I screwed this up - is it ISO?

[padrepaul77]

Sorry I can't re-post my picture apparently, but I took a night shot of Minneapolis last night in the "landscape" forum. I noticed it was quite noisy. I used the light meter and an aperture of about 7; probably had the shutter open 4 to 5 seconds. I had ISO on auto though; this must have been my SNAFU. Should I try a lower ISO for shots at night?

Thanks,
Paul

 

[Jaszek]

Yea it was probably the ISO. Can you link to the topic where the picture is?

 

[Big Mike]

Since the shutter speed was 4 to 5 seconds, I assume you had the camera on a tripod or something?

My rule of thumb is to always keep the ISO as low as possible, unless there is a good reason to increase it. The most common reason is that I'm shooting hand held and need faster shutter speeds to avoid blur from camera shake.

If you are shooting on a tripod, camera shake shouldn't be a problem so any shutter speed will do, so keep the ISO as low as possible.

 

[padrepaul77]

http://www.thephotoforum.com/forum/landscape-cityscape/154598-minneapolis-night.html

That's the link to it. There are many replies as I could not figure out how to upload; it had to do with file size being too big and took me forever to get. Pathetic.

I reviewed my image info and apparently the ISO was on "auto"; so I had the light figured out just fine, but being I'm used to daylight shots and ISO not being an issue, I neglected this setting. It was at 1600! Yikes. Probably not good and ends up like your night shot is on the old-school UHF channels I used to watch. I'll bet if I took that same picture with an ISO of 80 it would be better? And yes, I did use a tripod; I had little sensation in my hands though as even with gloves I froze my butt off. What was I thinking going out and doing this on a Minneapolis January night?!

So, ISO of 80 for most of night shots with a aperture of about 7 and use whatever the light meter tells me for shutter speed?

Many thanks,
Paul

 

[Jaszek]

yea for night shots you should use as low of an ISO as possible (in your case 80) and just go with the light meter or what effect you want for shutter speed.

 

[Chris Stegner]

I may not be a technically inclined as some so excuse any laymen's terms.

I have tried many variations of exposure vs ISO for night shots. I also try to keep the ISO as low as possible, but I have learned that there's a happy medium.

High ISO, shorter exposure = noise

Low ISO, longer exposure = noise

Middle of the road ISO, middle of the road exposure = Better all around image

We all know what happens with high ISOs and noise, but I have read longer exposures also increase noise. I'm talking 30 seconds to multiple minutes. I don't remember all the technical mumbo jumbo but basically the sensor starts to "whack out" after a while.

I know... I know, but don't say I didn't warn you of the lack of technical speak.

I have found my 5D does pretty well at 400-800 ISO. I try to stick around 400 though.

Maybe someone could better explain what I mean here, or tell me I'm nuts?

 

[Jaszek]

Well your %D compared to my XSI has a much better sensor (I think) and better in camera noise reduction. If I had my XSI on 1600 ISO I would also get a lot of noise. Fir night shots I always use a tripod and long SS since if I'm taking night shots Im usually not in a hurry. Also there are two types of noise (I think) Long Exposure Noise and High ISO noise. Long Exposure noise is not as bad. High ISo noise is caused by the heating up of the sensor and pixels just "bursting" at the first sign of light causing different color dots on the image. My teacher explained this too me but it's too much to write.

 

[padrepaul77]

Thanks for the tips. I think the camera must assume I'm not using a tripod so hence the higher ISO; I'll go lower and I'm sure I'll have a clearer image.