Tip: How to stop Apple Photos from launching for all devices in OSX

This is a short but useful snippet of code if you use a Mac to edit your photos that I found on Reddit. This stops Apple Photos from launching when you insert an SD card or any external USB device.

To stop Apple Photos from ever launching again when you connect any device/memory card do the following:
Launch a ‘Terminal’ session
Enter the following line:
defaults -currentHost write com.apple.ImageCapture disableHotPlug -bool YES

There is an option in Photos to stop it loading “for this card” but that doesn’t work if you format the card which is very likely a part of your workflow if you use Lightroom (and it’s more sensible to copy rather than move in case your drive goes belly-up while transferring).

combined

More fun with long exposure stacking of photos

A few months ago I experimented with Imagemagick by using it to merge very similar photos of flowing water to give the impression of a longer exposure.

Here are a few more examples.

By merging a series of thirty photos taken two seconds apart I created a pleasing image that looks like a sixty second exposure. The day I took these photo was overcast and dull, but not dark enough to do an actual long exposure like that without the help of some fairly dark filters. I used the intervalometer in Magic Lantern to shoot this so I didn’t even need a remote release. My camera did all the work! This was created using the following Imagemagick command line:

convert *.jpg -average average.jpg

2015-11-27-2608-m

2015-11-27-2637-m

average

I combined 60 long exposure shots of the night sky in the mountains of Utah (during the Automattic Grand Meetup a few weeks ago) to create a single long exposure of the stars moving through the sky. Thanks mkaz for publishing this post on interval shooting where I got this command line:

convert *.jpg -evaluate-sequence max combined.jpg

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2015-10-15-9757-m

combined

Finally, another series of sixty shots taken in Utah. The same convert command line was used to process these.

2015-10-15-9758-m

2015-10-15-9817-m

combined

In the image above I should have cloned out the wires in the bottom left of the image. Lightroom makes it easy to make the same modifications to every image. Work on one image, then select all the ones you need and click “Sync Settings”.

It can be frustrating taking these types of photos as your camera is shooting a long series of very ordinary shots, and the final result can’t be seen until the images are processed correctly but it’s certainly worth it.

Update on December 1st: here’s one that didn’t work out so well. It was so windy the camera shook the whole time.

combined photo

Aperture ƒ/8
Camera Canon EOS 6D
Focal length 24mm
ISO 100
Shutter speed 1/50s
Lightroom - dng

The Limits of Lightroom’s Smart Previews

I just stretched the limits of Lightroom’s Smart Previews this morning.

After editing the following image I decided to see what it looked like as a smart preview. I pushed the image quite a bit, exposing the colour in the sky as the sun set behind me in Lanzarote a few days ago.

Lightroom - original image

The original image is dull and lacks contrast but with a little work I was able to expose the lovely shades of magenta and orange present. Here’s what it looked like when Lightroom was editing a DNG file:

Lightroom - dng

But when I removed the file and Lightroom had to use the smart preview this is what that lovely colour gradient looked like:

Lightroom - smart preview

There’s visible compression artefacts visible that aren’t in the original and it looks more pronounced in Lightroom. I didn’t push the image too much, but these sort of artefacts can be seen in Jpeg images of smooth colour gradients like a blue sky has. They’re really visible if you push the contrast at all, or modify the colours in the gradient like I did with this image.

Smart previews create images that are 2500px wide or tall which is a good compromise between full size RAW and not being able to edit the image at all, but on a high resolution screen like a Macbook Retina screen you won’t be able to zoom much.

I will continue to use smart previews. My 1TB+ photo archive can be crunched down to less than 200GB which is within the reach of a laptop, and still leave free space. Once I plug my external drive back in and fire up Lightroom I can then export the images and be sure that the final image is what I want.

The Hills

Lightroom Tips and Videos

At the recent Automattic Grand Meetup in Utah I presented a Lightroom tutorial. During the course of the tutorial I went through the various Develop panels explaining what (most of) the sliders did, offering some advice sometimes on how to use them.

Here’s a few tips from the night and links you’ll find useful:

  • Use ALT/OPTION to tune the white and black sliders to see how much the highlights are blown or shadows totally black.
  • Hold down SHIFT and double click the white and black slider titles to auto set them. Be warned that Lightroom will stretch the histogram to do this and avoid losing data but that might not be what you want to do.
  • Use the Upright tool (lens correction) to correct distortions and horizons.
  • Don’t overdo “clarity”. It’ll introduce halos.

When editing a photo it’s useful to begin by setting highlights to -100, shadows to +100, and adjust the whites/blacks using one of the techniques above. Pull back the highlights and shadows to suit your taste, and increase the contrast.

Lightroom Basic Panel

Serge Ramelli has a great Youtube channel. He has an over abundance of “subscribe to my newsletter” and “buy my course” notifications but his videos are still worth watching. If you want to download the RAW files he uses you’ll find them here. I enjoy his sunset tutorials and videos:

And I love what he did with this:

I think I discovered his channel first by searching for black and white tutorial videos. This one got me hooked:

Also check out Anthony Morganti’s channel. His video on sharpening and noise reduction is excellent.

Light Trails

Use Back Button Focus to Pre Focus

Sometimes it’s useful if the shutter button doesn’t focus. Instead you press another button to focus. I’ve used it in the past when shooting street photography (focus on the ground and I know anything a metre away will be in focus), and at night on a tripod when taking long exposure shots of moving lights.

Back button focus is when you don’t use your shutter button to focus the camera. Instead you’ll use a button on the back of your camera. Not every camera can do it but check your manual or use Google to search for your camera name and “back button focus”. Here are two good videos describing why it’s good for sports photography:

Here’s a video I found to get it working on the Canon 6D using the AF-On button. I usually use the Q menu now to disable focusing on the shutter button.

The beauty of back button focusing is that you can focus your camera before the proper shoot and then take as many photographs as you want of the scene, often when the lighting has changed and focusing is impossible. This is especially important at night, but it also lets you shoot faster as the lens is already focused. This may just mean the difference between a great street photo and a missed opportunity.

Finally, here’s a photo I shot last night using back button focus to set up the shot. I could as easily have manually focused the lens but this worked just as well.

Light Trails

Aperture ƒ/4.5
Camera Canon EOS 6D
Focal length 17mm
ISO 100
Shutter speed 10s
Sensor dust

How to clean your camera sensor

One of the horrors of owning a DSLR and using multiple lenses is the dread of getting dust on the camera sensor. In small amounts it’s visible whenever you shoot using a small aperture like f/22 but if you leave it go too long you’ll see round smudges show up on your every day snaps at f/8 or f/4 too.

This video describes part of the process I go through when I clean my camera lens. A Nikon body is used in the video but the method is similar for Canon and other manufacturers. I only have a blower and soft brush but they have served me well over the course of the last decade.

Cleaning the sensor is risky. It’s a sensitive piece of electronics but there’s an infrared filter in front of it and that’s what you’re really cleaning. It’s sturdy and tough but if you pushed too hard on it you will scratch it. I’ve never scratched the sensors of any of my cameras though so I don’t worry too much about it as long as I’m careful.

After blowing and wiping the dust away you should do the same with the inside glass of your lens. It’s likely that’s where the dust came from in the first place.

Once I’ve rebooted my camera I’ll test the sensor by doing the following:

  • Grab a sheet of clean white paper.
  • Set the lens to manual focus, the camera to shoot RAW, and change it to aV (or A) mode to change the aperture to f/22. If you use any exotic shooting styles reset them to standard.
  • Prop the paper on a shelf in clear light.
  • Shoot the paper. You don’t have to worry about it being a long exposure and camera shake. The dust on the camera sensor won’t move!
  • Examine the picture on the camera LCD, zoom in and you’ll see any remaining dust particles as black dots. They’ll look like the images below.
  • Repeat the “mirror lockup, clean, check” cycle until you’re happy with how much dust is left.

dust on the sensor

dust on the sensor

Aperture ƒ/22
Camera Canon EOS 6D
Focal length 24mm
ISO 100
Shutter speed 1.3s
average-3

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:

average-3

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.

2015-06-19-4106-gp-2

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:

average

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

average

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.

average

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

average

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