Manual Focus

[loon]

I am wondering...i have a g1 and my auto focus tends to lag behind, causing me to miss shots. have you ever used manual focus....mainly i am wondering if i can prefocus to lets say 4 feet. and set the app to something so i would have 4 feet to infinity all in focus. any insight would be GREATLY appreciated.

 

[richard_l]

You need a hyperfocal distance chart. If you set the focus at hyperfocal distance, everything from one-half the hyperfocal distance to infinity will be in "acceptable" focus. For example, for a 40mm lens at f/16, hyperfocal distance is about 11 ft, so if you set the focus at 11 ft, everything from 5.5 ft to infinity will be in "acceptable" focus. There is a hyperfocal chart at http://dfleming.ameranet.com/charts.html

 

[Socke]

Hyperfocal is one possibility another is zone focus.
For street photography the 45 at f8 set to 4 meters gets you accatable focus from 2.5 to 7 meters. Good enough for this site of the street

 

[loon]

what about the 35mm lens for street use.

 

[NoTx]

Check out a DoF calculator, it can save a lot of headaches.

Here is on:

http://www.dofmaster.com/dofjs.html

 

[richard_l]

what about the 35mm lens for street use.

That's where zone and hyperfocal focussing is most useful. You should be able to find a free DOF chart for a 35mm lens with instructions on how to use it. Some kind of slide rule thingie would be the quickest to use. Most old fashioned manual focus lenses have a built-in DOF scale.

 

[Socke]

It's a real pitty that Zeiss left out the DoF markings on the G lenses!

In this thread you'll find a remedy for this fault, ugly but usable.

http://www.rangefinderforum.com/forums/showthread.php?t=12059

 

[richard_l]

Here's a slide rule DOF calculator. http://abetterphotoguide.bizhosting.com/depth_of_field_calculator.html

It says it's for SLRs, but there's no difference between the DOF properties of SLR and rangefinder lenses. I think the DOF calculations even use the Zeiss standard 0.025mm for the circle of confusion.