Low light focusing

[Diane Maher]

As I was photographing just at/after sunset last week, I was having a few issues with focusing. Because I had focused without my center filter in place, and once I went to put it on the lens, I found I had lost the focus due to accidentally moving the front standard while putting on the filter. :mad: I did take a couple of shots w/o the center filter just to see how it affected this particular subject.

However, I found it difficult to focus on the gg with the center filter on, even wide open on the lens (f/5.6) due to the rapidly failing light. Any thoughts or suggestions on focusing methods in low light would be helpful (aside from the obvious, get there before the sun goes down and then wait).

[Peter De Smidt]

You could figure the extension needed to focus your lenses at their hyperfocal points for various apertures. You can then mark the camera or use a measuring tape to set the camera. You can also determine the extension of the camera needed for infinity focus, and then put something in the foreground, such as a small flashlight, that'll allow you to focus on the closest subject. (If you know the extension need to focus on the near and far subject elements, you can then set focus by putting the camera extension mid-way between then, using the proper f stop to keep everything in focus.)

You can also try using a laser pointer and focusing on the dot.

[Don7x17]

As I was photographing just at/after sunset last week, I was having a few issues with focusing. Because I had focused without my center filter in place, and once I went to put it on the lens, I found I had lost the focus due to accidentally moving the front standard while putting on the filter. :mad: I did take a couple of shots w/o the center filter just to see how it affected this particular subject.

However, I found it difficult to focus on the gg with the center filter on, even wide open on the lens (f/5.6) due to the rapidly failing light. Any thoughts or suggestions on focusing methods in low light would be helpful (aside from the obvious, get there before the sun goes down and then wait).

Well, if you are focusing on something relatively close, say 100-200 feet or less....get a good lasar pointer. I've used one for two decades focusing in dim light -- have a friend shine it on the subject while you focus...when you are out of focus you'll see a blob of red, and can focus precisely by making it a tiny red spot on the ground glass. Of course this won't help you if you are focusing on the opposite wall of the Grand Canyon or the moon, etc....but it will help greatly in near subjects.

[Ron Marshall]

There are 2 situations where an SLR/DSLR will have focus issues. Solid colors and low light. This is due to the fact that focus lock is acheived when a camera has a contrasting item for which it can determine where best to get the highest level of contrast bewteen the items, which it determines that an object is in focus.

The OP was referring to a view camera.

[kev curry]

Two small flashlights placed in the scene to focus on.... one at the near focus point and the other at the far focus point. Never had to do it yet, but carry the two tiny flashlights.

[Joanna Carter]

There are 2 situations where an SLR/DSLR will have focus issues. Solid colors and low light. This is due to the fact that focus lock is acheived when a camera has a contrasting item for which it can determine where best to get the highest level of contrast bewteen the items, which it determines that an object is in focus.
Just in case you hadn't realised, this is a discussion forum dedicated to the art of Large Format photography, where you have to do all the work yourself, not leave it to some fancy electronic gizmo like auto-focus.

[Diane Maher]

Thanks for all the replies. I think the laser pointer would work the best, as in this case, I couldn't get to the subject which was some tree roots that had been exposed by the river eroding away the surrounding soil.

[Rhemz]

Laser pointer... Ingenious!

[drew.saunders]

I finally tried the laser pointer trick, but, lacking any extra hands, I used a Wimberly Plamp (http://www.tripodhead.com/products/plamp-main.cfm) to both hold it and hold down the button:

http://farm5.static.flickr.com/4047/4282680575_d6d60b21a1.jpg

It's a bit too bobbly for such close-up work, but should work well enough for longer distances in dark forests and the like.

[Drew Wiley]

Astronomers use high-powered lasers to create "artificial stars" to calibrate their big
telescopes, when atmospheric disturbances tend to wiggle around the points of real
stars. But for us mere mortals, along with a simple pointer or focussing flashlight, a bit
of shiny metal as a target will provides a more specular reflection, easier to focus on.
I do this on the copystand sometimes.