focus @ night

[nuttyleong]

I'm doing some night photography and having problem focusing on my canon kiss x 2 with sigma 18-200 DC OS.
Some how all the buildings look blur, the setting that i used is AV F8 30", self timer on tripod. Is my setting correct or someting wrong with camera?

[hark40]

It could be a couple of things:

• As you are doing night photography, a lot of lenses/cameras have problems focusing due to the very low light. So, you may have to switch to manual focus rather than use auto focus. (Do you get a focus lock from the camera? I think the 350D uses a flashing circle in the viewfinder to indicate a focus problem.)
  
• Tripod. You are using one which is a good thing. How stable is it? How much of a breeze is there? These can cause the tripod - and hence camera - to move just a little bit and so give a blurry picture.
  
• You are also using a lens with OS (Optical Stabilisation). I know the early Canon IS lenses had problems when IS was enabled and the camera was mounted on a tripod. There would be a feedback loop between the IS on the lens and the minor vibration from the tripod which caused image quality problems. If you can turn off OS on the Sigma lens, then do so. Its not really required when mounted on a tripod.
  
• Do you have mirror lock up on the Kiss X2 (450D)? You probably should have as I have it on my 350D. When doing tripod night photography, especially with a long lens, its useful to use it, to minimise vibrations from mirror slap.
  
• A remote shutter release is also handy but as you are using the timer, its not as necessary.

These are just a couple of things from the top of my head that could be causing problems. Auto/manual focus is probably the main item to check.

Mark P.

[nuttyleong]

Thanks Mark P,
I will try out mirror lock and hang more weights on tripod this weekend. The KISS x 2 does have focus lock.

cheers,

Eugene.

[aim54x]

if you continue to have problems with that tripod you may want to use it with the legs closed down (ie lower to the ground) and maybe even ditch the tripod and place the camera on the ground or on a steady surface (I have done taht in the past). Also try a few different lenses as well as you may find that it may have been the lens you were using.

[gstark]

Eugene,

It would help us to help you if you could post some of your images displaying the problems that you're experiencing. That will let us see what you are seeing, and much more easily diagnose the issues that you are experiencing.

[zafra52]

This sounds silly, but do you have dust on the lens? Sometimes a bit of dust could cause the lens no to focus properly.
Do you have the lens on the self-fucusing setting, because sometimes it does not do as well as manual focusing.
I suggest you start considering the obvious fisrt and start eliminating possible causes.

[nuttyleong]

I hope img works, (1st timer).

[aim54x]

http://picasaweb.google.com.au/eldy3leong/Focus?authkey=Gv1sRgCOqiyJnZ3pT3nAE#5330278405679084498
I hope img works, (1st timer).

I tried to get that picture to show but I couldnt, so I have jsut linked it

[SuperJT]

Can't really tell from the first photo without going to 100% but from the second photo, you look to have movement issues. You have some trailing in the lights and the structures.

[gstark]

On the linking of the images, it seems as though Picasa doesn't like direct linking. When you do the linking, make sure that you have a matching pair of tags. You posted with two opening tags, rather than a pair with one opening, and one closing [/whatever] tag.

Regarding the images ... these are both shot with a long time exposure. This is evidenced by the texture of the water.

That means that you need to be using a good, solid tripod. The ones that the stores give you for free with their so-called "enthusiast kits" are worth pretty much exactly what one pays for them.

I'm mentioning the tripod first up because of what I'm seeing in the second of these images ... look at the archway, where it starts to rise above the roadway on the lh side of the image, just above the centre. There is a section of this archway that almost looks as if it's vibrating at the time that you made this image.

And that may well have been the case.

But now look at the streetlights below the bridge, on the far side of the watercourse. These are all shaped like small golden arches. This is unlikely to be an effect of bokeh, and more likely to be related to camera movement of some kind.

That, in the first instance, brings us to two points, both of which have already been mentioned in this thread: your tripod, and the use of IS for these images. Basically, when you're using a tripod, kill IS.

And when you're using a tripod, make it one that's solid and won't dance around in the breeze. What sort of tripod do you have?

And one item that I don't think has been mentioned as yet: how are you triggering your exposure? Directly by hand? With a remote? Using the self timer?

[nuttyleong]

http://picasaweb.google.com.au/lh/photo/SFdVhpSV94Mj0KE3I4vd2A?authkey=Gv1sRgCOqiyJnZ3pT3nAE&feat=directlink
http://picasaweb.google.com.au/lh/photo/MU2jY-Hq84D5kgMc9-3qKw?authkey=Gv1sRgCOqiyJnZ3pT3nAE&feat=directlink

I can't wait till Friday night, so I took these last night with mirror lock and weighted tripod. I also used 10" self timer.
One with OS (IS) OFF, the other ON.
My tripod is Giottos VT809
Thanks guys, i think is the IS that cause the movements.

[gstark]

Eugene,

That looks a lot better.

Now, a couple of other points.

Before shooting, check that your camera is level, on the tripod. The buildings in these appear to have a slight lean.

Also, it always pays to make a number of exposures, bracketing them with different EVs in order to ensure that you get the inage that you want. Rather than use the camera's auto values as gospel, they should be noted, and then switch the camera to manual, with those values taken merely as your starting point.

Don't be afraid to vary both your aperture and shutter speed settings (but only one at a time) throughout your bracketing session.

As a guide, start with an aperture of, say, F/8, and cycle through a variety of exposures using shutter speeds of 0.5 secs, 1 sec, 2 secs, 3 secs, 4 secs, and so on. Then do the same using aperture values of f/5.6 and f/11 ...

Don't be afraid to extend both the shutter speed and aperture ranges that I've suggested: you will get a variety of shots, it won't cost you a cent, and you will learn heaps.