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Long Exposure Photography through Stacking

The usual way of taking long exposure photos is by leaving the shutter open for a long time. This requires either a dark location or ND filters of some sort on the end of your lens. There is another way and that’s called image stacking.

In a nutshell, you take a series of well exposed photos of short exposure for the same duration you’d use for a long exposure shot. Then in development you create a number of images files which are then merged together to create a final “averaged” image. You can use Photoshop, GIMP, Imagemagick or I presume many other apps to create this image. I used Imagemagick here as I don’t have Photoshop and didn’t want to load all those images into GIMP and I had read that “convert” would do a good job.

Here’s one I created earlier today in the slightly shady but bright gardens of Blarney Castle:

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The images that went into creating that image all look like this. They were shot at f/4, mostly shot at 1/80 of a second and ISO 100. I wanted fast images with minimal noise and the scene is mostly flat so I wasn’t too worried about depth of field.

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To make this image I took 27 photos of the scene. I imported them into Lightroom (didn’t do much apart from applying my default settings) and exported Jpeg files. In the directory where I exported them I ran the convert programme from ImageMagick like this:

convert *.jpg -average average.jpg

That command was used by Luis Argerich, the author of this post who created a simulated 4 hour exposure of the sky and went on to say:

Averaging can be used in static scenes to create a new photo with less noise. Noise is reduced in the function of the square root of the number of images. So if you average 25 shots you have 5 times less noise than in a single image.
Averaging can also be used in non-static scenes to simulate a long exposure.

Patrick David in this post suggests a slightly different command which I tried and it created a similar photo.

If your exposure somehow went wildly different with some images bright, some dark, use the “Match Total Exposures” feature in Lightroom to pull them back.

ImageMagick is fairly easy to install. If you are using Linux you probably already have it installed. You can download it from this site or if you use Mac OS X, install Homebrew and then it’s as simple as this to install:

brew install imagemagick

Here are a few more examples:

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This one didn’t work out. I was trying to capture the swirling of the bubbles on the water.

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This one works better. The source photos are all around 1/25th of a second which is certainly not fast enough to freeze the water.

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Almost happy with this one. The source photos go from 1/60th to 1/100th of a second.

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I like this. It was created from ten photos shot at f/4, 1/60th sec, ISO 100.

I didn’t try very hard to make the images here pretty. They’re purely experimental and done with minimal effort but I’m very happy with most of the results. In shaded daylight I was able to take the equivalent of five to ten second exposures without ND filters or reducing the size of the aperture. It would have been easier to make the aperture smaller and add an ND filter but that’s not the point of this exercise.

One issue that may bite you is the speed of your media. My camera quite often flashed a “busy” notice because it was writing to the SD card. Then again, I was shooting 20MP images and my card says it’s rated at 30MB/second which is a problem as each image is around 20MB. As they’ll only ever be viewed online that’s probably not really needed. I might try the half-size option next time.

One nice bonus to this method is that Google Photos will generate nice animated GIFs from your image stack. I posted mine here. I won’t embed them as the files are huge!

I’m definitely trying this out again!

Aperture ƒ/4
Camera Canon EOS 6D
Focal length 24mm
ISO 100
Shutter speed 1/60s
San Francisco, 2007

Shoot … in the Style of Garry Winogrand

Tomorrow I’ll be braving the streets with Cork Streetphotography taking photos in the style of Garry Winogrand.

I’d never heard of Garry but a quick Google brought me plenty of digest. First this documentary, filmed in 1982, that showed his technique and friendly nature:

Then I came across this excellent blog post about the man. To summarise his technique:

  • Shoot, shoot, shoot.
  • Garry Winogrand shot with a 28mm lens. That’s fairly wide, so he was always in the thick of the action. No telephoto lens allowed.
  • He would frame his shot by looking through the viewfinder, so no shooting from the hip.

You can see in the video above how he fiddles with his camera to distract the people around him. That’s not a bad idea, especially when you have a wide lens!

Camden Wharf, Cork

The tips from that post, which I urge you to read:

  • Shoot, a lot
  • Don’t hesitate and follow your gut
  • Smile when shooting on the streets
  • Don’t shoot from the hip
  • Don’t crop
  • Emotionally detach yourself from your photographs
  • Look at great photographs
  • Focus on form and content
  • Become inspired by things outside of photography
  • Love life

Camden Quay, Cork

I’ll be only using my wide angle (17-40mm) lens so I won’t be tempted to zoom in too much. Tomorrow will be challenging.

The photos in this post are mine, just in case you’re not familiar with Cork. I shot the first photo in San Francisco in 2007. You can find many images by Garry Winogrand on Google Images.

Aperture ƒ/8
Camera Canon EOS 6D
Focal length 24mm
ISO 100
Shutter speed 1/200s
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Use Lightroom Collections to Publish Photos

Since I started posting photos online I’ve always created two images:

  1. A web sized version to go online.
  2. A full size version for my archive.

This has served me well as I have from time to time changed the software I use to develop photos. Otherwise, I might have the web version and not be able to recreate a full size version for printing or other uses.

Up until very recently after I worked on an image I would add it to an “inphotos” default collection (press B), then right-click and export twice. Once for web, once for full size. I had to do this for each image. Sometimes I could select a bunch of them and export if I knew I had a number of “keepers” from a shoot but otherwise it was tiresome.

Collections

I’m now experimenting with smart collections in a Hard Drive Publish Service. I still have an inphotos.org collection, but I added another one called, “Published inphotos”. That’s a smart folder that contains all the published photos that have already gone up on the site. That folder contains every image that comes from the inphotos.org collection and is labelled Yellow.

Aside: I also added a “Potential” smart folder for photos I’d like to work on. Labelling a photo RED will put it in this folder.

Lightroom_collections

Obviously I haven’t added every published photo to it and I probably won’t. I don’t have time to, but I will fill in older photos when I have a spare moment.

If you’re not familiar with collections here are two videos from Adobe on ordinary collections and smart collections that are worth watching:

 

Publish Services

I then created two publish services. One for full size images, the other for web images.

Lightroom_publish_services

The 00-inphotos and 00-Large smart folders initially contained every image that is in the inphotos.org collection. I soon realised I’d have a problem with the web sized 00-inphotos folder. If I published a photo how would I remember that event easily? In the past I moved the file into a different physical folder, but I wanted Lightroom to track this. To do this I decided to add a yellow label to every photo I published. I created a new “00-published” smart folder. This folder collects every image that is labelled Yellow from the inphotos.org collection.inphotos_published_smart_folder_settingsI modified the 00-inphotos smart folder so it contained every image except those labelled Yellow.inphotos_smart_folder_settings

So, when I published an image I went into the inphotos.org collection in Lightroom and labelled the image yellow by pressing “7”. This would cause the 00-inphotos smart collection to delete the image, and the image would be added to the 00-published smart collection. I just had to hit Publish on each of them and the file would be “moved” from one physical folder to the other.

It’s early days yet and I’ve only posted a few photos using this method but it works well. Editing photos and adding them to the inphotos.org collection is a breeze but this is a process that’s not set in stone and will be refined with time. If it’s too awkward I’ll move on to something else.

I use the WordPress “new post” interface to make new posts, or if I have time to do so, I’ll schedule a number of posts using Postbot.

How do you use Lightroom to post to your blog or social media site?

The Brenizer Method – shallow DOF and wide angle

I love shallow depth of field and the Brenizer Method (or bokeh panorama) is an intriguing way of achieving that in a wide angle shot.

Basically, with your lens zoomed in you take many overlapping photos of your scene like you would a panorama but you don’t go for the traditional 360 degree image. It’s more like 50-90 degrees, or what a “normal” lens would see. The beauty of the technique is achieving a very shallow depth of field because your lens is zoomed in and the DOF is shallower still than it would be wide open, or so I’ve read. I haven’t managed to take such a photo yet!

Here’s a great video showing how to do it with Photoshop, but you could use Hugin or Microsoft Ice as well.

Take a look at the stunning photos here, here and here. Beautiful.

Quickly Match Exposures in Lightroom

I had no idea this existed, but then I’ve rarely had to match the exposures of multiple files. When I used the GIMP to edit photos I would play around with multiple exposures more often but Lightroom can extract so much information from RAW files it covers 99% of my image development.

tl;dr – fix the exposure of one image, select other relevant images and click on Settings->Match Total Exposures.

Shoot manual mode with E-TTL flash just once

If you have an external flash (and this even applies to the onboard flash but that’s a lot weaker) for your DSLR try shooting with the camera in manual mode and let the flash light the scene for you.

Canon flash units use E-TTL to figure out what power to use, Nikon and other manufacturers use something similar. In the bad old days photographs had to figure out the right settings with a light meter but now the tiny computer in your flash does the job automatically. This means you have a lot more freedom with your camera.

Instead of shooting in Program or auto mode switch the dial to M and change the aperture to F8, and the speed of the shutter to match how wide your lens is (or faster if you’re hand holding, try 1/50th of a second to start). Try shooting an indoor scene with objects at various distances. Do the same in Program mode too. You’ll probably find that objects that are blurry in Program mode are in-focus in manual mode!

By shooting in manual mode you’ll have more control over the depth of field, that is the area of the scene that will be in focus. F4 means that only a narrow sliver of the scene will be in focus but F8 broadens that. This is why those family portraits you shot in Program mode had some blurry faces in the background!

Many lenses produce sharper and better looking images at a certain aperture setting. F8 is widely suggested as a good starting point but it depends on the lens in question.

Unfortunately changing the aperture means less light gets to the sensor but your flash will do a good job of compensating for that. It can’t cope with every aperture setting or scene so experiment and get to know your equipment.

On Canon cameras Manual mode is better than Aperture priority mode for simple flash photography. In Aperture priority mode the camera adjusts the shutter speed for the ambient light and doesn’t use the flash in this calculation. In a dim room this will result in a long exposure. The flash will illuminate the subject but the background will be exposed for too. This is of course a valid way of taking photos but you have to be prepared for some camera shake, or you can underexpose the image on purpose to reduce the shutter speed. Long exposure shots with a flash produce some great looking action shots too, but be sure to set the 2nd curtain sync correctly! Here’s a good comparision of 1st and 2nd curtain sync.

Here’s some good advice and tips on the subject for Canon EOS owners.


Aperture ƒ/5.6
Camera Canon EOS 40D
Focal length 88mm
ISO 100
Shutter speed 1/30s

Save instead of Export in GIMP 2.8

Version 2.8 of GIMP saves images as .xcf files by default when you hit CTRL-S. I remember a development version did this years ago but it was reversed before final release due to user feedback AFAIR.

I can understand the reasoning behind this decision but I hate it. It really, really bugs me. I don’t think it’s going to change in the future but if you must have your CTRL-S “save as a bloody jpeg because I said so” there is a way around it. You’ll use keyboard shortcuts.

Go to Edit->Keyboard Shortcuts and then search for export. Now change the shortcut to CTRL-S for either “Export…” or “Export to”. The former shows a save dialog, while the latter overwrites the file you have loaded. I prefer the save dialog.

You’ll still get the “close without saving” dialog. If it really bugs you (and I think it will) there’s a checkbox in the preferences asking you to, “confirm closing of unsaved images”.

*sigh* what a mess.