memobug
October 17th, 2002, 02:52 PM
One common complaint with the S2 is related to soft focus. Before getting too far into this subject it is important to consider possible sources for out-of-focus (OOF) images. These usually occur because of some combination of three factors:
a) The camera is focused on the wrong object or in the wrong plane
b) The camera or subject moves during the exposure
c) The lens is not critically sharp at the exposed settings
Focus on the wrong object - this is usually a result of improper CSM settings. It's more complex so let's deal with the easier to understand causes first and then come back to the CSM settings.
Camera shake This is a frequent cause of OOF. The shutter speed of the camera during the exposure can result in a blurred image. Many 35 mm users are familiar with the "rule of thumb" that suggests that the maximum shutter speed for a given focal length is equal to 1/(focal length in mm). This would suggest that most users should be able to produce acceptable images with a 125mm lens with the shutter set to 1/125 or faster.
It does not help much that the camera is rather light and more prone to shake, nor that the lowest ISO rating 100 is not suitable for some types of handheld photography.
The problem is that this "rule of thumb" takes into account moderate reproduction sizes and does not factor in the 1.5 mm "crop factor" of 35mm lenses used on the S2. If you consider that this rule was based don maginification of a 35mm negative or slide to a 5x7 image, you'll be very surprised when you open your 12million pixel s2pro image in photoshop at 72dpi and see a photo that is 3 or four screens wide and rather blurry.
1. Consider that for the S2pro, the rule of thumb is more akin to 1/ (2 times focal length) for 8x10 reproduction.
2. Use a tripod or monopod for critical exposure
3. Boost the ISO to 200 or 400 to increase the shutter speed
4. Use flash or flash-fill to capture movement
5. Practice squeezing the trigger gently as opposed to jabbing it with a fingertip.
Subject movement This is caused when the subject moves slightly during the exposure.
1. Boost the ISO to speed the effective shutter speed
2. Use flash or flash-fill to capture movement
Mirror slap and camera vibration
Exposures in the vicinity of 1/15 to 1/30 seccan be troubled by Mirror slap, which is vibration induced in the camera when the mirror in the SLR swings up out of the way. Some cameras offer a mirror lockup mode to help avoid this problem. The S2Pro does not. You can drape an arm over the top of the camera and lens to help absorb some of the vibration and trigger the camera with a remote release to help avoid pushing on the camera body. There is no electronic release provision, so you will need a standard mechanical release cable.
Camera settings.
a) CSM SETTINGS Keep in mind that the S2Pro can be set for "closest subject Priority" this is one of the CSM settings hidden in the manual. If you have CSM active, the camera will attempt to focus on the closest subject under one of the five brackets [ ] that may or may not be your subject! Disable CSM-7 closest subject priority unless you know what you are doing!
b) Focus Area Selector - You can also inadvertently select the wrong focus area. They thumbpad on the back of your S2 can be used to move the highlighted bracket [ ] to five different positions. If you accidently bump it, you might focus between a couple standing side by side, and pulll focus on the wall behind them. Use the lock provided to keep this from happening.
c) Continuous or Single servo focus. The switch on teh front of the camera that says C S M will determine what happens when you half press the shutter. In continuous mode, the camera will change focus continuously as the object under the [ ] crosshair moves. In S mode, the camera locks on the position of the object at the time the shutter was pressed and will not hunt around. In M mode, focus is manually controlled with the focus ring on the lens.
d) Dynamic focus [+] CSM-8 - active in Continuous focus mode. Enables the camera to track a moving subject. Again - I'd turn this off unless you are tracking fast moving objects like racecars, airplanes or soccor balls.
e) Focus Area Rotation CSM 4 - this enables you to use the command dial in lieu of the thumpad to change the focus area. Very confusing. I'd turn this off unless you are familiar with how it works.
f) ISO Setting - Standard ISO is 100, which is quite useful for outdoor exposures. Indoors or in shade you may well want to increase the ISO setting to get more handholdable shutter speeds. ISO 200 and 400 generally give perfectly acceptable results.
Lens selection
Please see comments in the LENS Faq (http://theswampbbs.com/forums/showthread.php?s=&threadid=206). Lenses with wider apertures (lower F number) are called "faster" lenses because they can use correspondingly higher shutter speeds. They gather more light and may give better performance at equivalent apertures for sharper images. Primes and short range zooms (2x) are often better optically corrected for distortions which plague super zooms
a) The camera is focused on the wrong object or in the wrong plane
b) The camera or subject moves during the exposure
c) The lens is not critically sharp at the exposed settings
Focus on the wrong object - this is usually a result of improper CSM settings. It's more complex so let's deal with the easier to understand causes first and then come back to the CSM settings.
Camera shake This is a frequent cause of OOF. The shutter speed of the camera during the exposure can result in a blurred image. Many 35 mm users are familiar with the "rule of thumb" that suggests that the maximum shutter speed for a given focal length is equal to 1/(focal length in mm). This would suggest that most users should be able to produce acceptable images with a 125mm lens with the shutter set to 1/125 or faster.
It does not help much that the camera is rather light and more prone to shake, nor that the lowest ISO rating 100 is not suitable for some types of handheld photography.
The problem is that this "rule of thumb" takes into account moderate reproduction sizes and does not factor in the 1.5 mm "crop factor" of 35mm lenses used on the S2. If you consider that this rule was based don maginification of a 35mm negative or slide to a 5x7 image, you'll be very surprised when you open your 12million pixel s2pro image in photoshop at 72dpi and see a photo that is 3 or four screens wide and rather blurry.
1. Consider that for the S2pro, the rule of thumb is more akin to 1/ (2 times focal length) for 8x10 reproduction.
2. Use a tripod or monopod for critical exposure
3. Boost the ISO to 200 or 400 to increase the shutter speed
4. Use flash or flash-fill to capture movement
5. Practice squeezing the trigger gently as opposed to jabbing it with a fingertip.
Subject movement This is caused when the subject moves slightly during the exposure.
1. Boost the ISO to speed the effective shutter speed
2. Use flash or flash-fill to capture movement
Mirror slap and camera vibration
Exposures in the vicinity of 1/15 to 1/30 seccan be troubled by Mirror slap, which is vibration induced in the camera when the mirror in the SLR swings up out of the way. Some cameras offer a mirror lockup mode to help avoid this problem. The S2Pro does not. You can drape an arm over the top of the camera and lens to help absorb some of the vibration and trigger the camera with a remote release to help avoid pushing on the camera body. There is no electronic release provision, so you will need a standard mechanical release cable.
Camera settings.
a) CSM SETTINGS Keep in mind that the S2Pro can be set for "closest subject Priority" this is one of the CSM settings hidden in the manual. If you have CSM active, the camera will attempt to focus on the closest subject under one of the five brackets [ ] that may or may not be your subject! Disable CSM-7 closest subject priority unless you know what you are doing!
b) Focus Area Selector - You can also inadvertently select the wrong focus area. They thumbpad on the back of your S2 can be used to move the highlighted bracket [ ] to five different positions. If you accidently bump it, you might focus between a couple standing side by side, and pulll focus on the wall behind them. Use the lock provided to keep this from happening.
c) Continuous or Single servo focus. The switch on teh front of the camera that says C S M will determine what happens when you half press the shutter. In continuous mode, the camera will change focus continuously as the object under the [ ] crosshair moves. In S mode, the camera locks on the position of the object at the time the shutter was pressed and will not hunt around. In M mode, focus is manually controlled with the focus ring on the lens.
d) Dynamic focus [+] CSM-8 - active in Continuous focus mode. Enables the camera to track a moving subject. Again - I'd turn this off unless you are tracking fast moving objects like racecars, airplanes or soccor balls.
e) Focus Area Rotation CSM 4 - this enables you to use the command dial in lieu of the thumpad to change the focus area. Very confusing. I'd turn this off unless you are familiar with how it works.
f) ISO Setting - Standard ISO is 100, which is quite useful for outdoor exposures. Indoors or in shade you may well want to increase the ISO setting to get more handholdable shutter speeds. ISO 200 and 400 generally give perfectly acceptable results.
Lens selection
Please see comments in the LENS Faq (http://theswampbbs.com/forums/showthread.php?s=&threadid=206). Lenses with wider apertures (lower F number) are called "faster" lenses because they can use correspondingly higher shutter speeds. They gather more light and may give better performance at equivalent apertures for sharper images. Primes and short range zooms (2x) are often better optically corrected for distortions which plague super zooms