ISO Setting ?

[daltoned]

I went on a bit of a shoot today, took loads of pics, some with auto, raw and shutter priority. When I loaded them up on Pc, I found most of the JPEG appear under exposed (mainly those with shutter priority)while the raw appear over exposed. Closer look at the image properties revealed that the camera ISO was set at 400 ( had tried that setting on some indoor shots a few days back). Would this explain the under/over exposures and should the auto setting not have overruled the ISO 400. Any advice would be welcome.
EddieD

[gjtoth]

I went on a bit of a shoot today, took loads of pics, some with auto, raw and shutter priority. When I loaded them up on Pc, I found most of the JPEG appear under exposed (mainly those with shutter priority)while the raw appear over exposed. Closer look at the image properties revealed that the camera ISO was set at 400 ( had tried that setting on some indoor shots a few days back). Would this explain the under/over exposures and should the auto setting not have overruled the ISO 400. Any advice would be welcome.
EddieD

Could be. Depends on your shutter speed.

[daltoned]

Hi Gary,
Had quick look at some of the images, samples speeds are, Auto 1/640th to 1/800th. Shutter priority ave 1/500th, raw ave 1/400th.
Eddie

[gjtoth]

Hi Gary,
Had quick look at some of the images, samples speeds are, Auto 1/640th to 1/800th. Shutter priority ave 1/500th, raw ave 1/400th.
Eddie

Hmmmmmm.... ok, Eddie. I've reached the end of my "expertise" heheh. Haven't a clue now. Sorry. I'm sure someone will be picking up on this soon, though.

[jerryph]

Eddie, do you make it a habit to view the meter and choose shutter speed based on what it tells you? If not, that would explain the differences in exposures.

Ideally, no matter what mode you use (besides auto), you change your settings so that your meter reads in the center, meaning, properly exposed.

Now, if "properly exposed" indoors means a very slow shutter speed, you raise ISO and then raise the speed to a point where you do not get motion blur.

Does that make sense to you?

[dkippen]

Eddie -

When shooting using shutter priority, you're basically telling the camera to decide what shutter speed to use and I believe the camera will determine the shutter setting based on available light. If I remember correctly, nothing else will change, including your ISO because that is a setting you have chosen.

I typically shoot manual and have on occasion forgotten to change my ISO or WB, but like the rest of us, I'm learning to check everything before I take the shot.

[daltoned]

Thanks Debbie, Jerry and Gary. What is obvious is that there is a world of difference between the DSLR and P&S. I had a good think about where I went wrong. What I need to do for the moment is shoot in Full Auto ( did some this morning in my garden & will put some up later in the nature section). I now need to get on with the course and work through the different lessons to fully understand speed, exposure etc., and how are all interact. Guess I was trying to get too far ahead without knowing enough and not being fully alert as to what settings are set. As said watch the meter, I also need to use the preview to full effect and spend more time on my shots.
EddieD

[daltoned]

Eddie, do you make it a habit to view the meter and choose shutter speed based on what it tells you? If not, that would explain the differences in exposures.

Ideally, no matter what mode you use (besides auto), you change your settings so that your meter reads in the center, meaning, properly exposed.

Now, if "properly exposed" indoors means a very slow shutter speed, you raise ISO and then raise the speed to a point where you do not get motion blur.

Does that make sense to you?

Hi Jerry

Just to clarify, is the meter you refer to , the top screen on the camera which shows the various settings. Not sure I understand when you say " you change your settings so that your meter reads in the center, meaning, properly exposed.".
EddieD

[jerryph]

When you look into your camera's viewfinder (eye piece), there is usually something that looks like this:

{-2 .. -1 .. 0 .. +1 .. +2}

It usually has this indicator that moves along the lone left and right. When in the center, it means it has a proper exposure. We can manipulate where this small indicator goes by playing with the settings. For example in shutter priority mode, if I increase the speed, the indicator in the meter moves to the left, reducing speed makes it move to the right.

Now, I do not know what kind of camera you have, just going by my experiences with the Nikon E8800 and my D200. But I know Canon cameras have this as well as others... however many Point and Shoot cameras are fully automatic only, so do not have this feature.

[daltoned]

Thanks Jerry for that detailed reply. My camera is a Pentax K10D, only bought at Christmas so in my hands not being used properly. Up till then I had the Fuji S9600. Will do some checks based on the your answer, so I see I've a lot to learn.
Thanks again
Eddie

[daltoned]

It's me again, just noticed that some more answers about Metering are in another thread, " metering by Kimapali ". thanks again
EddieD

[jerryph]

No problem. Once you get metering down, your pictures will come out consistantly well exposed, so no more excessively dark or light pics after that. :)

[coffee]

Eddie -

When shooting using shutter priority, you're basically telling the camera to decide what shutter speed to use and I believe the camera will determine the shutter setting based on available light. If I remember correctly, nothing else will change, including your ISO because that is a setting you have chosen.

I typically shoot manual and have on occasion forgotten to change my ISO or WB, but like the rest of us, I'm learning to check everything before I take the shot.

Actually. in shutter priority the operator chooses the shutter speed, and the camera decides the apature. In apature priority, the operator chooses apature, the camera decides the shutter.

[jerryph]

... and ISO is left basically untouched... unless like in some cameras, it cannot get the proper exposures even at extreme settings without changing the ISO.

In my camera, if I cannot get the proper exposure and the shutter speed is too slow, it ups the ISO.

[daltoned]

Hi Jerry, been having a look this morning, boy am I learning about my camera. I found and tested the use of metering ,through camera top lcd & the viewfinder. On my Pentax it would only seem to be operative in full manual mode. There is also a simuliar scale visable when bracketing is used but I think this may be +/- exposure values adj, need to recheck my camera workbook. Thanks once again for pointing me down this road, it confirms how much one can learn by taking part in the forum.
EddieD

[jerryph]

My pleasure!

Concerning bracketting... thats an exposure technique that specifically concerns varying exposure.

Lets say that you set the camera to bracket 5 pictures and a 1/2 stop in between them... you put the camera on a tripod, and take 5 pictures. The camera automatically adjust the exposure to take them in this order:

1 - Exposure comp set to 0
2 - Exposure comp set to -0.5
3 - Exposure comp set to -1.0
4 - Exposure comp set to +.5
5 - Exposure comp set to +1.0

So you have 5 pictures of the same thing in 5 different exposure levels. You then can choose which of those 5 is the "creative" best exposure.

Or... it could be used as an entrance introduction into HDR. HDR is High Definition Resolution. Using a HDR program (like Photomatix Pro), you take all 5 of those pictures and at it's most basic, it tone maps out all 5 pics into 1 picture that has all the dark areas taken out of it and all the over-bright areas taken out... so what you end up seeing is a picture that has an incredible dynamic range not normally captureable on any digital camera.

Ok, hope I did not freak you out with the additional inof on HDR... lol If yes, just place this info in the closet for now, and it will come out when you need it later on. :D

[daltoned]

Hi Jerry, HDR is a little down the road but I'll print your note on same and keep as a reminder for the future. Have seen some images done in HDR and they are fantastic.

EddieD

[jerryph]

That high end HDR look is a little beyond me too. Though I have the program for it, I have so many other things to do that it's taking a back shelf. I've not even had time to do this week's challenge... and I may have to do it a week late, between all the snow storms and work this coming week.

[LensBaby]

I am going to have to wait as well Jerry, because getting to what I want to photography will be a real treat!