How do you get focus for night long exposure?

[David]

So Im looking at a great night image (1.30am), tried experimenting at home and discovered that when I try to take a BULB exposure shot pointed at something 99 percent in the dark the camera refuses to work with AUTOFOCUS, assumably because AF on the lens will not focus without something with light on it to focus on ?

If I switch to MANUAL MODE and MANUAL FOCUS on the LENS it will fire off a shot and hold the exposure time for as long as I like, but I cant MANUALLY FOCUS the shot anymore than the camera can with the lens on AF....i end up with a nicely exposed shot but completely out of focus.

So, how do people get shots like this ? Had the same issue trying to shoot lightning strikes at night.

Got me caffudled.

[Invictus]

I'm interested in hearing other peoples methods.

I tend to:
- find something else to focus on, at a similar distance and recompose + lock focus by switching to manual + stop down the aperture to something over 10. eg f16 for maximum DOF
- Use a torch, focus, switch to manual focus.
- Use the AF beam on the flash + switch to manual focus.

Any of those three methods and re-evaluate exposure.

[Bax]

If it's close and lit enough to see with the eye, but not well enough for af, I'll switch to manual and use liveview or go by eye through the lens.

I was thinking about getting a laser pointer, apparently very helpful.

If it's star trails, I switch to manual, take a short sample, 30s 3200 iso and zoom in on the result to check.

[DAdeGroot]

Depends what I'm shooting. If I want focus on a foreground element - use a torch to light it, gain focus, switch to Manual focus on the lens to lock it in.

Otherwise, manual focus on the lens, set either to the distance of my subject (if close), or Infinity if a long way away (17-40L has markings for 0.28, 0.5, 1, infinity m)

[mercho]

As Stated if its close i usually use a torch and get the auto focus to pick it up and then flick it over to manual, and if its something like star trails infinity usually is on the money

[MCS_80]

With a Canon 400D, I switch to AF, press the shutter button down half way to allow it to fire the flash and auto focus, then switch back to MF making sure I dont bump the lens or bump the focus ring.

I will be investing in a good torch in future though, this seems to be the most popular method.

[ricktas]

AF works by seeking out contrast in a scene, so if your scene has a light or something lighter in it, put the AF focus point on the edge of that where you have both dark and light, you will find that your AF can often lock to that. If not, as per above, use a torch. A torch for night shooting can be very handy for all sorts of reasons. (focusing, digging around in your camera bag for the other memory card, changing lenses and walking to and from the location, and more).

[DAdeGroot]

Touching on Rick's post, glow stick bracelets are fantastic for locating your tripod in the dark. Whack one on before you set out and then if you need to walk away from the tripod to say, light paint something, you can find your kit in the dark without running into it or spoiling the shot with a torch.

[TOM]

you should only need to look through the viewfinder to compose your shot. use your dof/distance markings on your lens to set the focus point in manual mode. af is only useful for sport.

[Miaow]

I tend to manually focus on something at the same length in the pic as my subject - I do have a led torch though and never thought about using that to light paint the subject - might try that next time

[jjphoto]

If you have live view then use it, it really works, even in very dark situations.

If close enough use a torch.

Other wise focus bracket to be sure.

I spit on your Auto Focus! Don't use Auto Focus if the subject is stationary. Learn to focus manually, it's much more reliable.

http://www.johnjovic.com/images/l_247_1000.jpg

http://www.johnjovic.com/images/l_264_1000.jpg

http://www.johnjovic.com/images/l_236_1000.jpg

http://www.johnjovic.com/images/l_262_667.jpg

http://www.johnjovic.com/images/l_256_1000.jpg

http://www.johnjovic.com/images/l_261_1000.jpg

http://www.johnjovic.com/images/l_140_1000.jpg

I should start taking pictures during the day time like normal people...

JJ

[MarkW]

Most Nikons have a low light focus lamp which I normally have turned off as it will disturb wildlife. These are only good for a few metres and generally a waste of time to use.

Alternatively with a Nikon you can use a flash such as the Sb800/900 which has an IR beam to bounce for the auto focus. Once your focus distance is set, you can turn off or remove the flash and set your focus to manual to prevent focus hunting.

[Seesee]

Depends what I'm shooting. If I want focus on a foreground element - use a torch to light it, gain focus, switch to Manual focus on the lens to lock it in.

Otherwise, manual focus on the lens, set either to the distance of my subject (if close), or Infinity if a long way away (17-40L has markings for 0.28, 0.5, 1, infinity m)

Ditto

[Kym]

I manual focus for night work.
** What everyone said above; especially using a torch for closer stuff.

AF is great for wildlife, daytime landscape, sports etc. Modern AF is very good, but not perfect.
Portrait work is often better with MF as you are trying for the eyes; but it depends on the DoF you are planning as well.
Macro - MF all the time.

[ving]

if its close i use a torch and switch off AF when focus is reached, for night sky and lightning shots i just set it to infinity, or AF on a really far object... of course it also depends on what FL lens you are using.

[phild]

I use live view, works quite well for me.

[DAdeGroot]

I use live view, works quite well for me.

In the dark ? Where your exposure will be greater than 30 secs ?

[phild]

In the dark ? Where your exposure will be greater than 30 secs ?

Obviously not in the pitch dark, but focussing on a bright star for example works nicely for a night sky shot (zoom in to maximum on the LCD), a distant light for a night shot as long as there's some light to illuminate the display.

Often you won't see anything on the LCD until you have zoomed the display to maximum.

[oiisxc]

i have tryed a laser pointer and a torch and torch works best for me with my 450D