Archive for the ‘Scribbles’ Category
A new release of the Instant Guide to DSLR Dashboard is available for your reading pleasure. In addition to minor tweaks and improvements, this version of the guide includes information on setting up wireless tethering and using Raspberry Pi as a DSLR Dashboard server.
If you’ve already purchased Instant Guide to DSLR Dashboard, you can download the new version as described in the guide.
Our garden residents provide ample opportunities to make use of my Tamron SP 300mm f/5.6 Adaptall 2 lens mounted on a Canon EOS 1100D. Most of the time, I have to shoot through the thick double-layer glass of a terrace door, but I managed to capture this photo through an open window on the second floor of our apartment. This is, by the way, our blackbird named Haru. These days, he is busy feasting on apples we put for him and his lady (more about her in another post) and patrolling his territory, a.k.a. our garden.
Sunday wasn’t a very good day for him, though. After he took a bath in a plastic tray we put for that purpose, the poor bugger flew right into the glass terrace door. He hid then in a corner of the garden, and sat there for a while slightly confused. He is alright now, dashing around the garden and looking busy as usual.
Taken with Canon EOS 1100D and Tamron SP 300mm f/5.6 Adaptall 2. Processed in digiKam. Shutter speed: 1/250 sec. Aperture: f/5.6 ISO: 400
The Sharpen tool in digiKam offers three sharpening methods: simple sharp, unsharp mask, and refocus. Each method has its advantages and drawbacks. The simple sharp technique uses a standard convolution matrix algorithm to improve image details. If you are curious about the nitty-gritty of the convolution matrix, the GIMP documentation provides a brief description of the algorithm. In fact, the simple sharp tool in digiKam is ported from the GIMP project. The main advantage of the simple sharp method is its simplicity. The Simple Sharp tool in digiKam has only one adjustable parameter called Sharpness which determines the strength of the applied sharpening filter. On the downside, the simple sharp method doesn’t handle image noise very well: it tends to introduce more noise in photos taken at lower ISO settings.
Unsharp mask is a popular sharpening method which sharpens the edges of the elements without increasing noise. The unsharp mask technique creates a slightly blurred version of an image, which is then subtracted from the original in order to detect edges. The resulting mask is then used to increase contrast along the detected edges to produce a sharper final image. The Unsharp Mask tool in digiKam has three adjustable parameters:
Radius specifies how many pixels on either side of an edge will be affected by sharpening. High-resolution photos allow higher radius.
Amount determines the strength of sharpening.
Threshold specifies the minimum difference in pixels that indicates an edge where sharpen must be applied. This lets you protect areas of smooth tonal transition from sharpening, and avoid creating blemishes in face, sky or water surfaces. 
When using the unsharp mask tool, you should keep in mind that it can introduce subtle color shifts and halo artifacts visible as dark or light outlines near edges.
Finally, the Refocus method is based on the Refocus plugin for GIMP which uses a technique called FIR Wiener filtering to sharpen the image (see http://en.wikipedia.org/wiki/Wiener_filter). Similar to the original plugin, the Refocus tool in digiKam offers several adjustable parameters:
Circular sharpness is a key parameter which determines the radius of the circular convolution. Basically, it specifies the strength of the refocusing action.
Correlation helps to reduce artifacts. Increasing the correlation value reduces the sharpening effect. Useful values are 0.5 and values close to 1 (e.g., 0.95 and 0.99).
Noise filter may help to reduce artifacts. Similar to the Correlation parameter, increasing the noise filter value reduces the sharpening effect. A useful value is 0.01.
Gaussian sharpness is used to specify the radius of the Gaussian convolution for correcting Gaussian blur. In most cases, it should be set to 0, as it introduces artifacts. When using non-zero values with Gaussian sharpness, you might need to increase the Correlation and Noise filter parameters, too.
Matrix size determines the size of the transformation matrix. Increasing this parameter may give better results, especially when large values are chosen for the Circular sharpness or Gaussian sharpness parameters. In most cases, you should select a value in the range 3-10. 
Refocus is the most powerful and effective sharpening tool in digiKam’s arsenal, as it not only offers a superior sharpening method and granular controls, but can also handle noise.
 Source: http://refocus.sourceforge.net/
It all started with a Tamron 70-150mm f/3.8 CZ-715 Adaptall lens I got thrown in as a freebie when I bought my Nikon F-301. Although I had a vague idea of the Adaptall technology, I knew nothing about this particular lens. While doing research on the lens, I discovered that Tamron had a strong product line of the SP series Adaptall 2 lenses targeted at serious amateurs and professional photographers. One lens, in particular, piqued my interest: Tamron SP 300mm f/5.6 Adaptall 2 54B. While this model is a bit slow, it has an impressive 300mm focal length and features 1:3.3 macro capabilities. More importantly, the lens is rather inexpensive, and I’ve managed to find a unit in excellent condition at a very reasonable price on a local online auction.
Tamron also produced a 2x converter for use with Adaptall 2 lenses, and I was lucky to find one on eBay. This converter doubles the focal length, but it does so at the expense of the aperture. So the converter transforms a Tamron SP 300mm f/5.6 into a 600mm lens with the maximum aperture of f/11. Tamron lenses with the Adaptall 2 adapter for Nikon F mount are compatible with Nikon’s analog and digital SLRs. When bolted onto a Nikon DSLR with a DX sensor, the lens’ focal length equals 450mm. Add the 2x tele converter, and you get an whopping 900mm focal length.
To test the lens, I went to our local botanical garden. I started with my Nikon F-501 film SLR loaded with Fujifilm Fujicolor C200.
I also tried the lens with my trusty Nikon D90 DSLR. Using Tamron Adaptall lenses on a modern DSLR is only possible in the Manual mode. The camera can’t read aperture values either, and you have to switch to manual focusing. In other words, shooting with the Tamron SP 300mm f/5.6 Adaptall 2 lens is a full-manual affair. On the positive side, focus confirmation seemed to work just fine.
So how did the lens perform? For its age, the lens did admirably well. Sharpness is good, and the lens produces pleasing and creamy bokeh. Overall, it’s not so shabby for a twenty-something-year old lens, especially considering the price.
By the way, if you are looking for information about Tamron’s Adaptall lenses, the Adaptall-2.org website got you covered.
The green houses in our botanical garden are still closed to the general public, but a few lucky ones (including yours truly) had a chance to take a sneak peek inside the buildings. The missus and I thoroughly enjoyed the time we had in the green houses, and we got back home with loads of photos. I’ll be processing and sharing them in the time to come.
Here is a quick snapshot I took with my Canon PowerShot S90 and hastily processed in digiKam.
I like my Yashica Electro 35 GTN a lot. It’s a stylish rangefinder camera capable of taking excellent photos. The only fly in the ointment is its size and weight. The camera wouldn’t fit even the largest pocket, and at 750g, it weighs more than my trusty Nikon D90. In other words, schlepping Yashica Electro 35 GTN around is not always fun. So I reasoned that a lightweight, no-frills, inexpensive film camera would be a useful addition to my analog toolbox.
While there are several cameras that meet these requirements, I went with Olympus XA2 for several reasons. This camera features a unique capsule design, and it’s so small that it easily fits in the palm of my hand. Better still, there are plenty of Olympus XA2s on eBay at very reasonable prices. I bought mine in near mint condition for ~75 U.S. dollars (this included the original box, manuals, and A11 flash as well as shipping and handling). But if you are not picky, you can find one for much less.
I won’t bore you with a description of the camera’s features as they are covered extensively elsewhere on the web. I’ll just say that it’s a real gem of a camera which feels great in the hand and is ridiculously easy to use. The only thing you need to remember is to set the focus slider to the appropriate focus zone, and the camera does the rest. I took my Olympus XA2 for a short photo walk, and here are a few photos for your viewing pleasure.
If you want to know more about Olympus XA2, the XA2 page should be your first stop.
Install the DSLR Dashboard app on your Android device, and you can use it to control a Nikon DSLR camera via a USB connection. But in certain situations, tethering the Android device to a camera using a cable is not ideal. This is where DSLR Dashboard’s wireless functionality can come in rather handy. Using this feature, you can link up two Android devices running the app via a Wi-Fi connection. In this case, the device connected to the camera acts as a wireless bridge (or client in DSLR Dashboard’s terminology) between the camera and the master (or server) Android device. And the latter is used to control the DSLR camera remotely. Here is a diagram that illustrates this setup:
- Nikon DSLR camera
- Android device running DSLR Dashboard that acts as a client
- Wi-Fi access point (AP)
- Android device running DSLR Dashboard that acts as a server
As shown on the diagram, both devices must be connected to the same AP. Instead of using a regular wireless router, you can opt for a mobile router like TP-LINK TL-MR3020 to make the entire setup portable. The clever part is that many mobile routers can be powered via a generic power adapter which can be bought cheaply on eBay. This allows you to create a wireless network whenever and wherever you need it and use it to link Android devices running DSLR Dashboard.
To set up this portable wireless remote control solution, you need the following items:
- Two Android devices running Android 2.3 or later
- A USB OTG cable (can be bought cheaply on eBay)
- A USB cable supplied with your DSLR camera
- A mobile wireless router like TP-LINK TL-MR3020
- A battery power adapter
Power up the mobile wireless router and configure it as an AP (consult your router’s documentation on how to do this). Connect the Android device that will act as a server (i.e., the device for controlling the DSLR camera) to the wireless network created by AP. Tap the Menu button and choose the Start Network Server command. Connect the other Android device to the DSLR Camera using the USB OTG and the USB cables. Enable Wi-Fi on the device and connect it to the wireless network created by AP. Turn the DSLR camera on and launch the DSLR Dashboard app. Once the app has detected the camera, tap Menu and choose the Start Network Client command. This should automatically hand over control to the server device which you can then use to operate the DSLR camera in the usual manner.
A wireless shutter trigger for a DSLR camera can come in handy in many situations. And if you already own an Android device, you don’t have to splurge on a dedicated remote trigger. To turn an Android device into a flexible tool for triggering the shutter wirelessly you need three things:
- The DSLR Remote app installed on your Android device
- TriggerTrap dongle and cable combination for your specific DSLR model
- Generic Bluetooth A2DP receiver (can be purchased on eBay)
Start with installing the DSLR Remote Control app on your Android device. Connect then the Bluetooth receiver to the DSLR camera using the TriggerTrap cable as shown below.
Enable Bluetooth on the Android device, and turn the Bluetooth receiver on. On the Android device, switch to Settings → Bluetooth and pair the device with the receiver.
Next, configure the DSLR Remote app. The exact configuration profile depends on the particular receiver. In most cases, you only need to specify the appropriate cable type in the app’s Settings section. To do this, launch the DSLR Remote app, switch to the Settings section, and set the Remote Type option to Cable S. Close the settings screen, switch to the Remote section and press the S button. This should trigger the camera’s shutter. If this doesn’t work, then try enabling the Bluetooth option, or set the Remote Type option to Cable A.
While GIMP offers a wide range of tools for working with photos, it lacks one feature that is essential for serious photographers: the ability to automatically fix lens distortion. Fortunately, the GimpLensfun plugin fills the void quite nicely.
Continue to read Correct Lens Distortion in GIMP with GimpLensfun
I’ve finally come up with an idea for a photography project that should keep me busy in 2013. Instead of doing the ever so popular 365 thing (I’m so not ready for this kind of commitment), I’ve decided to do a week number project. The idea is simple: for each week I’ll take a photo with the week’s number in it. Obviously, I’m a bit behind with the project, so I have no time to waste. So here is the Week 1 photo:
This is a macro shot of a 1 yen coin placed on a 1000 yen note. Taken with Nikon D90 and Raynox DCR-250. Processed in digiKam. Shutter speed: 1/60 sec. Aperture: f/9.0 ISO: 200