Slower shutter speed = Overexposure? Grr

mooker · Sep 18, 2006

Happy Monday all!

Yesterday evening was beautiful in Indiana (before the rain, that is!) so around 6:30 pm I walked over to the park and was taking some pics.

I'm still playing with the settings on my camera. I have messed with the Aperture settings for awhile, so I thought that I'd mess with the shutter speed. I have seen a lot of pictures of water fountains that various people have taken with differing shutter speeds. There's a really nice fountain near my house, so I tried my hand at a few pics with a slower shutter speed. On each picture, they were very overexposed, which I suppose makes sense (longer shutter opening means more light on the CCD). How can I avoid this? I took the pictures at around 6:45 pm, and while it wasn't dark per se, it wasn't bright and sunny either. I tried to lower the exposure (my camera will do -2 to +2 in 1/3 increments) all the way down to -2, and that didn't help.

So I switched off Tv mode and went to the dreaded M (dreaded for me, cuz my pics never look good! :lol:

) I tried to decrease the aperture down to f/8 (the minimum), and it was still overexposed.

I also noticed on my camera that I can't change the exposure in manual mode (the exposure setting changes to a flash output setting). ARGH!

So how the heck can I take slower shutter speed pics during the day without it being overexposed??

Here is a pic of probably the best one (f/8 1/2 sec) - don't mind the blurriness. I wanted to use an even slower shutter speed, but when it was this overexposed at 1/2 sec, I gave up.

Help!

DeepSpring · Sep 18, 2006

What kinf of camera do you have? I'm sdduming its not an SLR because with those you can have a much higher f stop then just 8. it could be a about 16 and bigger depending on the lens.

think about a tripod too because there is some camera shake

Digital Matt · Sep 18, 2006

The law of reciprocity states that if you change one factor of the exposure equation, which is exposure = Intensity + Time, then you must change another.

If you are leaving the shutter open for longer (time), then you must decrease the intensity of the light (aperture). As you said, your camera has a max aperture of f/8. Apparently, you need to decrease the intensity further. You'll need a neutral density filter. It decreases the intensity of the light without affecting color balance. It's a dark grey filter. They come in varations, that provide different amounts of light reduction.

mooker · Sep 18, 2006

Hi DeepSpring,

My camera is a Canon PowerShot A95. Here are the specs:
Steve's Digicams

Believe it or not, that WAS on a tripod. Since it wasn't windy when I took the shot, I can only assume that when I pressed the button, that's where the shake happened.

Digital Matt: Thanks for the tip! I didn't think about a filter. Once I'm no longer poor I will look into that option

JDS · Sep 18, 2006

mooker said:
Believe it or not, that WAS on a tripod. Since it wasn't windy when I took the shot, I can only assume that when I pressed the button, that's where the shake happened.

If your camera has a self-timer, set that before pressing the shutter. That way your hand won't be anywhere near it to shake it when the actual photo is taken.

mooker · Sep 18, 2006

JDS said:
If your camera has a self-timer, set that before pressing the shutter. That way your hand won't be anywhere near it to shake it when the actual photo is taken.

Good call! My camera does have a 2 and 10-second timer. I'll do that next time. I know my camera doesn't have an input for a remote "clicker", so that's my next best option.

xfloggingkylex · Sep 18, 2006

Also, this picture's EXIF data doesnt list your iso, but if you can change it, the smaller the number will make the sensor less sensitive to the light, meaning you can open the shutter longer without over exposing. Also, your manual mode should allow you to change both aperture and shutter speed. Read the manual for your camera and you'll find out how.

Rob · Sep 19, 2006

ND filter is the way forward - basically you've reached the limit of your camera and the ambient light, so you need to artificially reduce the amount of light hitting the sensor using another method.

Rob

mooker · Sep 19, 2006

Thanks everyone for the tips. As many have suggested, it looks like I'll need to get some kind of filtering lens to reduce the light (or wait till later in the evening).

xfloggingkylex: I have been using manual mode without any problem. I'm aware that I can set both the aperture and shutter speed in manual mode. I've referred to the manual many times, and am getting more and more familiar with the camera. My dilemma with manual mode was that while I can adjust aperture and shutter speed, it will NOT let me adjust exposure. Seems kind of odd to me, as I can adjust it in Av or Tv mode. Ah well, a camera limitation I suppose. But I will try the lower ISO and see if that helps.