Digital Cameras

Introduction

Digital Cameras have their advantages and disadvantages. What follows are my thoughts and observations on the subject.

I've decided to limit my discussion to 3 megapixel digicams. These cameras have a fairly reasonable price, and offer very good resolution. The next step up would be an SLR-style digicam with removeable lenses. Unfortunately, this means prices in the neighborhood of $4000-$5000. Definitely not reasonable.

As for me, I'm a very advanced amateur film and digital photographer. My DigiCam experience includes the 3.3 megapixel Canon Powershot G1, the 1.2 megapixel Fuji FinePix 1300, and the ultra-cheap .3 megapixel JamC@m 2.0. So, take my opinions with the pillar of salt they deserve.

The Minus Side

Resolution. Cameras in the 3 megapixel category provide a typical resolution of 2048x1536. This falls short of Kodak Photo CD's 2048x3072, and the resolution of most film scanners.

fig. 1, Color Aliasing

Because of the design of a digicam's CCD, the resolution isn't as high as it seems. Adjacent pixels in a digicam CCD are used for capturing different colors. With a film scanner, each point on the film is scanned for all three colors (red green and blue). This is equivalent to a digital camera with three CCD's, something that is common in very expensive digital video cameras but not in digital still cameras. The most noticeable sign of a single CCD digital camera is called "color aliasing". This is when areas of fine detail (most commonly hair and clothing texture) exhibit odd color shifts. Figure 1 is an example of color aliasing in a photograph of blonde hair. The image has been magnified by 2 to make the color aliasing more apparent. Fortunately, color aliasing can be removed in Photoshop. See my Color Aliasing page for more info.

Price to Performance Ratio. As of this writing (October 2000), 3 megapixel "prosumer" cameras are in the $800-$1000 range. For that much money, you can buy a very nice 35mm SLR, and have the option to change lenses. Digicams in this range have lenses that cannot be changed. These lenses usually offer a fairly wide zoom range from wide angle through telephoto, and macro capability. If you can put up with the limitations of the DigiCam, then your savings in film and processing costs will more than make up for the inflated price over time.

Dynamic Range. The dynamic range of the current crop of DigiCams is similar to that of color transparency film. The LCD preview (when you can see it) does let you get the best possible exposure given this limitation, but it is impossible to capture the wide tonal range possible with black and white negative film. Bonus points for a digicam with a histogram display.

Shutter Lag. Shutter lag due to auto-focus in both digital and film cameras can make action shots difficult. By switching off the auto-focus, the shutter lag usually becomes significantly shorter. Unfortunately, digicam manual focus abilities range from good to bad.

Recycle Time. The time from one shot to the next also tends to be very slow particularly as the resolution gets higher. This is because the camera must move the picture to memory. The more resolution you have, the more memory this takes and consequently the longer it takes to move the picture. Even without a motor drive you can shoot faster with a 35mm SLR film camera. With a motor drive, there's no comparison.

Non-SLR models. You would think that little LCD display on the back of the camera would take care of any complaint about the camera not being an SLR. For composition and exposure, this is usually true, although some models are difficult to see in bright light or dim light. For focusing some digicams offer aids to help you see what's in focus in the tiny LCD. Those that don't are very difficult to focus.

Bad CCD pixels. There are a number of problems that can surface with pixels on the CCD of a DigiCam. Hot pixels are the most common, when the pixel lights up on a long exposure. Personally, I find this to be a non-issue. Compared to the dust specks you might get with film photography, bad CCD pixels are much easier to correct.

The Plus Side

Instant Gratification. Just like with Polaroid materials, digicams give you instant gratification and verification that you had the right idea. You can delete the bad ones (assuming you can tell they are bad on the tiny LCD display) and keep shooting. The freedom to shoot without worrying about processing delays and film costs is a great advantage when working on your photography skills.

No Lab. With a digicam there's no lab to deal with, you have complete control over the image from start to finish. Having film scanned by a lab can lead to all sorts of nightmares from improper scan exposure to damaged film. Scanning film yourself is very time consuming and requires the equivalent of a clean-room to keep dust off the film.

No Film. You don't have to buy film. Given an estimate of $.65 per frame for Kodak Photo CD processing and film costs, you'd have to shoot 1538 frames to save $1000 in film/processing. That's equivalent to 41 rolls of film. So far I've had no trouble shooting 1500-2000 frames per month on my digicams. They've easily paid for themselves.

Useful Tool. Because there are no film costs and the results are instantaneous, the DigiCam can be a perfect compliment to a film camera. They can be used for scouting locations, and trying out ideas before shooting them with your film camera. In these applications, the limitations of the digicam become less of an issue.

In Use

Here are a few things to keep in mind when shopping for a digicam. Unfortunately, the review sites don't necessarily cover all these items in detail, so you'll need to either try out the camera, or borrow one before making up your mind.

LCD - The LCD on some digicams is difficult to see in bright sunlight. Digicams with a coated LCD help a lot. On the other hand, many digital cameras' LCDs are difficult to see in low light.

Focus - Focusing on different cameras ranges from good to bad. The Olympus digicams zoom in when you manual focus, and offer spot focusing. The Nikon digicams sharpen the preview so you can more clearly see what's in or out of focus. The Canon digicams offer no focusing aids at all, and a full frame contrast detecting focus algorithm. It can be very challenging to focus a Canon digicam.

Low-Light Focus - Focusing in low light is difficult for most cameras unless they have a focus assist light.

Built-in Flash - Many digicams suffer from red-eye since their built-in flash is so close to the lens. Usually there is a way to attach an external flash to alleviate this problem. Also, some digicams use a preflash metering system which might cause your subject to be caught in the middle of an eye blink.

Features Matrix

This is the features matrix I pieced together when I shopped for my "prosumer" level digicam. I ended up with the Canon G1. You can also check out my review of the G1.

Prices above from various random retailers. Don't forget memory cards and batteries.

Conclusions

On February 2, 2001 after racking up 3000 images on my Fuji FinePix 1300, the Canon G1 I ordered arrived in the mail. It is quite a camera. Although not perfect, it certainly has the ability to take the place of my film cameras for 95% of my shooting. Check out my review.

Links

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