blog.TheArtOfTheMoment.net

Cactus V2s mod to eliminate banding problem

2009-01-13T00:59:00.022Z

I was not very pleased to discover that the Cactus trigger interferes with my Canon 5D CMOS sensor, producing ugly banding and noise problems, especially at high ISO, e.g. 3200 as on the example on the very left. At 100% you can spot clearly a vertical noise band that is just "horrifying".

I have only found one post on Flickr with a solution to that problem (thanks OliverDavidPatrick):

It seems that the sync connection is conducting the interference to the camera. One solution to filter noise and high frequency signals is to put a ferrit e ring between this connection, which acts as a resistor to these unwanted signals. I had no ferrite ring or bead at hand, but found an old monitor cable with one attached :) Next, I pulled the Cactus trigger apart and connected the sync connection with a cable that has was wrapped around the ferrite ring twice. After a successful series of tests, I put the trigger back together and glued the ring to its side.

The solution is simple, not very scientific, but yet works perfectly fine. Check out the 2nd picture on top and compare at 100%.

With this fix, the Cactus trigger can serve me well again.

PS: Why do I shoot a Teddy bear here as a main subject ?
Well, indeed there is a reason for that; they are just like humans, aren't they ? Teddies have a "round" head, a nose, eyes, etc. Therefore it is very easy to test e.g. new lighting concepts and transfer these to a real shooting. I was amazed when I figured out that pro photographer Bert Stephani from LIME (www.squeezethelime.com/podcast/) also suggested Teddy bears in one of his recent podcasts. Funny. Nevertheless my two bear pix clearly demonstrate how little attention I gave the lighting setup: the right eye is in complete darkness, oh well :)

Cactus V2s mod to increase range

2008-11-18T23:30:00.018Z

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.

RAW file conversion with Lightroom 2

2008-11-16T12:33:00.007Z

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.

Canon 5D ACR calibration

2008-08-16T12:30:00.002+01:00

Is it worthwhile calibrating a RAW converter or is this just a hip subject ?

For all my RAW conversions I use ACR since I love Lightroom. ACR gave me very good colours for my Olympus system, but horrible reds with my Canon setup (more red-orange). Therefore I made a few test shots of the "Munsell Colorchecker Mini" card and run "ACR calibrator L". The minimal colour delta was reported for these values:

Red Hue: -16, Red Sat: 20
Green Hue: -8, Green Sat: -4
Blue Hue: -2, Blue Sat: -4

Adding these parameters to the "Calibration" tab in ACR adjusts automatically the default ACR settings. Is it worth the effort ? Yes, I think so !

Canon BG-E4 versus Camdapter

2008-08-16T01:38:00.002+01:00

Together with my 5D I bought the vertical grip (BG-E4); handy for vertical shots, for attaching a hand strap like the Canon E1 and doubling the battery life. Well, why did I get rid of the vertical grip ?

I try(!) to do a lot of street photography. First thing people ask me when I get into conversations: "Whom do you work for?". After a while I realized why they ask me this with the 5D & grip, but never did with the little Olympus E-510 I had before: simply because of its sheer size.

For the sake of a smaller footprint, I got rid of the grip today and instead attached a Camdapter.

The Camdapter allows to attach a hand strap and the neck strap, comes as a standard tripod adapter (e.g. Acra-Swiss or Really Right Stuff) and is made specifically for various camera types, so it snugly fits the body.

I also used a black waterproof marker and got rid of the white CANON on the camera and on the camera neck strap :)

The result:
I believe the system looks less sophisticated. Vertical shots are still possible, however, without the extra comfort of the vertical grip. I will have to test it now in real life :)

ISO 1600: Olympus E510 vs Canon 5D

2008-07-16T22:12:00.001+01:00

View the image on the left at 100% and not many words are necessary...

Photos were taken under equivalent settings. RAW files were developed in ACR 4.4. Noise reduction was turned off.

Since noise is strongly correlated to pixel density and the sensor surface of the 5D is about 3.84 times larger than the 510 sensor, what would you expect other than what we see in this example here ? The 5D gives you much much better low light performance, although technologically the camera is 2 years behind the E510 :)

Note: If you don't shoot in ambient light and you don't fancy shallow depth of field, the 4/3 system is still an excellent option, in particular for sport and wildlife photography.