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.
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.
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.
|Camera||Canon EOS 40D|
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.
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\
After some editing and experimenting I found that these settings worked well:
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
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!
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..)
|Camera||Canon EOS 40D|
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.
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.
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)
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.