National Boards > General Highway Talk

Roadgeeking and Serious Photography Stuff (ping agentsteel!)

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I finally have a camera again (yay for birthdays!), and the new one is a bit of an upgrade from the old one, which I lost somewhere. I have the Canon Powershot A590 now. I'd like to make the most of it, and it has a bunch of different modes with names like Auto, Portrait, Landscape etc but I'd really like to learn to use the Manual mode, where it lets me set various things such as ISO, f-stop (I can assume that's what it is, it just says "F4.5" and lets me adjust the number), and something that says "1/400" (aperture?) as well as a bunch of white balance, flash levels, and other various things.

So I guess what I'm wanting is some sort of brief explanation of what ISO, f-stop, and the 1/400 thing, are and how to best set them for various roadgeeking circumstances. Also, is there any magic setting that will let me get some halfway decent photographs of signs on the road at night?

ISO is your camera's light sensitivity. At higher ISO, your camera's imager will be more sensitive to ambient light. This means it will be able to make the most of a low light situation and use fairly quick shutter speeds. However, higher ISO settings generally mean more noise (makes an image look grainy). You don't need high ISO in daylight or bright light.

I still don't understand aperture (f-stop) all that well, but I know it affects depth of field, and higher f-numbers generally means a longer shutter speed needed to take a photo.

1/400 is your shutter speed in seconds. It means the camera takes 1/400 of a second to capture an image. In low light, you generally need longer shutter speeds if you don't increase your ISO or decrease your aperture. In normal sunlight or good incandescent/fluorescent light, the camera will be able to take photos more quickly since the lens doesn't need to be open as long for enough light to get into the camera.

I hope that's simple enough, though agentsteel will need to explain aperture for you. :P

Okay, so if I were wanting to take night photos I'd want to bump the ISO up so that I could catch more of the reflectivity off the sign. I'll have to try it. I was playing around taking them at ISO 80 (the lowest on my camera) on the way home from work tonight and obviously it didn't do very well. :-P

It would seem the problem would be finding a setting that could handle the signs going by at 70 MPH while also being picking up enough light to be visible!

One of the keys when taking shots out your windshield is to use a fast shutter speed.  If the shutter stays open too long, the motion of the car will cause a blurry photo.  For this reason, taking night shots out of a windshield are difficult (the low light means the shutter needs to stay open longer).  So a lower ISO setting might be a solution, although as another poster already pointed out, this will result in a grainier image.

By the way: while shutter speed refers to the duration of the opening, aperture refers to the diameter of the opening.  F2.8 opens very wide, and therefore requires less light (and can use a faster shutter speed).  However, focus is more important with wider apertures, because anything closer than the focal length, or farther away, will be blurry.  So use a more narrow aperture to capture more depth of field.

I leave my camera on the "auto" mode, since I cannot drive, shift gears and mess with the manual properties at the same time.  :-P


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