Delta-T SLM8 Manual de usuario
User Manual for the
Self Levelling Mount
typeSLM8
SLM8-UM-1.0
Delta-T Devices Ltd
Notices
Copyright
All rights reserved. Under the copyright laws, this manual may not be
copied, in whole or in part, without the written consent of Delta-T Devices
Ltd. Under the law, copying includes translation into another language.
Copyright © 2003, 2009 Delta-T Devices Limited.
Design Changes
Delta-T Devices reserves the right to change the designs and
specifications of its products at any time without prior notice.
Author:
Nick Webb.
User Manual Version: 1.0 Mar 23 2009
Delta-T Devices Ltd
130 Low Road, Burwell
Cambridge CB25 0EJ
UK
Tel: +44 1638 742922
Fax: +44 1638 743155
email: [email protected]
tech.support@delta-t.co.uk
web: www.delta-t.co.uk
SLM8 User Manual v 1 Contents z3
Contents
Introduction 4
Features 4
Overview 5
Instructions 6
Assembly Instructions 6
Complete Systems supplied by Delta-T 6
Quick Summary of Operation 6
Setting up the Self Levelling Mount 7
Using the Canon EOS 50D Camera 8
Taking Hemiphotos 8
Image Size and Compression 8
Camera Settings 9
Exposure 9
Taking the Picture 12
Use of Canon Remote Controls 14
Downloading Images to a PC 14
Trouble Shooting 14
Image Alignment in HemiView 15
Setting the Lens Equation in HemiView 16
Appendix 17
Assembly of HemiView System Parts 17
Warranty and Service 19
Terms and Conditions of Sale 19
Service, Repairs and Spares 20
Technical Support 20
Contact Details: 20
Introduction
Features
The self levelling mount SLM8 is intended for use with either a tripod or a
monopod. It helps keep a camera and fisheye lens aligned to the horizon
and North. This is necessary when taking hemispherical photos for use
with Delta-T’s HemiView canopy analysis software.
The SLM8 is designed for use with the Canon 50D digital SLR camera
with a Sigma EX DC 4.5mm F2.8 circular fisheye lens.
For ease of use, the mount is equipped with the following features:
•Bubble level and adjustable levelling weights
•Compass for North/South alignment, viewable from above or below
•Markers used to align hemispherical photos in HemiView, illuminated
by the camera flashgun
•Optional rugged carrying case
•Optional monopod or tripod
Image capture,
processing and analysis
in the field is possible
via a ruggedised
notebook or tablet PC
(not included)
Optional rugged, waterproof
carrying case
4 zFeatures SLM8 User Manual v 1
Overview
Gimbals Bubble
level South
marker
Compass
Sigma
EXDC lens
Canon
EOS 50D
Flash
adapter Fibre optics
light pipe Tripod
North
marker
Balance weights
Mounting the camera
Locating pins Tighten bolt
Levelling adjustments
SLM8 User Manual v 1 Overview z5
6 zAssembly Instructions SLM8 User Manual v 1
Instructions
Assembly Instructions
Complete Systems supplied by Delta-T
Complete HemiView systems supplied by Delta-T come with camera,
memory card, lens, flash assembly and self-levelling mount pre-
assembled.
Charge up and insert the camera battery.
Mount the self levelling mount to a camera tripod or monopod.
The system is now assembled.
See also Assembly of HemiView System Parts on page 17
Quick Summary of Operation
1. Mount system on a tripod or monopod.
2. Orient it to North using the compass.
3. Level it using the bubble level and balance weights.
4. Select appropriate camera settings.
5. Avoid camera wobble using the self timer, or a remote control (not
supplied), or a laptop PC running the Canon EOS image capture
software.
6. Use the live preview and review options in the camera, or on a PC, to
check the image is OK.
7. Replace the camera lens cover after use.
8. Open, review, annotate, classify and sort images on your PC in
Canon ZoomBrowser software, as required.
9. Process and analyse selected images in the HemiView software on
your PC.
For step 9 refer also to the HemiView User Manual and online help.
Setting up the Self Levelling Mount
Remove the lens cover completely (note it has two parts).
Rotate the mount to point North.
NORTH
Level the mount using the balance weights and bubble level indicator.
Check the flash adapter and fibre optics are in place.
Balance weights
SLM8 User Manual v 1 Setting up the Self Levelling Mount z7
Using the Canon EOS 50D Camera
This is a great camera with great software. So spend some time
familiarising yourself with it.
The software manuals are available as PDF files on the Canon CD.
These may be also downloaded from the Canon website.
Taking Hemiphotos
The Canon EOS 50D is a very capable camera, and the user has a lot of
control over the settings. This does mean that getting the right settings
can be complicated. It is well worth taking some time to learn how the
camera works before using it in the field. The following notes will point you
towards the appropriate sections of the camera manual.
Page numbers refer to current English version of the Canon manual.
Image Size and Compression
There is a trade-off between image quality and the number of images you
can store on a memory card. Keep image size at 4752 x 3168 pixels for
maximum spatial resolution. At this setting, a typical hemiphoto will take 5
MB as a JPEG or 20 MB if saved in the native Canon RAW format. Lower
image quality may be adequate for many canopies, particularly broad-
leaved canopies, and can significantly increase the number of images you
can store. Do a trial comparison on your site to see if the image quality
makes any significant difference.
8 zTaking Hemiphotos SLM8 User Manual v 1
Note that HemiView does not accept the native Canon RAW image file
format, but you can convert it to a bitmap on your PC.
Camera Settings
The optimum setting depends on the nature of the picture.
We recommend the following Shooting Menu settings as a starting point
for new users (see Canon 50D Manual, Image Settings p. 59 onwards).
Setting Canon 50D
User Manual
Sigma Lens Manual *see Note 1
Camera mode Manual p. 98
Menu: Quality p. 60
AEB 0 p. 102
WB SHIFT/BKT K 5200 *see Note 2 p. 71
Metering Centre-weighted
Average Metering p. 100
Picture Style Standard p. 65
Histogram Brightness p. 134
*Note 1: Manually focus the lens to infinity, unless you are in a very low
canopy.
*Note 2: The presumed colour temperature of daylight coming through
gaps in the canopy.
Saving Settings
You may fine tune your settings and save the configuration on the camera,
using the camera controls.
You can also configure it from your PC using the Canon software.
See also the Canon 50D User Manual and EOS software manual
Exposure
Getting the exposure right can have a significant effect on how easy it is to
classify an image in HemiView, and on the accuracy results.
Aim to have areas of sky at the top end of the brightness range, and areas
of canopy at the lower end. Check this on your image by looking at the
brightness histograms.
On the Camera, select to play back the image onto the LCD monitor
and toggle the INFO button to display image information, including a
histogram. (It is easier to inspect histograms on your PC using the Canon
EOS software)
SLM8 User Manual v 1 Taking Hemiphotos z9
10 zTaking Hemiphotos SLM8 User Manual v 1
If the image is over-exposed, the sky areas will have a tendency to spread
in the final image. Under-exposure is less of a problem, but will reduce the
amount of visual detail of the canopy. The camera’s automatic exposure
will tend to adjust the exposure too much for very open and very closed
canopies. We suggest two approaches to dealing with this.
1 Manual Exposure
•Select the Tv: Shutter Priority AE exposure mode (Camera Manual
p. 94). Set the shutter speed to, say,1/80 second to minimise camera
shake. Note the exposure values under a section of canopy with
about 50% sky visible. Use the smallest aperture hole size possible
(i.e. largest f/number) to give the greatest depth of field in focus.
•Set the camera to manual exposure, and set the shutter speed and
aperture to these values.
•Having decided on an exposure setting, (as in 1 above) press the
<À> button to lock the exposure. All the hemiphotos you now take
will be at the same exposure setting.
•Use this exposure setting for all your hemiphotos, as long as lighting
conditions remain the same. The exposure meter will indicate over-
exposure for open canopy, and under-exposure in closed canopies.
2 Auto Exposure
•Set the camera to Programmed Auto mode.
•For more open canopies, over-expose using the exposure
compensation setting, up to the full +2.0EV for very open canopies.1
•For more closed canopies, under-expose, up to the full -2.0EV for
mostly closed canopies.
•If you have sufficient memory, try exposure bracketing to take photos
with higher and lower exposures. Choose the image that gives the
clearest canopy edges.
1This seems wrong at first. Why would you do you want to make a light picture lighter and a
dark picture darker? The reason is that in auto-exposure mode the camera will compensate,
darken a picture of all bright sky, and brighten a picture of an all dark canopy. That is why it
is better to work in fixed, manual exposure mode if you can – but that option depends on the
light being stable – which, of course, is not always so! So we suggest, when working in auto-
exposure mode, to auto-bracket the exposure and pick the best picture with the clearest
canopy edges.
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