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Adventures adding a new lens to Aftershot Pro

Donncha O Caoimh — Thu, 15 Mar 2012 21:39:28 +0000

Bibble 5 and Aftershot Pro have a useful lens correction function that will fix the distortion created by a camera lens when a photo is taken. You won’t even recognise the distortion unless you’re looking for it but quite often it can look like straight lines are slightly bent or bulging.

The animated gif above shows you what that distortion looks like in my favourite zoom lens, the Sigma 18-200mm DC. The middle of the image is clearly bulging out. The bottom of the sign isn’t straight but after correction it’s much better.

Unfortunately not every lens is supported. In the lens correction widget of Aftershot Pro you’ll see an “Uncalibrated Lens” message if your lens isn’t there.

Bibble 4 supported this lens and I only realised today that a bug in Bibble 5 and Aftershot identified the lens incorrectly and led me on a merry dance across the Internet. Bibble 5 and Aftershot Pro think my lens is the “Sigma 18-200mm DC OS” but my lens doesn’t have an Optical Stabilizer! Bibble 4 probably detected the lens correctly.

Unfortunately for me there’s no mention of “Sigma 18-200mm DC” in the “Canon Lens Table” or profile_canonlenstable.txt. Only the OS lens is mentioned and I presume the non OS lens was removed in Bibble 5 by error. Once I added an entry for my lens and added settings for the OS lens everything worked ok again.

Anyway, thanks to this ASP forum post and this Bibble forum post I was able to add my lens to Aftershot Pro. The nice thing about the lens database is that it is composed of text files that are easy to edit. I found a basic uncalibrated entry for the non OS lens. Unfortunately I didn’t search further or I’d have found the “Sigma 18-200mm DC” settings I wanted and saved myself some time! I created a new file called profile_mylenses.txt and added that filename to profile.txt.

First of all, I had to find the lens correction parameters that would fix things. The Bibble 5 post above links to sites that will help you figure out the correct a, b and c coefficients but thankfully I didn’t have far to look to find working figures.

I checked out PTLens first. It’s a programme that corrects lots of different lens distortions and it’s reasonably priced at US$25 per license. The author has shrewdly kept his lens distortion database in a secret format so I had to continue looking.

I then found LensFun, an open source tool to do much the same thing but using an older version of the PTLens database. The source is available so I went digging and found this interesting file! All the info I needed in one XML file!

All that remained to do was edit profile_mylenses.txt. In Windows and Linux the file can be placed in the following locations respectively. Mac OS X is probably in “Application Support” or somewhere obvious like that. In Windows you’ll want to use WordPad as the other profile files don’t have Windows line endings. You’ll also have to open it as an administrator to edit it.

C:\Program Files (x86)\Corel\Corel AfterShot Pro\supportfiles\Profiles\LensProfiles\
/opt/AfterShotPro/supportfiles/Profiles/LensProfiles/

After some editing and experimenting I found that these settings worked well:

begin lens
group: genericSLR
multiplier: 1.6
aperture: 3.5
menu_lens: Sigma 18-200mm f/3.5-6.3 DC OS
cal_abc: 18 0.018238 -0.045992 0.000000
cal_abc: 21 0.013683 -0.026594 0.000000
cal_abc: 24 0.007113 -0.008911 0.000000
cal_abc: 33 0.000000 0.010791 0.000000
cal_abc: 59 0.000000 0.012006 0.000000
cal_abc: 88 0.000000 0.010958 0.000000
cal_abc: 144 0.000000 0.008752 0.000000
cal_abc: 200 0.000000 0.007390 0.000000
end

I had to restart Aftershot Pro to test new settings each time.

If editing files like that puts you off you can create a preset to apply the lens correction. Click on the Manual tab in the Lens Correction widget where you can enter the a, b and c coefficients. Now go to the Presets widget and follow the instructions in my HOWTO: Add a copyright notice in Aftershot Pro tutorial except you’ll want the Lens Correction function to be active.

I suspect that these changes will be overwritten whenever I upgrade Aftershot Pro but maybe Corel will notice this little post of mine and they’ll fix the detection, or duplicate the settings in the next version..

While writing this post I found entries for the “Sigma 18-200mm f/3.5-6.3 DC” lens in profile_genericSLR.txt. Because the programme misidentified my lens it never used those settings. The 1.5 multiplier settings have the same settings as above, the 1.6 multiplier one is slightly different but there’s not much difference when applied to my test image.
Let that be a lesson to you if you’re trying to get this work. Look harder for an existing profile and make sure your lens is identified correctly! Argh!

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Aftershot Pro B&W Workflow

Donncha O Caoimh — Mon, 12 Mar 2012 09:30:47 +0000

Martin, over at Photoakademie.eu created a workflow video showing how a photo was processed and eventually turned into a black and white image using Aftershot Pro.

Coming from a GIMP background I used layers and layer masks but never used adjustment layers to keep changes separate. Quite an eye opener for me!

Plus another demonstration of Aftershot Pro and a Google Plus account dedicated to sharing presets.

You can download a 30 day trial of Aftershot Pro here (I should be on commission for this..)

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Stupid Photo Thief

Donncha O Caoimh — Fri, 20 May 2011 10:02:00 +0000

It’s inevitable that photos put online will be stolen. It’s a fact of life unfortunately. People think that just because something is on a website they can use it and claim the photo is there own.

Sometimes it just gets silly however.

Check out this guy’s photos on photo competition site pictures2win.com. If you’ve been reading this blog for a while you may recognise this photo. It looks very familiar doesn’t it?

With the help of Google Goggles on my Android phone I checked a few more photos. This photo of Venice (despite the author saying it’s in Pakistan) looks suspiciously like this one from the National Geographic. I’m sure they won’t be too happy to see that.

The Pictures2Win T&C of course include the condition that photos “must be the work of the individual submitting them” but there’s no link to report stolen images. I contacted Martin at that site. Hopefully he’ll take a look at that user’s account and take appropriate measures.

Thanks to _jmphotography for telling me about this photo theft.

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Straighten and Crop with the GIMP

Donncha O Caoimh — Fri, 13 Nov 2009 10:49:15 +0000

One of the more awkward tasks to do in the GIMP is straightening horizons. You have to manually rotate the image using that tool which always seems to be fairly hit and miss.

I had hoped that GIMP 2.6 would have the “draw a line and rotate” function that Bibblepro and I think Photoshop have but unfortunately it’s not there. Not to worry because the Straighten and Crop plugin by Bert Hinz does the job too! (There’s another Straighten and Crop plugin too. I haven’t tried it. What’s it like?)

Install the plugin by copying the .py file into .gimp-2.6/plug-ins/. You might need to chmod it to make it executable. Fire up the gimp and using the Path tool (press B) mark two points on the horizon with left clicks of the mouse. Run the plugin (from Image->Transform->Straighten and Crop) and it will rotate the image.

Nice and simple and has worked on the couple of images I tried it on. (via)

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Montenotte Photowalk

Donncha O Caoimh — Sat, 05 Sep 2009 19:46:20 +0000

When: Saturday 26th of September at 10am.
Where: Start at the Montenotte Hotel (map), Cork and continue into town.
Who: Me, you and anyone who likes taking photographs.

So, next photowalk is on the 26th. It’s a Saturday but this time it’s early in the morning at 10am. We’ll start at the Montenotte Hotel, where we (or some of us) may get access to the roof to shoot a cityscape of Cork City. Bring your wide angle and telephoto lenses!

After that it’s a stroll down the hill to Dillon’s Cross, and then wherever we fancy. We’ll be close enough to the train station to pop over there (although there may be questions of public liability insurance if we go in there as a group unfortunately).

We can head down to the quay then and on towards the bus station and into town or towards City Hall. Wherever.

Will suggested having a scavenger hunt on the walk which is a great idea. Anything else we can do to mix it up a bit?

As I mentioned previously, The Montenotte Hotel is putting on a special deal for us photowalkers:

As a special deal for photographers, the hotel is setting aside 20 rooms for us on the night of the 25th. 17 are discounted with single rooms costing 39 Euro including breakfast and double/twin rooms at 29 Euro/pp, also including breakfast.
After the photowalk we’ll descend on the Boardwalk Bar & Grill for a complementary lunch, and there may even be an opportunity for a select few to head out on a speed boat along the river.

The 3 free rooms are already allocated but that still leaves the 17 discounted ones. If you’re interested, email Pat O Neill at pat @ hotelconsult.ie and he’ll organise the room for you. Don’t bother ringing the hotel.

I guess the complementary lunch was originally intended for those who stayed in the hotel but as the take up of the rooms on Friday night has been so slow I don’t know for sure what’s happening. I’m pretty certain the ride in the speed boat is still on though. I’ll pass on that, I prefer to stay on land!

So, if you’re interested in going on the photowalk please leave a comment here! This doesn’t mean you’re going to stay in the hotel. I don’t want to hear about it. I just want to go on a photowalk. Email Pat if you want to stay at the hotel! (it is a good deal, and the hotel is a gorgeous one!)

If you left a comment on the previous post expressing interest in the walk, please leave a comment here again, just so we have a rough idea of numbers without having to go digging into old posts.

If you don’t want to walk up the hill to the hotel, meet us in town later. I’m not sure how we’ll organise this but it’ll probably be “12 noon at the bus station” or some such arrangement.

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15% off prints for 3 days only

Donncha O Caoimh — Mon, 24 Aug 2009 09:20:27 +0000

Woo! Redbubble are offering 15% off all framed and canvas prints until the 27th. The promotion has been running for the last few days but they only emailed everyone this morning. Grrr.

Anyway, if you’re interested in a print, leave a comment on this post with the url of the photo and I’ll do my best to upload it today so you can get that discount.

I need to upload a few more shots anyway as a few people have asked about prints.

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Walking the photos in Cork

Donncha O Caoimh — Sat, 18 Jul 2009 09:34:37 +0000

Here’s a possible route for our 2 hours photowalk around Cork today:

Start at the GPO, near the big A marker above.
Head south (down) to the river to Morrison’s Quay where we can shoot Holy Trinity and the river bank of the South Channel.
Head west towards Sullivans Quay where we can shoot Parliament Bridge and St Finbarre’s Cathedral in the distance.
Over either Nano Nagle bridge to the Grand Parade or the bridge to St Main Street. The old Beamish Brewery is on South Main street and we can then go back to Grand Parade.
Shoot the sparkling new streetscape of Grand Parade and then into The English Market.
Bump up the ISO and shoot indoors in the English Market.
Out again eventually and either wander over to Cornmarket Street or down Patrick Street to do some street photography.

Throwing a spanner in the works is the Lee Swim, a swim down the North Channel, around the tip near the docklands and up by the Clarion. Here’s the course map. It could be starting at 2pm and if it is, it would be worth our while heading down the Clarion to photograph the finish and the crowds. The Clarion itself is worth a look and the nearby Elysian too. I’ll update this post when I know more.

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Spencer Tunick photos went online today

Donncha O Caoimh — Mon, 08 Jun 2009 17:17:00 +0000

Spencer Tunick’s Irish photos might be online but you wouldn’t know it as the site is down, probably from the rush of people trying to see their neighbours or friends in the nip. Oops. Should have done a deal with Pix.ie!

I did manage to grab one image off there this afternoon and Vic has a few shots which I’ve added to a small gallery. Photos from Cork (he shot in Blarney and in the City) will eventually be seen here. Give it a few days until the site quietens down again.

Photos copyright Spencer Tunick.

Edit: Link to www.tunickireland.com removed as it’s now a domain squatter’s website.

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Worldwide Photo walk in Cork

Donncha O Caoimh — Wed, 20 May 2009 15:03:43 +0000

On July 18th, photographers all over the world will be holding photowalks. There’s going to be events in Belfast, Dublin and Cork that day, and who knows. Might be a few more around the country by the time that day arrives!

I’ve just filled in a few details on the Cork Photowalk page on the Worldwide Photo Walk website. You can register on that page. While places are limited to 50, I’d be surprised if we get that many.

I think 2pm is a good time to start. It’ll give people a chance to grab a bite to eat, the city should be busy with shoppers and tourists, and the sun will have passed overhead, giving us some shade to play with. Is that too late? Too early? What about 10am in the morning? Town is nice and quiet in the morning but some people aren’t up that early at the weekend!

If you’re not in Cork on the 18th, there’s also a Dublin photowalk and a Belfast photowalk too. Dublin one is almost booked out though so hurry to register!

We’ve had other photowalks in Cork. Some of my photos from those events are tagged Cork Photowalk and iba09. Take a look. There’s plenty to photograph in Cork!

See you on July 18th?

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The irony is lost on Paul

Donncha O Caoimh — Mon, 23 Mar 2009 14:01:26 +0000

It’s about time I posted this. Months ago this photo on Flickr was spammed by a company selling “all of categories for industries and life”.

I’m sure he never looked closely at the title of the image or translated it in to his local language..

Flickr Support promptly removed this individual’s comment and replied,

Dear Sir:

I am a vice director of Flickr Report Abuse Co., Ltd to
supply all of categories for photo-sharing industries and
life.

I am content to contact you for deleting this business.

Joe

I had to read it twice, but cracked me up once I got it!

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