[Aerial Mapping] What is best Sony Nex 5 setting for Aerial Mapping mission?

Dear All,

I was using Cannon S100 previously for mapping purpose with CHDK, 1/2000 shutter speed, IS turned off and focus set to Infinity but still get around 50% blurry image.

Now I will use Sony Nex 5n camera on Flatmap1 gimbal with 16mm stock fixed lens and IR triggered from APM for more ground coverage and quality image (hope so..)

Please share your Nex 5n camera setting (Auto or manual or shutter priority?) and any experiences, pros & cons using Nex 5n for mapping purpose.

Let me start from what I was reading from some forum (forgot the link):

Sony Nex 5 series  Camera Setting for Mapping:

Recommendations:

Pros:

  • More pixel compare with S100 = More ground coverage
  • Fixed lens 16mm = less blurry image result
  • ??

Cons:

  • Heavier compare with S100
  • No GPS onboard
  • Nex 5n Time between shutter > 2 sec = S100 faster < 2 sec (if you need to fly really fast)
  • ??

I will update first page regularly that may be useful for others.

Many thanks in advance for your contribution.

Waladi

Views: 15443

Reply to This

Replies to This Discussion

That is correct. I haven't used aperture priority, mostly because I want to keep the shutter speed high. I haven't had any issues with manual, so I've continued to use it. I have been lightening up shadows with post-production, but the RAW allows me to shoot in manual without worrying about lighting changes.

You had told me previously that you liked the 30mm -  I may pick one up so I can still fly high and get good GSD. I've had some issues reproducing buildings with the 19mm, since I fly fairly low (lots of perspective change).

I am working with an Engineering student at KU to develop a product for drones. Would you be open to answering a few questions about your drone(s)?

Thanks

Sure thing, feel free to email me at dlocascio@tenboair.com

David, do you process the image one by one or do you batch process them?  

Thanks,

I batch process by similar characteristics. For example, if half of a set is cloudy, I'll do that half separately, and alter the temperature, exposure, and blacks more than I would otherwise. It's pretty easy to get them close enough that Photoscan can deal with them - I mostly worry about matching amount of green color when doing grass/forested areas. Haven't done as many urban or suburban areas yet.

Hi Waladi

I've similar questions moving from Canon SX260 to Sony NEX-5.

Like to sum up and please correct me where I'm wrong.

My profile is for a SkyWalker
- 15m/s
- 100m altitude
- Sigma 30mm (intended)

main points for me

model

-5T for low weight, app loadable and reasonable costs

min shutter interval (using a >90MB/s write speed SD)
mentioned here ~1/s for jpeg
What is the max speed for RAW?

interval trigger
I can't see the point why the app with delay and trigger interval time
isn't sufficient? Get rid of what I don't need later on.

power consumption
Can't remember where I saw this but 900 pics/charge in practice?

shutter speed
I would like to go for a fixed high shutter speed priority like discussed
here already. Seems that RAW and post-processing is the consequence.
By my profile when should I expect to get rid of any blur? My feeling
is going for 1/2000s or even more.

thanks for all the valuable info found in the forum already
Wolfgang R.

Hi Wolfgang.

I finally modified my Nex5n since IR trigger failed several times during mission and sometime it is trigger the video, not the photo, also using Stratosnapper to trigger it directly from Pixhawk.

But we are talking about camera setting.

On some clear day, I would use shutter trigger and set manual ISO to 200 or even 400, let the aperture managed by the camera.

On couldy day, I prefer to use manual setting with following thumb rules:
1. Shutter should faster than 1/1250
2. Aperture set to minimum 5.6 since my stock 16mm lens will give blurry edges more with lesser value.
3. Play with the ISO and manual focus, test it on the ground by shoot an object at some distance with my flight height.

I occasionally have to turn off the Auto focus and viewer/result photo viewer after taken the picture (forgot what is the menu name).

Regarding your questions:
I don't know RAW speed shutter and I never flown that fast and required 1 sec trigger because I'm using multirotor.

imho it's useless to take so many pictures (example: interferometer) and sort it afterward because s MP geo tagging tools will found discrepancies between photos and CAM message number, then it will "refuse" to geo tag the pictures. And don't forget the longer time to process the image if your computer is an average household spec.

I don't know about the power consumption, on my Nex5n, one full charged batteries will last for more than 3 x 25 minutes flights.

Hope that help

Hi Waladi

thanks for the additional information.

I'll hope that I can go for open aperture with the Sigma 30mm.

Regarding the intervalometer.

As I'm going for large area coverage with a plane
more than 95% of the pictures are useful. Only the
pictures within turns need to be dropped.

For now I'm concentrating on collecting pictures and
do not care so much about post-processing. Friends of
mine do some 3D modelling and yes a home computer isn't
enough. But I hope this scales better over time.

Concerning the geo tagging I did assume that a low number
of GCPs assigned to pix in the stiched image would be
sufficient. But I have to learn what's going on in this
area.

Wolfgang R.

Hi Wolfgang,

If the geotagging process and post processing is not problem then I think more pictures are better for quality map (or not..)

Just sharing my result.

Using Sony A5000, running all manual; manual exposure and manual focus

Set shutter speed at 1/1600 to get good still photo

Set aperture at f/8 to get longer sharp zone (might be better at f/11, haven't tried yet at this small aperture)

Set focus at infinity

Set iso to auto iso (but testing on the ground first to ensure that with above setting the iso won't go higher than 800)

The aim is to get consistent exposure on every photo, use auto iso to anticipate on cloud changing during flight...

I got a very nice consistent exposure, process it on agisoft and none of my photo rejected by agisoft...

Ps: don't forget to put a tape on the focus ring, it moves during flight due to the shaky platform...

Hi Arga,

can you please complete your info, which lens, AGL, speed?

thanks
Wolfgang R.

Using sony 16-50mm set to 16mm, flying 140m agl on 14 m/s (actual speed 12 m/s). Using highest resolution on jpeg (using raw will kill my computer).

Total got 865 photos for 215 Ha area. Post processing took 12 Hours on my monster laptop (core i7 3.2Ghz octacore, 16Gb ram, 4 Gb graphics card).

The photo's exposure is really consistent (usually got slightly darker or lighter between images on Aperture or shutter priority). Focus is a bit blurry due to drift focus on flight (forgot to put a tape on the focus ring), but the post processing result is really satisfying.

I'm using 9 gcp surveyed with static rtk gps.

Reply to Discussion

RSS

© 2019   Created by Chris Anderson.   Powered by

Badges  |  Report an Issue  |  Terms of Service