Posts Tagged RAW converters

RAW Deal

Sat, Jan 9th, 2010  |   Equipment, Technique 4 Comments

While I was in PNG recently, I tested a lens set up that I hadn’t used before, a Tokina 10-17mm zoom lens coupled with a 1.5x teleconverter, attached to my Canon 5D Mark II.

The Tokina 10-17mm lens is made for cropped-sensor cameras, so I had used it previously with a Canon 40D body. It’s a beautiful lens, and I recommend it for anyone who’s using a cropped-sensor camera.

With a 1.5x teleconverter attached, the lens works from somewhere around the 11.5 to 17mm range on my 5D Mark II, which has a full-sized sensor. Short of the 11.5mm mark, there’s a bit of vignetting, which can be cropped out in post. I prefer to do as little file-processing work as possible, so I made sure to zoom in past the point of vignetting while testing this set up.

The combination worked perfectly (after trying a couple of different port configurations, I ended up with 40mm of extension + the Pro-One dome on my Zillion 5D Mark II housing), but there was a bit of an unexpected surprise.

The following image is how Canon’s DPP software converted the RAW file from the 10-17mm + 1.5x TC set up…with the photograph taken at about the 13mm mark:

test shot DPP

Just looking at the file, it seems as if there’s significant vignetting…in other words, it looks like this hardware combination doesn’t work.

In fact, the apparent vignetting also appeared on the LCD panel at the back of my 5D Mark II, so when I looked at the LCD preview while I was in the water, I thought something along the lines of: “$@%*(^#!$)!@%$(%^^&*!!!!!”.

But later, when I imported everything into Aperture, the same RAW file looked like this:

test shot Aperture

If you inspect the image corners, you’ll see that the Aperture version has real pixels…i.e., the software isn’t doing something tricky like interpolating data.

Actually, what seems to be happening is that DPP and the in-camera software controlling the 5D Mark II’s LCD monitor are unable to handle this unusual hardware combination. Somehow, the software deletes/ obscures data from the four corners of the file…creating the impression of vignetting.

Out of curiosity, I gave the file to a couple of other people on the trip, and we opened it in Photoshop CS4 and Lightroom as well. No problems.

I don’t understand why DPP creates a vignette, but this is an interesting, if somewhat quirky, illustration of the fact that differences exist among RAW converters. It’s also worth noting that there’s a noticeable difference in colour-rendition between the DPP and Aperture versions, which I wrote about previously.


RAW Results

Fri, Oct 24th, 2008  |   Equipment, Technique No Comments

I’m back from a great trip to Ambon, in the midst of going through images, which essentially means staring at a computer screen for hours on end while downing litres (or quarts, depending on your preference of measurement units) of caffeinated beverages. It’s amazing how glamorous underwater photography can be sometimes.

One of the issues I have to contend with is choice of RAW converters. If you shoot in RAW (Note: If you don’t…you should.), then your choice of RAW converters can make a substantial difference in how your final output looks.

Each converter interprets files slightly differently, and after extensive experimentation, I’ve concluded that there’s no one clear choice for every occasion. In short, this means having to take a look at each image with different converters, then selecting the output I like best…a time-consuming, eye-straining process.

Taking a short break from seemingly perpetual pixel-pushing, I did a quick comparison to illustrate this point.

Below are four versions of a nice, simple image. There’s not a lot of colour, so the primary emphasis is on how the blue portion looks and how contrasty the image appears. The RAW converters I used are (in order of images below): Aperture 2.1.2, Canon DPP 3.2.0.6 (Standard picture style), Adobe Camera Raw 4.6, Canon DPP 3.2.0.6 (Landscape picture style).

aperture

dpp_standard

adoberaw

dpp_landscape

All the files were converted with the same settings with no additional modifications (except minor sharpening), so in theory, the only differences should result from the RAW converters. As you can see, there’s a noticeable difference in how the colours, saturation and contrast levels appear.

There are other RAW converters out there, and (in the case of Canon files) with Canon DPP, there are several alternative picture styles you can select, so the potential variation doesn’t end here.

As I mentioned above, there’s no one formula that I follow for converting files, but here are a few guidelines I use:

  • For blue images (like the ones above), I try Canon DPP first, tuning the white balance settings to try to achieve the precise hue and saturation I want. One thing I’ve learned is that with DPP, you have to be careful of potentially over-saturating the image.
  • For colourful macro images, I use Canon DPP the most. The high saturation is often a bonus, and smooth colour transitions make the files looks really nice. The major exception is with intrinsically high contrast subjects (see next point).
  • For images with a lot of inherent contrast, I try Aperture first. Aperture seems to reduce/ minimise contrast (as is apparent in the images above).
  • Adobe RAW is a good middle ground, giving a not-too-contrasty, not-too-saturated, not-too-mute result. This makes sense, as you can then proceed to fine-tune with Photoshop.
  • When I’m lazy or short on time, I use Aperture, because it’s quick and convenient. I use Aperture to organise my files, so it’s easy to find a file, do minor adjustments, then export to the specs I need.

Back to picture processing…