Areal Photogrammetry with Sony Nex7

[gatsri]

Heey

Has anyone tested the Sony Nex7 with Sigma 19mm f2.8 dn for aereal photogrammetry?

I will use it to create DEM and Orthophoto

Thanks

[nadar]

does it accepts a remote controller ?

will you use it from an UAV or a "normal" plane ?

[gatsri]

I will use it from a UAV.
they control the camera directly, without remote...
http://www.asctec.de/uav-anwendungen/luftbild/asctec-falcon-oktokopter/drohne/

[mobilexcopter]

If you will purchase that drone, then try to get sample dataset for evaluation.  I was using NEX5N and got some decent results, but replaced it because of the limited trigger options as IR is not reliable enough in higher speed flying.

NEX7 is also a nice camera, but I believe it has only an IR remote trigger option or direct servo push trigger ( or hacked trigger button  )

I would suggest a camera with direct trigger option ( remote port or LANC trigger option ). You might check A7, A7R or A6000.

Best regards,

Alex

[Walex]

I'm using this exact combination right now and am getting decent results. I am using a gentLED trigger, along with a pixhawk. I am shooting jpegs as raw requires too long to write to the card. If you would like I can provide a sample data set.

[Aquila]

I use the NEX7 on both multirotor and fixed wing, the multi rotor initially triggered via the gimbal but now I have a simple gentLED intervalometer which will trigger every 3-5 seconds which is fine as I can sort throught the images during processing. The NEX on the fixed wing is triggered using a Stratosnapper2 via the autopilot and again works great. Images are very good and I have had some great results from this set up.

[voudas]

@walex, a sample data would be great!

[Darko]

Hi,

I had it before, the same combination of NEX7 and Sigma 19 with the GentLED intervalometer. My experience is that Sigma19 is not the best lens and it seems like when pointed downwards and exposed to the wind (12 m/sec flying speed) the sharpness on the corners was reduced. Although that lens outperformes the Sony 16 mm pancake when used in regular manner, when used in UAV the Pancake is better.

The best results I have now with my cheapest camera and lens combination which is Samsung NEX 1000 (1100.. whichever). I have tested it with few wide prime lenses and the final and the best result I have achieved with it's original zoom 20-50 mm set and taped to 20 with the aperture 5.6 to 8, speed 1000 and sensitivity 400 ASA (or 800 depending on situation). So manual setup with the manual focus. The intervalometer is GentLED again but there is a micro USB connector for it on the side of the camera. No more LED triggers, direct cable that never fails.

Best wishes and good luck,
Darko

Should I mention that this camera is 20 MPix and 400 g with the lens and battery. And what is best about it you can find it for 200 - 300 USD.
 

[MortarArt]

I use the Samsung NX-1100 as well, in a Phantom 2, although I use the 30mm lens, which is one of the best that they have on offer. Mine weighs 340g, and I use a 3D printed hack to hold the trigger down. There is also some scripted solutions for Samsungs for continuous shooting, but I haven't investigated them yet.

[Cavi_Ing]

Hi,

I currently also use a nex-7 with the sigma 19mm objective. I'm like darko not very satisfied.

Does anyone have a good advice for an Nex-7 objective (E-Mount) for areal photogrammetry (fixed lens) and "low weight".

Lens should simply produce good quality images!!!

thx

[Darko]

Hi,

Seems like Panacake Sony 16mm is the only good solution for it. Close the aperture to at lest 8, go with the 1/1000 exposition and set up the speed to 400 or 800 ASA.. Try it yourself to make few pictures with different aperture setting and use the best. As I remember 8 was usefull but 11 was the best. For aperture 11 you need a lot of sunshine since the 800 ASA is the latest that is good for aerial shooting and you cannot go under 1/1000 expostion because your camera is moving.

Best regards,
Darko
 

[Oli63]

The NEX-7 is perfectly fine. We used it with the 16 mm pancake. The A7R of course is the even better choice due to the larger sensor and 36 MP, together with ZEISS lenses. The shutter release with USB-cable is also great. Only disadvantage is the slower processing speed. It does less than 1 frame per second with JPGs, so continuous firing is the better choice, though it doesn't allow to get GPS-positions.

[Cavi_Ing]

Hi Oli63 and Darko,

many thank for the inputs.

I need to take pictures for areal photogrammetry projects (surveying tasks -->
stable geometry when shooting). I'm using a multicopter system and i collect the images in a height between 80 and 100 meters. Now we are using a sigma 19mm. The images are actually nice, but on the corners the sharpness is sometimes very bad.

My questions:
1) Do you think the 16mm is better suited for our kind of projects?

2) in which mode you recommend to capture the images?
(Aperture Priority, Shutter Priority, Manual Exposure, Programm Auto,..?)

3) Recommended settings:
> aperture: 8-11?
> shutter speed: about 1/1000 ?
> ISO: Auto?
> focus: manual?
> format: jpg or raw?

I'm very thankful for your tips.

 

[Darko]

1. Yes 16mm is better solution for the aerial photogrammetry. Smaller, lighter and sharper in the corners, vibration proof?
2. Manual exposure! Aperture 11 is appricited with 16mm Sony. Exposure time is min. 1/1000 because of the moving camera. ISO, try it, my experience is that NEX7 works fine with the ISO setting of 400, 800 and even 1600 ASA. You need good lighting conditions, bright sunny day to get good results.
3. Aperture 8-11,
   Exposition, faster than 1/1000
   ISO depending on the light conditions 400-1600 ASA
  Focus : MANUAL
  Format ; JPG

[jtuhtan]

We typically use a NEX-6 with a Sigma 30mm F2.8 and are generally satisfied. We also use the time lapse app to set the image intervals, you can download it here:

https://www.playmemoriescameraapps.com/portal/

If you speak German, I can send you a recent B.Sc. thesis we supervised where the optical properties and camera settings of various setups were tested. Might be interesting for you.

Jeff