View Full Version : focus problem
10-10-2010, 06:58 PM
i need some help with the following focusing problem. the picture is of a winding drive way under overhanging live oaks. i am useing a 8 x 10 camera for the first time and trying to get the driveway inf ront of me in focus and the end of the drive in focus. i focused on the far and used rear tilt to focus on the gravel about 20 ft to my front both came in to focus no problem . however ther is a very large live oak limb that is overhanging the road around 15 feet up, it is not in focus it is about 25 feet from the camera. how do i get it in focus, it does't come in to focus when i stop down to f22 and after that the ground glass is to dark to tell if it come in with a different f stop.
for your help.
10-10-2010, 07:20 PM
Everything is a compromise.
Try setting up square and use check your focal spread (focus change between distant road and the close tree) in millimeters on the front or back standard. If it is 10mm then you should be using f64.
David William White
10-10-2010, 10:34 PM
(let me try this again...)
As far as I can figure from your description, it would probably be best as ice-racer suggests to square up and stop down. Changing the plane of focus (and it will always be a plane) with the front standard, or changing perspective with the rear standard, or both, probably does not serve the scene.
Hyperfocal focusing is probably indicated here, as critical focusing of the far field is likely not needed. Hyperfocal distance is equal to 1000 effective apertures.
10-12-2010, 07:02 AM
If you have near elements at the top and bottom of your composition at the same distance, then tilting to get one or the other in focus along with the more distant elements will just result in throwing the other one out of focus.
However, if your near foreground (bottom of the scene) is closer than the overhanging branch, you may be able to use a bit of tilt to find an intermediate position for the plane of focus that will give you less focus spread and, subsequently, allow you to use a faster shutter speed or wider aperture and still get everything in focus.
The trick is to set up the camera leveled and in "0-position" and then measure the focus spread between nearest and farthest elements plus the offending overhanging branch (which should fall somewhere between the two extremes). Now, tilt just a bit and make the same measurements. If the focus spread is less, and the overhanging branch still falls between the two extremes, you've made an improvement in the position of the plane of focus.
Continue this process till the overhanging branch focuses at the same distance as the near focus or just a little ways in from it (i.e., between the extremes, but just a bit). Determine the focus spread (which should now be less than when the camera was in "0-position" and use this to find your optimum f-stop. (If you don't know how to do this, then you need to search on that and figure it out).
10-14-2010, 12:10 AM
There is a reason those big lenses stop down to f/64. I never needed such a small setting until I owned an 8x10. The folks above gave a boatload of advice I can't improve other than to say practice makes perfect, and even after lots of practice it's still easy to screw up an 8x10 shot. Good luck and stick with it!
10-14-2010, 08:57 PM
thanks for all the info.doremus your advise worked out and i was able after a time to get the picture, and i leartned alot along the way.
David William White
10-14-2010, 10:27 PM
Mitch, can you post a scan here?
10-15-2010, 07:33 AM
when i stop down to f22 and after that the ground glass is to dark to tell if it come in with a different f stop.
for your help.
A REALLY good Darkcloth helps with this
A good Darkcloth helps keep the light out of the rear of the camera - so the ground glass is brighter - which enables you to keep seeing the GG
10-16-2010, 08:31 PM
i would love to but the 700 epson i havs has bitten the dust so am trying to sell a few things to buy a new one.