[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: 15425

Reply to This

Replies to This Discussion

thanks, great info
that's complete ;)

Wolfgang R.

What is the quality of Image like with the NEX5? I ask because i have been offered two cameras at more or less the same price. One being a Sony A6000 with out a lens and a Sony NEX-5R with 2 lenses. Not sure which to go for.

I would go for A6000 simply because of 24 MP resolution and it's lightweight.
You will get more mapping coverage area compare with Nex5 series.

In my experience, having more resolution is great but useless if your mapping area is large as you will dealing with gigabytes of data that took up to several days on large computer to process. The processing time can be speed up by lowering the resolution that makes utilising very high res camera become useless. Somehow i found 20Mp is more than enough. The next thing to consider is the weight and camera's sensor size. Sony nex3, nex5, A5000 and A6000 using an exactly same sensor size but has different resolution. Nex3 and A5000 is the lightest while A6000 is slightly heavier.

Thanks for your input Gents. I believe the common size lens would be 15- 20mm wide angle for mapping? I like the Sony Cams because there seems to be more trigger options for them.

Hi David,

what is the max frequency for RAW (which SD-card)?
Do you know the power consumption?

thanks
Wolfgang R.

My setup for fixed wing use S100

  • f3/5
  • 1/1000
  • ISO 400
  • mode : TV
  • W/B : Daylight

Hi Waladi,

The following info may be of interest to plane users.

I wonder about the low shutter speed most of you can
live with. Are all of you flying copters or turtles ;)

I finally got a used NEX-5R with the Sigma 30mm f/2.8.
Now I can compare between the Canon SX-260HS, a Sony A7R
and the NEX. All wing mounted to my Skywalker 1900.

The A7R I had for a weekend only and it's far beyond my
budget. But a major step is going away from the Canon to
the NEX size. I run a few missions with 600 shots each.
No single blurred picture! The Gentles IR trigger cable
works fine for me. For my missions the missing CHDK isn't
an issue. The distance trigger of the APM 2.5 is sufficient.

For the cam I setup everything manually. Today I choose 1/2500s,
ISO400 and f/4. The pictures are taken in RAW format only. I'll
hope this will allow me to fix low light issues later.

The Skywalker is going for up to 15m/s at least and even by
low wind I've to calculate for 20m/s.

As I'm concerned about the shutter speed my calculation is
as follows. The nice Pteryx whitepaper mentioned to go for
shutter speed related to 1/2 pix or even better use 1/3 pix.

Now my math

AGL: 100m =>
pixel (height): 52.2m/3264pix =>0.01599m (measured, not calculated)
pixel (width) : 81.7m/4912pix =>0.01663m
1/3pix size: 0.016m/3 => 0.005333m
15m/s: 0.005333m/15m/s => 1/2812s

Some variations for AGL and speed
1/ ((0.522 * 100 / 3264) * (1/3) / 15) = 2812 [1/s]
1/ ((0.522 * 120 / 3264) * (1/3) / 15) = 2344 [1/s]
1/ ((0.522 * 100 / 3264) * (1/3) / 10) = 1875 [1/s]
1/ ((0.522 * 120 / 3264) * (1/3) / 10) = 1563 [1/s]
(http://web2.0rechner.de/ for copy&paste)

It's hard to judge the subpixel setting but for me it
sounds reasonable to go for high shutter speed.

A second point is overlap.

The paper mentioned here to go for 60% or better 80% (3d modelling).
For a plane this isn't that easy. Here the calculation

overlap: 60/80% height: 100/120m speed: 15m/s
(1-0.8)*(0.522*120 )/15 = 0.8352 [s]
(1-0.6)*(0.522*120 )/15 = 1.6704 [s]
(1-0.8)*(0.522*100 )/15 = 0.696 [s]
(1-0.6)*(0.522*100 )/15 = 1.392 [s]

That needs a closer look at the write speed of the NEX (-5R).

From what I found on the net it seems that the limit is
somehow around 45MB/s to SD. I bought a
SanDisk SDSDXN-032G-FFP Extreme SDHC 32GB UHS-I Class 10 U3 60MB/s.
A test on an 80MB/s did not give any better results. My
measurement for the 60MB/s shows 0.89s/pic. This means you
can save some money compared to the mentioned 95MB/s. But
be careful and look at the write speed. The math shows that
trying to go beyond 60% overlap is asking for good calculations.

A very nice point I didn't expect is the low power consumption.
The 600pics consume less than 20% of my battery. That means
I can go for up to 3000pics in one mission. This is much much
more than I did expect.

Be aware that my figures are from some very first missions and
not collected over months. But I thought I should contribute a bit.

HTH
Wolfgang R.

Great to see a lot of different setups being used for geo-mapping :) thumbs up!
As I see most of you guys are working with Sony MULTI equipped cameras. Would like to share a great trigger solution for your aerial photography, ''Plug & Play'' solution with ON/OFF function (great to save battery life and for landing plane type crafts) and features multiple trigger modes. Super small and light weight with an option to chose ANGLED connector to fit your design best. We have a 10% discount coupon: DIYDRONES  @ www.seagulluav.com
Hope you found this helpful guys!

I have skywalker 1900 with pixhawk using Sony NEX5 with 19mm sigma lens.

So far after a few first test flights I have decent results with shutter priority set to 2500 and auto iso. In my experience with aerial imagery from aircraft, anything below 2000 and you will get blur in your photos.  

I have tried both trigg_dist and digicam_control, the distance flight didn't go well, I only got a hand full of images from one survey flight. Digicam control seemed to work much better but I am still missing a couple areas from survey flights, any ideas why this is happening? I have overlap and sidelap set to 60% and it still misses photo locations. Speed was 12m/s and using flytron IR trigger. For my next flight i'll be setting overlap/sidelap to 80% and decrease flight speed to 10m/s.  I'll also try trig_dist again and set distance to around 20 meters per shot and see what that gets me.  

What are people using for camera trigger settings and overlap? 

Photo attached is settings using shutter priority 2500, auto iso, auto f stop, manual focus

How quickly (seconds) are your pictures being taken? There are two issues I can see.

1. You're in auto iso mode - your camera has a limit to how fast it can refocus and take a picture (~2 seconds)

2. The IR trigger sending signals while your camera is still taking the last picture.

We had this issue - you can decrease overlap or fly higher.

Hi Darryl,

I've just checked my last log and don't miss a single shot (363 pics).
My cable is a Gentle IR trigger.

Here my setup
CAM_DURATION,10
CAM_TRIGG_DIST,20
CAM_TRIGG_TYPE,0
speed: 12-18m/s

Did you check the log of your RCOUT trigger channel? Matches the
trigger/pics count?

Wolfgang R.

Reply to Discussion

RSS

Groups

Season Two of the Trust Time Trial (T3) Contest 
A list of all T3 contests is here. The current round, the Vertical Horizontal one, is here

© 2019   Created by Chris Anderson.   Powered by

Badges  |  Report an Issue  |  Terms of Service