PHOTOGRAPHING THE NIGHT SKY
by Vincent Hénault-Brunet
of the Institute for Astronomy, University of Edinburgh, Royal Observatory Edinburgh
Some very basic tips for photographing the night sky:
- Find a spot with little ambient light from cities
- Lower humidity in winter makes clearer pictures!
- Long exposure: tripod + remote trigger
- Scene + starry sky = huge depth of field >>> small aperture ~ f/16
- B (bulb) shooting mode
- Low ISO
- Lens to manual focus, focus to Infinity
- Lens hood to prevent ambient sidelight
- Start with exposures of ~30 seconds
- Noise reduction ‘on’
PREPARING IMAGES FOR CLUB WEBSITE GALLERIES
Use your preferred graphics package to save the images as JPEG format (use high quality - around 80% for systems that use the numerical format), 72dpi, and with the longest side at 400 pixels. Remember to do this with a copy of the original! Save the file with your initials and a name that has no spaces, or symbols such as '&' in it. For example, if Ann Other were sending a picture currently called PICT1001356.jpg, she would save it as AO_HerChoiceOfTitle.jpg (or AO_her_choice_of_title.jpg). Then email it to Lesley, who keeps the website updated. Include your full name and the title of the photo in the email. A description and location are optional.
Email your images to Lesley at firstname.lastname@example.org
by Gordon Andrews
Use a tripod or something very stable to place your camera on.
Long exposures are involved.
Use a cable release.
You can also lock up the mirror, or use screen view to reduce vibration.
Use a telephoto lens. If you are in close you will see a lot of smoke in the images. Distance helps to reduce this, so I suggest a 70-200mm lens and stand a good distance from the bursts.
Set your lens to manual focus and turn off image stabilisation.
Set your camera to manual, turn your shutter speed to “bulb” – usually found after the longest exposure on your camera.
Set the aperture to f8/f12.
Set ISO to 100.
Set focus to infinity.
If your camera has a long exposure noise reduction setting turn this on too.
Aim you camera at the display.
Open the shutter for the duration of the firework you want to photograph.
Check your images and adjust the aperture to correct the exposure. Increase f stop to darken, reduce to lighten.
Try to include objects or people in the image to give a sense of scale.
Take lots of pictures, there is luck as well as judgement involved.
by Gordon Andrews
For all techniques start with the picture open.
Select the Crop tool, make a selection over the image, then expand that selection beyond the borders of the image. When you click ok the background colour will be added as a border.
Go to Image, then Canvas size, add the amount of border you wish, then choose the colour, the dropper will select from the image as well as the palate.
To create a border around the entire picture, open the Select menu and choose Select All. To create a border around a certain section, use the Selection tool in the toolbar and select the area you want. Remember if you want to move your selection press the spacebar while holding down the left button of your mouse. From the Select menu, choose Modify and then Border. In the dialog box, choose the pixel size of your border. Locate the colour palette on the left-hand side of the screen. Click on the top square and select a border colour from the palette. (You can also alter this by using the refine edge in the Select menu.) Click OK, and then select Fill from the Edit menu. In the dialog box, choose the options to apply to the border. Finally deselect the selection (Ctrl +D) to leave the border.
To add a line, again select the position you want the line with the selection tool. Then go to the Edit menu, and select Stroke. Choose the width, the default colour will be the foreground colour, but if you click on it you can select another. Click ok, and then deselect to leave your line.
To add a textured border, first duplicate the background layer (Ctrl +J). Next make a selection, and create a background mask by clicking on the mask icon (rectangle with circle in it) at the bottom of the layers palate. Next select the background layer, and duplicate it again. Select this new layer and go to the Filters menu. Here, select an appropriate filter for your "Frame" e.g. texture then stained glass. Ok this and you should have your frame.
To add the border with the textured edge, see "Adding a sloppy border" in the photoshop tutorials of "The digital photography connection"- find it in the club website's links.
To boost the colour depth in images, add a black and white layer to an image, and then simply change the blend mode of the B&W layer from normal, to soft light.
PREPARING PROJECTED IMAGES FOR COMPETITIONS
by Gary Moffat
How to SIZE, Set sRGB COLOUR SPACE and SAVE your file
using Photoshop or Elements
From the Menu options:
a) Click FILE > OPEN, ‘left mouse-click’ on your chosen file and click ‘OPEN’
b) Click IMAGE > MODE > RGB Color and 8 BITS (In Elements, if you are not prompted on opening, convert to 8 bits)
c) Click IMAGE > IMAGE SIZE (In Elements click IMAGE > RESIZE > IMAGE SIZE), tick all three boxes, ‘Scale Styles’, ‘Constrain Proportions’ and ‘Resample Image’ and choose one of the ‘Bicubic’ options (if you are not sure then just select ‘bicubic’) (Older versions of Photoshop only have two boxes. Tick both of these.)
d) Still in the IMAGE SIZE palette, you now need to set the PIXEL DIMENSIONS.
If a LANDSCAPE (horizontal) image in ‘Pixel Dimensions’ > 'Width' type ‘1400’ (the height will be automatically filled in) OR if a PORTRAIT (vertical) image in ‘Pixel Dimensions’ > 'Height' > type ‘1050’ (the width will be automatically filled in) and left mouse click ‘OK’.
TO CONVERT TO sRGB COLOUR SPACE
From the Menu options:
e) Click EDIT > CONVERT TO PROFILE. In ‘Destination Space’ for Profile select ‘sRGB IEC…’ which will be near the top and for ‘Conversion Options’ choose Engine ‘Adobe (ACE)’ and Intent ‘Relative Colorimetric’. Leave ‘Black Point..’ ticked. If the other two boxes, ‘Use Dither’ and ‘Flatten Image’, are not greyed out tick them too.
f) Then click ‘OK’. Your image will now be in sRGB.
NB: You can only do a basic conversion in Elements, you will not be able to do all of the above – you will find your settings in EDIT > COLOR SETTINGS, and if the file you are opening does not have a profile you will get a message coming up, you can select sRGB here.
TO SAVE YOUR FILE
From the Menu options:
g) Click FILE > SAVE AS
h) Create a new folder by left mouse clicking on the folder icon (if you are not sure which icon, hold your cursor over the icon to find the right one) & type in your ‘Name’, (just type where you see ‘New Folder’ appear) as the ‘New Folder’ name, and then press the ‘RETURN’ key.
i) Type in your choice of filename, select ‘JPEG’ from the ‘format’ drop down list and click ‘SAVE’. Choose HIGH Level 8 Quality.
j) You can now continue to size and convert your remaining images following the steps above and save them in the folder you created at step f).
After you have done all the images you wish to submit, you are ready to exit Photoshop or Elements and burn your images to CD-R.
THRESHOLD LAYERS TO INCREASE CONTRAST IN CS3
by Andy Bennetts
- Check that the cursor is set up properly. Edit>Preferences>Cursors – Other Cursors must be set to “Precise”
- Make sure you can see the Info tab in the palette and also the Layers tab. We will use these later.
- Open the image – it can be any type of file.
- Select the Color Sampler Tool from the toolbar
- Layer>New Adjustment Layer>Threshold. We are going to use the threshold layer to establish where the lightest and darkest parts of the image are.
- There is no need to name the threshold layer – just accept the defaults. The color should be “None” and the Mode should be “Normal”. Click on OK.
- The threshold histogram appears – the white triangle below the historgram can be slid right and left.
- Slide the histogram triangle to the left until there is only a tiny amount of black visible. Click on OK.
- Position the Color Sampler tool cursor over the black area and click – you are taking a sample of the darkest part of the image. This should leave a “target” on the black area, which will stay there.
- Go to the layers palette and double click on the screen shape immediately to the right of the “eye” – this will bring up the histogram again.
- This time, slide the histogram triangle to the right until there is only a tiny amount of white visible. Click on OK.
- Position the Color Sampler tool cursor over the white area and click – you are taking a sample of the lightest part of the image.
- With the two targets established, we don’t need the adjustment layer any more, so you can drag it to the bin to discard it. The original image will reappear, and this time the darkest & lightest parts of the image will be indicated.
- Layer>New Adjustment Layer>Curves. We are going to use the curves layer to correct the colours for the two target areas. Accept the defaults & click on OK. The Curves histogram will appear.
- Look at the Info panel. Towards the bottom, you will see two entries #1 and #2. These are the two samples, and beside the samples are the readings of Red, Green and Blue (RGB) we will deal with each colour separately.
- In the curves histogram, click on the Channel drop down and select Red. For #1 and #2 we are going to set Red values of 10 and 245. You can do this on the histogram, by clicking and dragging the top and bottom of the straight line lying at 45 degrees on the graph.
- Do exactly the same for the Green and Blue channel. When finished click on OK.
- In the Layers palette switch off the “eye” in the curves layer to see the effect.
- To get rid of the targets, click and drag off the image.
- Save the file – flatten if you wish.
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