Digital Asset Management and Linux

For several years I have been using the Organiser within PhotoShop Elements to catalogue and tag my photos. I have found that having indexed and searchable photos is indispensable when preparing for some of the talks I have done. How else would I find the photo I wanted to use of the Grasshopper Warbler that I took on Baildon Moor?

Occasionally I used the editor within Elements, but only because it was easy to get from the organiser to the editor. This meant that I was only using a small part of the Elements power. There have also been a few hiccoughs with Elements on the way. I was forced to upgrade quite soon after an upgrade because the map display within Elements was broken. I also get pestered by notifications about upgrades, or new features, or “have you tried this?”

I am a fan of Open Source and for several years my photo editor of choice has been GIMP, but it doesn’t work with RAW files so I had been using Digital Photo Professional 4 provided by Canon to process the RAW file and then export to GIMP. The RAW processing in DPP4 seemed better than the Adobe Camera RAW that is part of Elements, it seemed better at handling highlights and noise reduction. This probably means that DPP4 automatically did some stuff that I could also have done in Adobe Camera RAW if I had spent the time to investigate.

Using Elements and DPP4 meant that I was tied to Windows but on another PC I use Ubuntu Linux. I had already installed GIMP on it and occasionally used it when working on my website development. A while back I decided to start looking for programs I could use within Linux so I could move completely over from Windows. I was already using the LibreOffice suite and Scribus DTP on Windows that are also available on Linux so I needed alternatives for Elements Organiser for Digital Asset Management and Canon DPP4 for RAW processing. I used the software centre within Ubuntu to look for RAW processing applications and came across RawTherapee and darktable. I also let friends know I was looking, so I had a go with darktable on Windows

darktable has some neat ways of working and I soon got to like it and I was quite pleased with the results. If anyone is thinking of trying it I would suggest watching some of the videos to get started. I was now only tied to Windows by the Elements Organiser

With a bit more investigating I came across DigiKam (the header image above is pinched from their site) that looked as though it worked in a similar way to Elements Organiser. It was available for Windows and Ubuntu so I tried it out first on Windows. I wrote all the image tags to the image files using Elements Organiser and then imported everything into DigiKam. The terminology in the program was a bit different and I had to rebuild the tag hierarchy from the imported tags but that only has to be done once and I was able to make some improvements on the way. After trying DigiKam for a while I decided to migrate to it as my asset manager. This means that I am no longer tied to Windows. One neat feature of DigiKam is that it will find similar photos and rank them by how similar they are. I used it to find duplicates of images even though the file size was different due to different EXIF data etc. It also found the same photos but at different resolutions where I had created reduced resolution/quality images for the web where I could then decide whether to keep the high or low resolution file. If the photo was for nostalgia, e.g. a photo of the changing use/demolition/refit of a local building, I would only keep the low res file.

I have yet to have a serious go with the scanner under Linux. The software that comes with the printer/scanner is Windows only but generic Linux scanner software looks as though it might be more than adequate and I have already had to use Linux software to stitch the PDFs together after scanning booklets.

As part of this migration I have decided to have a rethink about the PCs in use, i.e. have some serious upgrades. The Windows desktop PC has been replaced with an Intel NUC 8i3BEH with 16GB RAM and 1TB M.2 SSD. It is tiny and only an i3 but it is a lot faster than the desktop it is replacing. The Linux box is being replaced with a custom build Ryzen 7 with 32 GB RAM, 1 TB M.2 SSD and 2 TB HDD. Given that the Linux box was the cast off from the previous Windows box this should be a dramatic upgrade. I might provide a blog update when the Linux box is up and running. In amongst this I am also going to try a Raspberry Pi4 for displaying the CCTV cameras.

Shipley Glen Tree

I am a member of the T&A Camera Club facebook group. Each month there is a different topic for people to submit photos to, and one photo is chosen each month by the admins as the “winner”. I have only submitted photos a couple of times but this month the topic is Changing Seasons so I have finally got round to selecting some photos of the tree on Shipley Glen and putting them together to make a single image.

Back in January 2013 I went up to some of the rocks near the tree with my camera and tripod. I took a few shots of the tree and made a note of where the tripod was and how my camera was positioned. I then went back to the same place 22 more times, on one occasion with my flashgun, to take photos of the tree. I can’t remember whether anything happened to stop me but the photos range from 13 January to 24 October. Why did I not carry on through November and December?

I have been promising to go through the images for ages but it was the T&A topic that prompted me to finally do something with them.

A Glimpse of GIMP

GIMP is being forked to Glimpse.

On several occasions when I have told people I use GIMP as an image editor I have seen smirks. Not a good start, and that is before I have started talking about applying masks to layers. The situation does not improve when they ask what it means and I tell them that it stands for “GNU Image Manipulation Program”. Why would you want to manipulate a GNU Image? However “What is GNU?” is often the next question. And the answer is “GNU’s not Unix”. How is this supposed to entice someone serious about photography away from Photoshop or Lightroom? You can even find “photoshop” in the English dictionary now.

I am pretty sure that the use of GIMP is quite widespread but when a department head tells their graphic designers that they are to use a different editor instead of PhotoLab or PhotoShop or PhotoScape I reckon they’ll tend to use the name as little as possible.

What percentage of people picking up a digital camera know what Unix is? And of those how many might be interested, or care, that something is not Unix? But perhaps most people don’t care what software is called, and they are the ones that are never influenced by advertising.

If you have come from an IT background you can tap the side of your nose knowledgeably and install the new version of GIMP from the command line. Why would we want to let Windoze or Mac users into our world?

The answers are that it is a powerful image editor and it is Open Source i.e. free.

Apparently the project name has been a discussion topic on several occasions in the GIMP Project community and up until recently those in the know have tapped the side of their noses and carried on. I have not read the discussion itself but according to one source (The Register) it recently got a bit bad-tempered. As a result someone stuck their finger up and created a fork of the project in the best open source tradition and the current name for it is Glimpse. The new project has grand plans for major improvements to the user interface (AKA make it look even more like PhotoShop?) but is this looking for ways to justify the fork?

I don’t think I will be switching over for a while yet but it will be interesting to see if Glimpse gets past the geeky image or adolescent smirks of its parent.

Thoughts on Birds of Prey Centre shots

Barn Owl

Here I have put together some of my thoughts on the photography aspects of the Shipley Camera Club day at York Birds of Prey Centre. It presented several opportunities to use different camera settings and techniques for the different situations we found.

I felt obliged to go on the trip because I was promoting wildlife photography to the camera club and several skills needed in the wild could be practiced. However I don’t think I will go to such places again and now feel that I would have made more of a case for wildlife photography by not going.

Depth of Field

Several of the birds were on perches in front of their wired enclosures. In this particular situation I was not trying to show the plight of the birds but to get a “good” bird shot. Therefore I wanted to minimise the distraction of the background. Using the maximum aperture (smallest number) of your lens gives the minimum depth of field. To make the best use of this minimum depth of field it is then necessary to make the distance from the camera to the background as great as possible in relationship to the distance from the camera to the subject. This can be done by getting in reasonably close to the subject and positioning yourself so that the background is a long way off or by getting in VERY close to the subject so that any background, even though not very far away, is still blurred out of all recognition.

In the example above the focal length was 250mm and aperture f:5.6 which is the maximum for the Canon EF-S 55-250mm lens.

Lens size and depth of field

The diameter i.e. maximum aperture, of the lens you have plays a big part in controlling depth of field. For a given framing the focal length has negligible effect on depth of field.


The larger the achievable aperture on the lens the smaller the depth of field and therefore the more blurred the background. With the perched birds in front of their enclosures the largest aperture would normally give the best results but check the results. If you are lucky enough to have a lens with a really larger maximum aperture it is possible that the depth of field is so small that other parts of the bird are too out of focus.

Focal Length

a) When measured from the camera a short focal length lens apparently has a much greater depth of field than a long focal length but for a given framing situation the depth of field of a short focal length lens will be the same as the depth of field of a long focal length lens and so the blurring of the background will be similar. With the smaller focal length you need to get in close to frame the subject and hopefully with the apparent larger depth of field the background is blurred. With a long lens you are further away from the subject to get the framing you want and so the ratio of camera>background distance to the camera>subject distance is a lot less than with the short focal length but the blurring of the background will be similar.
b) Feature distortion varies with the focal length of the lens. With a short focal length you can get close to your subject but be wary of causing feature distortion. With a birds head you can get close and, of course, focus on the eyes. Let’s take the extreme example of a long beaked bird where you have got very close. When compared to the eyes the beak is a lot closer to the camera, in relative terms, than the eyes and as a result the beak will fill more of the frame and appear much larger in comparison to the eyes. With a long focal length the comparative distance of camera>beak and camera>eyes will mean that the beak will appear normal size in relationship with the eyes. (This is why, when doing people portraits, where the head and shoulders or more is in the frame, a lens of 50mm focal length or more is used; 85mm is very popular I believe. Feature distortion is reduced.)

Birds in Flight

If the bird is against a bright sky think about whether you need to overexpose to compensate, otherwise you may get just a silhouette of the bird and any attempt to reclaim detail in post processing may be disappointing. The photo above was taken with +1.5 stops compensation.

For the photographer the best way to take a photo of a birds in flight is when it is coming towards you. It is then easier to keep it in the frame but it can make focusing more difficult because the distance is continually changing. Because the bird’s motion across the frame is comparatively low you don’t need to use a high shutter speed, as a result you can get motion blur in the wings to show the movement and at the same time get a nice sharp and steady eye.


  • Use panning when the bird is flying across your view. Follow the bird in the viewfinder and take shots as you smoothly follow it across your view.
  • If it is available set the lens to the appropriate image stabilisation setting for panning, otherwise the lens will try to cancel out the movement, on my lenses this is OS2.
  • Use a small set of focus points and get focus on the eye.
  • Use back button focusing to separate focus and shutter firing.
  • Start following the bird in the viewfinder as early as possible.
  • Take several shots. If you start shooting early you will at least get some images even if the bird is erratic and you loose it in the viewfinder. Think about the noise of the shutter, switch to “silent” shooting and/or don’t start shooting early if you think the bird will be disturbed by the noise.
  • Use a small aperture bearing in mind you also need a reasonable shutter speed so that even though you may not get focus on the eye it is still sharp.
  • Use a reasonably fast shutter speed but not one that will freeze the background if there is one. The blur in the background helps to add to the impression of movement.


With a moving subject it can be difficult to get it in the viewfinder quickly (hence start trying to do that well before you will want to take the shot). And the longer the lens the more difficult it is to do.

I recommend trying to keep both eyes open. Even though it might not consciously be registering, the eye that is not to the viewfinder will provide information that with practice will help you get onto the subject quicker.

Manual settings

I have had a bit of a re-think about using my camera on program mode. On many of my trips out I have the Sigma 150-600mm lens on and my camera seems happy to try to use what I would consider slow shutter speeds. On my recent outing to RSPB Bempton Cliffs, for some of the time, I decided to set the shutter to 1/500s and aperture to f:8.0 or 1/250s at f:11 and let the camera choose the ISO for exposure. With my previous cameras I would probably not do this because the quality at higher ISO was poor.

With the photo above the camera selected ISO100 which is the slowest it goes. If the sun had been any brighter the image would have been over-exposed. This means that in future I need to keep an eye on the exposure guide or I need to have another re-think.

I can set a minimum shutter speed for the camera which involves going into the menus but when I am shooting at 17mm it is silly to limit to 1/500s or faster. Perhaps this is another use for the custom settings on my camera? Or perhaps I simply need to get into the habit of using partial manual settings.

You can see other photos from my trip here.