For aperture or shutter priority you set one setting and the camera sets the other. which to use depends on the type of scene and situation..
Indoors at a hockey rink you would use shutter speed priority in order to stop the action. also the metering is not a minor item, but that is not what we a talking about here. taking a portrait you would use aperture priority and a small(low numerical) fstop to control dof and separate the face from the background. OR outddors taking general landscape shots, you would want a large dof, high numerical) fstop to give a lot of items in focus..
You are only stuck on fixed aperture if the existing light conditions do not change. you still have to have the correct amouint of light to get a properly exposed picture. if you are on 1/250 and f4.0, AND you want f11.0 for dof but you insist on keeping 1/250 then it cannot be done because you would get an improperly exposed picture. you do have a little leeway in that you may be able to adjust the iso to help get the other setting that you want. but by changing the iso you are also changing the background noise. that may not be desireable..
Please note that just because there is a dial and you have the ability to change it does not mean that it is a good idea. you may be getting a completely blown out picture or a totally black one. with that said all adjustments are possible in manual mode but the results may not be usable at all. you still have to conform to the rules of correct exposure. you the photographer have to determine what is possible and what results you want and can get and what techniques and gear are needed to get those those results that you want..
This is not getting into the different techniques available or the other gear that makes some things posssible. such as neutral density filters. and tripods...
Thanks guys.. was prompted to question my camera since the expected change in aperture did not appear in the EXIF data for each image where shutter priority was selected. Shows the same F Number for all images in this cam...but did change the F number as expected (in the EXIF file) for another cam I was using. The EXIF data should show the 'image' taken F number..right?..
For instance, if you're doomed to underexposure because the lens -can't- open up as wide as it would need to be (based on the metering, exposure compensation, ISO, shutter speed and lack of sufficient illumination), it'll be wide-open. If you push things even more by halving the exposure time without adding more light, upping the ISO, or switching to a faster lens it'll still be wide-open..
In this case, the camera will probably be warning you by making something blink or so forth..
If you were using an interchangeable-lens camera, some lenses don't have changeable apertures (mirror lenses, notably)...
You haven't got the camera set to 'Manual', have you? That will most certainly give rise to the sort of problem you describe.Rob.
Everyone, everywhere, has to do everything for a first time. There is no shame in failure, only in failure to try...
The EXIF data should showthe 'image' taken F number..right?.
It may show you both the MIMIMUM f stop for that lens or cam AND further down the info the actual setting of the aperture. I think the cam mfr decides what info is in the EXIF and in what order..
An alternative explanation might be that all shots are underexposed and the cam really wants to use a wider aperture which it does not have. How do the photos look? If you raise the ISO that might cure it.
*Nikon* D Eighty + Fifty - Other equipment in Profile.
Thanks for your suggestions. I will get out and take some more pics to see what is happening. Noticed in all recent shots that the EXIF f no. is showing a constant 2.8. My cam has a limited range from f2.8 - f8.0As the Shutter Priority was being used recently I did not take notice of the cam f stop when taking the pics. Was surprised to notice that they are all listed as f2.8 in the EXIF with varying shutter speeds used. I'll do some testing tomorrow...