[Russell01]

If im using an iso speed of 1600 on a nikon d40x what is the best f-number to use for portraites in well light rooms+churches at night, and WHAT are they. my camera manuals about as vauge as my history teacher, not good...please help. i tried taking still life pictures indoors with the same lightting as the church im doing the photos would have. I used 1600iso not sure bout the f-numbs but the shutter stayed open for a long time, a bit too long for really crisp handheld shots of people because i amagine the subjects would move, would the f-numbers affect this.?? and if not how do i make the shutter speed faster...sorry, i kmow ive been asking loads of questions about photos latley, but im kinda in at the deep end here, and im stuck at boarding school and iv had very littl time to practice, my bad!Thanks

[_MB_]

Forget ISO for now.

Think of aperture in your lens like the valve in a water pipe.

Small aperture (big f number), little trickle of water.
Big aperture (small f number), big gush of water.

So this is where you get artistic and I'm afraid there are no rules. Pick your subject of interest. Is it the eyes? Is it the whole person? Is it just the person? Is it the background too?

A wide aperture translates to quite a small depth of field (the region in front of you that appears in focus on your camera) so that might be more suitable if you're interested in a specific detail and want the rest of the photo softer so that the viewer spends their time looking at what you want them to look at.

A smaller aperture translates to a larger depth of field, so more of whats in front of you will be in focus on the camera, so if you have say a couple of people standing at different distances from you, or if you want the viewer to be able to make out the detail of a staircase behind the person, then maybe thats what you're after.

ISO - low ISO lowers the sensitivity of your sensor but makes for smoother pictures. High ISO increases the sensitivity, so you can take fast pics in lower light, but it makes the sensor occasionally choose a tone that's slightly different in different parts of the sensor so the results aren't so smooth.

There are no standard aperture/shutter speed combinations that are "correct" for a photo - you're only going to find out what you like by screwing up and finding out what you don't like. Experiment!

[Russell01]

Thaaaaaaaaaaaaaaaaank youuuuuuuuuuuuuuuuu!

[Steve]

As a simple rule of thumb, to get crisp, sharp photos without any camera shake you should be using a minimum shutter speed of 1/60 sec for wide lenses and when using anything else follow this simple rule...

Focal length = minimum shutter speed....so...

75mm you should use a minimum shutter speed of 1/75sec
100mm you should use a minimum shutter speed of 1/100 sec
150mm you should use a minimum shutter speed of 1/150 sec
300mm you should use a minimum shutter speed of 1/300 sec
....etc

If you follow that simple rule generally you will eliminate most of human introduced camera shake. If your chosen settings will not allow fast enough shutter speeds you'll either have to increase the iso, choose a smaller F stop, use flash or additional lighting or finally use a tripod.

Be aware that a tripod will only help remove movement of the camera and will not prevent blurred pictures if the subjects are moving.

Hope that helps a little.

[GainfulShrimp]

I would recommend using a wide aperture (small f-number) for most of these shots. Assuming your lens isn't very fast (i.e. the maximum aperture is probably a higher f-number than 2.8), you will get adequate depth of field for most portraits etc, even when using the lens wide open. Of course this isn't a fixed rule and if your subjects are standing diagonally to the camera you might need greater depth of field to keep all the essentials in focus... but my hunch is that you'll need to use a low f-number to get a quick enough shutter speed, if your experiments so far have resulted in long exposures.

Finally, just to break the rules again...

I have had decent enough results handheld at much lower shutter speeds than 1/60sec. Your mileage may vary, but if you brace your arms against your chest or lean on any available prop - table, doorframe, etc - you can often get away with 1/30 or even 1/10 second, especially when using wideangle lenses. You will need to practice this though, and of course if doesn't help when the subjects themselves move a little.

Good luck!

[brian wright22]

This may not be the correct forum to post but it does concern a Problem I have recently whist experimenting with small apertures.
The use of very small apertures has highlighted the annoyance of dust/dirt in my camera light path.
I can see no dust particles in or on my Canon 17-85mm Zoom lens elements. The lens was originally sent to Canon for cleaning shortly after purchasing it ,due to particles of dust visible on its front inside element. I mention this because I now think the lens is ok.
Can any Pixalo members suggest the likely cause of the problems shown in the F32 picture. Clearly there is dust/dirt somwhere in the system and the extreem depth of field offered at F32 highlights this. At F5.6 the problem is much less noticeable.





Many Regards Brian

[GainfulShrimp]

Apologies if this is a dumb question, but have you checked your camera sensor carefully? Even bodies with 'sensor cleaning' will need a proper (wet) sensor clean to remove any stubborn bits of gunk. If you don't want to do this yourself, there are companies who will do it for you for a fee, including Canon, but it'll be cheaper to DIY it. There are many online guides to sensor cleaning and I'm sure you'd find advice on Pixalo too, of course.

As it's showing in the pics and not just through the viewfinder, I would say the only possible culprits are the lens and/or the sensor. (If dust was seen through the viewfinder then it might be the viewfinder, mirror or screen...)

[_MB_]

That looks like sensor dust to me.

[brian wright22]

Thanks for reply GainfulShrimp, no don't appologise your comments they are very helpful.
There is no apparent dust showing through the viewfinder and using the manual stop down preview at F32 there is not the extent of marks showing as in the first picture.
So you are suggesting the Sensor ? I will look into this and report back.
Many thanks also to MB for your suggestion.
Brian

[brian wright22]

I have had a go at cleaning the sensor. Looking at the face of the sensor surface there appeared to be only visable "using a x4 magnifier" three significant blemishes.
Blowing with an air duster had no affect in removing the dirt.
Moistening a chamois leather 10mm wide wipe and very gently "stroking" the sensor surface has improved the captures to my satisfaction. I have attached the results with the resulting capture.
Without you suggestions MB & Gainfull I would not have suspected the sensor
cleanliness.
Regards Brian

[_MB_]

Looks much better and now you're not scared of cleaning the sensor