Just a quick note before we begin to say that this month's edition of Tech Tips marks the 3rd anniversary of the column here on The Digital Journalist. A hearty thanks to Dirck Halstead, Cecilia and Connie White, Mark Wilkie, and others who make this Web site possible month in and month out, and as always an especially warm thank you to all of our readers, especially those who have taken the time to send in their questions and comments.

I have owned or extensively used the 1D, 300D, 20D, Rebel XT, 1D Mark II, and the Rebel XTi. I mainly shoot JPEGs because, given my time, I want shots that are pretty much good-to-go right out of the camera, without need of too much post-processing. Notwithstanding ISO advances and increased megapixel counts, when I look back at my many thousands of pictures, I often find that the 1D shots look noticeably sharper, despite being the oldest, smallest MP of them all. One neat feature of the 1D, absent in the 1D Mark II, was the ability to set the sharpness all the way to 5, but at the superfine setting, seemingly minimizing undue roughness to the images.

Is one Canon DSLR model's sensor sharper than the next, or is it a function of different algorithms in the JPEG processing as the shots are written to the card? My understanding is that even "RAW" images have been processed in many ways before being written. If one were to take the same shots with the same lenses, but with different Canon DSLRs, and process them all from RAW with the same settings, would there be substantial differences in sharpness?

Default sharpening for in-camera JPEGs with EOS Digital SLRs is affected by several factors including the strength of the camera's anti-aliasing filter as well as the camera's sharpness settings. Image sensor resolution by itself has almost nothing to do with it.

One school of thought holds that for maximum control over sharpness, digital images should be recorded with no sharpening, and that all sharpening should occur during post-processing. Another school of thought holds that for speedier workflow, sharpening and other image processing parameters such as contrast and saturation should be applied in-camera so that the resulting JPEG images can be printed immediately with little or no post-processing.

Canon has always provided enough control in its EOS Digital SLRs for photographers to pick the image processing parameters they prefer, without forcing the photographer into an either/or situation. In this scenario, RAW data provides the greatest flexibility, but each camera model is equipped with a variety of settings to control the sharpness, contrast and saturation of in-camera JPEGs. That said, it's true that the default settings for in-camera JPEG sharpness have varied widely across different models in different eras. For example, the 1D Mark II by default had zero sharpening in its in-camera JPEGs and was equipped with a strong anti-aliasing flitter, while the original 1D had a much weaker AA filter, and was tuned for higher sharpness with in-camera JPEGs at its default settings. Starting with the 1D Mark II N and 5D in 2005, Canon updated to its current "Picture Style" settings, which set default sharpening to a mid-scale value rather than zero. Canon has maintained this basic philosophy ever since, in great part because the company wished to unify the image quality settings of all current EOS models.

Ultimately, for photographers like you who wish to control the sharpening of in-camera JPEGs in order to reduce post-processing, it's a good practice to make test prints at each of the offered sharpness settings so that you can decide which setting you prefer. If for some reason you find that you want even more control over sharpening than the in-camera settings provide, it's always possible to apply more (or different) sharpening during post-processing. Current models like the Mark III series and the 40D also provide in-camera noise reduction for high ISO settings, which can further improve the appearance of in-camera JPEGs shot at those settings. Last but not least, these same current models are also compatible with Canon's new "Picture Style Editor" software that lets photographers fine-tune many image processing parameters beyond the capabilities of the in-camera settings, then upload that fine-tuning to the camera for use with in-camera JPEG images. This program is bundled with new EOS cameras at no extra charge.

I'm the AP staff photographer in Salt Lake City. Our standard camera for the past several years has been the EOS-1D Mark II. I got the first batch before the 2004 Summer Olympics. I requested a 5D to take advantage of its full-frame chip. It came a couple of days ago. So far, I love it. However, I'm finding color and contrast differences between it and my Mark IIs when both are set at the same white balance, including Kelvin. Both cameras are set at Adobe RGB. I realize that both have different electronics and software. But before taking the time to map both cameras via testing, does Canon have a comparison chart online or somewhere that already has equivalents?

The image quality settings for the EOS-1D Mark II, which used the old Color Matrix system, are not directly comparable to the EOS 5D, which uses Canon's current Picture Style settings. Unfortunately, Canon Inc. R&D never provided an official conversion guide for all the Picture Style settings to match up to all the Color Matrix settings, so the instructions for matching image quality characteristics between these two models depends on which camera you're trying to match. For example, the "Standard" Picture Style on the 5D has considerably more contrast and saturation than the Color Matrix 4 Adobe RGB setting on the 1D Mark II. If you want to match the 5D to the 1D Mark II set to Matrix 4, you'd have to start by setting the 5D to Adobe RGB, and then select a different Picture Style, such as Neutral. Next, you would need to dial down the contrast and saturation in Neutral to get close to the effect of the Matrix 4 setting on the 1D Mark II. I can't tell you definitively how far to dial down the contrast and saturation on the 5D in Neutral and Adobe RGB to match Matrix 4 on the 1D Mark II, but my unofficial recommendation is to try a -2 on both settings in the 5D as a starting point. On a related point, the original concept behind the low contrast and low saturation of Matrix 4 on the original 1D and 1D Mark II cameras was to preserve as much image information as possible in a JPEG file, so as to enhance editing flexibility during post-processing. Canon got a lot of feedback from pros that they wanted more control over these settings for in-camera JPEGs in order to speed up their workflow, and that's one of the main reasons why the company migrated to the Picture Style concept starting in 2005 with the 1D Mark II N and the 5D. All current EOS Digital SLRs use Picture Style settings.

Is it possible to use manual flash exposure control with a Speedlite 430EX, 550EX, 580EX or 580EX II when it is in slave mode and it is triggered by a Speedlite Transmitter ST-E2 mounted on my EOS Digital camera? If so, how?

Manual flash exposure is available when using the ST-E2 and any compatible EX-series Speedlite including the 430EX. Here's how:

1) Set the 430EX to slave mode and power up the flash.

2) Hold the MODE button down for three seconds or until the ETTL icon on the LCD data panel switches to a flashing M. This indicates that the 430EX is now in manual flash exposure mode. The M icon will continue to blink on and off as long as the 430EX is in manual flash exposure mode during wireless operation. This is normal.

3) To adjust the manual power setting on the 430EX in slave mode, press the SEL/SET button for a second or so until the power ratio icon begins to blink. Press the gray semi-circular adjustment buttons to the left or right of the SEL/SET button to adjust the power ratio from 1/1 (full power) to 1/2, 1/4, 1/8. 1/16, 1/32 or 1/64. Do this within five seconds of pressing the SEL/SET button or the current setting will be registered.

4) Position the 430EX as desired, then activate the ST-E2 on camera and fire away. Note that the communication channel on the ST-E2 must match the communication channel on the 430EX. Also, note that the ETTL LED on the ST-E2 will light up even though the 430EX is set to manual flash exposure mode. This is normal.

I've just bought a Canon 40D and am having problems setting it up for second curtain flash with a 550EX flash. The flash control settings for setting it are grayed out and for C. fn settings, I get the message, "incompatible flash." I have tried it on three different 550ex's, with no change. Searching threads and Google told me nothing. Any and all suggestions welcome.

Speedlite 550EX (discontinued about four years ago) has the same level of compatibility with the EOS 40D as it has with other EOS bodies. Accordingly, second-curtain sync with the 550EX is set on the flash itself whether it's used with the 40D or any other EOS camera. To set it up, press the + and - buttons on the back of the 550EX twice simultaneously. Look for the second-curtain sync icon in the upper right corner of the 550EX's LCD panel.

Currently, the flash control menu on the camera is fully compatible only with the built-in flash and Speedlite 580EX II. All it can do with the 550EX is to set flash exposure compensation and E-TTL II flash metering patterns. That's why the other settings are grayed out and you're getting an error message when you attempt to set the 550EX's custom functions from the camera body.

Many thanks, that works a treat. I knew Canon would have a way ! One more question: How do I get the Info Button Shoot Function information to return to the back screen automatically after reviewing a shot. I have to press the Info button again to show the present settings of the camera.

Here's how:

1. Go to Setup Menu 1 on the 40D's LCD screen. (Press MENU, then use the main dial next to the shutter button to select the first yellow icon on the top row, the one with the wrench and a single dot.)

2. Scroll down to "INFO button" with the Quick Control Dial on the back of the camera and press SET to access the submenu.

3. Select "Shoot. func." and press SET to register that setting.

4. Tap the shutter release halfway to extinguish the menu display, then press the INFO button to see the camera settings on the rear LCD screen.

The camera settings should remain illuminated on the screen for as long as the 40D's Auto Power Off setting has been set or until you take a picture, whichever comes first. If you take a picture while the settings are illuminated, the display will return automatically as soon as your "Review time" expires, and this cycle will repeat indefinitely. Note that you can adjust both the Auto Power Off setting and the review time setting in the LCD menus. Defaults are 1 minute and 2 seconds, respectively.

If the display shuts off before you take a photo, or if you are just powering on with the camera's main on/off switch, all you need to do is press the INFO button again before the next shot to reset the sequence.

Thanks for reading Tech Tips! That's it for now. See you in June!

You are invited to submit questions about photo equipment, imaging technology, or photo industry trends that may have a bearing on your work or interests. I cannot promise to answer all inquiries, but I pledge to do my best to address the issues that concern you. (Please use the e-mail link provided at the end of this article.)