Category: How To

Articles on how to do a variety of things in photography

Canon 1Ds Mark III Sensor Clean

I have a question for anyone that reads this post.

One of the exciting features of the new generation of Digital SLRs is a function called sensor clean.  Every time you power up or power down the camera, it vibrates the sensor at an ultra-sound frequency to shake off any dust that may have accumulated when you change lenses.  My understanding that, in addition to the vibrating sensor, there is a statically charged plate below the sensor that attracts the dislodged dust particles.

My question is this – Does the orientation of the camera have an effect on how well the sensor is cleaned?  Is it better to have the camera sitting on its base (lens pointing horizontally)?  What if you’re holding it in your hand and pointing the lens down; is sensor cleaning still as effective?

If you have a thought on this, please feel free to leave a comment.

See the photographs on my website.

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Canon 1Ds Mark III

Well, there’s not a whole lot new to report tonight.  I took a couple of shots out the back today and really like the RGB histogram.  Have you ever had a shot that didn’t look like it was clipped but ended up clipped in one of the channels?  Well, now you’ll know and can do something about it while you still have a chance.

I also played around some with exposure bracketing.  In addition to planning on doing HDR I also plan to try out Uwe Steinmueller’s High Speed HDR technique.  That’s where you do HDR hand held.  At 5 frames per second it’s a good bet the 1Ds Mark III will be fast enough to do hand held HDR (although it’s only half as fast as it’s little brother the 1D Mark III which Uwe shoots).  Well, it turns out that to do High Speed HDR you need to turn off High ISO Speed Noise Reduction.  It turns out it cuts the buffer to about 1/4 its size.

No photographs uploaded to the computer yet but we’re making some progress.  So,…

Stay tuned.

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Canon 1Ds Mark III

It arrived yesterday, my new Canon 1Ds Mark III.  Graduating up from a 10D is like graduating from a slide rule to a computer (does anyone still remember slide rules or have I limited the people who will understand that analogy to pre-baby boomers?)  I spent about two and a half hours last night going through the instruction manual.  Yes, there are people who still read the manual, at least in some situations and this was one.

There are so many things that amaze me just from first impressions.  The first thing I noticed was that it was actually much lighter than I expected.  But my first impressions were made before the battery was installed.  😉  But even with the battery installed it was lighter than I expected.  Then I put my 24-70 f/2.8L on it and it got heavy.

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Experiences with CIE Lab Processing – Follow-up

I worked more on the CIE Lab photo from the previous post and have some thoughts on what I’d do differently.

 First, I didn’t do a whole lot of value and contrast adjustments the first time.  I just created one Curve to adjust luminance.  Next time around I’ll add curves for brightening/darkening and for contrast enhancement/reduction.  All of these will operate on the L channel.

What I won’t do is get into Hue/Saturation or Selective Color.  If that’s needed I’ll do that once I get back into RGB mode.  Hopefully not much will be needed as we’re back with the old problems of RGB.

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Experiences with CIE Lab Processing

Last night I tried processing an image in Lab color space for the first time.  If you’re not familiar with Lab, it is the most accurate color space and has a gamut that covers the entire human visual spectrum.  There’s an interesting article written by Jeremy McCleary that describes how human vision works and compares it to the Lab color space which is as close of a match as you can come – Human Vision and Digital Imaging.

Basically, Lab separates luminance (think black and white) from color.  Similar to RGB, there are three channels.  However, with RGB the channels are Red, Green and Blue.  With Lab the channels are L for luminance (brightness and darkness), a for magenta green opposition and b for yellow blue opposition.

The advantage of Lab over RBG (or CMYK) is that the luminance can be adjusted without affecting color and vise versa.  In RGB changing luminance will affect color saturation; in Lab it doesn’t.

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