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Telephoto Test With the
Canon Powershot A590is

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Views since 10/29/2008

Recently the question arose as to how well a high magnification (10X or better) zoom lens could be used from an airplane or other moving vehicle.  Much discussion followed with my doubting the utility of that much magnification from a moving vehicle even with electronic image stabilization.

More discussion followed and we agreed at that photos of a full size car at 300 feet would be representative of the environment.  Therefore I set out to take some photos using the camera that I like and recommend for the application, the Canon Powershot A590is.


Photo compliments of Canon Inc.

This camera is 8 megapixels,  has 4x optical zoom, 16x digital zoom and electronic image stabilization.  And maybe the biggest feature of all, it uses 2 standard AA batteries.  No more expensive proprietary lithiums. Using Ray-O-Vac's Hybrid 2100 mah low-self-discharge batteries, I've yet to run down a set while filling a 1 gig memory card, about 400 pictures.

At a street price of about $150, it's a hard camera to beat for a "pocket rocket".

My argument is that at 8 megapixels, digital zoom is now useful, as the "lost" resolution doesn't matter for normal viewing and printing.  The image stabilization helps greatly at high magnification, though as you'll see, it has its limits, .

This afternoon I set out to shoot some photos representative of what we'd discussed.  I used my high-zoot Leica Disto to set up a range of 337 feet between a pickup truck and my shooting position.  This Disto is a gadget every gadget junkie ought to have.  Unlike hunter's rangefingers that shoot an infrared beam, this one uses a visible red beam.  Whatever the beam is shining on is what the range is measured to.  The unit can be set to measure from the front of the unit, the rear or the end of the red stand.  Accuracy is listed as +- 1/8th inch.  It'll do about 150 feet against ordinarily reflective objects in daytime.  About twice that in daytime using that reflective material that they make street signs out of.  The most I've gotten, around 600 ft, has been at night against a reflective sheet.  I'd love to shoot it against a surveyor's retroflector but I don't have one.  This thing stays in one of my photography goodie bags so that I no longer have to guess at distances for manual focus or futz around with a tape measure.

It has a bunch of other goodies, including math, the ability to compute area and volume, the ability to find the corner (sweep the beam across the interior corner.   The longest distance is the correct one), perpendiculars (sweep the beam and the shortest distance is the correct one) and using Pythagoras, can measure the height of a distant object like a tree or telephone pole.  Kewl toy.  As usual, my timing was awful.  Right after I got mine they brought out a version with a USB interface for logging.  So it goes.

Back to the job at hand, I picked that range because it was close to the 300 ft range we'd agreed on and it put me on a nice gravel driveway where I could sit comfortably.

In addition to shooting with the camera's built-in zoom, I decided to also use my Nikon 4X tele lens designed for my Nikon CoolPix 995.  This lens is actually a very bright monocular that presents an upright image to the camera.  When not being used as a telephoto lens, it is handy as a 4X monocular.  It's so bright that it's almost like night vision in dusky light.  That is a package of 4 AA rechargeable cells to give some scale to the lens.


Here is another photo of the lens being held in my big fat hand to further show scale.  This was a tricky photo, as I was shooting against the ceiling with my 590.  the ceiling was completely black in the first photo so I used a little trick.  I put the HF-DC1 flash unit that is made for this camera on a table behind my hand, set it on high power and aimed it at the ceiling.  As you can see, the ceiling illumination was almost perfect.




(warning: from here on out, clicking on the thumbnails brings up about 4mb files.  This lets you view the photos as they came from the camera, shot as the camera's highest res/quality.  I should also note that these have not been touched.  Other than being renamed, they're straight from the camera to this website.)

This is a photo of the blue truck set at "normal" magnification, what the camera defaults to.


This is the truck at 4x, the maximum optical zoom of this camera.




This is at 16x, the maximum digital zoom.  This was fairly late in the afternoon and the sun was behind the mountains so lighting wasn't optimum.  The image stabilizer icon on the screen was screaming at me that my jiggle, even though I was sitting and braced, was overwhelming it.  That's why the photo isn't crystal-clear.  I'll go back later with good lighting and do this one again.


This photo is with the camera at 4x and the Nikon 4x teleconverter held in front of the lens.  16x optical magnification.  Again the image stabilizer was screaming at me for jiggling too much.  The light gathering power of this tele lens can really be appreciated in this shot by how much brighter it is that the one above.



This is max magnification, with the camera set at 16x digital zoom and the  Nikon 4x tele converter held in front of the lens.  The image stabilization icon was practically deafening me, so to speak, it was flashing so rapidly.  Still, a remarkable photo in not-very-bright light and hand-held.


To demonstrate how hard it is to hand-hold at these magnifications, I put the camera in movie mode and shot two short videos.  The first is at 16X digital zoom.  The second is 16X digital zoom plus the Nikon 4X tele converter.  These vids make you really appreciate how hard it is to hand-hold at high magnification AND how well the image stabilization works.  Note that both of these vids were shot with image stabilization turned ON.  They would likely have been un-viewable without the image stabilization.

Canon makes their own line of converter lenses, both tele and wide angle.  Since the main lens retracts into the camera body, the converter can't attach to the lens itself.  Instead the large silver ring visible in the camera photo above turns off after being released by the small button at the lower left of the ring.  An adapter snaps on bayonet-style and the converter lenses attach to that. 

The camera configuration menu has settings for each of the converter lenses, presumably to make the auto-focus and stuff work optimally with each.  Note that I did NOT mess with these settings during this test.  Selecting the Canon tele-converter would probably have made the camera work a bit better with the Nikon converter but I didn't get a chance to try.  The light was failing too fast.

All these photos were shot in "program" mode with center-weighted exposure and focus.  I probably could have done a little better with shutter priority mode and speeded up the shutter a little.  I ran out of light and time.

When I get a round tuit, I'll make an addendum to this page with photos with better lighting conditions.  I don't think that more light will changes things much, other than maybe letting the image stabilization have a little less work to do but we'll see.

The main message is clear, though.  Hand-holding a camera at high magnification, even when sitting still on terra firma is quite difficult.  I used all the tricks that I use when competitive shooting, including breath-holding, slowing my heartbeat and triangulating as much as possible.