Minolta DiMAGE A1Minolta updates their revolutionary five-megapixel electronic SLR with faster shutter speeds, an Anti-Shake mode, 14-bit A/D, and a tilting LCD monitor, among other improvements.<<Optics :(Previous) | (Next): Shutter Lag & Cycle Time Tests>> Page 6:Exposure & FlashReview First Posted: 08/08/2003, Updated: 11/10/03 |
Exposure
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The DiMAGE A1 offers excellent exposure control, with very fine-grained adjustment
of such image attributes as sharpness, contrast, and color saturation. While
I found the camera's user interface a little confusing at first, with its myriad
buttons, dials, and switches, I liked it a lot once I got the hang of it. (The
combined use of functional dials, selection buttons, and the rotating command
wheel is similar to the design of Minolta's film cameras, and very reminiscent
of the earlier Sony DSC-D770, a camera that developed a significant "cult"
following. While something of a departure for the digicam market, this interface
has proven very popular with users of both Minolta's film cameras, and the much
earlier Sony camera.)
The Mode switch on the rear panel selects the basic operating mode: Record,
Playback, or Movie. Within Record mode, the Exposure Mode dial selects the camera's
exposure mode. Choices are Manual, Shutter Priority, Aperture Priority, Program
AE, Auto, Memory Recall, Portrait, Sports, Sunset, and Night Portrait modes.
In straight Auto mode, the camera controls everything about the exposure, except for flash, zoom, and focus. Program AE mode keeps the camera in charge of the exposure, while you have control over all other exposure options. While in Program AE mode, you can rotate either of the control dials to scroll between a range of equivalent exposure settings. Thus, you can bias your exposure toward a faster shutter speed or greater depth of field as circumstances dictate. Aperture Priority mode lets you select the lens aperture setting, from f/2.8 to f/11 depending on zoom, while the camera selects the most appropriate corresponding shutter speed. In Shutter Priority mode, the user selects the shutter speed, from 1/16,000 to 30 seconds, while the camera chooses the best corresponding aperture setting. Switching to Manual mode gives you control over both shutter speed and aperture, with a Bulb setting available for longer exposures. Exposure time in Bulb mode is determined by how long you hold down the Shutter button, up to a maximum of 30 seconds. (I strongly recommend use of the optional wired remote in Bulb mode, as the pressure of your finger on the shutter button is bound to jiggle the camera somewhat, blurring the image.)
As described above, the DiMAGE A1 also offers four preset scene modes (referred to as Digital Subject Programs). Controlled by a button on the earlier DiMAGE 7Hi, these modes are now accessed via the Exposure Mode dial. Portrait mode produces better-looking people shots by enhancing skin tones and decreasing the depth of field (to create a slightly blurred background). Sports mode provides faster shutter speeds to freeze action, and maintains focus on quickly moving subjects. In Sunset mode, the camera employs slightly slower shutter speeds to let in more of the ambient light, and lets you record the warm colors of the scene without compensating for them in the white balance system. In Night Portrait mode, the camera also uses a slower shutter speed to allow more ambient light into the image, however it also records true black values and preserves the bright colors of artificial lighting. The Exposure Mode dial also features a Memory Recall setting, which lets you save as many as five registers of settings. Selecting a setting automatically applies the settings to the camera, which can be recalled by turning the Exposure Mode dial to another position.
The DiMAGE A1's default metering mode is a 300-segment evaluative system, which takes readings throughout the image to determine exposure. Center-Weighted and Spot metering options are also available via the Function Dial. Spot metering is useful for high-contrast subjects, as it bases the exposure reading on the very center of the image, letting you set the exposure based on a small portion of your subject. Center-Weighted metering also bases the exposure on the center of the image, but the camera takes its readings from a much larger area in the middle of the frame. You can also hold or lock the exposure reading for a particular part of the image by pressing the AE Lock button on the back panel. This button can be programmed to act as either a "hold" or "toggle" control. "Hold" mode does just that, it holds the current setting until you release the AE Lock button again. Toggle mode locks and releases the exposure/focus setting with successive actuations of the AE Lock button. Halfway pressing the Shutter button also locks exposure and focus, but only in autofocus mode.
The DiMAGE A1's light sensitivity can be set to Auto, or to ISO equivalents of 100, 200, 400, or 800. As with other consumer and prosumer digicams that sport ISO 800 options though, I didn't find the ISO 800 setting to be particularly useful, as the image noise level was so high. A Noise Reduction option is newly available for longer exposures and higher ISO settings, and greatly reduces the amount of image noise that would otherwise result. Exposure compensation is adjustable from -2 to +2 exposure equivalents (EV) in one-third-step increments, and an auto-bracketing option can snap three shots in rapid succession, varying the exposure between each in steps of 0.3 or 0.5 EV units. Exposure compensation is adjusted using the Digital Effects dial, while auto bracketing is activated by rotating the Function Dial to the Drive position, pressing the center, and then rotating the Control dial until the auto bracketing icon appears in the LCD or EVF display. Exposure step size for auto bracketing is set through an option in the record-mode menu system.
Like the DiMAGE 7Hi before it, the DiMAGE A1 offers very flexible control over white balance, color rendition, and tonal range. Its white balance system offers a total of seven options, including Auto, Daylight, Tungsten, Fluorescent, Cloudy, Shade, and Custom, which is the manual setting. The Custom Set mode determines white balance by snapping a picture of a white card. The camera then adjusts its color balance to render the white card with a neutral hue, and saves the setting as the Custom option. As many as three Custom settings can be saved, very useful if you need to switch back and forth between different lighting conditions quickly.
Contrast and Color Saturation controls are adjustable in 11 steps across a fairly broad range of settings, using the Digital Effects dial on the camera's left side in conjunction with the Front Control dial next to the Shutter button. To make adjustments, you rotate the Digital Effects dial to either setting, press the button at its center, and then rotate the Control dial to choose the desired setting. The DiMAGE A1 also offers a Filter setting on the Digital Effects dial. Depending on the color mode selected through the Custom Settings menu, the Filter option adjusts the overall color cast of the image, again in 11 steps. The color range here varies from rather blue to rather yellow, exactly the color axis that you'd want to adjust to compensate for different color temperatures in your lighting. Positive adjustments warm the image, while negative adjustments produce a cooler color balance. In Black and White mode, the Filter effect tones the image from neutral to red, green, magenta, blue, and back to neutral (zero position).
The combination of fine steps and wide adjustment ranges in the Digital Effects controls mean you can really customize the A1 to exactly suit your preferences for color and tonality. Most cameras offering saturation, white point, and contrast variations treat them more as special effects, rather than as adjustments for fine-tuning camera response. We seem to be seeing more evidence of other manufacturers offering "fine tuning" options like this (Olympus prominent among them), but I'd really like to see it become more widespread.
The Color Mode option of the Record menu offers Natural and Vivid sRGB color modes, as well as Adobe RGB, Embedded Adobe RGB, Black and White, and Solarization settings. Adobe RGB color space has a much broader gamut or range of reproducible colors than does sRGB, the color space used by most digital cameras and computer monitors. (The Embedded option simply means that the color space information is embedded in the image file.) Adobe RGB images will look rather dull when displayed on monitors tuned to the sRGB standard, but when used in a color-managed work environment, they can capture and reproduce a much greater range of colors. For its part, Solarization partially reverses the tones in an image, while the Exposure Compensation adjustment controls the intensity of the effect. The record menu also offers a Sharpness adjustment, for controlling the amount of in-camera sharpening applied to an image.
Continuous Modes
The DiMAGE A1 features a range of continuous shooting modes, accessed via the "Drive" setting on the left-side Function dial. In addition to the standard Continuous Advance mode, the DiMAGE A1 also offers Interval, High-Speed Continuous, and Interval and Time-Lapse Movie modes. (Note that the Drive setting also access the Self-Timer and Auto Exposure Bracketing modes as well.) In standard Continuous Advance, the DiMAGE A1 captures approximately two frames per second, for as long as the Shutter button is held down (numbers are for small/basic images). Depending on the resolution and quality settings, as well as the amount of memory card space, the maximum number of frames and the frame rate will vary. In my testing, I found Continuous mode captures did indeed have a frame rate close to two frames per second, but saw some variability in the timing when shooting at smaller image sizes. The buffer seems to hold three shots, as the camera would grab three frames at the roughly 2 frame per second rate, then pause briefly before grabbing the next three. The pauses grew longer as more frames were captured, eventually becoming as long as 12-13 seconds.
High-Speed Continuous mode captures a series of full-size images at approximately 2.8 frames per second. Behavior was otherwise very similar to that of normal Continuous mode.
Interval mode captures a series of images at specific intervals over time, providing a built-in time-lapse capability. The DiMAGE A1 can capture up to 240 images in the sequence, with frame intervals ranging from 30 seconds to 60 minutes, and a delayed start time from 30 minutes to 24 hours.
Interval and Time-Lapse Movie mode creates a series of still images and a 640 x 480 movie clip at the Interval settings specified through the Record menu.
As mentioned above, the Drive setting also accesses the Self-Timer and Auto Exposure Bracketing modes. The Self-Timer fires the shutter either two or ten seconds after the shutter button is pressed. The shorter delay is very handy when you need to prop the camera on something to take a photo in dim lighting, and don't want the pressure of your finger on the shutter button to jiggle the camera. The ten-second delay is long enough that you can run around to get into the photo yourself. An LED lamp on the front of the camera blinks and the camera beeps as the self timer is counting down, the blink and beeps becoming faster in the last few seconds.
Auto Exposure Bracketing mode captures a series of three images (one at the
metered exposure, one underexposed, and one overexposed). You can set the exposure
variation between exposures to 0.3, or 0.5 EV. The A1's automatic bracketing
options go beyond simple exposure bracketing though. Turning the Rear Control
dial cycles through a range of bracketing options, including Continuous-Advance
Bracket, Single-Frame Advance Bracket, and Digital Effect Bracket (which brackets
either Filter, Contrast, or Color Saturation settings). The ability to bracket
hue, contrast, and color saturation is really helpful for handling difficult
subjects.
Movie and Sound Recording
The DiMAGE A1 has a Movie mode that records moving images with sound, for as long as the memory card has available space. The amount of recording time appears in the LCD or EVF monitor display, and appears to be limited only by memory card capacity. (That is, there is no arbitrary limit on the length of individual clips.) Movies are recorded at 320 x 240-pixel resolution. Through the Record menu, you can set the movie mode to Auto, Standard, or Night. Night mode records black and white movies in low lighting situations, and is far more effective in dim lighting than the vast majority of digicam movie options I've seen. The Auto setting tells the camera to automatically decide between Standard and Night modes, based on the exposure conditions.
A Voice Memo mode records either five or 15 seconds of audio to accompany still images. This mode must be enabled before image capture. When enabled, a microphone icon appears in the LCD/EVF display, and the camera automatically begins recording audio for the specified amount of time immediately after image capture.
Flash
The DiMAGE A1 features a
built-in, pop-up flash, which operates in either Fill-Flash, Red-Eye Reduction,
Rear Flash sync, or Wireless modes. To release the flash from its compartment,
pull on the two small tabs on either side of the casing and lift up the flash
head. Close it again by simply pushing the flash head back down. The Flash mode
is changed through the Record settings menu. In Fill-Flash mode, the flash fires
with every exposure, regardless of lighting conditions. Red-Eye Reduction fires
a series of small pre-flashes before firing the flash at full power for the
exposure itself. This makes your subjects' pupils contract and reduces the occurrence
of the Red-Eye effect. The Rear Flash Sync mode fires the flash at the end of
the shutter time, rather than the beginning. If you have moving objects in a
relatively brightly lit environment, this will produce a sharp image of your
subject, with a "motion trail" following behind it. The flash is in
the Off position when it's closed. The Wireless mode lets the camera work with
wireless remote flash units, with four channels available through the settings
menu, so different camera/flash setups working in the same area won't interfere
with each other. (Minolta makes two flash units that support the DiMAGE A1's
wireless capability, the Program Flash 5600HS [D] and 3600HS [D].)
The DiMAGE A1 is also unusual in that it offers two methods of flash metering. Its default mode is called ADI, which stands for Advanced Distance Integration. In this mode, it bases its flash exposure on the lens aperture and distance feedback from the autofocus system, as well as on the light reflected back from a pre-flash. By determining how far away the target subject is, the camera knows how much flash power is required to illuminate it, and so is less likely to be fooled by subjects that are unusually light or dark overall. As a fallback, a Pre-Flash TTL (through the lens) method bases the exposure determination solely on a small metering flash before the main exposure. Used in conjunction with the spot autofocus option mentioned earlier, the ADI flash metering should be much more accurate with small subjects against a different colored background than the pre-flash method.
For use with studio strobes and conventional slave triggers, the DiMAGE A1 has a manual flash power option. This lets you set the flash power to Full, 1/4, or 1/16 power manually. In this mode, the flash fires only once, at the moment of exposure. The single flash prevents false triggering when working with conventional slave triggers.
The DiMAGE A1 also includes a top-mounted hot shoe for attaching an external
flash unit. The shoe design and contact arrangement are set up for Minolta's
own dedicated flash units, but I imagine that compatible models are available
from the major third-party flash manufacturers (Sunpak et. al.). Minolta's own
Program Flash models 2500(D), 3600HS(D), and 5600HS(D) work with the DiMAGE
A1, and two macro flashes (Macro Twin Flash 2400 and Macro Ring Flash 1200)
will work with an accessory macro flash controller.
An external flash sync terminal (the so-called "PC" style connector)
accommodates just about any third-party flash unit. This makes the DiMAGE A1
much more appealing to photographers who already have an existing strobe system
for the studio.
I had a chance to play a bit with a couple of Minolta's dedicated flash units
while I was testing the previous DiMAGE 7Hi, and must say I was impressed. I
only shot with the 5600 model (a conventional hot-shoe mounted unit, but with
the added capability of wireless control) in a fairly small area, so didn't
test the maximum range over which the wireless TTL control would function. (I'm
sure it has some maximum range over which it's effective, but don't know what
that is.) That said though, the camera/flash combination worked exceptionally
well. Very slick, given that no extra controller or other hardware is needed
to establish the wireless link between the flash and the camera. (This has to
be one of the neatest flash arrangements I've seen yet on a digicam!)
For closeup work, the T2400 macro twin flash is a very capable setup too. -
A large ring mounts to the front of the lens, and serves as a support mount
for a pair of tiny flash heads. The little flash heads are powered by a flash
controller that looks just like a normal hot-shoe flash unit, but has two sockets
on its front instead of the flash tube. The ring has multiple mounting points
around it for the little flash heads, so you can direct the light to come from
top, bottom, or either side with equal ease. The flash controller also lets
you set the power ratio between the two heads, so you can have a "main"
and "fill" light on your macro subject. Very flexible, very slick
(if not a little odd-looking). Highly recommended if you intend to do any really
extensive macro work. (This should be a great solution for people selling tiny
objects (coins, jewelry?) on eBay, looks like a sure winner for dentists looking
to document their work, entomologists wanting really good bug pictures, etc,
etc.)
Color Space
This is probably as good a place as any to talk about the DiMAGE A1's color
space. The original DiMAGE 7 used a proprietary color space with a much wider
color gamut than the sRGB space used by most digicams. (As well as by most computer
monitors, consumer-grade printers, etc.) The result was that it could capture
a much broader range of colors than other cameras, but this also meant that
the raw JPEGs straight out of the camera looked rather flat and dull when viewed
on a typical computer monitor. To get the full color to appear, you needed to
run the image files through Minolta's DiMAGE Viewer software utility, and convert
their color space back to sRGB. (Or whatever other working space you wanted
to use. Many graphics professionals work in the so-called "Adobe RGB"
space popularized by Photoshop(tm), which is supported by many graphics programs
and printers, and also offers an expanded color gamut.)
While the expanded color gamut was a real boon to graphics professionals and
others interested in breaking free of the constraints of sRGB, for the average
amateur it amounted to just one more step to go through before they could fully
enjoy their photos. Worse, if someone wasn't aware of the color space issue,
they'd probably write off the DiMAGE 7 as having rather flat, undersaturated
color.
With the DiMAGE 7i, Minolta stepped back closer to the mainstream in the color
space department, adopting a color space that was much closer to sRGB, to the
point that files from the 7i could be used in an sRGB environment without special
processing. While there was still some undersaturation in parts of the spectrum,
the 7i's unprocessed JPEG images were much more visually appealing than those
from the original 7.
With the DiMAGE 7Hi, Minolta further moved to embrace standard color space definitions,
but this time they also included an option for a space with a larger color gamut
than that supported by sRGB. The 7Hi had three color space options (plus black
& white and sepia), two based on sRGB, the third being the broader-gamut
"Adobe RGB" space. The two sRGB spaces are the default one, with normal
color rendering, and a "vivid" sRGB option, which boosts color saturation
a fair bit. The DiMAGE A1 follows in the footsteps of the 7Hi in this regard,
with the same color space options available.
This increased color-space flexibility will come as a welcome addition for many
pros and advanced amateurs who want to use their cameras in a color-managed
environment. The Adobe RGB space avoids many of the color limitations of the
sRGB space, which are most evident in highly-saturated reds. Working in Adobe
RGB lets you maintain detail in bright reds and greens that can't be properly
represented in sRGB space. Switching to Adobe RGB for your photography does
involve a fair degree of commitment though, as you'll need to set up your entire
workflow to support it, including both screen rendering on your computer's CRT
or LCD, and printing to your printer. Computer monitors are built to the sRGB
standard, and require software support (as in Adobe Photoshop or other high-end
image manipulation package) to portray Adobe RGB images properly. Likewise,
most consumer-grade photo printers assume sRGB as the starting point, again
needing color management to properly output Adobe RGB files. (Many professional
photo printers are set up to work in Adobe RGB by default though, so check to
see what your printer's default color space is.)
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