R u in 'S' mode or 'M' mode?
If u r in S, the cam will select the aperture for u once u have choose ur shutter speed.
In M, u have to manually set both.
In both cases, using of ISO 800 is not necessary if u have tripod.
It will be helpful if u can tell us more on the metering u use too.
It seems u are using shutter priority, for ur focal interest (landscape e.g.), u shd been using A priority or M mode (if u wan to go long exposure) to capture eveything from front to back in sharp focus (at least f8 & above)
ISO shd still kept to a minimum.
Thats the reciprocity law (shutter duration and aperture size)
Shutter decrease in duration, aperture increase in size and vice versa.
if ur low aperture is referring to big f stop nos, u are correct.
Do you really know what you are doing there? Why do you set f/32? That's inviting diffraction. F/16 is perfectly fine, f/11 sufficient. Use ISO 100 and Evaluative metering (check your manual). Do note that metering at night is tricky and the camera metering is fooled sometimes. In Av mode you use Exposure Compensation to adjust further. The aperture is set by you and shutter speed is determined by the camera based on metering results.
In addition, do read about the very basics of exposure. No point tinkering around without some baseline knowledge. Photography Notes for Newbies
You should have experimented a bit more with the settings on the spot, then you'd have saved the trouble of having to ask, and possibly getting confused with the answers.
You can try put to Av with ISO800, then:
- shoot at f/32
- shoot at f/22
- shoot at f/11
- shoot at f/5.6
then repeat, this time at ISO200
then repeat, this time changing the WB to tungsten or something
With these 12 shots (or perhaps more), you should be able to deduce how the settings affect the picture output once you view the EXIF data.
12 shots probably takes about 2-3 minutes to execute.
Another 1 hour to transfer and review on PC.
Within 1hr 15min you have your answers.
Initially u r telling us that u r using Shutter priority and set at 20secs, then u said u actually use AV mode, and f stop was set at 32. :dunno:
Very confusing. I guess u r in manual mode, and that why u r able to set both.
Just to clarify something, coz you sound very confused.
In Av mode, you choose the aperture (eg. f/8, f/11, etc) and the camera calculates what the shutter speed should be in order to get the exposure required.
In Tv mode, you choose the shutter speed (eg. 1/60s, etc) and the camera calculates what the aperture value should be in order to get the exposure required.
BUT BUT BUT if you set it Tv and 1/250s for example, and the place is quite dim, the camera goes up to the maximum aperture it can reach (smallest f-number), and cannot go anymore than that. So on the 18-55 kit lens, it might go to f/3.5 and the picture might still be too dark.