Long Shutter Mode - was:I know this has been discussed to death..

[JLeigh]

Still confused about "-2_ _ 1_ _0_ _ 1_ _ 2+". Is it something that is utilized in night shots along with long shutter mode? Or do you mess with it to avoid using long shutter mode? I'm sorry if this seems like a silly question, but I am hopelessly confused -and believe me, I have tried to do my own research. I'm just having a hard time understanding what it's supposed to do, especially with regards to night photos. :confused:

[Jon]

It's different from that. Long shutter mode allows you to set (surprise!) a long (slow) shutter speed, like 5 sec., for instance. The Exposure Compensation scale you're asing about is for use when you're photographing something tht isn't a classic 18% grey average tone. For instance, if you're photogrpahing a black cat, the meter will try to make it a middle grey - to avoid this, you dial in some - on the Exposure Compensation and the index mark will move toward -2 (the exposure will get longer - either the shutter speed will get longer or the aperture will get bigger or both). If you're photographing a bright snow scene, again the camera's going to make that a grey - so dial in some more light toward the + side. Either the shutter will go faster or the aperture will stop down (get smaller) or both. But that will work whether or not you're in long shutter mode.

[Johan007]

I am a beginner and I can understand the confusion. We are using Digital Camera but it seems the manufacturers try and emulate analogue features making it confusing for people like me coming from a purely digital background. According to the manual I think "-2_ _ 1_ _0_ _ 1_ _ 2+" is a mixture of a little Long Shutter(time delay) and Aperture(contrast+brightness).

But what is the frigging point when it would be better to avoid blur and just increase the Aperture. I presume the Aperture is not enough and time delay is need to magnify the brightness further?

I also understand there is a mode for Long Shutter to use with a tripod for Waterfalls and night time shots (motorways, firefworks) that go way beyond the above. To prevent these photos from over exposure I presume we reduce the Aperture.

Now what the hell is ISO I have been trying to figure? I think it is simply not needed. I presume it simply tries to increase the brightness of dark areas similar to what Photoshop can do and in the same way it degrades the quality of the picture because there is not enough colour dept (this where most people arguably claim RAW images are better in photoshop)

Being new to photography I am probably wrong so please correct me.

[Sonic Infidel]

ISO explanation at Wikipedia: http://en.wikipedia.org/wiki/Film_speed

Helped me understand a lot better. Hope it does the same for you.

[Jon]

I am a beginner and I can understand the confusion. We are using Digital Camera but it seems the manufacturers try and emulate analogue features making it confusing for people like me coming from a purely digital background. According to the manual I think "-2_ _ 1_ _0_ _ 1_ _ 2+" is a mixture of a little Long Shutter(time delay) and Aperture(contrast+brightness).Depends on what mode you're in. If you're in P, then, yes, EC will alter both shutter and aperture. If you're in Tv (shutter priority), it'll just change the aperture. If you're in Av (Aperture priority) it'll alter your shutter speed. And the values aren't "digital" or "analog" - they're "amount of light", which works the same for either digital or analog work (and your sensor really is analog, but the output's converted to digital in the camera's processor).

[tedr]

Still confused about "-2_ _ 1_ _0_ _ 1_ _ 2+". Is it something that is utilized in night shots along with long shutter mode? Or do you mess with it to avoid using long shutter mode? I'm sorry if this seems like a silly question, but I am hopelessly confused -and believe me, I have tried to do my own research. I'm just having a hard time understanding what it's supposed to do, especially with regards to night photos. :confused:


Hi there, I am familiar with this stuff from years of film photography, I can understand it might be difficult to grasp. Digital cameras are fantastic little beasts, and there is alot to learn especially if you are beginning from zero. I understand you want to take night photographs, here are a few tips.

The scale you are referring to is called exposure compensation. Leave it set on zero for the time being. +1 means one stop more exposure. +2 means two stops more. Leave it set on zero, normal exposure.

If your camera has nightime scene modes, try them, check with the manual. Use a tripod to prevent camera shake.

The concept of exposure is good for film and digital camera sensors. It is a combination of two things, length of time and size of hole in lens. Bigger hole lets in more light, smaller hole less light, the hole is called an aperture, it is given two symbols, f number, and sometimes the letter A. You have multiple choices for A typically f2.8, f4, f5.6, f8, f11. Odd numbers huh we won' go into that here. f11 is a small hole lets in less light. f2.8 is a big hole lets in lots more light. The f is often omitted but when you see an aperture scale the same number series is always used, sometimes with sometimes without the f.

Length of time is how long the hole stays open. In daylight the period of time is measured in small parts of a second such as 1/1000th (0.001) second and 1/100th (0.01) second. At night the times are more like 1 second or 10 seconds. The time is given the symbol T and it is measured in seconds. Sometimes you see values like 05 this means 0.5 seconds half a second. 03 means 0.3 seconds. When it gets to whole numbers they are seconds.

With the camera set to auto mode exposure is under automatic control, you can't change it, the camera is programmed with what to do and doesn't want your intervention. In auto mode the camera exposure meter is control of A and T. As a concession you are given the exposure compensation control. For the time being leave it at zero.

With the camera in manual mode you have to decide the exposure settings. The camera has a light meter in it that helps you decide what settings to use. There are several combinations of T and A that match the meter reading. Camera speed is also a factor here, the ISO number. 100 is normal.

Let's set up an example: The meter scale is 0 to 20.

the camera meter says the scene measures 7 and is set on 100 ISO.

The settings which will give normal exposure, which is the "0" on the compensation scale we talked about, are these:

1 second and f11 = 0
0.5 second and f8 = 0
0.25 second and f5.6 = 0
1/8th (0.125) second and f4 = 0
1/15th second and f2.8 = 0

All these settings will give normal exposure.

When you want more exposure increase either A (make the hole bigger) or T (make the hole stay open longer).

2 seconds and f11 = +1 and the picture will be lighter
1 second and f8 = +1 and the picture will be lighter.
1/8th second (0.125) and f2.8 = +1

When you want motion blur chose the first combination 2 seconds and f11, use a tripod. When you don't want motion blur use 1/8th second and f2.8, also use a tripod. Both are combinations of A and T are correct for an exposure meter reading of 7. If the result is too dark then increase exposure. Try 4 seconds and f11, or 1/4 second and f2.8.

Does this help?

Ted

[JLeigh]

Thanks a bunch! These explanations are extremely helpful. With my specific camera (SD750), I don't have any manual aperture controls. I can control the "-2_ _1" etc, the shutter speed (up to 15 sec.), the ISO from 80-1600 (although why anyone would use 1600 is beyond me, but I'm new at this, so..), and of course the usual "day", "cloudy", "fluorescent" settings. The night scene mode in the SD750 is, to put it bluntly, useless -unless of course you are in the middle of NYC surrounded by 2.3 skillion lights. ;) It's just not very good in low-light situations, which is why I have experimented with the manual controls when trying to shoot at night. Basically, I have been trying to push this camera to see what it can do, but the night shots are giving me the roughest time. Colors being off, the noise factor, etc etc are all driving me nuts, which is why I'm trying to understand more about shutter speeds and the exposure setting.

[Jon]

If night shooting's your thing I think you need to look at getting a Digital Rebel model for the more-usable ISO 1600 and the faster lenses.

[tedr]

Thanks a bunch! These explanations are extremely helpful. With my specific camera (SD750), I don't have any manual aperture controls. I can control the "-2_ _1" etc, the shutter speed (up to 15 sec.), the ISO from 80-1600 (although why anyone would use 1600 is beyond me, but I'm new at this, so..), and of course the usual "day", "cloudy", "fluorescent" settings. The night scene mode in the SD750 is, to put it bluntly, useless -unless of course you are in the middle of NYC surrounded by 2.3 skillion lights. ;) It's just not very good in low-light situations, which is why I have experimented with the manual controls when trying to shoot at night. Basically, I have been trying to push this camera to see what it can do, but the night shots are giving me the roughest time. Colors being off, the noise factor, etc etc are all driving me nuts, which is why I'm trying to understand more about shutter speeds and the exposure setting.


I think you are doing great with your determination to find the limits. Our eyes are incredibly good at seeing in the dark and night photography is very demanding of the camera and the photographer. You probably will find that a even a Canon SD750 has too many limitations for this work but keep trying. Things are not so great with film cameras for night images either, film especially color film has major problems with long exposure times. I agree with Jon you may find a digital SLR type camera better suited to this type of work. Anyway good luck.
Ted