Backfocus possible without Red Focus?

[Enrique Blein]

I'm getting the PL mount for the Scarlet, but before I do it, I'd like to know if backfocus can be adjusted without using the Red Focus or if this is a mandatory tool to have.

Are there any other ways of achieving backfocus adjustments?

 

[Sergei Franklin]

You can go to reputable rental house that has a lens collimator. Put a wide angle Master prime ( or Cooke S5) on the camera set to T1.4 and check with a Putora chart. The wider the lens the more critical backfocus. Also check with a wide angle zoom lens and see if focus holds as you zoom. If Backfocus is off check a few more lenses before adjusting as a lens can get out of alignment.

 

[Enrique Blein]

But the Red focus tool suggests that the alignment is made at the sensor. In the traditional way, the lenses would have to be adjusted, right?

I'm not very familiar with backfocusing....

 

[Enrique Blein]

anyone with PL mount experience?

 

[Jacek Zakowicz]

Both the camera and lenses need to be properly set in order to have truly interchangeable lens system.
The lenses need to be verified and, if needed adjusted on a collimator. The cameras come properly set from the factory but , in case of Red , they also can be adjusted if needed.
To adjust camera you need an instrument such as Optimator(that we make) or Red Focus, there are also others.
Alternatively, if you unable/unwilling to buy or rent such instrument you can use a lens that you are 100% sure is correctly set on the collimator.
Maximum precision is achieved with a zoom, fast, wide, long range, done at close distance. This way there is minimum depth of field which(DOF) is working against you(precision) in this case.
Hope this helps:wink5:

 

[Douglas Underdahl]

You can set depth, or what some people call back focus, with any wide angle lens that is known to be correct; that is, that the distance marks on the barrel of the lens are correctly set, usually on a collimator.

See this:

http://www.youtube.com/watch?v=IhmolBMtDzg

 

[Jacek Zakowicz]

Just to add to Dougs video and comment for zoom lenses the distance marks are irrelevant-you'd be looking for lens to maintain sharpness at both long and short extremes that's all. I find using zooms quicker and more precise for setting camera flange. But to each their own....

 

[Enrique Blein]

Thank you. I haven't gone deep in to the manual because I have Canon mount. Presumably, if I understand well, there are setting on the menus that will adjust the camera's sensor, if, as you say, a known lens that is 100% set on a collimator?

 

[Jacek Zakowicz]

No menus- it's a screw accessible through the top of the cam.