Making the picture brighter and clearer indoors and low light

Started Nov 8, 2012 | Discussions thread
DuncanDovovan
Senior MemberPosts: 1,277
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Re: Making the picture brighter and clearer indoors and low light
In reply to Bstevs, Nov 9, 2012

You have to understand the impact.

Every exposure is rules by Shutter speed / Aperture and ISO.

Shutter speed determines how long the chip will be exposed to the light. Faster shutter speeds freeze motion, but give darker pictures. Slow shutter speeds will give blurry motion, but more light. Long exposures also produce issues with pixels that perform differently than most of the others. This produces noise. Most cameras can cancel that noise by taking a dark frame after a long exposure (> 1 sec for example - not sure when it kicks in). After the shot you will notice that your camera is busy for the same amount of time. This is when it takes the dark shot. After the dark shot, it processes the original image to cancel out the long exposure noise.

Aperture determines how small the aperture/iris of the lens will be. Smaller apertures (bigger numbers) let less light through, but give a large depth of focus field (close to far). Wider apertures (smaller numbers) let more light through but will limit the DOF. Also, small apertures often produce soft results (as in not so sharp), because of a physics effect called diffraction. Wider apertures will also often produce soft results (as in not so sharp), because it is very difficult to have preciseness in all parts of the glass inside the lens to. The optimal sharpness lies normally around f/5.6 - f/11.

ISO determines how much the signal from the chip will be amplified. Obviously this will introduce noise at higher ISO. Normally up to 400 ISO results are acceptable. 800-1600 will give you noticeable noise but still acceptable in many situations. And 3200-above becomes very noticeable. But the advantage of higher ISO is of course that you capture more light and pretend the scene is might lighter using shutter speed and aperture combinations that you would otherwise only be able to use for much brighter situations.

Finally there are some modes like HHT and AMB that take multiple pictures and combine them to reduce noise by averaging the shots. HHT will use the lowest ISO available at the cost of shutter speed to give the least noise possible at the cost of introducing some motion blur. AMB will use the fastest shutter speed available by cracking up the ISO. This will introduce noise, which will largely be cancelled out again by averaging the shots it takes.

Night portrait focusses on the effect that when you flash, the background goes dark. Instead this mode tries to use higher ISO to capture more ambient light so that the flash can be less powerfull.

If this is all kind of new, I highly recommend that you buy yourselves a book about the basics of photography. I remember when I did that it opened up a world to me, because I finally understood that every shot requires me to make decisions. And really you start to think for every shot what will be the optimal balance between changes in Aperture, Shutter and ISO or depth of field and overall sharpness, movement freezing and noise.

Hope readers will not find this post patronizing. I know there are lots of people out there very new to photography. And after all they are the target group of the NEX series. =;-)

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