "JPEG Quality" on the Vision - over-compressed! It's not user-configurable. The only thing the S/M/L "Photo Size" setting controls is the number of vertical pixels (see the manual). The JPEG file sizes will not change a whole lot with these settings - LARGE has 25% more pixels than SMALL, so probably only a 25% JPEG file size difference.

    This "Photo Size" setting is really for controlling "Aspect Ratio" - not JPEG Quality. These settings SHOULD have been labeled "4:3, 3:2, and 16:9" - NOT "Large, Medium, Small". Not sure if this was a language translation issue, or the fact that DJI is new to manufacturing cameras, or both.
     
  11. Amra

    Joined:
    Sep 26, 2013
    Messages:
    60
    Likes Received:
    0
    I have a Sandisk UHS-1 32GB card in my P2V and it takes about 5 seconds to save the RAW, so even with that speed there's going to be some waiting.