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02-19-2011, 10:41 AM   #1
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645d aerial with 67 55mm

Today the visibility was good so it was time to do a pair of "job" shoots after one month on the ground.
The 645d performed as aspected, notwistanding the fact that I had to bring the D2X too, becouse one of them required GPS. I hope that the GPS upgrade will arrive soon for the Pentax.
The lens of choice was the 67 (late) 55mm F4 that I used at 5,6 iso 250 and with shutter speeds faster than 1/1000.
The 55 is a great lens, perfectly balanced and sharp from corner to corner. Moirč is present, but less invasive than with cameras with larger pixel to pixel spacing and no AA filter.

Full image first, than a pair of 100% crops.














For my work, this is the best camera I ever had, Linhof Aerotechnica included.

Sergio

02-19-2011, 01:11 PM   #2
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Thanks for posting Sergio. Wait until you make BIG prints. I made a 24"x32" (as big as my printer can handle), and it is awsome.
Dave
02-20-2011, 08:30 PM   #3
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Thanks for posting, Sergio. I agree with your GPS concerns on the Pentax; I have to cart along a D200 to get embedded GPS data. Apparently the GPS module is in works and/or close to release.

If you can obtain the 55-100mm zoom you might find that it is the equal or better than any of the primes (as my testing suggests). It might give you a bit more flexibilty in your aerial work.

-materialsguy
02-21-2011, 09:04 AM   #4
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Dave, hope to make some big prints soon, I am confident that quality will be very good.

Materialsguy, have you verified that the focus position does not change across the focal lenghts range
with the 55-100? I usually calibrate my prime focus lenses to infinity on the ground, and block them in that position with adhesive tape. This is not possible with Nikon zooms, as focus varies across the range, while the Pentax 45-85 seems to constantly maintain focus position with the various focal lenghts.

Thanks.
Sergio

02-21-2011, 09:31 AM   #5
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Why not try tagging your 645d pics with Geosetter? You just need a GPS track file from any gps device - a smartphone will do, as will a cheap gps datalogger. Geosetter is free, so you could download it straight away and test it on a file to make sure it doesn't do anything nasty to the 645 files (I've used it on k100D, k20D and k7 files with absolutely no problems, but not a medium format file).
02-21-2011, 10:10 AM   #6
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Cuchulainn, I use the method you suggest when the Nikon is unsuitable for the job, but it has a few downsides. Clock syncronization between camera and GPS must be very precise, as a few seconds difference means several hundred meters error (the aircraft speed is 40-50 meters per second) and this is not very easy to achieve, at least with the 645d that shows only minutes on the setting page.
Than there is the correlation work. Worst of all, you are not sure of the result before being again on the ground, and this creates a slight anxiety....
I prefer a direct connection between GPS and camera, with that little window (as on the Nikon) blinking when GPS position is unreliable.

Sergio
02-21-2011, 02:33 PM   #7
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QuoteOriginally posted by Cuchulainn Quote
Why not try tagging your 645d pics with Geosetter?
...
An even bigger problem with Geosetter for sergiolov, apart from what he already noted, is the following from their website:
" GeoSetter is a freeware tool for Windows (XP or higher)"
And according to the EXIF meta data on his shots, we have the following:
Software: Adobe Photoshop CS5 Macintosh
02-21-2011, 03:02 PM   #8
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QuoteOriginally posted by sergiolov Quote
Cuchulainn, I use the method you suggest when the Nikon is unsuitable for the job, but it has a few downsides. Clock syncronization between camera and GPS must be very precise, as a few seconds difference means several hundred meters error (the aircraft speed is 40-50 meters per second) and this is not very easy to achieve, at least with the 645d that shows only minutes on the setting page.
Than there is the correlation work. Worst of all, you are not sure of the result before being again on the ground, and this creates a slight anxiety....
I prefer a direct connection between GPS and camera, with that little window (as on the Nikon) blinking when GPS position is unreliable.

Sergio
Fair enough! Though if your gps unit has a display, then just take a photo of the time on the GPS. Then you can correct the EXIF to the nearest second.

Using an Apple might be the bigger problem here!

02-21-2011, 03:39 PM   #9
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What about using Wifi SD card.. Could work like this. SD1 in 645D for main SD card RAW files. SD2 card slot with wifi card. Set SD2 for lowest Jpg only format for fast data transfer.. To a Smartphone With the wifi SD card app with geo tagging running..
02-21-2011, 04:12 PM   #10
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That is a smart trick,but is practical only if the number of exif to modify is limited. As an example, saturday's job was to document the area of a planned new highway 100 km long, and the number
of shots ended at more than 700. (don't know if a batch processing procedure is available for that pourpose)
I tried many geotagging softwares, (for Mac or windows), but direct connection of GPS to camera is
much preferable and practical.
A possible problem with the Pentax GPS module (from the images I have seen ) is that it must be connected to the hot shoe, while I need to position the antenna at least on the glareshield, for sky visibility. Hope that a cable or an external antenna will be available.

For Adrian: I have the eye-fi card. It is so slow that I will be back home before the transfer is finished.....but if you are not in a plane, a smart idea!

Sergio

Last edited by sergiolov; 02-21-2011 at 04:26 PM.
02-21-2011, 04:50 PM   #11
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Geosetter does allow for batch processing - it's much more powerful than you would think at a first glance. I can completely understand why you would want to use a dedicated gps module though!

Depending on the chipset used, the Pentax module may well get reception inside the plane once you have a lock before getting into the place. I have seen tracks from my brand of gps logger from commercial flights where it got knocked on in someone's bag and tracked the whole flight!
02-21-2011, 11:27 PM   #12
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moire appears to be the sort easily removable with some saturation/luminance tweaking.
12-10-2012, 07:58 AM   #13
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Geotagging without camera GPS

Hi guys,

some time has passed since you discussed geotagging without external GPS.

Sergio, I`ve had the same problem. My humble, not to say puny equipment I use for aerials, a K110D with 28mm and 50mm A lenses, provides no GPS interface.

There actually is a simple solution, without having to adjust your camera to the second:

- Use any GPS to produce a tracklog of your flight
- Before or after flight, take a picture of your GPS screen showing actual GPS time.
- Look at the picture`s EXIF data, to get the camera`s time at the moment the GPS picture was taken.
- Calculate the time offset between your camera`s time and the time showing on the GPS screen picture.
- Convert the GPS tracklog to gpx format
- Use exiftool to geotag your images, specifiying the tracklog and the time offset you have calculated before, and it will do the dirty work for you.

I use an old but trusty Garmin III+ to produce the tracklog, and record one trackpoint every 200m (~600ft). exiftool will interpolate the position with sufficient precisison, as long as you don`t turn and keep your speed somwehat constant. I fly at about 55 knots. If you fly faster or need to turn while taking pictures, shorter trackpoint intervals will do better. Consumer hardware like Garmin portable GPS or a common smartphone will allow to log once every second. That should be sufficient for nearly everything but jet airplanes.

Best regards,

Hans
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