18 Nov 2008

Cactus V2s mod to increase range

Anyone who wants to use off-camera flash needs a way to trigger the flash remotely. The state of the art method is to use the Pocket Wizards which are pricey (per transceiver ~180US$ ). Good reliable alternatives seem to be the AlienBees remote triggers (transmitter ~60US$ and per receiver ~70US$). However, there is a cheap alternative that may work as well for you from Gadget Infinity. They are sold as "Cactus V2S" and cost ~30US$ for a transmitter/receiver pair, each extra receiver is ~20US$. Say you want to trigger 3 flashes, you end up with about 70US$ for the Cactus and 720US$ for the Pocket Wizard set! Now, what would you choose for amateur/semi-pro usage ?

OK the price is hot, but what is the downside of these little Cactus triggers?
In short: Reliability, interference issues and operating distance!

My Cactus set for example only worked within a range of 10 paces! However, there are many suggestions out there, particularly within the Flickr Strobist group on how to overcome these limitations. Many suggest to use an external 433MHz antenna (Jeremy Kuster), but alternatively there are people who suggest a simpler solution that seems to work as well (Strobemonkey) and therefore I gave it a shot, with slightly different parameters though (figure on the left for illustration):

(a) I have disconnected the PCB trace (the original antenna) and (b) used a 17cm coiled wire (+0.5cm remaining PCB trace corresponds in total to about 1/4 wavelength).

Results were pretty astonishing:
The flash was triggered reliably up to 100 paces (that is ~300ft!). With reliable I mean that I got the flash triggered 10 out of 10 times :) Only practice will show whether there is also a downside to it.

16 Nov 2008

RAW file conversion with Lightroom 2

Some people have asked me how I do my RAW file conversion.
I let you look into my kitchen!

When I go out for a typical photo-walk, I tend to shoot for 2-3 hours and may end up with about 200 RAW files.

At home all the post-processing and "digital negative development" is done with Adobe Lightroom (LR), and since version 2 is released, there is hardly ever the need for me (!) to use Photoshop (PS) in parallel. To say it right away, I love Lightroom, probably more than anything else that is installed on my machine (and there is loads), but I won't go into this right now. Although this is a very subjective statement, there may be a lot of people out there who are able to objectively (?!) tell you why LR rocks.

So, here's the workflow I tend to follow:

First thing, import and convert on the fly the vendor specific RAW files into "quasi" standard DNGs files. Next, I force myself to bin (and I mean delete!) at least 3/4 of all the pictures. I feel there is no point in keeping mediocre images and clutter my photo library.

Then I start to develop one picture "roughly", hence adjust exposure, contrast (using curves) and brightness if necessary. Done with this picture, I tend to sychronise the develop setting to pictures that were shot under similar conditions (just hit the "sync" button and you're done). I keep doing this for the remaining pictures. The synchronisation helps a great deal to speed up. After maybe 3-5 minutes the 50 pictures are crudely developed. Now I tend to have another look over the pictures and bin again those that do not get my attention.

Now, after this rough tour, I start to look more closely at each individual picture, do the B&W conversion carefully and if necessary make a few local edits. Now with LR 2.0, the amazing thing is that for local edits I don't need PS any more and all is non-destructive, such as brighten the eye sockets, eyes or dark hair, slightly burn the background highlights or add a gentle vignette etc etc etc. Infinite possibilities. It just feels all so natural and it makes one feel like almost being back in the darkroom, developing the B&W prints, though it may not be as romantic and smelly (sorry folks) and most importantly, it is all non-destructive applied dynamically on top of the RAW data (unlike Aperture from Apple). Impressive job Adobe!

After development is done, you can keyword, sort, catalogue, print and upload to the web.

I have made a few screenshots to demonstrate the development process of one picture below, including the new and lovely local adjustments tool.

Step 1: B&W conversion.
Step 2: Cyclist too dark: push 1 stop. Also, added clarity and sharpness.
Step 3: Background too bright, -1.3 stops and lower contrast.
Step 4: Vignetting (I like that style).

Very rough mask for this demo, but with the maximal feathering result is still OK.