The View Up Here

Random scribblings about kites, photography, machining, and anything else

Playing with the Canon T2i

Posted by Tom Benedict on 27/04/2011

I probably won’t have my new camera in the air for at least a few weeks.  More realistically it’ll be closer to a month.  In the meanwhile I’ve been playing with it on the ground to see what it can do and what possibilities it opens up.  The most interesting outcome of all the testing I’ve done is to realize it’s fun re-learning how to do photography with a viewfinder!

Some months ago we lost one of our cats, but I was able to make signs to put up around the neighborhood thanks to some photographs I’d made of her when I was doing KAP at the end of the driveway.  She was posing, I had a camera, ’nuff said.  It was lucky happenstance.  But I realized we didn’t have any photos of the latest additions to our cat herd, and that I’d be hard-pressed to describe them on a poster if any of them went missing.  Perfect opportunity!

Echo

I actually have photographs of Echo, which I’ve used to make posters in the past when she has gone missing.  But she’s photogenic and presents a good lighting problem:  Her white and black fur are difficult to photograph without losing detail, especially if her white fur is facing the light and her black fur is in shadow.  This is similar to a lighting problem I’ve run into with KAP that I’ll describe later.

This was done as a RAW file, processed in the Canon Digital Photo Professional software that came with the camera, and finished in Photoshop 7.  The brightest part of her white fur is still blown, but there’s enough detail elsewhere that the eye skips over the blank part.  The black fur also has detail that’s maintained.  It’s a good start.

Can your tongue do THIS?!

Echo had four kittens, one of whom died.  We kept the other three.  I still haven’t photographed her third kitten, but this is one of hers: Ember.  Of all the cats he’s been the hardest one to photograph.  He and I have formed a tight bond, and I think it disturbs him that I grew this giant black eyeball I keep pointing at him.  About five seconds after making this photo he freaked and ran off down the driveway.  It’s not my favorite photograph because of the blown-out background.  But it’s what I can get, so I’m taking it.

I really like the quality of the Canon glass.  This is done with the 18-55mm kit lens that came with the camera, racked to 55mm.  It’s one of Canon’s least expensive lenses, but the quality is still outstanding compared to the compact camera I’ve been using for KAP.  The reflections in Ember’s eyes and the detail in his tongue sold me on the idea of using this lens in the air.

Mr. Peep

Mr. Peep is another of Echo’s kittens.  He’s much more patient with the idea of having a camera pointed at him than Ember is.  Again, the image quality I’m getting, even from a kit lens, is fantastic.  I know if I stuck L glass on the thing I’d be even happier, but L lenses are typically heavy, and weight is a big concern in the air.  I’ll take it.  This was done under overcast skies, so it doesn’t present the lighting problems the other two photos had.  I still did RAW processing, more to get the practice than anything else.  Mr. Peep was patient with me.

Four for Sunset

Hapuna Beach is one of my favorite proving grounds for KAP gear and KAP cameras.  It’s where I did the bulk of my sunset testing with the A650, so it seemed like a natural for testing the T2i as well.  There’s a short cliff at the back of the beach, so I even got to try an elevated viewpoint.  Sunsets are problematic for KAP because the light is falling fast, and the short exposure times necessary to avoid motion blur are tough to get.  Higher ISOs cause higher noise, and on my A650 anything over ISO 100 was unacceptable.  From the numbers it looked like the T2i could push to ISO 800 without too many problems.  In my mind ISO 800 is still too noisy for my taste.  But ISO 400 is quite nice.  The DPP software also does noise reduction, though it’s pretty heavy-handed in how it’s applied.  At ISO 400, though, it does a good job.

Sunsets and golden hour photography poses another problem as well:  The difference in brightness between sky and ground can be extreme.  As with the photograph of Echo, it’s tough to get a good exposure that treats both sky and ground well.  When doing sunset photography from a tripod, the normal approach is to let the foreground go dark and make a silhouette against a properly exposed sky.  With KAP the sky and the foreground both have to deliver, so this isn’t an option. Last year I added a graduated neutral density filter to my KAP bag to help with this.  It does a good job, but it reduces the light the camera sees.

Another approach is to save sunset photography as RAW files since it’s possible to recover highlight and shadow detail that would be clipped from an in-camera JPG.  This photo was made as a RAW and processed similarly to how Echo’s photo was done.  The foreground actually had a good deal of texture in it.  I could’ve processed it differently and bumped up the light level in the foreground.  If it was a KAP image, I might have.  It made a good silhouette, so I dropped it instead.  There’s still texture in the foreground on this one, but the people are almost completely black.

Full-Frame T2i JPG

Full-Frame T2i Processed RAW

This last pair was done both as an in-camera JPG (top) and as a RAW file (bottom).  I posted them both to Flickr full-size and un-cropped, so if you’re interested in the T2i and want to see what a from-the-camera image looks like, feel free.  When discussing Echo’s photograph above, I mentioned that sunlit whites and shadowed blacks can cause exposure issues.  The best example I have of this is a rocky beach with surf.  Some months ago I did a KAP session at Laupahoehoe Point, a great spot on the Hamakua Coast that I’ve tried to do KAP at numerous times.  The session went great, the kite flew like a dream, everything was perfect!  Until I got home, that is.  The black rock, dark water, and bright surf meant the camera blew just about every exposure I made.  I didn’t post a single photo from that session.  It was a dead loss.

Here I wanted to see if I could get a good exposure on the rocks, but still retain detail in the surf.  By using RAW files I could, as you can see.  But herein lies the catch with RAW: processing.  If you take a close look at the processed RAW file on the bottom, there’s a cluster of purple spots in the lower 1/3 of the frame, just off-center to the left.  A friend and fellow photographer pointed out that this can happen with RAW processing if an area truly is blown out and the processing is too strong.  DANG!

If I came away with this from a KAP session, I’d probably use rubber stamp to get rid of the purple spots.  But a better approach would be to see what I can do to avoid them in the first place.  RAW processing is new ground for me.  I have a lot to learn.

So why is it taking so long to get the T2i in the air?  I’ll get into the details in a later post, but the upshot is I’m building a custom rig for the camera that should help it make the kinds of photographs I want in the air.  Here’s a sneak-peek:

Mystery KAP Bit v3

It’s a panoramic KAP rig that uses a Geneva mechanism to rotate the camera.  As drawn it has ten stations on the Geneva wheel.  Given the field of view of the camera this should work well. If not I’ll build another one with more stations.  It’s driven by a DC gear motor, controlled by a microcontroller, and will maintain a given pan rate to within a few hundredths of a second, even as the batteries run out.  The reason for the Geneva is so that the camera is not panning when an exposure is made.  Burst KAP typically requires a 1/1000 sec or faster exposure speed to compensate for the camera’s continuous panning motion.  By using a Geneva, I hope to be able to push that down into the 1/250 sec regime with the help of an image stabilized lens (which the kit lens on this camera is!)  It should make sunset and golden hour panoramas a real possibility.

More on the rig design later.   For now, I have a lot to learn about this camera.

– Tom

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