Thursday, September 27, 2007

Sony W80 review

Imaging resources just finished a complete review of the Sony W80 camera. They feel the image quality stinks - lots of distortion in the lens, lots of blurring, and way too much noise reduction, resulting in soft images.

Disappointing, given what a bargain the W80 is going for right now ($150, if you sign up for a sony credit card).

Tuesday, September 25, 2007

Megapixels compared

So how much of a difference is there between a 2 megapixel image and a 5 megapixel image? A lot less than you might guess. This is because the number of pixels grows as the square of the dimensions of the image. For instance, a 2 megapixel image is 1600x1200; if you double each dimension to 3200x2400 you would then have a 8 megapixel image. But do you really need an 8 megapixel image?

Keep in mind that your home LCD is unlikely to display even a 2 megapixel image at full resolution - a common LCD size is 1280x1024. A common widescreen form factor is 1680x1050, which is still too small to show a 2 megapixel image unless you crop or squash the image. If the image is any larger than your LCD's maximum resolution, the image will have to be re-sampled down to the LCD's native resolution before display.

That said, display technology is getting better. Today's high end LCD will likely be the common size in a few years. So to future proof your pictures in terms of monitor display, might you want to shoot higher than 2 megapixels? For instance, a $1500 LCD monitor usually can display 1920 x 1200. Again, unless you crop, that's still just big enough for a 2 megapixel image.

The only real argument for shooting higher than 2 mega pixels, then, is if you engage in one of two practices: cropping your photos after you take them, or printing your photos.

For printing, you could argue that the more pixels the better, but here again current technology doesn't take advantage of all those pixels. For instance, 4 megapixels is enough to print a 8.5 inch by 11 inch photo a 200 DPI. That's a pretty high resolution photo at a pretty large size. Only if you want a huge, wall mounted photo will you really benefit from more megapixels. For cropping, of course, it is true that the larger the resolution the tighter you can crop final image. Of course, many of us never even get around to sorting our images, let alone cropping them.

Meanwhile the benefits from using fewer megapixels are quite measurable. You'll be able to fit more picture's in your camera's memory, your camera will likely require less delay between taking pictures, and you'll be able to fit a lot more photos onto a DVD when you make backups of your photo albums.

That's why I only rarely shoot at higher than 4 megapixels.

Here's a visual diagram that shows the relationship between the different megapixel sizes.

Powershot SD950 first review

ZDNet just posted a review of this camera. Like most ZDNet reviews it lacks the details that a camera centric site would have. In general they like the camera and recommend it, but they do highlight one notable issue: relatively high shutter lag (0.5s to 1.2s) and recycle time (2s). ZDNet's same tests ran on the SD850Is found a shutter lag of 05.s to 0.7s, and a recycle time of 1.7s.

Note that all of these times are at full resolution. Personally, I prefer to shoot at less than full size to get higher speed and less disk consumption.

Friday, September 21, 2007

Canon SD950, 870, and 850

Canon has some new cameras that might make the SD850 less appealing. Let's take a quick look (more details to come later).

The SD870, at least by name, seems like a straightforward upgrade to the SD850. Not true! It uses a wide-angle lens (presumably with the same distortion problems of the SD800), removes the optical view finder, and bumps the LCD up to 3in from 2.5in. Here's an early review from CNET that is lacking in detail. The lack of viewfinder really makes me lose interest.

More exciting is the SD950, which appears to be a more directly related upgrade to the SD850. Again, the lens is different, but with almost the same effective specs: 3.7x zoom, 36mm equivalent (ie not wide angle). Without any reviews it's unknown if this new lens has less corner blur, but we can hope.

Thankfully the 950 maintains the viewfinder. It's also slightly bigger: 3.8 x 2.4 x 1.1 in. Cipa is 240 images (LCD on, 580 if off) , a very slight bump. It also adds a battery level meter, something Canon should have come up with a long time ago. Amazon has it for preorder at 450; I'm not sure the specs bump warrant it over the 850. Hopefully this will push the 850 price down a bit, making it a really good buy.

More Canon SD850 IS

Here is another review of the SD850:

Good example pics of ISO noisiness and edge blurriness. (note, IXUS 950 IS is the SD850 in Europe).

Amazon still wants $309 for it & NewEgg wants sightly more. Sadly, its not clear that the price comparison places can really be believed when they quote lower prices - such as digital nerds, which says they will charge $230 for the camera. According to those same comparison sites, they are similar to many bait and switch vendors who call you up after the order is placed and up sell you accessories. If you refuse they then cancel your order. Note: I've never dealt with digital nerds, so I don't really know if this is their modus operandi; just that other customers have had that sort of experience.

Wednesday, September 12, 2007

Sony W80 vs Canon SD850IS: corner blur

Corner blur is a common problem in compact digital cameras. I decided to look at the W80 and the SD850 and compare the two.

The W80 has a smaller zoom lens (3x) and while it does have blurry corners, its not as bad as the SD850IS. Note that both cameras have the most problem with blurry corners at wide angle, with the SD850IS being particularly bad on the lower right, and the W80 having the hardest time at the lower left. Neither camera has much blurriness if you zoom in, but I take >50% of my photos at wide angle so this is a significant issue.

Check out these lab shots: W80 vs SD850IS. The W80 clearly wins.

But what about the real world? Check out this pair: W80 vs SD850IS

I would say that in the real-world shot the SD850, while worse, doesn't produce blurring that is that noticeable.

Tuesday, September 11, 2007

Canon SD850 IS powershot

The SD850IS ($308 at amazon) is an update of the SD700 IS. It's similar in many ways: optical image stabilization, 4x zoom lens, optical view finder, 2.5" LCD, and it even uses the same battery. It's also the same weight (165g) and size (3.6 x 2.2 x 1 in). The CIPA is slightly worse: 230 shots per charge, with the LCD on.

Pros relative to SD700:

* smart digital zoom if shooting at less than full 8 megapixel resolution (it uses cropping to simulate zoom, so there's no added blurring).

* one button ISO boost to reduce blur in low-light situations.

* Post-shot review mode where the center of the image is zoomed in full to show focus/blur/noise level of photograph.


* blurry corners, just like the SD700 (but not as bad as in the SD800).

I'm a big fan of image stabilization, so I'm petty excited about this camera. It has been around for a while, but now that Canon has released couple of newer Cameras in the PowerShot line the price should start dropping.

very positive review with good real-world tests. Says the image quality is really good except for the blury corner issue (common to many compact cameras).

Another positive review Not as much detail, but still has some good test photos

How your camera detects color

The CCD (charged coupled device) is the light sensitive part of your digital camera. Like black and white film, the response of each element in the CCD depends only on how much light energy strikes that element. Thus, a bare CCD would only produce black and white images. To detect color, a patterned filter is placed in front of the CCD, which only allows red, green, or blue light to pass. Thus, each element in the CCD becomes sensitive to one of three colors. The final color for each pixel is determined by blending the response of each of the nearest CCD elements for each color, though exactly how this is done depends on your camera. There are two unavoidable downsides to all this: your images are made more blurry because each pixel is based on the response of multiple CCD elements, and because of the filter in front of the CCD, you don't detect all the light that hits the CCD (that is, your image is made more noisy in low-light situations).

For more info on this process, take a look at this page.

Kodak has designed a new color filter which tries to address the low-light problem, by sacrificing color resolution.

Thursday, September 6, 2007

Picasa photo editing and viewing software

Picasa is a free photo organization program, currently developed by Google. Think of it as iPhoto for the PC.

It makes all of its edits non-destructively, which is great if you want to keep your original photos around and always view the modified versions in Picasa, but not so good if you want use multiple programs to work with your photo collection. The main reason I use it is that it makes generating web albums very easy, whether you are hosting the files on your own server, or on Google's server (Google gives you 1GB of space for free).

Tuesday, September 4, 2007

Photo Viewing software

I view my photos with IrfanView, a free but full featured program that offers the following features:
  • Very quick to load,
  • Delete photos with 'delete' key
  • Browse between photos with left/right keys
  • Rotate photos (using JPG EXIF flags) using hotkey
  • Full screen view with smoothed resampling.
  • Plus lots of other features I almost never need.
  • Thumbnail mode (but I prefer ZoomBrowserEX for that)
  • Hotkey to rename file.
  • No ads/malware.
There are lots of photo viewing programs, but IrfanView is my favorite because it's full featured without being bloated.

Saturday, September 1, 2007

Sony W80 reviews

In light of the low price on this camera I've started collecting reviews.

Pros: image stabilization, view finder, orientation sensor
Cons: new menu structure is a bit confusing and slow, if you turn off the LCD then there is no post-shot review option, unlike in canon cameras.

Limited review with lots of spec oriented test shots.

Full review with lots of real-world tests - concludes that camera's image quality isn't up to par.

Brief review - Cnet does not manage to say much, but they do like the camera.

More to come.

Sony W80 + 2gb memory stick + case for $154

Sony has a credit card sign-up incentive - spend $300 and get $150 back if you qualify for a Sony visa. Using this deal you can get a Sony W80 + a 2gb memory stick + case (or whatever accessories you wish that cost about $70) for just $154. For comparison, J&R is selling the camera for $230, without any memory stick. So if you can stand to sign up for a new credit card, it's a pretty good deal on a W80. I expect you could do the same deal with other cameras that Sony sells as well.

Canon ZoomBrowser

If you have a Canon camera, it's worth getting the newest version of ZoomBrowser EX (5.8b); the 5.8 series adds a very good "zoom" view which is a bit like the Windows Explorer thumbnail view except that you can scale the thumbnails up as big as you want. This makes it really easy to pick between duplicate shots taken at different exposures, etc. ZoomBrowser is a nice piece of software, for being free (for Canon users).

Digital photo manipulation software - not Photoshop!

If you don't have PhotoShop, an equally powerful program in most ways is The Gimp. The interface is rather different from PhotoShop, but if you don't use PhotoShop that's fine, right? The Gimp is free, and doesn't have any adware/malware. I have a copy on most of my computers.

Digital noise reduction

If you regularly shoot pictures in low-light you either have to use a flash, which distorts color badly in my experience, or shoot at a high ISO level. For a digital camera, high ISO really just means keeping the shutter open for a shorter period of time. This results in a noisy image because the CCD is a noisy image capture device (particularly when warm) and when you capture less light the camera has to turn the gain up more on the final image. The gain turns up the image, and also the noise. All cameras have algorithms to reduce noise, but since the camera has limited processing power, there is only so much improvement these algorithms can make. Post processing software on your PC can do a better job. One free/mostly functional demo program is Neat Image. It takes a bit of work to use it, but for important pictures it can really reduce the apparent noise without making your images look that much more blurry.

Canon PowerShot SD 800

Canon's 2nd compact powershot with image stabilization, an update of the SD700. Slightly lighter but same size. Features a wide-angle zoom with a 3.8x range.

Pros: Wide angle lens. Slightly improved battery life. Portrait mode which focuses on faces. After tacking picture camera shows full picture with zoomed inset to let you check focus.

Cons: Noticeable edge blurriness at wide zoom angle ( a bit worse than the SD700).

Reviews: - Excellent review with lots of real world tests, including ISO and nightshot tests. - nice review that focuses on usability and real world photos - Spec oriented review but with lots of good detail Some sample pics and good details about the menus

As of 9-2007 it looks like it goes for about $300 from reputable vendors.

Canon PowerShot 700

Canon's first compact powershot with image stabilization. About the same size as the SD110.

Pros: image stabilization, 4x zoom.

Cons: slightly blurry corners at wide zoom (example). Somewhat short battery life (CIPA 240).


DP Review




TrustedReviews - interesting sample pictures but otherwise poorly written.

Good Camera review websites

DP - spec oriented, with lots of somewhat artificial test, but lots of good details

DC - fewer specs, but good real-world tests. Conclusions and suggestions seem well grounded. - few specs, some good real-world tests, but not as good as DC Resources. Conclusions sometimes seem a bit more positive then is warranted.